低渗砂岩储层渗透率有效应力定律试验研究-岩石力学与工程学报.PDF

第 27 卷 增 2 岩石力学与工程学报 Vol.27 Supp.2 2008 年 9 月 Chinese Journal of Rock Mechanics and Engineering Sept. ，2008 低渗砂岩储层渗透率有效应力定律试验研究 李 闽，肖文联 (西南石油大学 油气藏地质及开发工程国家重点实验室，四川 成都 610500) 摘要：试验设计多个回路，各个回路的孔隙流体压力不同，每一回路在孔隙流体压力不变，增加和降低围压方式 下进行。试验过程中采用稳态法测定不同围压和孔隙流体压力下的岩芯渗透率，并用响应面法对试验结果进行处 理分析。结果表明，有效应力系数 随围压和孔隙流体压力的变化而变化。当围压很大时，试验研究得到的有效 应力系数很小，这与过去试验研究的结果差别很大。最后用有效应力系数 = 1.0 和本次试验获取的有效应力系数 对低渗砂岩岩样进行应力敏感性评价。用有效应力系数 = 1.0 评价的结果是储层存在强应力敏感，而用本次试验 获取的有效应力系数的评价结果是储层表现为弱应力敏感性。 关键词：岩石力学；有效应力；敏感指数；有效应力系数；响应面；最大似然函数 中图分类号：TU 45 文献标识码：A 文章编号：1000 –6915(2008)增 2 –3535 –06 EXPERIMENTAL STUDY ON PERMEABILITY-EFFECTIVE-STRESS LAW IN LOW-PERMEABILITY SANDSTONE RESERVOIR LI Min ，XIAO Wenlian (State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation ，Southwest Petroleum University ， Chengdu，Sichuan 610500，China) Abstract ：The experiments included many cycles from which the pore fluid pressures were different. Each cycle run under constant pore fluid pressure by increasing or decreasing confining pressure. Experimental data were dealt with by steady state method，and analyzed with response-surface method. It was found that the effect stress coefficient  varied with pore fluid pressure and confining pressure. At the higher confining pressures in the test， all of the coefficient  were below 0.11 ，which was contrary to conventional view. In order to analyze the stress-sensitivity of low-permeability sandstone sample，coefficient  = 1.0 and coefficient  obtained from the experiment were adopted. It was shown that permeability stress sensitivity was very strong as conventional  = 1.0 wa