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(40802027)
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 Yumin
1, 2
, TANG Dazhen
2
, XU Hao
2
(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 damage of 76.5% and permeability damage of 93.3%, that from
No.3 coal seam was lowest with the porosity damage of 38.5% and permeability damage of 77.9%, and that from
No.5 coal seam is relative high with the porosity damage of about 45% and permeability damage of 83.9%. It was
suggested that the occurrence of the fractures in coal is resulted mainly from the stress damage difference among
the coal seams. Additionally, the power function is more accurate than exponential function for fitting the measured
value of porosity and permeability in the range of test stress.
Key words: coal reservoir; porosity; permeability; stress sensitivity; difference
煤储层孔渗参数是反映煤层气开发过程中气/
水流动难易程度的重要标志,因其弹性模量小、泊
松比大的力学性质而极易受到应力伤害,受到国内
外学者的广泛关注。一部分学者通过实验研究了煤
层渗透率应力敏感性特征
[1-7]
,另一部分学者建立了
煤储层渗透率变化模型
[8-14]
。但受地质背景、沉积
环境及应力条件等因素的影响,煤层孔渗应力敏感
性存在差异。因此,煤层气田开发设计不能简单地
直接套用前人的研究成果,应通过具体实验,建立
适合本地区特定煤层的孔渗应力敏感模型。
韩城煤层气田是我国初步实现规模化开发的典
型中高阶煤层气田,研究其煤储层孔渗应力敏感特