Risk analysis of extended reach wells in the Liuhua Oilfield, South China Sea, based on comprehensiv

• 作 者: Zhang Hui Gao Deli Hao Zhiwei
• 机 构: MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China
• 出 处: 石油科学（英文版）
• 发表日期: 2009年2期
• 关键词: Extended reach well risk analysis comprehensive fuzzy evaluation weight value

Drilling engineering has great uncertainty and it always involves huge investment and high risk.Risk analysis of extended reach drilling (ERD) is very important to prevent complex failures and to improve drilling efficiency.Nowadays there are few reports on how to analyze quantitatively the drilling risk for extended reach wells (ERWs).Based on the fuzzy set theory, a comprehensive fuzzy evaluation model for analyzing risks of ERD is proposed in this paper.Well B6ERW07 is a planned 8,000-meter ERW with a high ratio of horizontal displacement (HD) to vertical depth (VD) in the Liuhua Oilfield, the South China Sea, China.On the basis of the evaluation model developed in this study, the risk for drilling Well B6ERW07 was evaluated before drilling.The evaluation result shows that the success rate of drilling this well is predicted to be 51.9%, providing important rational and scientific information for the decision-makers.