Bokor

Bokor Oil Field Profile

Location and Geology

The Bokor oil field is located approximately 45 km offshore Lutong, Sarawak, in the Malaysian portion of the South China Sea, within the Baram Delta area. The field is situated in shallow waters with a depth of about 67 meters (220 feet).

Discovery and Production History

The Bokor oil field was discovered in the 1970s. It began producing its first oil in 1982. The field has been operated by Petronas Carigali Sdn Bhd, a subsidiary of Petroliam Nasional Berhad (PETRONAS), with Sarawak Shell Berhad as a joint owner.

Field Characteristics

• The field is characterized by stacked sand-shale sequences.
• Oil gravities range from about 20° API in the shallower reservoirs to 37° API in the deeper reservoirs.
• Initially, oil recovery was achieved through a conventional gas lift process. However, as production declined and the supply of lift gas from an adjacent field decreased, the field's water cut increased.

Redevelopment and Enhanced Oil Recovery (EOR)

To improve production and reserves recovery, the Bokor Project Management Team (BPMT), a gain-share alliance between Petronas and Schlumberger, initiated several redevelopment phases.

Phase 3 Redevelopment

• This phase involves the installation of three new wellhead platforms (BOKOR-D, BOKOR-E, and BOKOR-F) and a new central processing platform (CPP).
• The new wells are equipped with electrical submersible pumps (ESPs) for enhanced oil recovery. These ESPs also include abrasion-resistant zirconium (ARZ) bearings, check valves over the pump, and mixed flow stages to protect against wear and tear and solids fallback during shut-ins.

Infrastructure

• The field currently has three solar-powered drilling platforms: BODP-A, BODP-B, and BODP-C.
• There is also a satellite platform named BOK-A, powered by a 400 kW generator, connected to BODP-C by a subsea power cable. A transformer on BOK-A steps up the voltage to 6.6 kV to reduce subsea transmission losses.

Contractors and Service Providers

• Brooke Dockyard and Engineering Works: Provided front-end engineering design (FEED) and engineering, procurement, construction, installation, and commissioning (EPCIC) services for the topsides and substructures of the new wellhead platforms.
• Malaysia Marine and Heavy Engineering (MMHE): Received a contract for the EPCIC of the central processing platform (CPP). MMHE subcontracted Boskalis for the transportation and float-over installation of the CPP topside.
• Jurunature: Contracted as the fabrication partner for the project. Labuan Shipyard & Engineering provided yard services for helideck storage and handling of the Bokor CPP.
• Paladon Systems: Supplied 6-inch valve actuators for the project in 2018.
• Berachah Group: Provided FEED and detailed engineering design services for the Bokor Phase-3 redevelopment project.

Production and Reserves

• The Bokor field has recovered approximately 78.41% of its total recoverable reserves. Peak production was around 30,000 barrels per day (bpd) of crude oil and condensate in 1990.
• The field is expected to continue production until it reaches its economic limit in 2044, currently accounting for about 2% of Malaysia's daily oil output.
• Remaining recoverable reserves are estimated at 87.83 million barrels of oil equivalent (Mmboe), which is about 0.20% of the total remaining reserves of producing heavy oil fields globally.

Artificial Lift and Performance Improvement

• In 2007, BPMT reviewed and implemented alternative artificial lift technologies. Three ESPs were installed in 2009, which were expected to add approximately 2.8 million barrels of incremental oil production over 10 years without a significant increase in water cut.
• The use of ESPs has improved field performance by freeing up lift gas for use in other wells and mitigating lost production during ESP downtime through a contingency gas lift system.

Project Timeline

• Construction works on the Bokor Phase-3 redevelopment project began in 2018, with completion initially expected in 2020. However, specific completion dates for all aspects of the project may have varied.