Oilfield Development

7/29/2019 Oilfield Development

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PROJECT DESCRIPTION

CHAD EXPORT PROJECT SUPPORTING DOCUMENTS - VOLUME 1

4.0 OIL FIELD DEVELOPMENT AREA

Oil, water, and limited gas will be produced in each of the Kom, Miandoum, and Bolobo fields.In the Kom and Miandoum fields, there will be gathering stations where free water is separated

from the oil, then treated and disposed of into the oil reservoir via injection wells. Water content

in the oil will be reduced to about 10 percent at the gathering stations. The remaining oil and

water, in the form of an emulsion, is piped to the CTF for processing to produce crude oil of a

quality suitable for export sales. The general layout of the oil field development area is shown in

Figure 4-1. A schematic illustrating the various steps in the product flow path is presented in

Figure 4-2.

In the oil field development area, approximately 1,080 ha are needed for facilities and their

related infrastructure (195 ha); of this, 325 ha of land will be made available for most pre-

construction uses, with the restriction that the use not interfere with normal operations and

maintenance. Another 490 ha will be reclaimed after construction and made available to pre-

construction customary land users.

4.1 FACILITIES DESCRIPTION

4.1.1 Well Site / Flowlines

Approximately 300 producing wells will be located in the oil field area. Fiberglass flowlines will

connect individual wells to the field manifolds. If required, the flowlines can be serviced using

portable launchers and receivers. Production from the Kom LK wells will be gatheredseparately using carbon steel flowlines and sent to the CTF where the gas will be used for

power plant fuel and the oil combined with other incoming emulsion.

4.1.2 Remote Manifolds / Well Testing

Field manifolds will be used as part of the gathering systems. The field manifolds serve two

purposes:

To collect production from several individual wells and direct it via a production manifold to a

gathering line, a gathering station, or a field pump station

To direct production via a test header from a selected well to a well test skid located at each

manifold


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PROJECT DESCRIPTION

SUPPORTING DOCUMENTS - VOLUME 1 CHAD EXPORT PROJECT

Well testing installation at each manifold site will consist of a vertical separator, proportional

velocity flowmeter, a watercut meter, a ratio tube-type densitometer, and associated

instrumentation and controls.

4.1.3 Kom and Bolobo Field Pump Stations

For the wells and manifolds located at the southern and northern ends of the Kom field, two

field pump stations (KP-1 and KP-2) will pump the production fluids to the Kom gathering

station. The pump stations will receive production from other field manifolds including the

manifold located at the pump station. The field pump stations will be designed to pump amultiphase mixture of oil, water, and gas using rotary screw pumps. Storage of field production

will not be provided at the pump stations. A similar multiphase pump station (BP-1) will be

utilized in the Bolobo field, sending all Bolobo production fluids to the Kom gathering station for

processing. No field pump station will be required in the Miandoum field.

4.1.4 Gathering Stations

Two gathering stations will be constructed, one in Kom and one in Miandoum. The gathering

stations will receive production from individual wells via field manifolds and field pump stations.

The Kom field gathering station will also receive production from the Bolobo field pump station.

The function of a gathering station is to:

Separate produced gas and sand from incoming well fluids

Dewater incoming well fluids to produce a 10 percent watercut emulsion and pump it via the

emulsion trunkline to the CTF

Measure the emulsion production rate and watercut to determine oil production from the

field

Treat produced water to remove oil and sand, and pump it to an injection well

Compress the produced gas for transportation to the CTF.

Major features of the gathering station design are discussed below.

4.1.4.1 Free-Water Knock-Out


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PROJECT DESCRIPTION


station, lower crude viscosities will allow the use of unheated FWKO tanks to separate free

water from the inlet emulsion to produce a 10 percent watercut emulsion.

4.1.4.2 Emulsion Pumping

At the Miandoum gathering station, rotary screw pumps will be provided to pump the emulsion

from the FWKO tanks to the CTF via an emulsion trunkline. At the Kom gathering station, 10

percent watercut emulsion will gravity-flow from the second stage FWKO tanks to the CTF

emulsion inlet tanks.

4.1.4.3 Produced Water Treatment

Produced water from the FWKOs will be pumped to skim tanks removing solids and oil prior to

reinjection of produced water. Clear-water surge tanks will be installed downstream of the skim

tanks to provide surge capacity for the water system and suction for the water injection pumps.

