Chevron’s recently started Lianzi (SEN, 31/23) oil and gas field off the west coast of Africa has employed a direct electrically heated (DEH) flowline system at a new record water depth.
Lianzi, in 900 m water depth, is located in a unitised offshore zone between the Republic of Congo and the Republic of Angola.
It is Chevron’s first operated asset in the Republic of Congo and the first cross-border oil development project offshore Central Africa. The project is expected to produce an average of 40,000 bbl/d of oil.
The field, discovered in 2004, includes a subsea production system and a 43-km DEH flowline system, the first of its kind at this water depth.
The system transports the oil from the field to the Benguela Belize-Lobito Tomboco (BBLT) platform in Angola’s Block 14 and utilises the DEH system to ensure fluid flow under a wide range of conditions.
Nexans supplied the DEH system under a $25 million subcontract with Subsea 7.
The design of the system was developed and qualified for Chevron over a three-year period before inauguration of the project.
The complete DEH system includes a DEH riser cable, an armoured feeder cable, a 43-km long piggyback cable and all associated accessories for connection to the flowline that will connect the Lianzi subsea facilities with the BBLT platform.
The DEH system is designed for both wax and hydrate management.
Nexans has delivered the DEH system at nine out of 10 fields using this technology.
The longest flowline with DEH technology currently in operation is at Statoil’s Tyrihans Field.
“As the first offshore energy development spanning national boundaries in the Central Africa region, Lianzi represents a unique cooperative approach to share offshore resources and may serve as a model for the development of similar cross-border fields between two countries,” said Ali Moshiri, president of Chevron Africa and Latin America Exploration and Production Co.
Chevron is operator of the Lianzi Field and has a 15.75% interest, along with its affiliate Cabinda Gulf Oil Co. Ltd. (15.5%), Total E&P Congo (26.75%), Angola Block 14 BV (10%), Eni (10%), Sonangol (10%), SNPC (7.5%) and GALP (4.5%).
Chevron Corp., Exxon Mobil Corp. and Royal Dutch Shell Plc, among other firms in Mexico’s Association of Hydrocarbon Companies (Amexhi), say they have met output targets and investment pledges worth hundreds of millions of dollars in the initial phases of their contracts.
Longer laterals and wider spacing are among the trends being seen, expert says.
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