摘要
依据弹性形变理论,建立了开发过程中煤储层渗透率应力敏感模型。根据兰格缪尔方程,建立了煤基质在解吸过程中渗透率反弹模型。综合渗透应力敏感和基质解吸渗透率反弹的研究成果,建立了开发过程中渗透率随地层压力变化的动态综合模型。研究结果显示:早期,渗透率以应力敏感为主,随着储层压力的降低渗透率降低;后期,渗透率反弹占主导地位,随着甲烷解吸和排出量的增加,渗透逐渐增大。根据对大量实际生产资料的分析,应力敏感在排水期、稳产期表现强烈;渗透率反弹主要发生在递减期,并且具有阶段性和多周期性。
The stress-strain law of coal rock under stress was analyzed through indoor tri-axial stress experiments. The permeability stress sensibility model of coal reservoir was built according to the elastic continuum theory. Similarly, the permeability rebound model of coal matrix during desorption process was acquired according to the Langmuir equation. A dynamic comprehensive model that the permeability changes with formation pressure was established integrating the research results of the above two effects. The results show that permeability is mainly affected by stress sensitivity at early stage, and decreases with formation pressure reduction. However, the influence of permeability rebound is more dominant at later stage, with the increasing of methane desorption and output, the permeability increases gradually. According to the analysis of a large number of actual production data, stress sensitivity is much fiercer during drainage period and stable production period. The permeability rebound mainly occurs at production decline stage, with stage and multi-periodic characteristics.
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2014年第A01期146-151,共6页
Journal of China Coal Society
基金
国家科技重大专项资助项目(2011ZX05038-001)
国家重点基础研究发展计划(973)资助项目(2009CB219604)
关键词
煤层气
弹性形变
应力敏感
渗透率
动态模型
coalbed methane
elastic deformation
stress sensitivity
permeability
dynamic model
