CNOOC Ltd. approved a fluid discharge and depressurization plan from operator ConocoPhillips China Inc. regarding oil spill response efforts in Penglai 19-3 oil field in Bohai Bay, and the plan was submitted to the State Oceanic Administration of China.
The government previously halted drilling and production at the field following two incidents in June. Since June 19, less than 1 bbl of oil has been released, ConocoPhillips said, adding that the total volume released is an estimated 700 bbl of oil and 2,589 bbl of mineral oil-based drilling mud.
On June 4, seepage was observed on the seabed along a natural fault near Platform B. Oil and gas bubbles were observed on the surface June 17 near Platform C, 2 miles from the Platform B seep. The bubbles were seen during drilling from the platform (OGJ Online, July 13, 2011).
Cause of the releases remains under investigation. Under the depressurization plan, ConocoPhillips intends to discharge fluids from various locations throughout the reservoir. A sealing plan calls for drilling on six wells to provide additional sealing barriers and to reduce pressure, CNOOC said in a Sept. 12 news release.
The Chinese oil company asked ConocoPhillips to strengthen its monitoring of the dynamic reservoir condition, in particular the reservoir pressure during the fluid discharge and depressurization. ConocoPhillips is expected to report its monitoring results in a timely manner, CNOOC said.
The fluid discharge and depressurization plan is an interim measure to ensure the safety of the field while additional precautionary measures to protect the environment are finalized, ConocoPhillips said.
“This is not a resumption of normal operations,” ConocoPhillips said. “Reservoir fluids must be discharged.”
The discharge will involve oil, natural gas, and water. Withdrawal rates will vary, ConocoPhillips said.
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