一种井漏层位钻前风险预测新方法

A new method predicting pre-drilling risk in lost circulation formation

金衍 卢运虎 李再均

JIN Yan LU Yunhu LI Zaijun

中国石油大学石油工程教育部重点实验室，北京102249 中国石油塔里木油田分公司,新疆库尔勒841000

MOE Key Laboratory of Petroleum Engineering in China University of Petroleum, Beijing 102249, China Tarim Oilfield Company, Korla 841000, China

钻井过程中井漏层位的确定是堵漏成功与否的关键因素，也是复杂地层钻井的难点。为了避免发生井漏和保护油气层，必须准确地找出漏失层位。传统确定漏失层位的方法都是在井漏发生之后根据井漏的各种特性来确定，这样不可避免地导致钻井液漏失和油气层污染。针对该问题，在对油田大量井漏参数进行数学处理和分析的基础上，运用模糊识别数学理论，根据井漏各参数之间存在的模糊关系，确立了欧氏贴近度与井漏程度的关系，建立起漏失层位模糊识别钻前风险预测模型。现场应用结果表明，该模型预测准确，可操作性强，经济成本低。该技术在预测井漏层位风险程度中取得了很好的效果。

To identify lost circulation formation is critical to successfully solve lost circulation problems. It is also a hard nut to crack in drilling complex formations. To prevent lost circulation and protect reservoirs, it is necessary to identify the lost circulation formation. The traditional methods are used to identify according to the properties of lost circulation after it occurs, which inevitably result in loss of drilling fluid and pollution of reservoirs. To solve the problem, based on the mechanical treatment and analysis of a lot of lost circulation parameters acquired from oilfields, using the theory of fuzzy mathematics, according to the relationship among lost circulation parameters, the relationship between lost circulation exent and Euclid approaching extent is determined, as well as a model used to identify lost circulation formation and predict pre-drilling risk is established. Field application shows that the model features in accuracy, good effetiveness, and low cost. The technology has good performance in predicting the risk of lost circulation formation.