2013.06.05.Canada John Brigden Directional Drilling

7/24/2019 2013.06.05.Canada John Brigden Directional Drilling

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Directional Drilling

- Acknowledgement

- History

- Present Day Applications

- Hardware

- Measurement Sensors

- Error sources and Equipment Limitations

- Mathematics

- Legislation


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Acknowledgement

This presentation has been inspired by many of the

items discussed in the publication at left.

It can be downloaded at:

http://www.uhi.ac.uk/en/research-

enterprise/energy/wellbore-positioning-download

Additional material has been obtained from

publications of;

APSG, OGP, EPSG, C-NLOPB and others


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History

Rotary drilling techniques were developed in early 20th century.

Deviated wellbores were usually drilled unintentionally.


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Early drilling for oil and gas was almost always performed by drillingvertical wells, usually considered to be within 2-3 of plumb.

Wellbores could naturally deviate from the vertical when certainforces were applied and/or geological conditions existed.

Until the 1970s downhole surveys were primarily used to monitorlateral deviations of a wellbore and take preventive measures tomaintain its verticality should it start to drift off to one side.

Deliberately causing a wellbore to deviate from the vertical wasknown as whipstocking and considered illegal.


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In 1930, California driller John Eastman was granted a patent for his

techniques of conducting downhole surveys and intentionallydeviating a wellbore.

Founded the Eastman Oil Well Survey Company.

He achieved fame and credibility in 1934 by drilling a directional

relief well to intercept and extinguish another that was burning

near Conroe, Texas.

Similar research by Sperry, a gyrocompass manufacturer, and Sun

Oil Company lead to Sperry-Sun Drilling Services.

Both Eastman and Sperry names live on as directional drilling

subdivisions of major Oil industry service companies.

In 1964 there was a test in Utah running competing survey tools

inside an aluminium irrigation pipe installed on a mountain side.

This proved the validity of such equipment and several lawsuits

were settled as a result.


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Present Day Applications


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Large numbers of present day production and development wells aredeviated.

Environmental and economic benefits.

Allows for enhanced recovery techniques


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Reuse old wellbores

Drill a relief well as required by regulations

Sidetrack around broken pipe and fish


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Hardware


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Measurement Sensors


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Retrievable Magnetic

Compass SurveyEquipment


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Equipment Limitations

and Error Sources

Measurements are limited to:Gyroscopes

Magnetometers

Accelerometers

All components have to be small to fit inside wellbore

Magnetometers cannot be used inside cased hole

From a surveyors point of view, directional surveys are

unclosed traverses and thus will always be suspect. Despite this, most errors are in the blunder category


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Gamma ray sensorinstalled behind bit to

identify rock formations

MWD probe tracks nearby

induced magnetic field

Alternative methods of wellbore steering.


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Mud Pulsing Data Transmission


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Electromagnetic Data Transmission

$$$$$$$$$$$$

$$$


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Getting the data back can be problematic.

Mud Pulse TelemetryLow data rate

Cannot be used in underbalanced drilling programs

Electromagnetic Telemetry

Depth limitations

Need to isolate components

Retrievable Tools

Low data rate

Time consuming

Small diameter components

Wired ToolsConnectivity problems

Wire damage potential

Wired Drill Pipe

High capital cost

A work in progress


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Mathematics


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Example - Wellbore Survey Calculations

The table below gives data from a directional survey.

Survey Point Measured Depth Inclination Azimuthalong the wellbore Angle Angle

ft I, deg A, deg

A 3,000 0 20B 3,200 6 6C 3,600 14 20

D 4,000 24 80

Based on known coordinates for point C well calculatethe coordinates of point D using the above information.


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Point C has coordinates:

x = 1,000 (ft) positive towards the east

y = 1,000 (ft) positive towards the north

z = 3,500 (ft) TVD, positive downwards

Z

E (x)

N (y)C

D

z

N

D

C

y

x


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I. Calculate the x, y, and z coordinates

of points D using:

(i) The Average Angle method

(ii) The Balanced Tangential method

(iii) The Minimum Curvature method

(iv) The Radius of Curvature method

(v) The Tangential method


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Summary of Results (to the nearest ft)

X Y Z

Average Angle 1,100 1,084 3,878

Balanced Tangential 1,097 1,060 3,877

Minimum Curvature 1,098 1,060 3,881

Radius of Curvature 1,095 1,080 3,878Tangential Method 1,160 1,028 3,865


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Even the most elaborate of

these five calculations can be

written onto an MS Excel

spreadsheet


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Do try to maintain standards for data exchange as described in:

http://www.epsg.org/exchange/p7.pdf


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Legislation

Surface Location

Canada Oil and Gas Drilling and Production Regulations - Section 74

Oil and Gas Conservation Regulations (Alberta) Section 2.020

Both require a licenced surveyor to certify plan

Directional SurveysCanada Oil and Gas Drilling and Production Regulations - Section 32The operator shall ensure that:

(a) directional and deviation surveys are taken at intervals that allow the position

of the well-bore to be determined accurately; and

(b) except in the case of a relief well, a well is drilled in a manner that does not

intersect an existing well.


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Oil and Gas Conservation Regulations (Alberta) Section 6.030

(1) Unless the Board otherwise directs in writing, the licensee of a well

shall make or cause to be made during drilling, tests, at depth intervals

not exceeding 150 metres, for the purpose of ascertaining to what

extent the well deviates from the vertical.

(2) Repealed AR 36/2002 s6.

(3) The licensee shall, immediately upon the making of a directional

survey, send to the Board the report of the survey(4) The Board may order the licensee to make such further deviation or

directional surveys as it deems necessary, and may give directions as to

the manner in which such tests or surveys shall be made.

Summary

Neither jurisdiction requires directional survey data to be tied to

surface location.

No certification requirement for directional survey.


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Nevertheless; directional surveys may be related to legal boundaries!


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Legal Cases

East Texas Scandal 1962

Several land owners believed that deviated wells had been drilled beneath

their properties from adjacent lands.

Surveys were ordered and over 380 wells were found to be deviated across

land boundaries.

The validity of surveying equipment used was upheld after the Utah tests in

1964.

Bocardo SA v Star Energy UK Onshore et al 2009

Land owner, Mr. Al Fayed, alleged that 17 years earlier Star had drilled a

deviated well underneath his property to extract oil and gas.

Star denied the theft in initial negotiations but admitted it in court several

years later.

Judgement for trespass in Bocardos favour ; awarded 9% of income over a

limited period of time.

2013.06.05.Canada John Brigden Directional Drilling

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