永久性弃置井封堵效果的试验评价  

Experimental evaluation of the plugging effect of permanently abandoned wells

作　　者：钟守明 邓宽海[2] 吴彦先 张浩 赵倩 林元华[2] ZHONG Shou-ming;DENG Kuan-hai;WU Yan-xian;ZHANG Hao;ZHAO Qian;LIN Yuan-hua(Engineering Technology Research Institute,Xinjiang Oilfield Company,Karamay 834099,Xinjiang,China;State Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering,Southwest Petroleum University,Chengdu 610500,China)

机构地区：[1]新疆油田公司工程技术研究院,新疆克拉玛依834099 [2]西南石油大学油气藏地质及开发工程国家重点实验室,成都610500

出　　处：《安全与环境学报》2023年第3期792-800,共9页Journal of Safety and Environment

基　　金：国家自然科学基金项目(51904261)。

摘　　要：随着油气资源的持续开发,无商业开采价值的油气弃置井日益增多,弃置井的封堵效果是其永久保持井筒完整性的关键。为此,基于永久性弃置井特点及封堵技术规范和要求,提出了一种永久性弃置井封堵屏障单元的封堵效果测试及评价方法,自主研发了评价套管内水泥塞和套管外水泥环封堵有效性及可行性的测试系统,并模拟我国西北典型井井下工况开展了弃置井管内水泥塞和管外水泥环的密封性能测试和界面力学性能测试,获取了水泥塞、水泥环的突破压力、击穿压力及其与套管之间界面力学参数,分析了水泥塞/水泥环长度对其密封性能的影响规律,并拟合得到了水泥塞/水泥环长度与封堵压力的函数关系,对比了水泥塞与水泥环的密封性能及界面力学性能,明确了水泥塞/水泥环密封性能与界面力学性能之间的相关性,发现了水泥塞与水泥环封堵屏障的薄弱区。研究成果可为永久性弃置井封堵水泥浆体系及施工参数的“量身定制”提供依据。With the continuous development of oil and gas resources,there are increasing abandoned oil and gas wells with no commercial exploitation value.The plugging effect of abandoned wells is the key to permanently maintaining the integrity of the wellbore.Therefore,based on the characteristics of permanently abandoned wells and plugging technical specifications and requirements,a method for testing and evaluating the plugging effect of plugging barrier units in permanently abandoned wells is proposed.We independently developed a test system to evaluate the effectiveness and feasibility of the cement plug inside the casing and the cement sheath outside the casing and simulated the downhole working conditions of typical wells in Northwest China.The sealing performance test and interface mechanical performance test of the cement plug in the abandoned wells and the cement sheath outside the pipes were carried out.The test results of maximum plugging pressure and breakdown pressure of cement plug and cement sheath under four effective bonding lengths and the mechanical parameters of the interface with casing were obtained.The influence of the cement plug/the length of cement sheath on its sealing performance,and the functional relationship between the cement plug/the length of cement sheath and the plugging pressure are obtained by fitting.The integrity failure mechanism under hydraulic impact and the weak area of the sealing barrier is clarified.The sealing performance and interface mechanical properties of cement plug and cement sheath are compared.The process parameters that the plugging length of cement plug in the pipe is more than 22.99 m and the plugging length of cement sheath outside the pipe is more than 36.92 m are defined,forming an economic and feasible permanent plugging process for abandoned wells.The research results can provide an important basis for the"customization"of cement slurry systems and construction parameters for permanently abandoned wells.

关 键 词：安全工程 永久性弃置井 封堵效果 水泥塞 水泥环 封堵屏障 封堵压力 

分 类 号：X37[环境科学与工程—环境工程]