Research on the New Prediction Method of Shallow Gas Channeling Risk for Bohai Oilfield
Author of the article:Li Jin1,2, Chang Peimin3 , Zhang Qilong1,2 , Liu Peng1,2 , Liu Hailong1,2 , Guo Minglong4 , Zeng Xuyang4
Author's Workplace：1.Tianjin Branch of CNOOC Ltd., Tianjin, 300459, China; 2. State Key Laboratory of Offshore Oil Exploitation, Tianjin, 300459, China; 3.PetroChina Southwest Oil & Gasfield Company, Chengdu, Sichuan, 610051, China; 4. Engineering Technology Company of CNOOC Energy Technology & Services Limited, Tianjin,300459, China
Key Words： Gas channeling; Cement sheath integrity; Shallow gas; Cementing; Bohai oilfield
Abstract：
The shallow gas channeling in offshore oil field causes the annulus
pressure of surface casing and riser, which not only seriously threatens the
safety of offshore oil platform operation, but also may cause marine
environmental pollution and shorten the life of oil and gas wells.In order to accurately predict
the risk of shallow gas channeling in offshore oil fields and effectively solve
the issue of annulus pressure in shallow gas wells,an analysis model of the impact
of cement sheath shrinkage on the integrity is established based on the
analysis of the characteristics and causes of shallow gas channeling in
offshore oil fields.A
new method of shallow gas channeling risk prediction is formed, whichis used to predict and analyze
the risk of shallow gas channeling in well E8 of XX oilfield, and the results
are consistent with the construction results.This method can effectively consider the effect of
volume shrinkage on the integrity of cement sheath,predict the risk of shallow gas
channeling,and
provide a basis for the optimization design of cement slurry performance and
the avoidance of shallow gas channeling. This method has broad application
prospects for Bohai oilfield shallow gas cementing.