F2-SUR-001Rev2 Survey Spec for Subsea Pipelines

8/18/2019 F2-SUR-001Rev2 Survey Spec for Subsea Pipelines

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WHJ BH-L08

ANDASSOCIATED PIPELINES

SURVEY SPECIFICATIONSFOR

SUBSEA PIPELINES

DOCUMENT NO. F2 -SUR-001 REV. 2

2 01/05/2001 ISSUED FOR WHJ BH-L08 RAB /RB R.A.B

REV DATE DESCRIPTION BY CHECK APP.

TABLE OF CONTENTS


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SURVEY SPECIFICATIONS FOR BH-L08 SUBSEA PIPELINES

DOC. NO. F2 SUR 001 REV2

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1 GENERAL .................................................................................................................................4

2 GEODETIC PARAMETERS ........... ........... .......... ........... ........... .......... .......... ........... ........... ...... ...5

2.1 SPHEROIDS AND PROJECTIONS................................................................................................................. 5

2.2 TRANSFORMATION PARAMETERS ........................................................................................................... 6 2.3 CO-ORDINATES..................................................................................................................................................6

2.4 COMPUTATION OF POSITION .....................................................................................................................6

3 OPERATIONAL REPORTING.....................................................................................................6

3.1 DAILY......................................................................................................................................................................6

3.2 PRELIMINARY REPORTS ............................................................................................................................... 6

3.3 FINAL REPORT...................................................................................................................................................7

4 BASIC SPECIFICATIONS FOR CONTRACTOR'S EQUIPMENT.... ........... ........... ...... .............. ...... 7

4.1 SURVEY VESSEL ............................................................................................................................................... 7

4.2 NAVIGATION SYSTEM .................................................................................................................................... 8

4.3 PRIMARY POSITIONING.........................................................................................................................................8 4.3.1 Calibration..................................................................................................................................................... 9

4.3.2 Secondary Positioning .............................................................................................................................. 9

4.3.3 GPS/DGPS Quality Indicators .............................................................................................................10

4.4 GYRO COMPASS.............................................................................................................................................10

4.5 COMPUTER SYSTEM..................................................................................................................................... 10

4.5.1 Minimum Specification............................................................................................................................ 11

4.6 BATHYMETRIC SYSTEM ............................................................................................................................... 11

4.6.1 Minimum Specifications .........................................................................................................................11

4.6.2 Acquisition of Bathymetry......................................................................................................................12

4.7 SIDE SCAN SONAR SYSTEM .....................................................................................................................12

4.7.1 Dual Frequency Side Scan Sonar .......................................................................................................12

4.7.2 Minimum Specifications .........................................................................................................................13

4.7.3 Calibration...................................................................................................................................................13

4.7.4 Digital Graphic Recorder ........................................................................................................................13

4.7.5 Survey Coverage .......................................................................................................................................13

4.8 SUB-BOTTOM PROFILER ............................................................................................................................ 13

4.9 ELECTRONIC DISTANCE MEASURING AND SPIRIT LEVELLING EQUIPMENT.....................14

5 SURVEY OPERATIONS ...........................................................................................................14

5.1 PERSONNEL ...........................................................................................................................................................14

5.1.1 Manning Levels.......................................................................................................................................... 15

5.2 PIPELINE ROUTE PRE-ENGINEERING SURVEYS ..............................................................................15

5.3 PIPELINE ROUTE PRE-ENGINEERING JACKET RISER FACE SURVEYS................................. 17

5.4 PIPELINE ROUTE PRE-LAY/CONSTRUCTION CLEARANCE SURVEYS .................................... 17

5.5 PRE-INSTALLATION ANCHOR CLEARANCE SURVEYS ..................................................................17

5.6 PIPELINE INSTALLATION SURVEY OPERATIONS ...........................................................................18

5.6.1 Positioning and Computer System .....................................................................................................18

5.6.2 Navigation System ...................................................................................................................................19

5.6.3 Monitoring of Touch Down Point..........................................................................................................20

5.6.4 Anchor Handling........................................................................................................................................20

5.6.5 Manning .......................................................................................................................................................20

5.7 PIPELINE AS-LAID CONDITION SURVEYS...........................................................................................20

5.7.1 Real Time Pipelay Records ...................................................................................................................21 5.8 POST-LAY PIPELINE AS BUILT/AS LAID SURVEYS. .......................................................................21

5.9 POST-INSTALLATION JACKET RISER FACE SURVEYS.................................................................21

5.10 POST INSTALLATION ANCHOR CLEARANCE SURVEYS ............................................................... 21

6 CHARTING AND REPORTING REQUIREMENTS ........... ........... .......... .......... ........... ........... .... ...21

6.1 PIPELINE ROUTE PRE-ENGINEERING SURVEYS ..............................................................................22

6.1.1 Data Processing .......................................................................................................................................22

6.1.2 Charting .......................................................................................................................................................22

6.2 PRE-ENGINEERING JACKET RISER FACE SURVEYS ...................................................................... 23

6.2.1 Data Processing .......................................................................................................................................23

6.2.2 Charting and Reporting ........................................................................................................................... 23


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6.3 PIPELINE ROUTE PRE-LAY/CONSTRUCTION CLEARANCE SURVEYS .................................... 23

6.4 PRE-INSTALLATION ANCHOR CLEARANCE SURVEYS ..................................................................23

6.4.1 Data Processing and Charting..............................................................................................................23

7 REPORTING...........................................................................................................................23

7.1 SURVEYS TO ESTABLISH THE AS LAID CONDITION OF THE PIPELINES ............................23

7.1.1 Data processing........................................................................................................................................23

7.2

POST-INSTALLATION JACKET RISER FACE SURVEYS..................................................................24

7.2.1 Data Processing .......................................................................................................................................24

7.3 POST INSTALLATION ANCHOR CLEARANCE SURVEYS................................................................24

7.3.1 Charting .......................................................................................................................................................24

7.3.2 Reporting..................................................................................................................................................... 24

8 FINAL REPORT.......................................................................................................................24

8.1 D ATA AND D ATA SUBMISSION............................................................................................................................ 25


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1 GENERAL

The contractor shall conduct survey works associated with the offshore construction requirements of

the Contract Scope Of Work, namely:

i. Pipeline Route Pre-Engineering Surveys

ii. Pipeline Route Pre-lay/Construction Clearance Surveys

iii. Pipeline Pre-Installation Anchor Clearance Surveys.

iv. Pipeline Installation Survey Operations

v. Surveys to establish the As Laid condition of the Pipeline and Appurtenances

vi. Post-lay Pipeline As Built/As Laid Surveys.

vii. Pipeline Post-Installation Anchor Clearance Surveys.

Surveys i will require the contractor to produce a new and full set of charts and drawings.

Surveys ii, iii, v and vii will require the contractor to update the existing QP Project Chart Folio as

appropriate with data acquired during each particular Survey.

The contractor shall use the charts updated as a result of the Pipeline Pre Installation AnchorClearance Surveys to produce his proposed anchor patterns.

Approved Data acquired during the Engineering Surveys may be combined with dedicated data to

produce e.g. the Pre Lay Construction Survey Charts.

The Survey Specifications define the minimum Contract Survey requirements and apply to the

contractor's survey personnel, survey vessels, installation barges, anchor handling tugs and all auxiliary

vessels comprising the survey spread or attached to the project.

