Geology of coalbed methane reservoirs in the Southeast Qinshui basin of China
Geology of coalbed methane reservoirs in the Southeast Qinshui basin of China
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DOI：
10.1016/j.coal.2005.01.002
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发表时间：
2005-06-22
影响因子：
5.6
通讯作者：
Song, Y
中科院分区：
文献类型：
--
作者：
Su, XB;Lin, XY;Song, Y
沁水盆地东南部的二叠系太原组15号煤层和二叠系山西组3号煤层厚度较大（> 3 m），横向连续，为无烟煤级（Ro =2.2-4.5%）。这些煤层的深度通常在200至700英寸之间。燕山期侏罗纪-白垩纪构造热事件控制了煤化作用和热生烃作用。沁水盆地东南部煤层气由于晚期细菌气的生成，可分为两个带，即靠近盆地边缘的混合型热成晚期细菌气带和盆地构造深部的热成优势气带。盆地水动力作用导致浅层天然气含量低（< 20 m3/t），而盆地深层天然气含量高（> 20 m3/t）。由于割理很少，且多为方解石充填，煤层气储层的渗透率受剪切裂缝控制。地下水的补给和流动不仅控制着含气量，而且控制着储层压力。深层滞流带异常高压储层是煤层气勘探开发的有利地区。目前的煤层气威尔斯井一般都是在深层滞流带完井。(c)2005 Elsevier B. V.保留所有权利。
The No. 15 coal seam of the Pennsylvanian Taiyuan Formation and the No. 3 coal seam of the Permian Shanxi Formation in the Southeast Qinshui Basin are relatively thick (> 3 m), laterally continuous, and are of anthracite rank (R-o=2.2-4.5%). The depth of these coal seams is generally between 200 and 700 in. A tectonic-thermal event during the Jurassic to Cretaceous Yanshanian Orogeny controlled coalification and thermogenic hydrocarbon generation. Because the generation of late-stage bacterial gas, coalbed methane in the Southeast Qinshui Basin occupies two zones, which are the mixed thermogenic and late-stage bacterial gas zone near the basin margins, and the dominantly thermogenic gas zone in the structurally deep part of the basin. Basin hydrodynamics causes low gas content in the shallow subsurface (< 20 m(3)/t) and high gas content at the deep part of basin (> 20 m(3)/t). Because cleats are rare and are mostly filled with calcite, the permeability of the coalbed methane reservoir is controlled by shear fractures. The recharge and flow of groundwater not only control gas content, but also control reservoir pressure. Abnormally high pressure reservoir in the deep stagnant zone is a favorable area for coalbed methane exploration and development. The current coalbed methane wells are generally completed in the deep stagnant zone. (c) 2005 Elsevier B.V. All rights reserved.