南海水合物储层固井过程高压气水反侵临界条件判别  

Critical conditions identification of generated high-pressure gas and water reverse penetration during cementing in hydrate reservoirs in the South China Sea

作　　者：郑明明 王晓宇 周珂锐 王凯[1] 吴祖锐 蒋国盛 孙嘉鑫 曹鑫鑫 ZHENG Mingming;WANG Xiaoyu;ZHOU Kerui;WANG Kai;WU Zurui;JIANG Guosheng;SUN Jiaxin;CAO Xinxin(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China;Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education,China University of Geosciences(Wuhan),Wuhan 430074,China;Key Laboratory of Gas Hydrate,Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences,Guangzhou 510640,China)

机构地区：[1]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059 [2]中国地质大学(武汉)构造与油气资源教育部重点实验室,湖北武汉430074 [3]中国科学院天然气水合物重点实验室(中国科学院广州能源研究所),广东广州510640

出　　处：《中南大学学报（自然科学版）》2022年第3期963-975,共13页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(41702389);国家重点研发计划战略性国际科技创新合作重点专项项目(2016YFE0204300);构造与油气资源教育部重点实验室开放基金资助项目(TPR-2020-03);中国科学院天然气水合物重点实验室(中国科学院广州能源研究所)开放基金资助项目(E129kf1701)。

摘　　要：传统油气固井遇到天然气水合物地层时,水泥浆放热易引起近井壁地层中水合物分解,所产生的高压游离气水易反侵入水泥浆而严重影响固井质量等问题。为了解决此问题,以中国南海神狐海域为研究对象,利用TOUGH+HYDRATE数值模拟软件,通过“连续分段模拟”真实还原水泥浆放热与侵入过程,采用控制变量法分别研究固井压差和水泥水化放热速率这2个主要工艺参数的影响。研究结果表明:水化热越低,水合物分解量越少,气水反侵可能性越小;当压差较小时,水泥浆侵入范围较小,无法达到有效的封堵效果,气水反侵的可能性大;随着固井压差增大,会出现极易反侵区,继续增大固井压差,虽然水合物分解量较高,但水泥浆侵入范围大,形成质量更优的二界面,气水反侵现象反而更难以发生;过大的固井压差易压裂地层,需将固井压差控制在地层破裂压力窗口内。在综合2个工艺参数进行的交叉分析基础上绘制高压气水反侵临界的临界条件判别简图,可有效预测不同固井工艺条件下气水反侵行为是否发生。When traditional oil and gas cementing encounter gas hydrate formations,the heat release of cement slurry is easy to cause hydrate decomposition in the formation near the wellbore,and the generated high-pressure free gas and water can easily penetrate into the cement slurry and seriously affect the cementing quality.In order to solve the problem,the hydrate reservoir in Shenhu sea area of the South China Sea was taken as the research object,and the multiphase flow numerical simulation software TOUGH+HYDRATE was used."Continuous segmented simulation"was used to more realistically restore the heat release and penetration process of cement slurry and the influence of the two main process parameters,cementing pressure difference and cement hydration heat,were studied separately using the controlled variable method.The results show that the lower the heat of hydration,the less the amount of hydrate decomposed,and the smaller the possibility of gas-water reverse penetration.When the pressure difference is small,the penetration range of cement slurry is small,which cannot constitute an effective plugging effect,and the possibility of gas and water reverse penetration is high.With the increase of cementing pressure difference,there will be an extremely reverse penetration zone.When it continues to increase,as the amount of hydrate decomposition is higher,the large penetration range of cement slurry is larger,and the second interface with better quality is formed,the reverse penetration is more difficult to occur.The excessive cementing pressure difference is easy to form the formation and needs to be controlled within the formation fracture pressure window.Based on the cross-analysis of the two process parameters,a diagram of the critical condition of high-pressure gas and water reverse penetration is drawn,which can effectively predict the occurrence of reverse penetration behavior under different cementing conditions.

关 键 词：天然气水合物 固井 高压气水反侵 临界条件判别 动态热源 连续分段模拟 

分 类 号：TE256[石油与天然气工程—油气井工程]