摘要
我国煤层的渗透率普遍偏低，一般比美国低2～3个数量级。并且煤岩本身具有强压缩性，进而导致我国煤层普遍具有压力敏感性强的特点。山西宁武盆地煤层舍气量较高，在10～20m^3／t之间，但试采结果并不理想。为了探索该问题，通过建立煤层气井流固耦合数学模型，对煤层气井的降压制度进行拟合，分析煤层气井附近储层降压漏斗的扩展情况和储层压力变换情况。结果表明，过快的排采制度使煤层气井筒附近煤储层在短时间内受到较为严重的伤害，煤层气渗透率急剧降低，阻碍煤储层降压漏斗的扩展，煤层气无法大规模解吸，因而无法形成长期稳定的单井规格产量。
The permeability of coal seams in China is very low, generally, about 2 ～ 3 times magnitude lower than that in US and the compressibility of coal is very large. All these reasons make the coal in China have a property of very strong pressure sensitivity. The gas concentration of coal seams at Ningwu Basin, Shanxi Province is quite high, between 10 m^3/t and 20 m^3/t, but the result of production test is not very good. To know the reason, a mathematic model with solid-fluid coupling for coalbed methane well is constructed to fit the drainage behaviors and to analyze the spread states of pressure-descent funnels of the reservoirs around the coalbed methane wells and the pressure transformation of the reservoirs. The conclusion is that too fast drainage in a short time makes severe harms to the reservoirs with low permeability of coal seams around the coalbed methane wells, reduces the permeability of coal seams quickly and then hinders the spread of pressure-descent funnels of reservoirs, resulting in no desorption of coalbed methane in large scale and no longtime and sustainable standard production of single well.
出处
《山东科技大学学报（自然科学版）》
CAS
2008年第3期27-31,共5页
Journal of Shandong University of Science and Technology(Natural Science)
基金
国家“973”项目(2002CB211705):中国煤层气成藏机制及经济开采基础研究
关键词
煤层气
渗透率
流固耦合
数值模拟
coalbed methane
permeability
solid-fluid coupling
numerical simulation
