苏里格气田多层理泥岩井壁坍塌机理分析  

Analysis of collapse mechanism of multi-bedding mudstone wellbore in Sulige gas field

作　　者：衣方宇 王琦 杨杰 朱子阳 王昶皓 庞皓安 Yi Fangyu;Wang Qi;Yang Jie;Zhu Ziyang;Wang Changhao;Pang Hao′an(Sulige Gas Field Branch,CNPC Great Wall Drilling Engineering Co.,Ltd.,Ordos 017300,China;National Engineering Research Center for Oil and Gas Drilling and Completion Technology,Northeast Petroleum University,Daqing 163318,China)

机构地区：[1]中国石油集团长城钻探工程有限公司苏里格气田分公司,内蒙古鄂尔多斯017300 [2]东北石油大学油气钻完井技术国家工程研究中心,黑龙江大庆163318

出　　处：《能源与环保》2024年第5期97-104,共8页CHINA ENERGY AND ENVIRONMENTAL PROTECTION

基　　金：黑龙江省自然科学基金项目(LH2022E027)。

摘　　要：井壁失稳是制约苏里格气田泥岩地层低成本钻进长井段水平井的首要技术难题。在评价泥岩矿物组分、层理发育及力学特性的基础上,综合理论分析、实验评价以及数值仿真模拟等手段,研究了多层理泥岩在流体作用下的力学行为及破坏失稳特征。由于苏里格气田山西组泥岩层理和微裂缝的存在,岩石在钻井液侵入后将会发生强度劣化。泥岩弱面的导流能力远高于岩石基质,钻井液沿弱面渗透到地层中,会直接导致泥岩结构面强度的下降,易发生井壁坍塌。对苏里格气田实钻过程中的泥岩地层坍塌压力进行了计算,将井斜角、方位角和钻井液浸泡时间分别代入岩石力学参数劣化模型,给出了目的层段安全钻井液密度,对实现苏里格气田多层理泥岩井壁稳定和安全钻井具有重要的指导意义。Wellbore instability is the primary technical problem restricting low-cost drilling of mudstone formations in Sulige gas field into horizontal wells in long well sections.Based on the evaluation of the mineral composition,bedding development and mechanical characteristics of mudstone,this paper combined theoretical analysis,experimental evaluation and numerical simulation to study the mechanical behavior and failure instability characteristics of multi-bedding mudstone under fluid action.Due to the existence of mudstone bedding and microfractures in Shanxi Formation of Sulige gas field,the strength of the rock can deteriorate after the drilling fluid intrusion.The diversion capacity of the weak surface of mudstone was much higher than that of rock matrix,and drilling fluid penetrated into the formation along the weak surface,which can directly lead to the decrease of the strength of the mudstone structural surface and prone to collapse of the wellbore.The collapse pressure of mudstone formation in the actual drilling process of Sulige gas field was calculated,and the well inclination,azimuth angle and drilling fluid immersion time were substituted into the rock mechanical parameter deterioration model,which gave the safe drilling fluid density of the target layer,which has important guiding significance for realizing the stability and safe drilling of multi-bedding mudstone wellbores in Sulige gas field.

关 键 词：井壁失稳 层理发育 泥岩地层 强度劣化 

分 类 号：TE256.1[石油与天然气工程—油气井工程]