川西地区气井环空带压条件下水泥环裂缝封堵规律研究  

Study on the Plugging Rules of Cement Sheath Fractures Under Sustained Casing Pressure in Gas Wells,Western Sichuan Area

作　　者：李顺雨 江涛[1] 杨桢剑 魏勇[1] 马羽晋 肖东 LI Shunyu;JIANG Tao;YANG Zhenjian;WEI Yong;MA Yujin;XIAO Dong(Northwest Sichuan Division,PetroChina Southwest Oil&Gasfield Company,Jiangyou,Sichuan 621741,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu,Sichuan 610500,China;Southwest Petroleum University,Chengdu,Sichuan 610500,China)

机构地区：[1]中国石油西南油气田公司川西北气矿 [2]油气藏地质及开发工程国家重点实验室 [3]西南石油大学

出　　处：《钻采工艺》2024年第3期153-160,共8页Drilling & Production Technology

基　　金：西南油气田分公司川西北气矿科研项目“川西地区天然气井环空带压治理措施优化研究”(编号:2023-09)。

摘　　要：川西地区弃置井环空带压普遍存在,有效封堵水泥环裂缝对于防止天然气泄漏和地下水污染具有重要意义。尤其是在环空带压的条件下,裂缝的封堵难度增加,对封堵技术和材料的选择提出了更高的要求。文章利用高温高压岩心多参数测量仪开展了裂缝内封堵剂流动性能模拟测试实验,采用数值模拟方法研究了不同压差下柔性堵剂在裂缝内的流动规律,评价了常规油井水泥和柔性堵剂在弃置井环空带压条件下的流动性能。研究结果表明当裂缝开度在207μm以下时,增大驱替压力,无法有效增加柔性堵剂的流动性;当裂缝开度在383μm以上时,增大驱替压力,可显著提升柔性堵剂的流动性,进而提高封堵效率;当裂缝开度在446μm以下时,增大驱替压力值,无法有效增加常规油井水泥的流动性;当裂缝开度较小时,柔性堵剂在裂缝内的流动属于层流流动,流动层次分明、平滑且有序;采用波动压力的注入方式可提高堵剂的封堵效率。文章为环空带压弃置井柔性堵剂的流动性能测试及评价提供了实验和数据支撑,同时为弃置井封堵作业中封堵剂的合理选择提供了理论依据。Sustained casing pressure is common in abandoned wells of Western Sichuan area,which makes the effective plugging of cement sheath fractures crucial to prevent natural gas leaks and groundwater contamination.Under sustained casing pressure plugging fractures becomes more challenging,requiring higher standards for sealing technologies and materials.This paper uses a high-temperature and high-pressure core multi-parameter measuring instrument to carry out simulation experiments to test the flow performance of fracture plugging agents.It uses numerical simulation methods to study the flow patterns of flexible plugging agents in fractures under different pressure differences,and evaluates the flow performance of conventional oil well cement and flexible plugging agents under sustained casing pressure in abandoned well.The results show that increasing displacement pressure does not effectively enhance the flowability of flexible plugging agents for fracture widths≤207μm,while for widths≥383μm,it significantly improves their flowability and plugging efficiency.For fracture widths≤446μm,increasing displacement pressure does not effectively enhance the flowability of conventional oil well cement.At smaller fracture widths,the flow of the plugging agent is laminar,distinct,smooth,and orderly.Using fluctuating pressure injection methods can improve the plugging efficiency of plugging agents.This paper provides strong experimental and data support for testing and evaluating the flow performance of plugging agents under sustained annular pressure in abandoned wells,offering a theoretical basis for the rational selection of plugging agents in plugging operations.

关 键 词：环空带压 弃置井 柔性堵剂 常规油井水泥 封堵效果 

分 类 号：TE358[石油与天然气工程—油气田开发工程]