含煤盆地深层“超饱和”煤层气形成条件  

Formation conditions for deep oversaturated coalbed methane in coal-bearing basins

作　　者：康永尚[1,2] 皇甫玉慧 张兵[3] 邓泽[4] 毛得雷[5,6] 何志平 王建[8] 袁春林[1] Kang Yongshang;Huangfu Yuhui;Zhang Bing;Deng Ze;Mao Delei;He Zhiping;Wang Jian;Yuan Chunlin(School of Geosciences,China University of Petroleum,Beijing 102249,China;State Key Laboratory of Petroleum Resources and Pros pecting,Beijing 102249,China;China United Coalbed Methane Corporation Ltd.,Beijing 100015,China;PetroChina Research Institution of Petroleum Exploration and Development,Beijing 100083 China;National Engineering Research Center of Coalbed Methane Development&Utilization,Beijing 100095,China;National Engineering Research Center of China United Coalbed Methane,Beijing 100095,China;China Energy Reserve and Chemical Group Corporation,Beijing 100107,China;&PetroChina Xinjiang Oil field Company Xinjiang Karamay 834000,China)

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]油气资源与探测国家重点实验室,北京102249 [3]中联煤层气有限责任公司,北京100015 [4]中国石油勘探开发研究院,北京100083 [5]煤层气开发利用国家工程研究中心,北京100095 [6]中联煤层气国家工程研究中心有限责任公司,北京100095 [7]中国国储能源化工集团股份公司,北京100107 [8]中国石油新疆油田公司,新疆克拉玛依834000

出　　处：《石油学报》2019年第12期1426-1438,共13页Acta Petrolei Sinica

基　　金：国家科技重大专项（2016ZX05041-001和2016ZX05044-005）资助

摘　　要：中国深层煤层气资源丰富,但总体勘探和认识程度较低,尚未形成较为系统的深层煤层气地质理论。通过解剖分析准噶尔盆地白家海凸起和鄂尔多斯盆地临兴区块深层“超饱和”煤层气井的试气/生产动态,估算原地游离气的含气量,分析了深层“超饱和”煤层气的形成条件。研究表明:(1)深层“超饱和”煤层气储层中除吸附气外,还含有原地游离气,用常规试气方法可直接获得气流,煤层气的产出不明显依赖于排水降压;(2)埋藏超过一定深度,在煤阶和温度的综合作用下,煤的吸附能力将随埋深的继续增加而降低,煤层中吸附气的饱和度有增加的趋势,在达到吸附饱和后,出现原地游离气并形成“超饱和”煤层气,盆地深层具有“超饱和”煤层气形成的优势条件;(3)由于地温梯度和压力梯度的不同,不同盆地“超饱和”煤层气出现的临界深度不同,异常高压和异常高热流可以降低深层“超饱和”煤层气形成的临界深度;(4)深层“超饱和”煤层气开发具有大大缩短见气时间、充分利用地层能量和累积产水量低等优势,有望成为未来煤层气勘探开发的一个重要领域。China is rich in deep coalbed methane resources,but the overall degree of exploration and level of understanding is low;there is still lack of a relatively systematic geological theory for deep coalbed methane.Through thoroughly analyzing the gas testing/production performance of deep oversaturated coalbed methane wells in the Baijiahai uplift of Junggar Basin and the Linxing block of Ordos Basin,this paper estimates the gas content of the in-situ free gas,and explores the formation co nd让ions of deep oversaturated coalbed methane.The study shows that:(1)the deep oversaturated coalbed methane reservoirs contain in-situ free gas in addition to adsorbed gas,which can be directly obtained by conventional gas testing methods and the production of coalbed methane is obviously independent of drainage and decompression;(2)when the burial depth exceeds a certain depth,under the combined effect of two major factors including coal rank and temperature,the adsorption capacity of coal will decrease with the increasing of burial depth»and the saturation of adsorbed gas in coal seams will increase,so in-situ free gas will appear and form oversaturated coalbed methane after reaching the adsorption saturation that the deep reservoirs in basins have the advantageous conditions for forming the oversaturated coalbed methane;(3)due to the difference in geothermal gradient and pressure gradient and the variation of critical depth of oversaturated coalbed methane with different basins,the critical depth of deep oversaturated coalbed methane can be reduced by abnormally high pressure and abnormally high heat flow;(4)the deep oversaturated coalbed methane development possesses such advantages as a sharp decrease in gas breakthrough time,making the best of formation energy,and low cumulative water production,and is expected to become an important field for coalbed methane exploration and development in the future.

关 键 词：深层“超饱和”煤层气 等温吸附 吸附饱和 原地游离气 准嶋尔盆地 鄂尔多斯盆地 

分 类 号：TE121.[石油与天然气工程—油气勘探]