Submissions shall be transm itted for approval in both hardcopy and in a 100% digital format

fully compatible with, and for introduction into, QP's software packages (Word, Excel,

AutoCAD 2000, Adobe Acrobat). All such submissions shall be subject to a dedicated and QP

approved Document Management System.

At least four weeks prior to the proposed mobilisation of any survey operations the contractor shall

submit a Dedicated Survey Quality Assurance Manual for QP's approval. This manual shall specifically

and comprehensively address and describe:

- the proposed equipment and personnel dedicated to the project,

- the equipment manufacturers’ relevant specifications and data sheets,

- the contractor's standard operating procedures, including, but not

limited to equipment operation, calibration, deployment and data handling and processing.

The contractor shall provide a method statement for each and every operation, calibration or procedure

intended as part of the works. The contractor shall deploy and operate all systems and equipment in

accordance with the manufacturers' recommended practices. The contractor shall demonstrate thequality and format of the data expected from his proposed equipment and operational procedures.

Copies of sample records shall be submitted with each method statement in hard copy and digital

format. Such data will have been acquired by the contractor from previous operations using equipment

similar to that proposed.

The contractor shall submit and maintain a dedicated Survey Programme. All subsequent revisions to

this Programme shall be transmitted for QP's receipt at least seven days prior to such revisions coming

into force.


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Demobilisation of or modifications to the contractor's survey personnel and equipment shall be subject

to QP's written approval.

The contractor warrants that all equipment supplied is thoroughly maintained and checked prior to

deployment and that it meets and performs according to the manufacturers’ minimum specifications.

An adequate level of spares and consumables shall accompany the equipment to maintain a

continuous operation.

The contractor shall maintain a record of his activities. Detailed logs are to be kept and shall be

submitted to QP on a daily basis. As a minimum, the logs shall make reference to the dedicated

survey personnel, their positions and responsibilities; equipment identification, calibration and user

defined settings; details of system mal-function and downtime; survey vessel sailing itinerary,

percentage completion status.

Any anomalies between the contractor’s field data and the Project Chart Folio shall be quantified and

resolved prior to the demobilisation of the survey spread.

Immediately upon the completion of each survey and prior to the demobilisation of the survey spread,

the contractor shall submit a preliminary report.

A Final Report shall be prepared both in hardcopy and digital format for each phase of the works and

shall be submitted for QP's approval within four weeks of his decommissioning /demobilising the survey

spread.

2 GEODETIC PARAMETERS

2.1 SPHEROIDS and PROJECTIONS

For all offshore operations, QP utilises the Universal Transverse Mercator (UTM) projection based on

the Clarke 1880 Spheroid, with an established datum at Nahrwan.

The following parameters define the QGPC system:

ITEM DEFINITION

Spheroid Clarke 1880

Semi Major axis (a) 6378249.145

Semi minor axis (b) 6356514.869

Flattening (1/f) 293.465

Horizontal Datum Nahrwan

Projection UTM Zone 39

Central Meridian (CM) 51°E

Latitude of Origin 0°

False Easting 500000

False Northing 0

Scale Factor on C.M. 0.9996


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2.2 TRANSFORMATION PARAMETERS

Spheroid δx δy δz

Nahrwan to WGS84 -250.20 -153.09 +391.70

The above parameters shall be used for transforming the Primary and Secondary Positioning Systems'co-ordinates between the Clarke 1880 and WGS84 Spheroids. All co-ordinates transformed shall be

computed via geocentric co-ordinates. DELTA NORTH and DELTA EAST factors SHALL NOT BE

USED in a simple additive form.

2.3 CO-ORDINATES

The QP database containing UTM Grid co-ordinates for the offshore control stations shall be made

available to the contractor. The contractor shall familiarise himself with this local survey network. The

contractor shall extend the network as necessary. Prior to using any newly established stations, the

observations, reductions, adjustments and final co-ordinates shall first be approved and confirmed

suitable by QP.

The contractor shall propose his methods and procedures for establishing the Co-ordinates of any

control station he may require in terms of the WGS 84 Spheroid.

2.4 COMPUTATION OF POSITION

Positions shall be presented as UTM Grid positions and computed by a least squares adjustment

method. The standard deviation and range residuals, where applicable, shall be available as an integral

part of each computation of position. The Quality Statement attached to the sub-surface computed

positions should reflect the achieved accuracies of both the surface and sub-surface positioning

systems.

3 OPERATIONAL REPORTING

The contractor shall develop and submit for approval a dedicated Survey Reporting Procedure. The

Procedure shall be tailored to suit the particular requirements of each phase of the works.

Comprehensive details of the proposed Reporting Procedures and a typical layout sheet shall be

submitted for approval prior to mobilisation.

3.1 DAILY

The contractor shall maintain a continuous and comprehensive record of his activities. On a daily basis,

he shall transmit daily reports to QP. Daily reports shall commence from the start of mobilisation.

3.2 PRELIMINARY REPORTS

Prior to demobilising the survey spread from the field, a Preliminary Report describing and concludingon the execution of the works and the results of each survey shall be prepared and formally transmitted

to QP for examination and approval.

The quality of the data and significance of the results shall be discussed and shall form an integral part

of both the Preliminary and Final Reports. Any anomalies between this data and QP's existing

database shall be quantified and resolved prior to the demobilisation of the survey spread.


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3.3 FINAL REPORT

A Report shall be prepared in 100% digital format for each phase of the works.

4 BASIC SPECIFICATIONS FOR CONTRACTOR'S EQUIPMENT

The contractor warrants that all equipment supplied is thoroughly maintained and checked prior to

deployment and that it meets the manufacturer's specifications. An adequate level of spares and

consumables shall accompany the equipment to sustain a continuous operation.

The contractor shall calibrate, and maintain in calibration, his Equipment in accordance with his

approved Quality Assurance Manual. Survey spread mobilisation shall include all wet testing and field

calibrations. The equipment shall be formally accepted only when all tests and calibrations have been

completed and accepted by QP.

The contractor shall demonstrate the quality and format of the data to be expected from his proposed

equipment and operational techniques. He shall include hardcopy samples of field records with each

method statement or procedure. Such data shall have been acquired by the contractor from previous

contracts using equipment similar to that proposed.

The following shall be formally transmitted to QP prior to acceptance of the survey spread:

- Calibration certificates

- Navigation station descriptions

- Computer configuration constants, geodetic parameters, run line data

- Trial printouts from the computer system

- Trial records from all sensors

- Field test data for all systems

4.1 SURVEY VESSEL

In addition to the standard minimum requirements, each principal survey dedicated vessel shall have

the following facilities:

Bathymetric To include a Survey quality survey echo sounder producing heave

compensated analogue and digital records.

Accommodation In addition to suitable accommodation for the crew and contractor's

PERSONNEL one single berth cabin with desk and chair shall be available for

one QP REPRESENTATIVE.

Survey Area Generous bridge space shall be available to allow for a smooth survey

operation.

Processing An area allocated for data processing/verification.

Deck Equipment A small crane for deployment of the over the side survey sensors.

At least one capstan or a winch drum to assist in recovering survey

equipment.

Photocopier, A3 capacity.

Marine Fax link to QP in Doha (to send and receive on a 24 hr. basis)

The facsimile facility is vital to the operations. The contractor's Survey Spread will be

considered incomplete and unacceptable without such a facility. If communications via the


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contractor's facsimile facility are not available to QP's standard, local equipment and local

charges, then the contractor shall, for the duration of the Survey Operations, install such

facsimile receive/transmit facilities at the QP Communications Centre at RAA Doha.

