4.0 OIL FIELD DEVELOPMENT AREA

Transcription

1 CHAD EXPORT PROJECT UPPORTING DOCUMENT - VOLUME OIL FIELD DEVELOPMENT AREA Oil, water, and limited gas will be produced in each of the Komé, Miandoum, and Bolobo fields. In the Komé 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 preconstruction 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 preconstruction customary land users. 4.1 FACILITIE DECRIPTION Well ite / 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 Komé LK wells will be gathered separately 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 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. Field manifolds (except the manifolds located at the gathering stations and field pump stations) will be located adjacent to a producing well. There will be 10 field manifolds within the Komé UK field, 3 within the Miandoum field, and 3 within the Bolobo field. The design of the test manifolds will be based on the use of rotary selector valves (RVs). RVs are multiport diversion valves that allow one of several inlet well streams to be diverted to a well test skid. Copy of PD English Text doc 4-1 May 1999

2 UPPORTING DOCUMENT - 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 Komé and Bolobo Field Pump tations For the wells and manifolds located at the southern and northern ends of the Komé field, two field pump stations (KP-1 and KP-2) will pump the production fluids to the Komé 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 a multiphase mixture of oil, water, and gas using rotary screw pumps. torage 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 Komé gathering station for processing. No field pump station will be required in the Miandoum field Gathering tations Two gathering stations will be constructed, one in Komé and one in Miandoum. The gathering stations will receive production from individual wells via field manifolds and field pump stations. The Komé field gathering station will also receive production from the Bolobo field pump station. The function of a gathering station is to: eparate 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 Free-Water Knock-Out At the Komé gathering station, tank separation will be used for free-water knock-out (FWKO). Two stages of separation are required. The first stage will be unheated and reduce the incoming emulsion watercut to 40 percent. The second stage will be heated and dewater the 40 percent watercut emulsion down to 10 percent. The heat source will be waste heat recovered from gas turbine exhausts at the power plant. Heat input to the process will include a produced water recirculation loop heating the fluids from 60 C to 71C. At the Miandoum gathering May Copy of PD English Text doc

3 CHAD EXPORT PROJECT UPPORTING DOCUMENT - VOLUME 1 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 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 Komé gathering station, 10 percent watercut emulsion will gravity-flow from the second stage FWKO tanks to the CTF emulsion inlet tanks 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 and Handling At the Komé 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. and and other solids carried to the produced water system will be removed in the skim tanks 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 Komé 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 Komé gathering station, Komé and Bolobo produced gas from the FWKO system will be recovered by vapor recovery units for fuel Utility ystems At each gathering station, the following utility systems will be provided: Potable and Utility Water Copy of PD English Text doc 4-3 May 1999

4 UPPORTING DOCUMENT - VOLUME 1 CHAD EXPORT PROJECT Pressure Relief and Flare Instrument and Utility Air Fuel Gas Chemical (Demulsifier) torage and Injection Hot Water Process Heating (Komé Gathering tation and CTF) Electric Power Open Drain ystem Water Injection ystem 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 Komé 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 disposal wells 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 Komé field, the water disposal system will consist of a water injection trunkline and lateral system from the Komé gathering station out to the disposal wells. For Miandoum, individual injection lines from the gathering station will run to each well Operations Center The Operations Center (OC), located in the Komé field, will include the following, as shown in Figure 4-3: Komé Gathering tation Central Treating Facility Power Plant Pump tation No. 1 (P No.1) Community Airfield Operations upport Facilities. The location of the OC is directed by the following criteria: Have high ground elevation, away from potential flood zones May Copy of PD English Text doc

5 CHAD EXPORT PROJECT UPPORTING DOCUMENT - VOLUME 1 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 Central Treating Facility The CTF will receive emulsion and produced gas from the Komé and Miandoum gathering stations, as well as produced oil and gas from the Komé 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 (B&W) specification eparate the Komé 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 B&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. Temperature limits for treated oil to pipeline P No.1 will be at a 74 C (165 0 F) maximum. All cooling of the treated emulsion will be accomplished by cross-exchange with inlet emulsion from the field. Copy of PD English Text doc 4-5 May 1999