Plot space will be provided in the water plant should it be determined that additional water

treatment equipment is needed.

4.1.4.4 Sand Handling

At the Kom and Miandoum gathering stations, the majority of the sand will be removed in the

FWKO tanks. As required, the tanks will be shut down and manually cleaned. The sand will be

disposed of in the landfill or another environmentally acceptable manner. Sand and other solids

carried to the produced water system will be removed in the skim tanks.

4.1.4.5 Water Injection Pumps

At each gathering station, a pumping system consisting of booster pumps and main injection

pumps will be provided to pump the treated produced water to injection wells. The Bolobo

produced water will be reinjected at Kom.

4.1.4.6 Gas Compression Facilities

At the Miandoum gathering station, vapor recovery units and multi-stage reciprocating

compressors will be provided to collect produced gas from the FWKO tanks and compress it for

transport to the CTF where it will be used as fuel gas for the power plant and tank blanketing.

At the Kom gathering station Kom and Bolobo produced gas from the FWKO system will be


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PROJECT DESCRIPTION


Pressure Relief and Flare

Instrument and Utility Air

Fuel Gas

Chemical (Demulsifier) Storage and Injection

Hot Water Process Heating (Kom Gathering Station and CTF)

Electric Power

Open Drain System.

4.1.5 Water Injection System And Disposal Wells

Both dry holes and converted high-watercut producers will be used as water disposal wells. The

total number of disposal wells is estimated to be 36 (including nine recompletions): 27 in the

Kom UK field, and nine in the Miandoum field. Water disposal at Bolobo is not envisioned.

Total produced water production is expected to approach 900 kbd. The total number of disposalwells and distribution between the individual fields may change as the development drilling

program progresses. A manual choke and a meter will be provided at each wellhead.

For the Kom field, the water disposal system will consist of a water injection trunkline and

lateral system from the Kom gathering station out to the disposal wells. For Miandoum,

individual injection lines from the gathering station will run to each well.

4.1.6 Operations Center

The Operations Center (OC), located in the Kom field, will include the following, as shown in

Figure 4-3:

Kom Gathering Station

Central Treating Facility

Power Plant

Pump Station No. 1 (PS No.1)

Community


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PROJECT DESCRIPTION


Avoid existing villages

Avoid cultivated areas and utilize existing large pad

Be close to the field having the largest reserves and the highest fluid viscosity

Have minimal impact on the environment.

4.1.7 Central Treating Facility

The CTF will receive emulsion and produced gas from the Kom and Miandoum gathering

stations, as well as produced oil and gas from the Kom LK.

The main functions of the CTF are:

Dehydrate the incoming 10 percent watercut emulsion from each field to produce pipeline

quality crude meeting a one percent maximum basic sediment and water (BS&W)

specification

Separate the Kom LK oil and gas

Receive the incoming produced gas and direct it to the power plant and CTF fuel gas

systems.

The key design features of the CTF are:

The emulsion production from each field will be commingled and treated in electrostatic

emulsion treaters.

The incoming emulsion will be combined and mixed in emulsion tanks upstream from the

emulsion treating system. The emulsion will be pumped from the tanks, split, and processed

in seven identical parallel treating trains. Each train will have an emulsion heating system

and a treater. The inlet emulsion will first be preheated in plate exchangers by hot-treated

crude and then by produced water from the treaters. Final heating to treating temperature

will be accomplished using a hot water heating medium in shell and tube exchangers.

The BS&W content of the oil will be measured after treating. Off-specification oil (wet oil)

will be directed to a separate wet oil system. The wet oil will be further treated in the tanks

by providing heat and retention time or it will be recycled to the inlet of the emulsion treaters.

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PROJECT DESCRIPTION


Short-term surge capacity for the treated crude will be provided at the CTF, but there will be

no storage facilities for treated oil within the CTF. Treated oil will be sent to PS No. 1 for

storage. The BS&W content of the treated oil flowing to PS No. 1 will be measured and wet

oil will be automatically diverted to the wet oil system.

Gas production from the fields will be handled separately from the emulsion. The Miandoum

gas and the Kom UK/Bolobo gas will have separate inlet systems. The gas streams from

the inlet separators will be combined and used as fuel gas for the power plant and the CTF.

Any liquids collected in this system will be sent to the emulsion treating system.

