Analysis on the nitrogen drilling accident of Well Qionglai 1 (II): Restoration of the accident process and lessons learned

Natural Gas Industry B

Xingyuan Chen¹  Yanping Zhang²  Zengnian Wang²  Sujiang Wu³  Xinhu Wang⁴  Yingfeng Meng⁵ 

[1] CNPC Counseling Center, Beijing 100007, China;CNPC Engineering Technology Company, Beijing 100007, China;CNPC Safety and Environmental Protection Department, Beijing 100007, China;CNPC Tubular Goods Research Institute, Xi'an, Shaanxi 710077, China;State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China;

关键词: Western Sichuan Basin;    Well Qionglai 1;    Fractures;    Tight sandstone gas reservoir;    Nitrogen drilling;    Rock burst and blowout by gas bomb;    Deflagration;    Accident;   

DOI  :  10.1016/j.ngib.2016.03.003

来源: DOAJ

【 摘 要 】

All the important events of the accident of nitrogen drilling of Well Qionglai 1 have been speculated and analyzed in the paper I. In this paper II, based on the investigating information, the well log data and some calculating and simulating results, according to the analysis method of the fault tree of safe engineering, the every possible compositions, their possibilities and time schedule of the events of the accident of Well Qionglai 1 have been analyzed, the implications of the logging data have been revealed, the process of the accident of Well Qionglai 1 has been restored. Some important understandings have been obtained: the objective causes of the accident is the rock burst and the induced events form rock burst, the subjective cause of the accident is that the blooie pipe could not bear the flow burden of the clasts from rock burst and was blocked by the clasts. The blocking of blooie pipe caused high pressure in wellhead, the high pressure made the blooie pipe burst, natural gas came out and flared fire. This paper also thinks that the rock burst in gas drilling in fractured tight sandstone gas zone is objective and not avoidable, but the accidents induced from rock burst can be avoidable by improving the performance of the blooie pipe, wellhead assemblies and drilling tool accessories aiming at the downhole rock burst.

【 授权许可】

Unknown