6 UPPORTING DOCUMENT - VOLUME 1 CHAD EXPORT PROJECT hort-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 P No. 1 for storage. The B&W content of the treated oil flowing to P 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 Komé 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 torage and Injection Fuel ystems (Oil and Gas) Process and Open Drain ystem anitary ewer Hot Water Heating ystem Electric Power Diesel Crude Oil Topping Plant Waste Incinerator (located in Komé field) Landfill remote from CTF Automation The Automation ystem 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. Control of the CTF and the field facilities to the wellhead level will be performed from a single control room in the CTF. econdary control rooms will be included in the gathering stations, from which each gathering station and facilities producing to that station are controlled. Typically, secondary control rooms will not be staffed. Control of the power plant at the Operations Center (OC) will be performed from the power plant control room (PPCR). Each May Copy of PD English Text doc

7 CHAD EXPORT PROJECT UPPORTING DOCUMENT - VOLUME 1 location will have a standalone, programmable logic controller (PLC) based system for emergency shutdown. The Automation and Control ystem 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 ystem to the gathering stations. Packaged equipment PLCs will either be connected directly to the Control ystem via serial link or interfaced via the Telecommunications ystem. Each gathering station Control ystem will communicate with the CTF Control ystem via redundant digital microwave links. Wellsites, manifolds, and pump stations will be polled using digital VHF (very high frequency) radios Power ystem Facilities This section provides an overview and the associated details pertaining to the electrical power generation, transmission, and distribution system Overview A power plant of 120 megawatts (MW) capacity will be installed to meet a peak electric power demand of approximately 105 MW. ixty-hertz electric power will be generated at the OC power station and transmitted by high voltage pole line to the Komé, Miandoum, and Bolobo fields facilities and wells. Approximately 70 percent of the power demand is for the well EPs. 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 Komé gathering station Power Generation Four combustion gas turbine generators (30 MW each, site rated) will be installed to meet the oil field development area and P No. 1 power requirements. During most of the project s 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 will be required. Due to the limited availability of natural gas, a maximum of two units will run on natural gas and the remaining units on crude oil. Waste heat will be recovered from the gas turbine exhausts using a hot water closed-loop system. The utilities and auxiliaries will include a black-start generator, a crude fuel treatment Copy of PD English Text doc 4-7 May 1999

8 UPPORTING DOCUMENT - VOLUME 1 CHAD EXPORT PROJECT system, fuel selection and forwarding skids, and diesel and treated crude storage tanks. The fuel treatment equipment will be part of the CTF operation Fuel ystems Combustion turbine generators (CTGs) will be operated on Miandoum crude, Komé 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 be used during plant commissioning, and to start and stop the units 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 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 Control The power plant will be designed to operate with minimum operator intervention. One full-time power plant operator will be located at the power plant control room. The power plant control system will be interconnected to the CTF Control ystem to permit exchange of operating data to the CTF plant operator in the CTF control room. Control of the power plant will be possible only from the power plant control room. The power plant main operator panel will be located in the power plant control room and incorporate terminals for monitoring, controlling, and generating reports relating to the power May Copy of PD English Text doc

9 CHAD EXPORT PROJECT UPPORTING DOCUMENT - VOLUME 1 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 field distribution substations. Adjacent to every generator set, there will be a standard, manufacturer-supplied local generator set control panel 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 generator step-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 Power Transmission ystem 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 Komé (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 Power Distribution ystem 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 EPs. For each EP, 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 EP-PLC, will be made available by transforming from the EP supply lines Facility Power Distribution At the gathering stations and field pump stations, 33 kv will be supplied from the field distribution substations to other substations where transformation to 3.3 kv and 480 volts (V) will be performed to meet site loads. At the CTF and P No. 1, 33 kv will be supplied from the power plant via 33-kV cables in cable trays to substations where transformation to 3.3 kv and 480 V will be performed. Onsite loads will be supplied by aboveground cables in cable trays. Copy of PD English Text doc 4-9 May 1999

10 UPPORTING DOCUMENT - VOLUME 1 CHAD EXPORT PROJECT witchgear and motor control centers will be in substation buildings. All power transformers will be oil-filled and located outdoors Operations Center Infrastructure The field Operations Center (OC) infrastructure facilities will include the following: Community Airfield Utilities (see ection 4.1.7) OC plant buildings Primary and secondary field roads Community The community will be located within the OC as shown in Figure 4-3. It will provide the following facilities: 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 - prinkler systems - moke detectors - Fire detectors - Alarms - Fire extinguishers. treet lighting to illuminate the streets and perimeter road for safety and security. May Copy of PD English Text doc