The following utility systems will be provided at the CTF:

Fire Water

Potable and Utility Water

Pressure Relief and Flare

Instrument and Utility Air

Chemical Storage and Injection

Fuel Systems (Oil and Gas)

Process and Open Drain System

Sanitary Sewer

Hot Water Heating System

Electric Power

Diesel Crude Oil Topping Plant

Waste Incinerator (located in Kom field)

Landfill remote from CTF.

4.1.8 Automation

The Automation System will be designed to meet the functional requirements of the process

design with safety of personnel, environment, and equipment paramount in the philosophy.

Other major considerations are reliability cost and accuracy over the life of the development


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PROJECT DESCRIPTION


location will have a standalone, programmable logic controller (PLC) based system for

emergency shutdown.

The Automation and Control System will be a hybrid system based on PLCs. An operator

controls facilities located at the CTF, gathering stations, and field sites (wellsites, manifolds, and

pump stations) from the CTF control room. The field information for wellsites, pump stations,

and manifolds will be relayed via telecommunications through the CTF Control System to the

gathering stations. Packaged equipment PLCs will either be connected directly to the Control

System via serial link or interfaced via the Telecommunications System.

Each gathering station Control System will communicate with the CTF Control System via

redundant digital microwave links. Wellsites, manifolds, and pump stations will be polled using

digital VHF (very high frequency) radios.

4.1.9 Power System Facilities

This section provides an overview and the associated details pertaining to the electrical power

generation, transmission, and distribution system.

4.1.9.1 Overview

A power plant of 120 megawatts (MW) capacity will be installed to meet a peak electric power

demand of approximately 105 MW. Sixty-hertz electric power will be generated at the OC power

station and transmitted by high voltage pole line to the Kom, Miandoum, and Bolobo fields

facilities and wells. Approximately 70 percent of the power demand is for the well ESPs.

The power system will be dedicated and isolated because no existing power system is available

in the Doba Basin. The power system is designed to the necessary reliability to meet oil

production needs. Waste heat recovery from power generation will supply process heat to the

CTF and Kom gathering station.

4.1.9.2 Power Generation

Four combustion gas turbine generators (30 MW each, site rated) will be installed to meet the oil

field development area and PS No. 1 power requirements. During most of the projects life,

there will be at least one spare generator since the power demand in the oil field development

area is estimated to be below 90 MW However during years four through seven all four units


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PROJECT DESCRIPTION


system, fuel selection and forwarding skids, and diesel and treated crude storage tanks. The

fuel treatment equipment will be part of the CTF operation.

4.1.9.3 Fuel Systems

Combustion turbine generators (CTGs) will be operated on Miandoum crude, Kom LK gas, and

other associated gas. The turbines are fueled on either gas, crude or a combination of both.

The Miandoum crude will be treated by centrifuging, filtering, and heating before injection into

the turbines. Natural gas availability is limited; however, all available gas will be consumed in

the turbines. The CTG will also be capable of operating on #2 diesel fuel oil. Diesel fuel will beused during plant commissioning, and to start and stop the units.

4.1.9.4 Prime Mover Auxiliaries

All turbines will be supplied from the following common equipment:

Fuel gas filtration and preheat package

Diesel oil storage

Crude oil storage, preheat, and treatment

Instrument air system.

A black-start diesel engine-driven generator for starting under blackout conditions will be

required. This generator will provide the necessary station service and engine auxiliary power to

allow one generator set to be started.

4.1.9.5 Power Plant Building

The power plant will include a 33-kilovolt (kV) switchgear building and a combined control room

and electrical equipment building. The latter building will include the power system central

control room. The gas turbine generator sets will be housed in individual, free-standing factory

enclosures with a fire detection and suppression system.

4.1.9.6 Control

The power plant will be designed to operate with minimum operator intervention. One full-time

l t t ill b l t d t th l t t l Th l t t l


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plant. The power plant main operator panel will control and monitor auxiliaries common to all

generator sets. The power plant control room will house the electrical distribution control panel

that remotely controls and monitors 66-kV and 33-kV switching operations at the five fielddistribution substations. Adjacent to every generator set, there will be a standard,

manufacturer-supplied local generator set control panel.

4.1.9.7 Power Plant Electrical

Generators will be connected to the buswork in a manner that allows a high degree of flexibility

for generator, bus, and load switching. Generators will be bussed together through generatorstep-up transformers. Auxiliaries for each generator will be supplied from a central power plant,

service motor-control center located near the generator set supplied from the power plant

station service bus and with alternate supply from the black-start system.

