影响煤层气水平井井壁稳定性的地质因素分析

Analysis of geologic factors affecting wellbore stability of CBM horizontal wells

杨健 倪元勇 王生维 秦义 刘伟 胡奇

YANG Jian NI Yuanyong WANG Shengwei QIN Yi LIU Wei HU Qi

中国地质大学武汉，湖北武汉　430074 国家知识产权局专利局机械部，北京　100088 华北油田公司钻采部，河北任丘　062550 华北油田公司采油工程研究院，河北任丘　062550

China University of Geosciences, Wuhan 430074, China Machinery Department of Patent Bureau, State Intellectual Property Office, Beijing 100088, China Drilling & Production Department of Huabei Oilfield Company, CNPC, Renqiu 062550, China Research Institute of Oil Production Technology, Huabei Oilfield Company, Renqiu 062550, China

通过煤矿井下实测，直观描述了煤层水平孔的失稳、垮塌特征，统计分析了煤层水平孔稳定性与埋深、煤坚固性之间的关系，并应用晋城地区现有煤层气水平井的实际排采数据进行了对比分析。认识到影响煤层气水平井井壁稳定性的主要地质因素是：小微构造、地应力、埋藏深度，其中小微构造导致水平井眼易穿过构造软煤区，地应力、埋藏深度会增加井壁的受力导致井壁失稳垮塌。研究结果为从地质方面预防井壁失稳提供了理论依据。

This paper intuitively describes the features of instability and collapse of coalbed horizontal wells by downhole measurement, analyzes the relation between the coalbed horizontal well stability and burial depth and coal sturdiness, and compares and analyzes the actual drainage data of the available CBM horizontal wells in Jincheng District. This paper identifies the main geologic factors affecting the CBM horizontal well stability as below: small and micro structures, ground stress and burial depth. The small and micro structures cause the horizontal hole to easily penetrate the soft coalbed, and ground stress and burial depth may increase the stress on the well wall and hence cause wellbore instability and collapse. The conclusions in this paper provide theoretical basis for preventing wellbore instability from geology.

10.13639/j.odpt.2015.05.002