11 CHAD EXPORT PROJECT UPPORTING DOCUMENT - VOLUME Airfield An airfield will be constructed to provide air transport during construction and subsequent operations. 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 in Figure 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 EP Maintenance Building Power Plant Building Guard House Roadways An all-weather laterite road will connect the OC facilities to the Moundou-ahr road at Bébédjia. 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. 4.2 CONTRUCTION PHAE Construction of the oil field development facilities will span a period of approximately 2.5 years. The first year will focus on preparation of the major sites including building the initial well pads and roads; building the construction camp; starting site preparation of the airfield; and site/foundation work for the production facilities. During the second year the construction effort will center on the major plants including the CTF, power plant, P No. 1 and Miandoum Copy of PD English Text doc 4-11 May 1999

12 UPPORTING DOCUMENT - VOLUME 1 CHAD EXPORT PROJECT 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 startup. 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 ite Preparation ite preparation includes clearing and grubbing, contouring, and laying down a laterite base to seal 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 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 incorporated. Borrow areas for laterite will minimize surface area disturbed and be reclaimed after use Construction Camp and Landfill The initial activities will include the construction of the Komé camp facilities, related workshops, and temporary offices. A portion of this construction camp will serve as the permanent housing May Copy of PD English Text doc

13 CHAD EXPORT PROJECT UPPORTING DOCUMENT - VOLUME 1 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 initial phase of activity will also include construction of a sanitary landfill as part of the overall waste management program 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 ystem pipeline. Tank, structural steel, and building construction will follow foundation preparation. etting 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 the mechanical completion of the facilities. Final pre-commissioning activities, such as instrument calibration, equipment alignment, and startup verification of equipment will then take place Construction taffing 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 Komé 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 Komé which will house 800 to 1,000 people during peak occupancy. Copy of PD English Text doc 4-13 May 1999

14 N Location Map Cameroon Bekia Existing Airstrip M-1 BP-1 # C.A.R. Chad MIANDOUM FIELD To Miandoum Kayra Bolobo PIPELINE Bedia Bella BOLOBO FIELD # Komé Nya Mbanga Begada Existing Existing Drilling Camp Airstrip # # N Loulé KP-2 Béro # KOMÉ FIELD # Central Treating Facilities # KP Kilometers K-1 # Community Airfield LEGEND #Y Proposed Well Existing Well Field Manifold Pump tation & Manifold Gathering tation & Manifold Not all proposed wells shown Export Pipeline Oil Field Outline Road River # Village/Town Chad Export Project OIL FIELD DEVELOPMENT AREA FIGURE 4-1

15 MIANDOUM PRODUCING WELL MIANDOUM FIELD MANIFOLD MIANDOUM GATHERING TATION WATER 90% OIL 10% WATER MIANDOUM PRODUCED WATER REINJECTION WELL BOLOBO PRODUCING WELL BOLOBO FIELD MANIFOLD BOLOBO FIELD PUMP TATION KOMÉ PRODUCING WELL KOMÉ FIELD MANIFOLD AND FIELD PUMP TATION KOMÉ GATHERING TATION WATER 90% OIL 10% WATER KOMÉ PRODUCED WATER REINJECTION WELL CENTRAL TREATING FACILITY WATER <1% BAIC EDIMENT AND WATER 99% OIL PUMP TATION No. 1 <1% BAIC EDIMENT AND WATER 99% OIL PIPELINE LEGEND WATER Chad Export Project CHEMATIC FLOW DIAGRAM FOR OIL PRODUCTION AND TREATMENT OIL D M GRO P D AME & MOORE D OOR RO PCO P FIGURE 4-2

16 N W E Komé Gathering tation Central Treating Facility Power Plant Pump tation No. 1 Administrative Offices Clinic Operations / Maintenance Center Community Airfield (3200 meter airstrip) Pipeline Approximate cale in Kilometers Chad Export Project OPERATION CENTER COMPONENT D M GRO P D AME & MOORE D OOR RO PCO P FIGURE 4-3

17 5.00 m Vegetation Clearing 1.00 m 2.50 m 3.00 m (Field Roads) (Regional Roads) 2.50 m 3.00 m 1.50 m 1.00 m 3% 3% Earthmoving Level m 0.50 m NOTE 1. Laterite thickness variable from 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. Not to cale Chad Export Project D TYPICAL OIL FIELD DEVELOPMENT AREA ROADWAY CRO ECTION M GRO P D AME & MOORE D OOR RO PCO P FIGURE 4-4