4.1.9.8 Power Transmission System

Electric power will be transmitted from the power plant to the field locations as follows:

To 66-kV / 33-kV field distribution substations at Miandoum (M-1) and Bolobo (BP-1) by 66-

kV overhead transmission lines

To 33-kV field distribution substations at Kom (KP-1 and KP-2) by 33-kV overhead

transmission lines.

The overhead power lines will be designed for the high incidence of lightning in the area.Transmission lines will share a common utility corridor with the pipelines when possible.

4.1.9.9 Power Distribution System

Overhead distribution feeders (33-kV) will supply power from each of the five field distribution

substations to the producing wells. Each feeder will supply between 6 to 12 ESPs. For each

ESP, the 33-kV overhead feeder will be tapped. The tap will be terminated approximately 50 m

from the well at a pole-mounted, fused disconnect. Other voltages for operating wellhead

equipment, such as 24-volt direct current for the ESP-PLC, will be made available by

transforming from the ESP supply lines.

4.1.9.10 Facility Power Distribution


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Switchgear and motor control centers will be in substation buildings. All power transformers will

be oil-filled and located outdoors.

4.1.10 Operations Center Infrastructure

The field Operations Center (OC) infrastructure facilities will include the following:

Community

Airfield

Utilities (see Section 4.1.7)

OC plant buildings

Primary and secondary field roads.

4.1.10.1 Community

The community will be located within the OC as shown in Figure 4-3. It will provide the followingfacilities:

Living quarters to accommodate 200 single-status people

Cafeteria and kitchen to serve midday meals for 385 people (185 day workers and 200

residents) and morning and evening meals for the 200 residents

Recreation center and outdoor sports facilities for the residents

Accommodations for support services staff and equipment

Laundry facilities to wash linens and personal clothing of residents and work clothes of all

employees

Fire protection for the community including the following:

- Hydrants- Hose reels

- Sprinkler systems

- Smoke detectors


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4.1.10.2 Airfield

An airfield will be constructed to provide air transport during construction and subsequentoperations. This airfield will provide for freight transport, personnel rotation, medical emergency

evacuation, and total emergency evacuation of expatriate employees.

The airfield will be a completely fenced, private facility and will operate during daylight hours

under visual flight rules. The runway bearing surface will permit operation throughout the entire

year. Its length will be approximately 3,200 m allowing material transportation by an

Anotonov 124 aircraft. The airfield will be located southeast of the community as shown inFigure 4-3.

4.1.10.3 OC Plant Buildings

The OC plant will have the following major buildings:

Administration Building

CTF Control Center and Motor Control Center Buildings

Mechanical, Electrical, and Instrumentation Maintenance Building

General Warehouse

Training Center and Vehicle Maintenance Building

ESP Maintenance Building

Power Plant Building

Guard House.

4.1.10.4 Roadways

An all-weather laterite road will connect the OC facilities to the Moundou-Sahr road at Bbdjia.

The OC facilities will in turn be connected to field facilities and wellsites by upgraded existing

laterite roads or new laterite roads. The road connecting the airfield, the community, and the OC

plant will have an asphalt surface on a laterite base. Major roads within the OC plant and

gathering stations will also have an asphalt surface on a laterite base.


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PROJECT DESCRIPTION


gathering station, bringing them close to mechanical completion. The majority of the interfield

pipelines, manifolds, and overhead electrical power lines will be installed during this time. Work

in the final six months will shift to precommissioning activities to prepare the facilities for start-up. Throughout the construction phase, wells will continue to be drilled and civil work

associated with drill pad and road construction will be ongoing. Forty percent of the drilling will

be completed at first oil.

4.2.1 Site Preparation

Site preparation includes clearing and grubbing, contouring, and laying down a laterite base toseal underlying soils, provide for water runoff, and establish a stable platform for construction.

Depending on subsoil conditions, excavation and recompaction will be required where large

tanks and heavy equipment are located.

Erosion control features will include localized silt fences and drainage course impediments to

slow runoff and contain sediment prior to reaching the sediment basins. Temporary drainage

channels will direct runoff to sediment basins to be used where possible for dust control.

Topsoil from the clearing and grubbing operations will be stockpiled for later use. The grading

operations and extent of the site preparation effort will be dependent upon the rainy season.

Excavation and other earthmoving activities will be kept to a minimum during the rainy season.