All Communications' Systems shall be suitably screened to avoid interference with the navigation

systems.

QP’s Marine, Survey and Safety Departments shall formally inspect and accept the survey vessel and

any auxiliary vessel prior to mobilisation.

4.2 NAVIGATION SYSTEM

The contractor shall provide, maintain and operate a complete NAVIGATION SYSTEM, with sufficient

spares, test and back-up equipment to sustain a continuous operation. The SYSTEM shall be

configured such that for all areas of operations where positioning control is required, positioning control

is available. Such a configuration shall take into account the potential occurrences of shadow zones,

signal re-radiation and cancellation, obstructions and reflections. The approval of any item of navigation

equipment shall be conditional upon the availability of sufficient spares and backup to complete the

works without risk of delay.

Procurement of the positioning systems' Frequency Licenses shall remain the responsibility of the

contractor. A copy of the licenses shall be supplied prior to the mobilisation of the system. The

licences shall remain valid for the duration of the works.

For navigation control during the surveys, the Surface Positioning System shall comprise two

independent means of deriving position, namely a Short range DGPS Primary System and a

medium/long range DGPS Secondary System

The contractor shall at all times be responsible for the maintenance and continuous operation of the

positioning systems. He shall ensure that no ambiguities occur in the position of the survey vessel, of

each system offset or of any features to be surveyed.

The contractor shall independently establish, operate and maintain his approved base stations. Certainof the QP's offshore platforms may be available for the installation of base stations. Base stations

deployed on operational or producing offshore platforms shall conform to Cenelec standards EN 50014

and 50039 for the particular zone category.

Comprehensive details of the complete arrangement shall be submitted for QP's approval at least four

weeks prior to the proposed mobilisation/installation.

4.3 Primary Positioning

The contractor shall be responsible at all times for the acquisition of the Primary System generated

signals. He shall provide a DGPS System with short range UHF or VHF locally generated Differential

corrections.

The contractor shall take into account the potential restrictions to operations caused by e.g. the non-

availability of sufficient Satellites, an unacceptable Dilution of Precision and the potential interference to

the transmission and reception of the locally generated Differential Corrections.

The contractor's work programmes shall reflect the predicted non-availability of suitable GPS data.

The contractor shall justify the local operational suitability of his proposed system and submit

comprehensive details of his previous experiences with the system. Field trial reports, case histories

and data sheets shall accompany all submissions.


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The contractor's Primary positioning system shall operate with, as a minimum:

- TRACKING: minimum of 8 parallel channels

- PERFORMANCE: as a minimum: real time display of estimated Dilution of precision,

Number of satellites in use, position quality statement.

- POSITION: within a relative horizontal accuracy of +/- 3 metres

The System shall not be used when less than 4 satellites are available for the computation of position.

The contractor shall provide full details of the previous and expected performance and capabilities of his

proposed system. Such performance shall indicate predicted satellite availability (SATVIZ) and

corresponding DOP values likely to be experienced during his proposed operations, the areas where

local masking of both the raw and differential signal is likely to occur and the system's resistance to the

effects of multipath signals. The provision of performance data shall apply to the acquisition and

processing of both the GPS data and the differential corrections.

4.3.1 Calibration

The System and spare equipment shall be subject to the following calibration:

- Static Calibration- Positioning of WHJ by transit fixes.

a) Static Calibration

A static calibration shall be carried out and witnessed by QP. The calibration shall consist of

measurements at existing WHJ survey control stations where data to establish the antenna UTM

position will be acquired. From ≥15 minutes of valid data, the observed UTM position will be compared

with QP's database to ensure the integrity of both Primary and Secondary Navigation Systems.

b) Jacket Transits Position and Orientation Check

QP shall designate those jackets available as offshore calibration points. The contractor shall confirm

system calibration by transiting the jacket in both directions, passing within 100m of the structure. Theobserved UTM centre position of the platform shall be determined from these fixes.

4.3.2 Secondary Positioning

The UTM positions derived from the secondary positioning system are required for comparative and

Quality control purposes. The data obtained from the secondary positioning system shall be stand-

alone. It shall not be used to influence the positions obtained from the primary positioning system.

The contractor shall supply a medium range Differential Global Positioning System (DGPS) for all

survey activities. He shall provide comprehensive details of his proposed DGPS equipment hardware

and software. If proposed by the contractor, QP will consider the suitability of The Middle East

Navigation Service (MENAS ) as a source for the secondary system differential corrections provided

that the available MENAS reference stations can be selected manually.

Both primary and secondary positions and the UTM co-ordinate differences of the datum shall be

computed and presented at each position fix. Comparative data shall be carefully collated for

subsequent analysis and for inclusion as a significant and dedicated section of the final report.


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4.3.3 GPS/DGPS Quality Indicators

Maintenance of the Quality Control and the Quality Assurance indicators shall remain the responsibility

of the contractor. Such control shall include and indicate the Quality of the differential data-link, the

differential reference station, the differential corrections, the raw GPS ranges themselves. compensation

for system latency, satellite azimuth and elevation.

The contractor shall monitor systems' performance in terms of the GPS SNR indicators; update rate;

success rate of transmission and reception of differential corrections; quality data as predicted and

achieved DOP values; LPME; discrimination between those satellites tracked and those used in

computation. The post computation validity of any LPME figures shall be available, taking into account

changes in individual velocities and range residuals.

4.4 GYRO COMPASS

The contractor shall provide a survey quality Gyro Compass aboard each vessel engaged in survey

activities, anchor handling activities and aboard the installation barges. Gyro Compass installations

shall be calibrated prior to deployment. The Gyro shall be interfaced to the survey computer system(s).

The dynamic error of the survey gyro shall not exceed +/- 0.5 degree. The contractor shall submit for

approval his proposed method of calibration, both alongside and in the field, prior to the acceptance

trials. The gyrocompass calibration offsets shall be confirmed during and upon completion of the survey

works.

4.5 COMPUTER SYSTEM

The contractor shall provide a Computer system or systems. The computer system shall be interfaced

to:

-the PRIMARY and SECONDARY positioning systems

-the gyrocompass

-the echo sounder (when specified)-the track plotter

-the track guidance monitor(s)

-the printer

-TSS annotator or similar for annotation of all analogue records.

The system shall include proven software capable of calculating the absolute datum UTM and offset

UTM positions of all static and towed sensors, including those aboard the installation barge, where a

surveying presence is required. The proposed configuration aboard the installation barges shall ensure

that at all times, the contractor demonstrates adequate survey control of the operations

Raw positioning and bathymetric data at the time of the event shall be logged to a magnetic medium for

subsequent retrieval. The system shall be capable of providing on-line navigational control, of preparing

track plots etc and of conducting standard survey computations.

The calculation of UTM position from the redundant information shall use the method of least squares

(minimum variance).

The resulting standard deviation in the single position shall be used as a measure of precision. The

software package shall include proven programs to plot S.D. histograms.

During vessel survey operations, end of line histograms shall be produced for all position updates to

show their Standard deviations and to confirm the vessel's across track error.


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4.5.1 Minimum Specification

The system shall be capable of simultaneously acquiring data from a minimum of two surface

navigation systems. The software shall be capable of accepting and utilising the calibration constants

relevant to gyro alignment and pitch and roll corrections.

