煤层气与页岩气吸附/解吸的理论再认识  

Recognition of absorption/desorption theory in coalbed methane reservoir and shale gas reservoir

作　　者：李相方[1] 蒲云超 孙长宇[2] 任维娜[1] 李莹莹[1] 张亚琦[1] 李靖[1] 臧加利 胡爱梅 温声明 赵培华 陈东[4] 翟雨阳[4] 

机构地区：[1]中国石油大学石油工程教育部重点实验室,北京102249 [2]中国石油大学重质油加工国家重点实验室,北京102249 [3]中石油煤层气有限责任公司,北京100028 [4]中联煤层气国家工程研究中心有限责任公司,北京100011

出　　处：《石油学报》2014年第6期1113-1129,共17页Acta Petrolei Sinica

基　　金：国家重大科技专项(2011ZX05038-004);国家自然科学基金重大项目(No.51490654)资助

摘　　要：为了解决一些煤层气与页岩气气田开发效果与预测的差异很大、产能低、递减快及开发成本高等问题,由于吸附/解吸基本理论直接影响开发方案的制定与实施,通过研究煤层气的煤化过程及页岩气的成藏过程,重新界定了孔隙中原始气-水分布状态。发现煤层气与页岩气的吸附气属于固-液界面吸附的研究领域,其吸附规律应满足适合固-液界面的Langmuir等温吸附定律,即气体的吸附量与溶液的浓度有关,而对环境压力不敏感。理论与实验研究表明固-液界面吸附气排水降压后解吸困难,吸附气多而游离气少的储层产气量很难提高,其显著不同于目前普遍使用的固-气界面吸附理论。同时研究了多孔介质中微小孔隙的气-水界面压降,发现对于微/纳米孔隙气相的压力可以远高于液相压力,而目前的测井及试井尚不能传感这种气相压力,因此会导致低估游离气的储量及其对产量的贡献。There are large differences between development effect and the prediction in a considerable number of gas fields.Low productivity,declining quickly and high development costs,can directly affect the formulation and implementation of development plans.This paper studied the forming process of coalbed methane reservoir and shale gas reservoir,then redefined the initial gas-water distribution in the pore,and found that the adsorption of coalbed methane and shale gas is not belongs to the field of solid adsorption.It is just to say the amount of adsorbed gas is related to the concentration of solution,but not sensitive to environmental pressure.Theory and experiments show that it is difficult for adsorption gas to desorb after drainage and decompression,and then demonstrate that it is difficult to improve production when the reservoir consist of much adsorbed gas is and less free gas.The result significantly differs from the prediction commonly used by current solid interface adsorption theory.This paper also studied the interface pressure drop of the micro pore in the porous medium,and found the pressure of gas phase can be much higher than that of liquid phase.The current methods of logging cannot measure the vapor pressure and therefore it will lead to underestimation of free gas reserves and its contribution to the production.

关 键 词：煤层气 页岩气 固-气界面 固-液界面 吸附 甲烷解吸 

分 类 号：TE37[石油与天然气工程—油气田开发工程]