鄂尔多斯盆地深部煤层气差异富集的地质控制  

Geological control of differential enrichment of deep coalbed methane in the Ordos Basin

作　　者：范立勇 周国晓[1,2] 杨兆彪 王怀厂[1,2] 卢本举[3] 张宝鑫 陈宇航 李存磊 王彦卿[1,2] 顾俊雨 FAN Liyong;ZHOU Guoxiao;YANG Zhaobiao;WANG Huaichang;LU Benju;ZHANG Baoxin;CHEN Yuhang;LI Cunlei;WANG Yanqing;GU Junyu(National Engineering Laboratory of Exploration and Development of Low-Permeability Oil and Gas Fields,xi'an 710018,China;Research Institute of Petroleum Exploration and Development,Petro China Changqing Oilfield Company,xi'an 710018,China;Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process,Ministry of Education,China University of Mining and Technology,Xuzhou 221008,China)

机构地区：[1]低渗透油气田勘探开发国家工程实验室,陕西西安710018 [2]中国石油长庆油田公司勘探开发研究院,陕西西安710018 [3]中国矿业大学煤层气资源与成藏过程教育部重点实验室,江苏徐州221008

出　　处：《煤炭科学技术》2025年第1期203-215,共13页Coal Science and Technology

基　　金：国家自然科学基金资助项目(42272195,42130802);中国石油天然气股份有限公司攻关性应用性科技专项资助项目(2023ZZ18)。

摘　　要：鄂尔多斯盆地深部煤层气资源丰富,开发潜力大,是中国深部煤层气勘探开发的主战场。明确深部煤层气富集规律、圈定富集区段是煤层气勘探开发的重要基础。以中国石油长庆油田公司在鄂尔多斯盆地最新实施的多口深部煤层气评价井数据为分析基础,采用数学统计、模型计算和地质分析等方法,重点研究了盆地内深部煤层气差异富集的地质控制因素和富集规律。提出了物质组分效应、深度效应和保存效应是影响深部煤层气差异富集的“3种控制效应”。物质组分是控制煤层气富集的基础因素,其中灰分和煤变质程度是主要参数,低灰分、高变质煤储层含气量高。深度效应则是叠加孔隙率、温度和压力变化的综合效应,孔隙率随埋深增加而衰减,导致游离气随埋深增加会趋缓,吸附气和总含气量存在明显的临界转换深度,后者临界转换深度深于前者,一般在2000~3000m,在此深度范围内,总含气量高。3000m以深,深度效应加剧,总含气量缓慢降低,往往低于20m^(3)/t。保存效应是深部吸附气和游离气,尤其是游离气富集的重要控制因素,其中盖层类型是保存效应中的关键因素,而地下水矿化度和压力系数则是保存效应的重要外在显现。研究区煤岩组合类型中煤泥、煤灰、煤泥-煤灰组合具有良好封盖性,相应其地下水矿化度高,压力系数较大。叠加深度效应,2000~3000 m埋深范围内,总含气量往往高于20 m^(3)/t,煤砂组合封盖性相对较弱,相应其地下水矿化度相对较低,含气量往往低于20m^(3)/t。耦合深度效应和保存效应,提出了鄂尔多斯盆地深部煤层气富集模式。The deep coalbed methane(CBM)resources in the Ordos Basin are abundant and have great development potential,making it the main battlefield for exploration and development of deep CBM in China.Among them,clarifying the enrichment law of deep CBM and delineating enrichment sections are important foundation for CBM exploration and development.Based on the analysis of data from a number of deep evaluation CBM wells recentlyimplemented by China petroleum Changqing Oilfield company in Ordos Basin,the geolo-gical control factors and enrichment rules of deep coalbed methane differential enrichment in the basin are studied by means of mathemat-ical statistics,model calculation and geological analysis.It has been proposed that the effects of material composition,depth,and preserva-tion are the"three controlling effects"that affect the differential enrichment of deep CBM.The material component is the main factor con-trolling the enrichment of CBM,among which ash yield and coal metamorphism degree are the main parameters,low ash content,high metamorphic coal with high gas content.The depth effect is a comprehensive effect of superimposed porosity,temperature,and pressure.The porosity decays with the increase of burial depth,resulting in the free gas will tend to slow down with the increase of burial depth,and the adsorbed gas exists obvious critical conversion depth,and the critical conversion depth of total CBM content is deeper than the critical conversion depth of adsorbed CBM,which is generally in the range of 2000-3000 m,and in this depth range,the total CBM content is higher.For depths deeper than 3000 m,the depth effect intensifies,and the total CBM content gradually decreases,often below 20 m^(3)/t.The preservation effect is an important controlling factor for the enrichment of deep adsorbed CBM and free CBM,especially free CBM,among which the type of cap rock is a key factor in the preservation effect,while groundwater total dissolved solids and pressure coeffi-cients are important indications of the preservation ef

关 键 词：深部煤层气 物质组分效应 深度效应 保存效应 富集模式 鄂尔多斯盆地. 

分 类 号：P618[天文地球—矿床学] TE375[天文地球—地质学]