Antenna offsets shall incorporate gyro, pitch and roll etc. corrections. Positions shall be computed in

real time.

The system shall be capable of performing all necessary calibration computations and analysis, WHJ

transiting computations and analysis may be achieved offline.

The operator’s display(s) shall provide sufficient real time information for assessing the instantaneous

and historical quality and status of the survey operations and acquired data. This shall include but not

be limited to:

- RMSE or standard deviation of a fix.

- Current run lines and targets and the vessels position in relation to them.

Display of approved field structure database

Prior to commencing survey operations, the correct input and computation of all offsets shall be verified

by manual computations.

4.6 BATHYMETRIC SYSTEM

The contractor shall provide, maintain and operate a complete BATHYMETRIC SYSTEM, with spares,

test, calibration and back-up equipment to sustain a continuous operation, comprising the following:

Heave Compensated Dual Frequency Echo Sounder

The echo sounder system shall have typical operating frequencies of 33 kHz and 210 kHz with a

minimum paper/recording width of 20 cm. Velocity of sound shall be adjustable up to 1580 m/sec.

The system shall use a heave compensated transducer located as close to the centre line of the vessel

as practical. The transducer draft shall be related to the vessel’s draft and measured at least twice a

day.

Velocity of sound observations shall be carried out prior to commencement and upon completion of

each bathymetric survey session.

4.6.1 Minimum Specifications

- Simultaneous dual frequency transmission comprising a high frequency (+/- 200 kHz) and a

low frequency (+/- 33 kHz).

- transducers located as close as possible to the ship's centre line.

- Heave compensation device of the accelerometer type only shall be acceptable.- Analogue records, and digital high or low frequency output to computer system.

a) Records

The analogue record shall be of good quality with the sea floor clearly represented throughout. The

paper speed shall be set according to the bottom topography. In addition to field record annotations all

unusual returns shall be highlighted. An attempt shall be made to quantify such returns or spurious

echoes (fish, kelp, suspended anchor wires, fresh water or gaseous emissions etc.).

b) Operating Standards


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The survey speed with echo sounder alone shall not exceed seven knots. However it will still be

necessary to conform to the data density for the particular survey. The low and high frequency depths

and the depth digitised shall always be displayed on the analogue trace.

c) Calibration Procedures

The echo sounder equipment shall be bench calibrated at least once a year to confirm that all

electronic components remain within design specifications. The bench calibration report shall be

supplied as part of the mobilisation.

Field calibration of the echo sounder shall be performed at the start and end of each survey day. This

calibration shall take place in the survey area and shall cover the whole water column. A bar check to

20 metres shall be deployed to determine and effect the system transducer draft and scale corrections.

The scale adjustment to the echo sounder shall be additionally obtained and confirmed by sound

velocity probe, calibration transducer or salinity/temperature bridge. A minimum of 10 evenly spaced

readings shall be obtained to compute the average sound velocity.

The vessel draft shall be obtained with reference to the load line or other conspicuous and recoverable

marks

The velocity of propagation, if derived by means of temperature, salinity and depth measurements, shall

be obtained from the empirical formula derived by CLAY and MEDWIN (1977):

C = 1449.2 + 4.6 T - 0.055T2 + 0.00029 T3 + (1.34 - 0.01T) x (S-35) + 0.016D

The temperature - salinity meter shall be capable of displaying temperature (deg C), salinity (0/00) and

depth (m) to the following accuracies:

§ Temperature +/- 0.l deg C§ Salinity +/- 0.1 0/00

Certified calibration certificates shall be submitted to QP prior to mobilisation.

4.6.2 Acquisition of Bathymetry

The contractor shall ensure that the processed bathymetry data is available in ASCII format. Reduced

Soundings submitted as such shall have their accompanying UTM position, E & N, thereby allowing

immediate plotting and editing.

4.7 SIDE SCAN SONAR SYSTEM

The contractor shall provide, maintain and operate a complete SIDE SCAN SONAR SYSTEM, with

spares, test and back-up equipment to sustain a continuous operation.

4.7.1 Dual Frequency Side Scan Sonar

The side scan sonar shall operate on a minimum of two frequencies and provide altimeter data for

reduction purposes.

Typical specifications of the side scan sonar transducer shall be:

- Frequencies 100 kHz / 500 kHz or 100 kHz / 300 kHz;

- Pulse length 0.1 / 0.02 msec.;

- Horizontal beamwidth 1 deg. / 0.2 deg.;


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- Vertical beam width 40 deg. tilted 10 deg. - 20 deg. below horizontal.

The contractor shall provide full details of his proposed means of positioning the Side Scan Sonar Fish.

4.7.2 Minimum Specifications

The Side Scan Sonar system shall, as a minimum, have the following features:

- towfish - shall be available with 100 kHz and 500 kHz cards

- Pulse duration 1ms

- Horizontal beamwidth 1º

- Vertical beamwidth 40º

- Transducer inclination to horizontal, typically 10° but adjustable to 20°

- Rugged armoured tow cable with separate signal lead screened for cross-talk-free reception of

sonar signals.

- Minimum 30cm wide side scan record via a thermal paper recorder.

- Minimum range scale of 25m on recorder.

- Remote event marker.

- Annotation capability

The Side Scan Sonar towfish shall be deployed over a metering wheel. The arrangement shall be

secured to the A-Frame or Towing davit by means of a spring loaded or strain-absorbing shackle. The

metering wheel shall indicate the length of cable out via a remote read-out to the sonar recorder's

operator. Winch controls shall be located at both the winch and at the sonar recorder operating

location.

4.7.3 Calibration

As part of the pre-mobilisation acceptance tr ials, the sidescan sonar system shall be calibrated for the

various water depths and laybacks expected during the surveys. The calibration of lateral sonar

contacts shall be confirmed by "boxing in" and positioning previously identified in field structures e.g.

sub-sea wellheads or mooring piles. The contractor shall submit a comprehensive procedure for all such

sidescan sonar calibration operations, carefully identifying the relative and absolute determination of thevarious sub-sea features.

4.7.4 Digital Graphic Recorder

The digital graphic recorder, of type Waverly or similar, shall use thermal paper with a minimum

recording width of 25 cm and have a minimum of three selectable channels.

4.7.5 Survey Coverage

200% coverage is required for all Side Scan Sonar work. The design of the proposed Survey line

spacings shall clearly account for congested areas where the anticipated coverage will only be achieved

by reducing the line spacing.

4.8 SUB-BOTTOM PROFILER

The contractor shall provide, maintain and operate a complete SUB-BOTTOM PROFILER system with

sufficient spares and test equipment to sustain a continuous operation.

The 2 kHz - 7 kHz system shall be capable of detecting the UTM position of buried pipelines and

investigating the first sub layers of the seabed. For optimum resolution, (typically 0.5 metres,

consistent with good penetration, typically 5 - 15 metres) output from the system shall be operated at

the lowest power setting.


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Data is to be displayed on a graphic recorder at the maximum scale available.

Swell filtering is to be employed.

4.9 ELECTRONIC DISTANCE MEASURING AND SPIRIT LEVELLING EQUIPMENT

The contractor shall provide, maintain and operate a complete set of Electronic Distance Measuring

equipment (infra red) comprising four stations (three reflector stations) suitable for forced centring.

- Theodolite: direct reading to one second of arc.

- Electronic Distance Measuring Unit Range 5 km, S.D. +/- 10 mm + 2 ppm.