Borrow sources for construction materials, such as sand and gravel, will be selectively

developed to minimize the number of disturbed areas. Where possible, local businesses will

supply and transport materials to the job site.

During construction, old exploration infrastructure, well pads, and borrow pits will be

rehabilitated. Laterite from abandoned well pads or airstrips will be reused in developing new

facilities to reduce the number of new borrow pits. Topsoil stripped from clearing and grubbing

operations will be used for rehabilitation of old facility sites and borrow pits. Excess topsoil

stored for more than six months will be fortified with fertilizers, soil enhancers, or other organic

materials to maintain viability.

4.2.2 Roads

Upgrading of existing roads and construction of new roads will conform to a typical roadway

cross section (Figure 4-4). Topsoil will be stockpiled and erosion control features will be


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PROJECT DESCRIPTION


for the operations staff. Also included in these initial facilities will be the construction material

laydown area and establishment of a fuel storage facility. Rather than using trailers for a

construction camp, preferentially buildings will be constructed using local materials. The initialphase of activity will also include construction of a sanitary landfill as part of the overall waste

management program.

4.2.4 Plant and Pipeline Construction

After completion of site preparation activities, underground utilities and flowline work will begin

with trenching and establishment of a pipe fabrication shop. Along with this underground work,foundation excavations and concrete pours will be completed. Field pipeline activities will follow

the same general construction techniques used for the Transportation System pipeline. Tank,

structural steel, and building construction will follow foundation preparation.

Setting of mechanical and electrical equipment such as turbine generators, pumps, vessels,

and heat exchangers will commence once quality checks are complete for concrete and

structural steel work. Plant piping, electrical, and instrumentation work will conclude themechanical completion of the facilities. Final pre-commissioning activities, such as instrument

calibration, equipment alignment, and startup verification of equipment will then take place.

4.2.5 Construction Staffing

The construction contractors will determine the size of the construction staff used for the project.

The anticipated construction staff for the oil field development area will consist of approximately

2,000 Chadian nationals and 1,000 expatriates during the peak construction period. Chadians

generally will provide their own housing, with the construction contractor providing transportation

from collection points in the villages. For expatriates, the existing Kom drilling camp will be

utilized prior to completion of the main construction camp. This camp will continue to be used

by drilling personnel during the development phase. Most expatriates will be housed in the

main construction camp at Kom which will house 800 to 1,000 people during peak occupancy.


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Section TOC


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SCHEMATIC FLOW DIAGRAMFOR

OIL PRODUCTION AND TREATMENT

MIANDOUMPRODUCING

WELLS

KOMPRODUCING

WELLS

BOLOBO

WELLSPRODUCING

KOM FIELDMANIFOLDS

ANDFIELD PUMP

STATIONS

BOLOBOFIELD

MANIFOLDS

MIANDOUMFIELD

MANIFOLDS

STATION

KOMGATHERING

BOLOBO

STATIONFIELD PUMP

MIANDOUM

STATIONGATHERING

MIANDOUMPRODUCED WATER

REINJECTION WELLS

KOMPRODUCED WATER

REINJECTION WELLS

CENTRALTREATINGFACILITY

No. 1

PUMP STATION

99% OIL

99% OIL

PIPELINE


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0 1 2

Approximate Scale in Kilometers

OPERATIONS CENTER

COMPONENTS

N

S

EW Kom Gathering StationCentral Treating FacilityPower PlantPump Station No. 1Administrative OfficesClinicOperations / Maintenance Center

Airfield(3200 meter airstrip)

Pipeline

Community

FIGURE 4-3

DM

GROGRO P

D & MAMES OOREDD O O OP C POR R

Chad Export Project

Section TOC


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TYPICAL

OIL FIELD DEVELOPMENT AREAROADWAY CROSS SECTION

Not to Scale

2.50 m3.00 m

2.50 m3.00 m1.00 m 1.50 m 1.00 m

5.00 mVegetation Clearing

0.50 m 0.50 m

Earthmoving Level

NOTES

1. Laterite thickness variable from 15-30 cm.

2. Road widths reduced through villages as required.

3. Regional roads inside oil field development area to include pedestrian path (not shown).

4. Ditch size/slope variable and sized to accommodate water level.

3%3%

1 13 22 3

1 1

FIGURE 4-4

DM

GROGRO P

D & MAMES OOREDD O O OP C POR R

Chad Export Project

(Field Roads)(Regional Roads)

Next ChapterSection TOC

Oilfield Development

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