南海莺–琼盆地复杂地层套管–井眼间隙优化  

Optimization of the Casing-Wellbore Gap in Complex Strata of the Ying-Qiong Basin, South China Sea

作　　者：巨然 管志川[1] 黄熠 罗鸣 李文拓 邓文彪 JU Ran;GUAN Zhichuan;HUANG Yi;LUO Ming;LI Wentuo;DENG Wenbiao(School of Petroleum Engineering,China University of Petroleum(Huadong),Qingdao,Shandong,266580,China;Zhanjiang Branch,CNOOC(China)Co.,Ltd.,Zhanjiang,Guangdong,524057,China)

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580 [2]中海石油(中国)有限公司湛江分公司,广东湛江524057

出　　处：《石油钻探技术》2019年第1期32-36,共5页Petroleum Drilling Techniques

基　　金："十三五"中国海洋石油总公司科技重大项目"莺琼盆地高温高压钻井关键技术研究"(编号:CNOOC-KJ135ZDXM24LTDZJ01)资助

摘　　要：南海莺–琼盆地地质构造复杂,存在高温高压地层,钻井液安全密度窗口窄,为预防下套管作业过程中产生的波动压力可能诱发的井漏、溢流甚至井喷等井下故障,在充分调研南海莺–琼盆地常用井身结构的基础上,建立了下套管过程中井筒内波动压力计算模型,分析了套管–井眼间隙等不同因素对下套管和注水泥过程中环空压力的影响,对套管–井眼间隙进行了优化。该方法在LD10–2–x井进行了应用,该井五开井段的套管–井眼间隙进优化结果为15.00～19.55 mm,其实际的套管–井眼间隙为17.45 mm,在设计的合理间隙范围内,该井套管下入安全,注水泥过程中未发生井漏、溢流等井下故障。这说明可以根据下套管过程中井筒内波动压力和下套管及注水泥过程中的环空压力优化套管–井眼间隙,为南海莺–琼盆地井身结构设计提供依据。The goal of this study was to eliminate well hazards and drilling problems associated with wide pressure fluctuations encountered in complex strata in the Ying-Qiong Basin of the South China Sea.This basin is characterized by its high temperature and high pressure strata,complex geological structure and narrow drilling mud window.In order to prevent complex downhole events such as circulation lost,overflow and even blowout induced from pressure fluctuations during casing RIH,a calculation model of pressure fluctuation during casing RIH was established on the basis of a full investigation over the common casing program in the Ying-Qiong Basin of the South China Sea,and the optimization over the casing-wellbore gap was conducted by combining annulus pressure analysis during casing RIH and cementing job under different factors.The casing-wellbore gap of the fifth spud section of Well LD10-2-x subject to narrow safe mud window was optimized,and reasonable gap in that section was defined to be 15.00-19.55 mm.The actual casing-wellbore gap in Well LD10-2-x was 17.45 mm within the reasonable gap range,and the casing was run in the borehole with no downhole events such as circulation lost and overflow during the cementing.This indicated that the casing-wellbore gap could be optimized according to surge pressure during casing RIH,as well as annulus pressure during casing RIH and cementing,which would provide a reference in the casing program design in the Ying-Qiong Basin of the South China Sea.

关 键 词：安全密度窗口 井身结构 波动压力 环空压力 间隙 LD10-2-x井 莺-琼盆地 南海 

分 类 号：TE256.1[石油与天然气工程—油气井工程]