The Spirit Levelling Equipment shall be deployed during Installation and As Built Survey Operations,

and seen capable of meeting the required tolerances

5 SURVEY OPERATIONS

The following Surveys shall be conducted as part of the Contract:

i. Pipeline Route Pre-Engineering Surveysii. Pipeline Route Pre-lay/Construction Clearance Surveys






5.1 Personnel

The minimum requirements for personnel are as follows:

Position Category Minimum Requirements

Party Chief A Formal qualification in Hydrographic Survey and 10 years

field experience with 5 years in related works

OR a minimum of 15 years field experience in related

works.

Senior Surveyor B Formal qualification in survey and 5 years field experience

Senior Engineer C Formal qualification in electronics and 5 years field

experience in related works


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5.1.1 Manning Levels

The Survey Party Chief will supervise and be responsible for all Survey Operations and Survey Project

Management. He will not operate as an On-Line Surveyor.

ACTIVITY MINIMUM PERSONNEL CATEGORIESPER 12 HOUR SHIFT

Pipeline Route Pre-Engineering Surveys B, C

Pipeline Route Pre-lay/Construction Clearance Surveys B, C

Pipeline Pre-Installation Anchor Clearance Surveys. B, C

Pipeline Installation Survey Operations:

i. Barge Operations

ii. Anchor Handling

B, B, C

B per AHV

Surveys to establish the As Laid Condition of the Pipeline

and Appurtenances

B, C.

Post-lay Pipeline As Built/As Laid Surveys. As per the requirements of E-S-L 60.

Pipeline Post-Installation Anchor Clearance Surveys B, C

5.2 PIPELINE ROUTE PRE-ENGINEERING SURVEYS

The surveys shall be undertaken for the engineering design of the proposed pipeline route and for all

temporary and permanent construction features e.g. pipeline crossings' temporary protection and

permanent supports, laydown areas and the pipeline anchorage areas. The contractor shall acquire

data on the bathymetry, sea floor topography and first sub-bottom layers to identify the presence of any

condition considered hazardous to the installation and operation of the pipeline. The contractor shall

acquire sufficient data and in sufficient detail to enable the detailed engineering of the submarine

pipelines and all appurtenances and to effect any modifications to the design of the pipeline's proposed

alignment.

The contractor shall, where necessary, increase the survey areas to ensure that all pre-engineering

data required, is in fact acquired. If the proposed route is seen to be unsuitable and requires significant

modification, then the contractor shall acquire sufficient extra data, if necessary outside the previously

defined survey corridors, to allow the revised route pre-engineering works to continue, without delay, to

completion.

The following systems shall be deployed during the Pipeline Route Pre-Engineering Surveys and

operated according to Section 4 above:

Survey Vessel, Navigation System, Computer System, Bathymetric System, Sidescan Sonar System,

Sub-Bottom Profiler, Electronic Distance Measuring and Spirit Levelling Equipment.

The Pipeline Route Pre-Engineering Surveys shall be undertaken to establish the actual seabed

conditions along and adjacent to the proposed pipeline route. The contractor shall determine the

presence of all structures, pipelines and pipeline crossings, metallic and non-metallic obstructions and

debris, undulations, outcrops and any other feature likely to influence the design or installation of the

proposed pipeline. For the detection of metallic debris close to the proposed pipeline route, the

contractor shall ensure that the equipment proposed is capable of detecting such debris and that as a

result of the equipment's sensitivity and detection capabilities, whatever remains undetected, will not

significantly affect the installation and operation of the pipeline. The contractor shall establish seabed


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conditions at the locations of all anticipated pipeline supports and at each proposed pipeline crossing or

supported span. All such features shall be comprehensively described and uniquely identified. Their

UTM co-ordinates shall accompany the descriptions of these features. The UTM Grid co-ordinates

defining the limits of each feature shall also be available to QP in ASCII format.

The Engineering Surveys comprise the Pipeline Route Pre-Engineering Surveys and the Pre-

Engineering Jacket Riser Face Surveys. The contractor shall deploy, on all survey lines, a dual

frequency sidescan sonar system, a sub-bottom profiler system and a dual frequency bathymetry

system to record water depths, the presence of seabed features, obstructions and existing pipelines

and structures. Seabed data will be acquired, examined and described with reference to the pre-

engineering design works.

Prior to each pipeline survey, the contractor shall submit, for QP approval, details of his proposed

survey line layout and proposed line and event numbering system.

Sufficient bathymetric data shall be acquired to ensure that intervals of no more than 5 metres appear in

the data set. The raw bathymetric data shall be processed and reduced to Chart Datum by means of

QP's Tidal Predictions. The processed and reduced bathymetry data shall also be available

independently, as digital x, y, z data, for direct entry to QP's database.

The positions of all Wellhead Jackets, sub-sea structures and pipelines falling within the prescribed

survey areas shall be determined and compared with QP's current database. Any anomalies resulting

from such comparisons shall be brought to QP's immediate attention. The anomalies of position,

configuration, heading etc. shall be resolved prior to demobilisation of the survey spread.

Preliminary charts and a report shall be produced and delivered to QP prior to demobilising the survey

spread.

The contractor shall satisfy himself and demonstrate that the survey is complete and free from

ambiguities.

The Pipeline Route Pre-Engineering Surveys shall be conducted for each pipeline within a corridor

extending a minimum of 100 metres perpendicular to and on either side of the proposed pipelinecentreline.

Pairs of straight and parallel survey lines shall be run at ≤ 25 metres line spacing. The orientation and

selection of such lines relative to the proposed pipeline alignment shall be selected for optimum target

detection. Adjacent sidescan sonar lines shall be run in opposite directions to achieve 200% sonar

coverage. Cross lines, at intervals not greater than 200 metres, shall be run perpendicular to the

proposed pipeline centreline.

Additionally, survey lines acquiring bathymetry and sub-bottom profiler data shall be run along the

centreline of each proposed or subsequently amended pipeline route.

Maximum deviation from intended lines shall be +/- 5 metres for 95% of line length or contiguous length

of line. All lines failing to achieve this level of vessel control shall be re -run.

The UTM position and orientation of each terminating platform shall be determined and confirmed during

the seabed survey.

To supplement the seabed data acquired from the longitudinal lines, pairs of survey lines shall be run

across the riser face(s) of each terminating jacket. The orientation of these transverse lines shall be

determined on site, to suit local conditions. The side scan range and frequency for these pairs of

transverse lines shall be selected for optimum target response.


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The proposed crossings of existing pipelines and the areas of potential free-spans shall be further

examined as a separate and dedicated operation. Pairs of lines, parallel and perpendicular to the

existing pipeline, shall be run to "box in" and provide high definition sonargrams of the crossing, free-

span and surrounding seabed. The examination shall extend at least 50 metres either side of the

construction limits of each proposed pipeline crossing or suspected free span.

Where significant obstructions or a potential hazardous condition are detected, additional survey lines,

10 metres apart, shall be run with the towfish recording at 50 metres range. Line length and orientation

shall be selected to best resolve the nature and extent of the hazardous condition. The UTM positions

and limits of such features shall be available as ASCII format x, y data.

The data shall be inspected during the course of the survey. The presence of seabed or sub-seabed

conditions, likely to result in a modified route alignment, shall be brought to QP's immediate attention.

5.3 PIPELINE ROUTE PRE-ENGINEERING JACKET RISER FACE SURVEYS

These surveys shall be undertaken to verify the Engineering Design Drawings and to confirm these

particular sections of the proposed route.

