韩城地区煤储层孔渗应力敏感性及其差异.pdfVIP

第 41卷 第 6期 煤田地质与勘探 Vol. 41 No.6 2013年 12月 COAL GEOLOGY EXPLORATION Dec. 2013 收稿日期: 2012-09-23 基金项目: 国家科技重大专项课题(2011ZX05038-001)；国家自然科学基金青年项目 作者简介: 吕玉民(1985—)，男，江西吉安人，博士，从事煤层气地质与开发研究. 文章编号: 1001-1986(2013)06-0031-04 韩城地区煤储层孔渗应力敏感性及其差异 吕玉民 1, 2，汤达祯 2，许 浩 2 (1. 中海油研究总院, 北京 100027; 2. 中国地质大学能源学院, 北京 100083) 摘要: 以韩城煤层气区块 3 号、5 号和 11 号煤层为例，进行不同围压条件下的煤心孔渗实验，探 讨了该区煤储层物性与应力之间的耦合关系，建立了相应的数学模型。结果表明, 煤心孔渗随围 压的增加而不断下降，渗透率应力伤害远强于孔隙度应力伤害，但各煤层的应力敏感性各不相同： 在实验围压从 4.14 MPa(600 psi)增加到 12.42 MPa(1 800 psi)条件下，11 号煤层孔渗应力敏感性最 强，孔隙度应力伤害达 76.5%，渗透率应力伤害达 93.3%；3 号煤层孔渗应力敏感性最弱，孔隙度 应力伤害 38.5%，渗透率应力伤害 77.9%；5 号煤层孔渗应力敏感性较强，孔隙度应力伤害约 45%， 渗透率应力伤害达 83.9%。分析认为，裂隙发育状况是造成各煤层间孔渗应力敏感差异的主要原 因。从实验数据的拟合情况看，幂函数模式比指数函数模式更能准确地获取测试围压范围内的孔 渗内插值。 关 键 词：煤储层；孔渗；应力敏感；差异 中图分类号：P618.13 文献标识码：A DOI: 10.3969/j.issn.1001-1986.2013.06.008 Stress sensitivity and difference of porosity and permeability in coal reservoirs in Hangcheng CBM block LYU Yumin1, 2, TANG Dazhen2, XU Hao2 (1. CNOOC Research Institute, Beijing 100027, China; 2. School of Energy Resources, China University of Geoscience, Beijing 100083, China) Abstract: In order to discuss the relationships between the physical properties of coal reservoir and the stress, the stress sensitivity experiments of the porosity and permeability of the coal samples from No.3, No.5 and No.11 coal seams in Hancheng coalbed methane (CBM) block were carried out under various pressure and the corresponding mathematical models were established. The results showed that the porosity and permeability of the samples de- crease as the confining stress increases and the stress damage for permeability is much larger than that for porosity. However, the stress damage is different for different coal seams. When the confining stress increased from 4.14 MPa (600 psi) to 12.42 MPa (1800 psi), the stress damage of the sample from No.11 coal seam was highest in the samples from three coal seams, with the porosity dam