柴达木盆地北缘鱼卡煤田侏罗系煤层气特征及含气性评价  

Jurassic coal bed methane characteristics and gas-bearing property evaluation in Iqe Coalfield, northern Qaidam Basin

作　　者：陈磊[1,2] 田景春 文怀军[3] 刘世明 杨颖 CHEN Lei;TIAN Jingchun;WEN Huaijun;LIU Shiming;YANG Ying(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Qinghai Bureau of Coal Geology,Xining,Qinghai 810001,China;Qinghai Coal Geological Exploration Institute,Xining,Qinghai 810001,China)

机构地区：[1]成都理工大学沉积地质研究院,成都610059 [2]青海煤炭地质勘查院,西宁810001 [3]青海煤炭地质局,西宁810001

出　　处：《石油实验地质》2019年第2期215-221,共7页Petroleum Geology & Experiment

基　　金：青海省地勘基金项目(2017042007ky007)资助

摘　　要：柴达木盆地北缘蕴含丰富的煤炭资源及煤层气资源,鱼卡煤田便是一个富含煤层气的典型区域,含煤地层为中侏罗统石门沟组和大煤沟组。鱼卡凹陷地区受区域构造影响,含气量分布不均,其中石门沟组M5煤层和大煤沟组M7煤层煤层气资源前景较好。通过深度—含气性关系分析,发现二井田地区含气性梯度明显且深度—含气性关系的离散性较小,M7煤层含气性随埋深增加呈"先减小后增大"的趋势;而尕秀地区、羊水河和鱼卡东部地区M7煤层含气性随深度增加呈"先增大再减小"的趋势。鱼卡凹陷侏罗系M7煤层的含气性在不同构造单元差异较大,呈现明显的不均一性,整体来看,鱼卡凹陷西部煤层含气性显著高于东部,北部略优于南部,由南向北呈现先降低后升高的趋势;鱼卡煤田北部F2断层和F10断层所控制的区域,在一个小型背斜构造存在2个相对高含气量区,由南向北煤层含气量逐渐增高;而鱼卡煤田东部北山和二井田地区,其煤层含气量普遍较低。The northern margin of the Qaidam Basin is rich in coal and coal bed methane resources.The Iqe Coalfield is a typical area rich in coalbed methane,which mainly occurs in the Shimengou and Dameigou formations in the Middle Jurassic.Gas contents vary in different areas of the Iqe Sag influenced by regional tectonics.The M5 coal seam of the Shimengou Formation and the M7 coal seam of the Dameigou Formation show a good resource prospect.The relationship between depth and gas-bearing properties shows a gas-bearing gradient and the discreteness of the relationship between depth and gas-bearing property is small in the Erjingtian area.The gas-bearing capacity of M7 coal seam decreases first and then increases with burial depth,and increases first and then decreases in the Caxiu,Yangshuihe and Yuka areas.The gas-bearing properties of M7 coal seam of Jurassic in the Iqe Sag vary greatly in different tectonic units and show obvious heterogeneity.On the whole,the gas-bearing capacity of coal seams in the western Iqe Sag is significantly higher than that of the eastern part,and slightly better in the north than in the south,which shows a trend of decreasing first and then increasing from south to north.There are two relatively high gas content areas in a small anticline structure in the north of the Iqe Coalfield,controlled by F2 and F10 faults,and the coal seam gas content gradually increases from south to north.While the gas content is generally lower in the Beishan and Erjingtian areas in the east of the Iqe Coalfield.

关 键 词：含气性预测 煤层气 侏罗系 鱼卡煤田 柴达木盆地北缘 

分 类 号：TE132.2[石油与天然气工程—油气勘探]