A Riser face survey shall be conducted at each connecting jacket. The survey shall confirm the preciseconfiguration and alignment of the new pipeline route and all appurtenances between the sub-sea riser

flange extending to the top of the risers and 5 metres above MSL at the Terminating Platform. The

alignment of the pipeline and piggy backed appurtenances shall be described relative to existing

features i.e. risers, riser clamps, anodes and centres of jacket legs, cross bracings etc.

5.4 PIPELINE ROUTE PRE-LAY/CONSTRUCTION CLEARANCE SURVEYS

Prior to the Installation of the pipeline and appurtenances, the contractor shall confirm the integrity of

each pipeline route. The contractor shall ensure that the pipelay conditions established as a result of

the Pipeline Route Pre-Engineering Surveys and upon which the pipeline route was designed have not

significantly deteriorated.

The contractor shall propose his means of establishing and confirming to QP that no significantchanges have occurred to the site conditions and that the integrity of the designed route has been

maintained since the Pre Engineering Surveys were conducted.

The contractor shall bring to QP's immediate attention the presence of newly found conditions

likely to affect the integrity of the proposed pipeline route.

5.5 PRE-INSTALLATION ANCHOR CLEARANCE SURVEYS

Within a corridor, 1200 metres either side of each proposed pipeline route, the contractor shall conduct

sufficient survey works utilising typically side-scan sonar, sub-bottom profiler equipment etc. to ensure

that the charted sub-sea locations of all pipelines, cables, jackets, wrecks etc. and significant sea-bed

features are as depicted by the QP 1:2500 database.

In the absence of approved anchor patterns and for the purposes of line planning, the minimum anchor

wire lengths shall be taken as 1200 metres.

Upon completion of these and any subsequent and extra verification works, the contractor shall confirm

or otherwise that the relevant QP Charts portray a complete, accurate and realistic indication of the

water depths and the presence of all structures and seabed details within his proposed anchor patterns.

The contractor shall quantify and resolve any anomalies between his data and QP's existing database

prior to the demobilisation of the survey spread. The contractor shall update and submit for approval

those QP charts revised by the contractor as a result of his surveys.


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Thereafter, the contractor shall utilise the updated Project Folio of QP 1:2500 Charts as baseline data

for the submission of his proposed anchor patterns.

5.6 PIPELINE INSTALLATION SURVEY OPERATIONS

The following systems shall be deployed during the Pipeline Installation Survey Operations and

operated according to Section 4 above:

Navigation System, Computer System, Survey Quality Gyrocompass, Electronic Distance Measuring

Equipment.

The pipeline, pipeline supports, pipeline anchorages and all temporary and permanent appurtenances,

shall be constructed and installed to the specified Engineering tolerances. During pipeline construction,

Survey operations shall be controlled and managed from the pipelay barge. The contractor shall

produce a Survey Procedure detailing all survey operations and his proposed means of fulfilling the

requirements of these operations.

During construction and installation operations, the contractor shall maintain precise

positioning and orientation control of the pipelines, of the start-up and lay-down heads, of the

pipeline anchorages (dead-men anchors) and of the temporary and permanent pipelinesupports at pipeline crossings and along unsupported spans. This control, together with the

proposed deployment of his personnel and equipment resources, shall be seen capable of

achieving the required installation tolerances of position, elevation and orientation. The

Navigation Systems and Gyro Compass shall be checked at intervals not exceeding 7 days.

The contractor's proposed Installation Procedure shall make particular reference to the means by which

he intends to position, install and check the location of all temporary works (pipeline supports, A & R

Equipment, dead-man Anchors etc.).

5.6.1 Positioning and Computer System

The contractor shall prepare a comprehensive SURVEY INSTALLATION PROCEDURE adequately

describing:Method of installation (pipelines, temporary sleepers, pipeline anchorages, start-up and

lay down arrangements etc.)

Monitoring of the installation,

Survey personnel, their responsibilities and deployment,

Proposed equipment.

Throughout the installation of each Pipeline, the contractor shall provide a Positioning capability to

maintain unambiguous control of the installation barge/vessel, the anchor handling vessels, the

pipelines and all temporary and permanent facilities required to ensure that the installation tolerances

can be achieved.

The system shall prepare and display a Pipelay Database (background structure file) using the Project

Chart Folio. This database shall include the positions of all pipelines and proposed pipeline crossings,structures and obstructions as identified during the Pre-Installation seabed survey and the anchor

clearance survey. The database shall contain the pipeline route alignment data and details of all

approved anchor pattern configurations, laydown areas and spoolpiece locations. The Structure files

shall be inspected and approved by QP prior to use. In this case, they shall be provided as

AutoCAD2000 compatible and editable data

The core of the Computer system shall be installed in the laybarge Control Tower. The system shall

include proprietary software dedicated to the pipeline construction environment. The system shall

provide continuous real time UTM co-ordinates for the following:

- The Navigation antennae.


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- The pipeline touch down point (TDP).

- The beadstall position.

- Each Anchor Handling Vessel's stern offset.

The graphics capability shall allow continuous display of the anchor locations, the design route

centreline, the lay corridor and the as laid pipeline. These data shall be superimposed on the approved

database (structure files).

For each predicted TDP position, the following information, as a minimum, shall be available to the

operator:

- the layback distance to T.D.P.

- the actual KP value.

- the pipe joint number.

- the "distance to go" to any selectable target (e.g. laydown location, tangent point, Tee

Piece location, pipeline crossing etc.")

- the distance offline.

- the barge survey gyro heading.

During pipelaying the computer system shall continuously portray and update the database

with each successive determination of the predicted TDP. VDU presentation of the TDP, bargelocation and heading, design corridor and neighbouring pipelines, structures and obstructions

shall be readily available in the control tower.

5.6.2 Navigation System

The Navigation system, its operation and calibration shall comply with the requirements of Section 4.

Positions shall be computed and supplied in terms of UTM Grid co-ordinates. The proposed Navigation

Systems shall be installed, calibrated and operated in accordance with the contractor's approved

procedures. The systems are required to provide all data necessary to compute the datum and offset

positions of the laybarge, the Anchor Handling Vessel and any other vessel requiring a surface

positioning capability. The Navigation System shall be maintained operational until all construction

survey activities have been successfully completed and approved by QP.

Each Anchor Handling Vessel shall have a dedicated and calibrated survey Gyrocompass, linked to the

Anchor Handling Vessel positioning system, to provide the UTM position of any offset. The vessel's

heading shall be available during each anchor handling operation. The UTM position of the Anchor

Handling Vessel and any offset shall be continuously available at the laybarge. The Anchor Handling

Vessel shall transmit its position to the survey system in the control tower. The track progress of the

Anchor Handling Vessel shall be logged and superimposed graphically on the database of existing

pipelines, structures and obstructions. The Anchor Handling Vessel shall be conned to the required

drop location. During anchor deployment and recovery, the track of the Anchor Handling Vessel shall be

logged, displayed and monitored in the control tower. A comprehensive record of all anchor-handling

activities, including the Anchor Handling Vessel track data and graphics shall be maintained and, on a

daily basis, submitted to QP's representative offshore. The contractor shall assess the requirements of

the Anchor Handling Activities and submit, for QP's approval, a suitable procedure to achieve theserequirements.


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5.6.3 Monitoring of Touch Down Point.

