渤海中深井复杂地层岩石特性及安全钻井周期研究  

Rock characteristics and safe drilling cycle of complex formation in middle-deep wells in Bohai

作　　者：李磊[1] 杨进[1] 周波 张昌超 邹欣 陈雷[1] 张灿 LI Lei;YANG Jin;ZHOU Bo;ZHANG Changchao;ZOU Xin;CHEN Lei;ZHANG Can(China University of Petroleum,Beijing 102249,China;CNPC Engineering Technology R&D Company Limited,Beijing 102206,China)

机构地区：[1]中国石油大学(北京),北京102249 [2]中国石油集团工程技术研究院有限公司,北京102206

出　　处：《中国海上油气》2022年第3期126-132,共7页China Offshore Oil and Gas

基　　金：国家自然科学基金创新研究群体项目“复杂油气井钻井与完井基础研究(编号:51521063)”部分研究成果。

摘　　要：渤海渤中中深层油气资源是渤海湾增储上产重点领域之一,钻井过程中复杂情况发生率高、钻井周期长等制约了中深层油气资源安全高效规模开发。针对渤中中深井井壁失稳等问题,开展了中上部泥页岩、深部潜山砂砾岩等复杂地层岩石特性研究,结合区域地应力分析,揭示了定向钻进过程中坍塌压力、破裂压力随井斜角、方位角的变化规律,建立了渤中区域中深层钻井安全密度窗口图版;基于钻井液浸入后岩石强度特性实验研究,建立了渤中区域中深井安全钻井周期图版。研究结果表明,渤中区域东营组泥页岩呈现明显的各向异性特征,垂直方向取心的强度显著高于水平方向的强度;随井斜角和方位角变化,潜山组地层破裂压力当量密度在1.84~2.73 g/cm^(3)变化;地层坍塌压力当量密度在1.15~1.40 g/cm^(3)变化;渤中区域风化带附近裸眼段安全钻井周期在15天左右,潜山安全周期在20天左右。本文研究结果对渤中区域中深井钻井设计、施工作业降低复杂情况、保障作业安全具有重要意义。The middle-deep oil and gas resources in the Central area of Bohai(also known as Bozhong area)are one of the key areas of increasing reserves and production in Bohai.However,the high incidence of complex downhole problems during drilling and the long drilling cycle constrain the safe,efficient and large-scale development of middle-deep oil and gas resources.In view of the hole wall instability in medium-deep wells in Bozhong area,the lithology characteristics of complex formation such as mudshale in the middle and upper section and buried hill glutenite in the deep section are studied.According to the analysis of regional in-situ stress,the change law of formation collapse pressure and fracture pressure with well inclination and azimuth in directional drilling is revealed,and the density window template of safe drilling of middle-deep wells in Bozhong area is established;Meanwhile,based on the experimental study of influence of drilling fluid soak on rock strength characteristics,the safe drilling cycle template of middle-deep wells in Bozhong area is established.Study results show that,the mudshale of Dongying Formation in Bozhong area has obvious anisotropic characteristics,and the core strength in vertical direction is significantly higher than that in horizontal direction;with the variation of well deviation and azimuth,the formation fracture pressure of buried hill formation varies from1.84~2.73 g/cm^(3),the equivalent density of formation collapse pressure varies from1.15~1.40 g/cm^(3);the safe drilling cycle of open hole section around the weathered zone of Bozhong area is approximately 15 days,and that around the buried hill is 20 days.The results concluded in this paper are of significant guidance to preparing the drilling program,reducing the complex downhole problems in drilling operation and ensuring the safe operation of middle-deep wells in Bozhong area.

关 键 词：泥页岩 井壁稳定 岩石强度 安全密度窗口 安全钻井周期 

分 类 号：TE21[石油与天然气工程—油气井工程]