海拉尔盆地褐煤全孔径结构特征及影响因素  

Characteristics on pore structures on full scale of lignite and main controlling factors in Hailar Basin

作　　者：杨青[1] 李剑[1] 田文广[1] 孙斌[1] 祝捷[2] 杨宇航 YANG Qing;LI Jan;TIAN Wen-guang;SUN Bin;ZHU Jie;YANG Yuhang(Petro China Reearch Institute of Peroleumn Exploruion&Delopmont,Beijing 100083 China;China University of Minting&Technology(Beijing),Beijing 100883,China)

机构地区：[1]中国石油天然气股份有限公司勘探开发研究院,北京100083 [2]中国矿业大学(北京),北京100083

出　　处：《天然气地球科学》2020年第11期1603-1614,共12页Natural Gas Geoscience

基　　金：国家科技重大专项“东北地区中低煤阶煤层气规模开发区块优选评价”(编号:2016ZX05041-004);中国石油天然气股份公司重大科技专项“煤层气勘探开发关键技术研究与应用”(编号:2017E-14)联合资助。

摘　　要：煤岩孔隙结构特征是判断煤储层含气性的关键因素之一,孔隙结构的精细表征对于厚煤层中优质储层的识别意义重大,但褐煤储层孔隙结构特征难以通过单一手段全面表征。以扫描电镜电子成像技术(SEM)为基础,利用低温液氮吸附实验、高压压汞实验在孔径探测范围及精度上的互补开展联合分析,实现海拉尔盆地下白垩统伊敏组褐煤样品全孔径结构表征,并探讨褐煤孔隙结构的影响因素。结果表明:①研究区煤样总孔容、总孔面积随孔隙尺寸分布存在明显差异。伊敏煤矿等煤样孔体积的贡献主要来自大孔;吸附面积主要由微孔及过渡孔提供。牙克石煤矿煤样孔体积的主要贡献来自微孔,微孔贡献总孔面积的82.07%。②显微组分中腐殖组含量增加有利于微孔、过渡孔发育;惰质组含量的增加有利于中孔、大孔的发育。③煤样结构保存指数、森林指数与总孔容呈正相关关系,与总孔面积呈负相关关系;总孔容随凝胶化指数增大而减小,与总孔面积变化规律相反;地下水流动指数与总孔容、总孔面积间关系不明显。④成煤环境为无覆水的氧化环境,形成原生组织孔丰富、中孔—大孔为主、孔隙形态以槽状孔或狭缝孔为主的孔隙结构。成煤期覆水程度较深时,煤层凝胶化程度高,植物原生组织孔减少,中孔—大孔优先被矿物填充,孔隙结构呈低孔容、高孔面积的特点。Pore structure characteristics of coal are one of the key factors for gas storage judgement of coal reservoir.The fine characterization of pore structure is of great significance for the identification of high-quality reservoir in thick coal seams.However,it is difficult for lignite reservoir to fully characterize the reservoir space characteristics by a single means.On the basis of scanning electron microscope(SEM),the full pore size structure of lignite samples of the Lower Cretaceous Yimin Formation in Hailaer Basin was characterized by using the complementary analysis of low-temperature liquid nitrogen adsorption experiment and high-pressure mercury injection experiment in pore size detection range and accuracy,and the influencing factors of pore structure of lignite were discussed.The results show:(1)The total pore volume and total pore area of coal samples in the study area are significantly different with the pore size distribution.The contribution of pore volume of coal samples from Yimin Formation is mainly from macropores;and adsorption area is mainly provided by micropores and transition pores.The main contribution of the pore volume of Yakeshi coal samples comes from the micropores and transition pores which contribute 99.73%of the total pore area.(2)The increasing increase of huminite is beneficial to the development of micropores and transit-pores.The increasing increase of inertinite content contributes to the development of mesopore and macropores.(3)The tissue preservation index and vegetation index of coal samples have a positive correlation with the total pore volume,and a negative correlation with the total pore area;the total pore volume decreases with the increase of gelification indices,and the change rule of the total surface area is opposite;the relationship between the groundwater influence and the total pore volume and the total pore area is not obvious.(4)The coal forming environment is dry forest swamp with an oxidation environment,forming a pore structure with abundant plant tissue p

关 键 词：褐煤 孔隙结构 总孔容 总孔面积 煤相 成煤环境 

分 类 号：TE121.13[石油与天然气工程—油气勘探]