During pipeline installation, aboard the laybarge, the UTM co-ordinates for the predicted position of the

Touchdown Point (TDP) shall be continuously plotted and logged to disk. The surveyor on watch shall

maintain a permanent record of the water depth and of the predicted horizontal distance from stern

datum to TDP.

5.6.4 Anchor Handling

The contractor shall maintain a history of each anchor deployment and recovery.

The intended position, the dropped position, the monitored positions the recovered position and position

differences OF EACH ANCHOR shall be recorded in UTM co-ordinates as a ms Excel worksheet.

During deployment and recovery, the Survey System on board the Anchor Handling Vessel shall

produce a continuous plot of the vessel's track.

On a daily basis, the UTM position of each anchor shall be acquired and monitored to determine anchor

drag or winch slip. Copies of the Tabulated positioning data and survey logs shall be maintained in anapproved format as a typical MS Excel spreadsheet.

These data shall be used to determine the survey line coverage required during the Post lay Anchor

Clearance Surveys.

5.6.5 Manning

The number and designation of Survey personnel dedicated to construction operations shall be

sufficient to adequately fulfil the requirements of the construction programme. It is normal for operations

to be continuous over a 24 hour period. Sufficient survey personnel shall be engaged to ensure the safe

and proper navigation and operation of the laybarge, the Anchor Handling Vessel, the survey vessel and

each auxiliary vessel; to perform the maintenance, repair and replacement of the survey equipment and

to acquire, interpret and process the survey data.

5.7 PIPELINE AS-LAID CONDITION SURVEYS

Immediately upon the installation of each pipeline, the contractor shall conduct the Pipeline As Laid

Condition Surveys. As a result of such surveys, the extent and nature of all construction remedial works

shall be determined. For the whole length of the newly installed pipeline, and prior to his commencing

any remedial works, the contractor shall establish the As Laid Condition and report on and submit in

both hardcopy and ASCII file format, as a minimum, the following:

1. At intervals not exceeding 5 metres, the As Laid UTM positions and KP values of the pipeline

and of all appurtenances

2. The UTM position, the KP value and the length of each unsupported section of pipeline.

3. Side Scan records demonstrating that the pipeline has sustained no significant damage duringinstallation and a visual record of those sections of the pipeline where damage has occurred

and where repair works may be necessary.

The contractor's procedure for Conducting and Reporting on The As Laid Condition of the Pipeline and

Appurtenances shall be approved prior to the laying of pipe.


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5.7.1 Real Time Pipelay Records

As laid charts at 1:2500 scale shall be maintained and updated daily to show the pipelay corridor, the

design route, the successive as laid positions of the pipeline, details of all unsupported sections and

areas of suspected damage.

For each pipeline, and prior to his commencing any proposed remedial works, the contractor shall

compile a preliminary Pipeline Installation Report for formal submittal to the QP offshore representative.

5.8 POST-LAY PIPELINE AS BUILT/AS LAID SURVEYS.

The pipeline As-Built Surveys shall be conducted on completion of all pipeline commissioning and

testing works in accordance with Document ES-L-60.

Sufficient data shall be acquired to accurately define, in terms of UTM co-ordinates, the pipeline

position including the positions and construction details of all spoolpiece configurations, riser

configurations, pipeline crossings and unsupported sections. These UTM positions shall be submitted

in ASCII format for immediate entry into the QP Survey database.

5.9 POST-INSTALLATION JACKET RISER FACE SURVEYS

The contractor shall determine the precise alignment of the pipelines and all appurtenances at each

jacket face, from riser bend to top of riser. Previously approved data acquired during the installation of

these "vertical" sections of pipeline may be incorporated and will contribute to the Project As Built

Alignment Records.

The contractor shall confirm the integrity of this installation data and take advantage of data acquired

and approved during the pre-installation jacket face surveys.

5.10 POST INSTALLATION ANCHOR CLEARANCE SURVEYS

The following systems shall be deployed during the Pipeline Post-Installation Anchor Clearance

Surveys and operated according to Section 4 above:

Survey Vessel, Navigation System, Computer System, Sidescan Sonar System, Electronic Distance

Measuring Equipment.

The contractor shall conduct post installation anchor clearance surveys and confirm that the integrity of

QP structures and assets has been maintained during the execution of the construction and installation

works. Prior to the start of each survey, the contractor shall submit, in ms Excel and AutoCAD2000

format, for QP approval, confirmation of the actual limits of the installation barge/vessel anchor patterns.

The contractor shall submit a proposed line and event numbering system for QP's approval prior to

commencing any survey works.

Parallel survey lines shall be run at ≤ 100 metre line centres. The line orientation shall be selected for

optimum target detection and accurate delineation of each feature. Adjacent lines shall be run inopposite directions to achieve 200% sidescan sonar coverage.

Crosslines at 200 metres centres shall be run perpendicular to the main survey lines.

6 CHARTING AND REPORTING REQUIREMENTS

A Project Chart Folio will be prepared comprising digital charts prepared by the contractor:

• from scratch using data acquired during the Pre Engineering Surveys

• using and updating/confirming QP baseline data


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Data from third party sources or data acquired from previous surveys shall be included provided that the

provenance and reliability of all such data can be established.

QP shall provide the titles and a numbering system for all final charts.

The contractor shall supply Charts, tabulated data and certain specific drawings in both hard copy and

digital form The digital data shall be suitable for detailed editing and subsequent inclusion, via QP's

AutoCad2000 Software, into the QP Mapping database. The UTM positions of all pipelines, pipeline

features, appurtenances, natural and artificial seabed features and structures shall be supplied as non-

compressed digital data, ASCII format, capable of individual editing and further plotting at user

determined scales. Text based documents shall be produced and submitted as MS Word doc. files.

6.1 PIPELINE ROUTE PRE-ENGINEERING SURVEYS

6.1.1 Data Processing

The data presented shall include bathymetry (reduced to ACD using Employer provided predicted

tides), sea floor features and sub-bottom geology. The data processing may include suitable data

acquired as a result of the Diver Surveys. Data shall be presented both on a stable medium, at a scale

of 1:2500 and in a digital form, for subsequent development on the Employer's AutoCAD2000 package.

Water depths and contour lines shall be additionally submitted as ASCII data. Charts shall be sub-

divided horizontally into three sections. Where more than one sheet is required to depict the pipeline

route, scale shall be constant for each plot sheet. Matchlines shall be indicated.

6.1.2 Charting

6.1.2.1 Top section - "Bathymetry and Sea Floor Topography"

Compiled soundings shall be shown at an approximate interval of 1 per 25 metres. All structures,pipelines, significant pockmarks, obstructions etc. shall be labelled and shown. Special care shall beexercised to ensure that extreme values of sea floor topography are represented by the soundings. Thechart shall be contoured at 0.5 m intervals. All data shall be used for the deve lopment of contours. Side

scan sonar data, such as structural features, pipelines, depressions and obstructions shall be suitablyannotated

The final proposed alignment of each pipeline route shall be superimposed on this section and indicatedby a dashdot line. The line shall be annotated to indicate the new works' radii of curvatures KP values,location and number of each tangent and intersection point, pipeline crossing, bend and tie in spoolpiece, Tee piece junctions etc. The UTM grid co-ordinates of these annotated features shall be added,in tabular form, to this section. The dashdot line and all annotations and tables shall be plotted suchthat the original survey data is preserved. The KP values shall be added wherever matchline andpipeline alignment intersect.

