鄂尔多斯盆地东部煤层气富集区预测——以午城地区为例  

Prediction of rich accumulation area of CBM in eastern Erdos basin——a case study of Wucheng area

作　　者：苏海[1] 田朋飞[1] 杜中东 文晓峰 赵慧 赖生华[1] 

机构地区：[1]西安石油大学地球科学与工程学院,西安710065 [2]东方地球物理勘探有限责任公司长庆物探处,西安710021 [3]中国石油集团测井有限公司长庆事业部,西安710201

出　　处：《地球物理学进展》2016年第2期775-781,共7页Progress in Geophysics

基　　金：国家自然科学基金(41372118);西安石油大学研究生创新基金(2015CX140219)联合资助

摘　　要：我国煤层气资源非常丰富,鄂尔多斯盆地东部地区是我国煤层气勘探开发的重点区域,随着勘探程度的不断提高,地震勘探已经成为煤层气储层评价的有效方法之一。本文研究了午城地区煤层气储层的地球物理特征以及富聚成藏条件,利用人工合成地震记录进行煤层顶部层位标定,依据该区测井速度资料、地震资料,根据煤层地球物理特征,准确预测出煤层厚度,经过横向外推得出午城地区煤层展布特征,结合该区构造条件,煤层厚度、成熟度和空隙特征以及盖层条件,确定出该区煤层气勘探开发的重点有利区。研究结果显示：鄂尔多斯盆地东部的午城地区煤层气勘探的主力煤层厚度较大且分布稳定,5-#煤层总厚度为2-7 m,个别达8 m;8^#煤层总厚度为2-8 m,最厚层段达10 m,总体埋深低于1500 m,北厚南薄,从东到西埋藏深度逐渐加大。预测出两主力煤层的煤层气富集区各3个,保存条件较好,非常有利于煤层气的勘探开发。CBM（ coal bed methane） resource is very rich in our country. Regions in eastern Erdos basin are important areas of China as exploration and development of CBM. With the advancement of exploration about CBM, seismic technology has become one of the effective methods to evaluate the reservoir. The thickness of the primary coal beds named No. 5 and No. 8 change respectively from 2 to 7 meters and 2 to 8 meters in Wucheng area.Both of the coal beds show ＂Three low figures ＂ of geophysical characteristics. The first ＂low value＂is low velocity of wave from^2200 m / s to 2500 m / s. The second ＂low value ＂is low density,from 1. 7 g / cm^3 to 1. 8 g / cm^3. The third ＂low value ＂ is low seismic wave impedance to the surrounding rock between 3520 mg /scm^3 and 4500 mg / scm^3. In this paper, the synthetic seismic record and logging data are used to calibrate top-horizons of the reservoir beds and to predict the coal-seam＇s thickness accurately,and the features of development about the coal-beds on horizontal direction is also deduced through geophysical characteristics in Wucheng area. Many factors are vital for circling the CBM favorable areas such as information of geological structure condition,coal seam thickness,evolution degree of the coal,porosity percent and the covers＇ permeability.The achievement of the prediction can be described mainly as following. No. 5 coal-bed can be divided into three parts,two areas for type-Ⅰ and one for type-Ⅱ in Wucheng region. The two areas with 503 km^2 and 507 km^2,which bellow to type-Ⅰ,locate at the two side of the reverse fault named Xueguan-Yaoliang. The type-Ⅱarea with area of 556. 8 km^2 lies in the thick coal bed region in the west of Wucheng. No. 8 coal-bed is similar with No. 5 which also have two type-Ⅰparts and one type-Ⅱpart. The difference between them is the area only. Two type-Ⅰfavorable areas＇ area are 648. 7km^2 and 224 km^2 and the type-Ⅰ＇s is 823. 5 km^2. Both of the coals＇ maturity of No. 5 and No. 8 are judged from

关 键 词：煤层气 人工合成地震记录 层位标定 成藏条件 有利区 

分 类 号：P631[天文地球—地质矿产勘探]