6.1.2.2 Middle section - "Centreline Profile"

A bathymetric profile shall be constructed from the echo sounder data acquired along and across the

pipeline route centreline. Care shall be taken to ensure that all extreme values are represented. Thepresence of any shallow seismic reflectors shall be shown on this same profile. The profile shall be

produced at a horizontal scale of 1:2500. The vertical scale shall be selected to clearly depict riser

bends and spool piece configurations, Tee pieces and other significant pipeline features shall be added

to the bathymetric profile. KP values shall be inserted above the profile and matchlines as appropriate.


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6.1.2.3 Bottom Section – “Sub-Sea Hazards".

A plan at 1:2500 scale shall be prepared to indicate all Geological Isopachs and anomalous conditions

considered hazardous to the works. These shall include areas of numerous pockmarks or shallow

gassy sediments, pockets of very soft sediments, rocky ridges, coral outcrops etc. The vessel trackplot

and fix numbers shall be plotted “behind” the isopachs etc.

6.1.2.4 Reporting

A detailed report is required in which the designed alignment, the construction details at each proposed

pipeline crossing, laydown area and pipeline anchorage, the nature, position and dimensions of any

hazardous condition are comprehensively discussed.

6.2 PRE-ENGINEERING JACKET RISER FACE SURVEYS


The data from the Jacket riser face surveys shall be presented as a new and dedicated set of large

scale, well annotated, survey standard drawings. Plans, cross sections and front elevations shall beprepared to show the jacket legs, cross members, risers, valves, anodes and clamps etc. All relevant

field dimensions are to be inserted. The precise alignment of the new pipework shall be superimposed

to clearly define the route from mudline to top of riser.

6.2.2 Charting and Reporting

Prior to commencing the survey, the contractor's proposed format for the Jacket Riser Face drawings

and reports shall be submitted for QP's approval.

6.3 PIPELINE ROUTE PRE-LAY/CONSTRUCTION CLEARANCE SURVEYS

The Data shall be presented on charts from the Project Folio and according to the contractor's approved

means of confirming, immediately prior to pipeline construction, the integrity of the pipeline route

6.4 PRE-INSTALLATION ANCHOR CLEARANCE SURVEYS

6.4.1 Data Processing and Charting

The Anchor Clearance Surveys shall be presented on charts from the Project Folio and shall adequately

demonstrate the integrity of these charts. Additionally, the processed bathymetry and contour lines

(reduced to Chart datum) shall be submitted as ASCII data, for editing within the AutoCAD2000

environment.

7 REPORTING

The quality of the data and significance of the results shall be discussed and shall form an integral partof both the Preliminary and Final Reports.

7.1 SURVEYS TO ESTABLISH THE AS LAID CONDITION OF THE PIPELINES

7.1.1 Data processing

The contractor shall provide sufficient personnel and facilities to conduct data processing operations

offshore, aboard the survey vessel, during the surveys. Project Folio Charts shall be prepared to

indicate the as built positions of each pipeline, pipeline feature and of all natural and artificial features.


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The data shall be compared with the pre-installation charts and the pipeline as-laid installation records.

Any anomalies shall be further investigated and accounted for.

The contractor shall additionally handover:

1. On a magnetic medium and in a format suitable for subsequent incorporation into the QP

survey database, AutoCAD2000, digital files containing:

a. The as installed positions of each pipeline. The intervals for these data shall be selected to

both realistically present each pipeline deviation and to allow further editing and subsequent

plotting at a scale no smaller than 1:2500.

b. In MS Excel format, a schedule detailing the final as built positions and limits of all pipeline

crossings, unsupported freespans, pipeline tie-ins and spoolpieces, riser bends and all other

significant construction features.

7.2 POST-INSTALLATION JACKET RISER FACE SURVEYS

Approved data acquired during the installation of the "vertical" sections of pipeline may be incorporated

as part of the POST-INSTALLATION alignment. The contractor shall however confirm the integrity of this

installation data and take advantage of data acquired and approved during the pre-installation jacket

face surveys.


Sufficient data shall be acquired to update the relevant Contract Engineering Pipeline Alignment

drawings and reflect the as installed status of the pipeline and all appurtenances.

Copies of the updated Engineering Drawings, in AutoCAD2000 compatible format, shall form part of the

preliminary as -built report.

7.3 POST INSTALLATION ANCHOR CLEARANCE SURVEYS

The contractor shall conduct Post Pipeline Installation Anchor Clearance Surveys for those areas within

the deployed anchor patterns. The results will confirm or otherwise that the integrity of QP structuresand assets has been maintained during the execution of the pipeline construction and installation

works.

7.3.1 Charting

Charts shall be updated and produced from the Project Chart Folio, at a scale of 1:2500, to show all

pipelines, jackets, mooring piles, sub-sea wells, permanent moorings and seabed features considered

potentially hazardous to future anchor handling activities.

7.3.2 Reporting

The quality of the data and significance of the results shall be discussed and shall form an integral part

of both the Preliminary and Final Reports.

8 FINAL REPORT

The contractor shall submit a Final Report describing and concluding Contract Survey Operations

namely:

i. Pipeline Route Pre-Engineering Surveys

ii. Pipeline Route Pre-lay/Construction Clearance Surveys




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The Final Report shall be first submitted in draft form, for QP's approval, and may comprise those final

reports prepared and prepared during each individual survey.

The DRAFT and FINAL REPORT shall be presented both in hard copy form and in 100% digital form.

The text and charts shall be presented on a magnetic medium (CD) for subsequent processing on QP's

word processing, Spreadsheet, Adobe Acrobat and AutoCAD2000 drafting packages.

The Final Report shall, as a minimum, comprehensively describe and cover:

the Scope of Work, the Survey Operations, the Geodetic Parameters, the Control Co-ordinates,

the Proposed Pipeline Route Alignment Co-ordinates, the Anchor Clearance Surveys, the Survey

Equipment operation and calibration, the Navigation Systems' performance, the As Built Pipeline

Alignments, the Route KP's and lengths, pipeline suspension co-ordinates, the accuracy of surface,

sub-surface and final quoted co-ordinates, the results of the As-Built and the Post Installation Anchor

Clearance Surveys, the Anchor Handling Activities, the Survey Quality Control input, the Quality of all

acquired data and subsequent computations, the performance of Personnel and Equipment, the Diaryof Events, the inclusion, preparation and production of all Charts, a discussion of the various error

budgets.

The following, as a minimum, shall be appended to the Final Report:

the contractor's approved survey procedures and Quality Assurance Plans, the Control Station

Descriptions, the Anchor Handling Records, vessel and lay-barge offset data, all equipment and system

calibration data including original observations, abstracts, computations and results, a print of each as -

built chart, anchor clearance chart and post installation anchor clearance chart.

8.1 Data and Data Submission

All raw survey data acquired by the contractor during the execution of the works shall remain theproperty of QP. During its acquisition, the contractor shall maintain a comprehensive inventory of all

such data. The contractor shall retain all raw data until such a time as QP has formally approved and

received the FINAL REPORT, whence the contractor shall formally handover this raw data and the final

inventory to QP.

Prior to the acquisition of Contract specific data, the contractor shall provide sample digital data to

confirm the suitability and acceptability of his proposed data format.

F2-SUR-001Rev2 Survey Spec for Subsea Pipelines

Documents

Transcript of F2-SUR-001Rev2 Survey Spec for Subsea Pipelines