摘要
为系统探究鄂尔多斯盆地东部深层煤岩储层特性与煤岩气富集规律,文章从地质、煤质、煤体结构、地化特征、孔隙结构和含气性等方面开展了深部煤岩成藏特征和含气性规律研究。结果表明,盆地东部煤层的埋深呈“南北分带、西深东浅”的分布格局。其自上而下发育有10余套煤岩,以山西组5#和本溪组8#为主力煤层,分别形成于陆相泥炭沼泽环境以及受海水影响的泥炭沼泽环境。研究区煤层自西向东由暗淡型煤逐渐向光亮型煤过渡,本溪组光亮型煤占比高达75.3%;煤岩孔隙以胞腔孔、气泡孔、割理缝为主,深层煤岩储层以原生结构煤体为主且连续完整性较好,裂隙发育特征明显,平均基质渗透率为0.339×10^(-3)μm^(2),为煤储层游离气和吸附气的共同赋存提供了条件;储层以介孔发育为主,其体积增量占比为42.94%,并且与微孔显示出较好的延续性,两者的比表面积贡献率达74.41%;实验表明储层压力对煤岩吸附特性的影响的提升不明显,主要取决于温度;煤储层具有“高饱和度,高游离气”的双高特征,平均含气饱和度为125.04%,深部煤岩气游离气占比为27.41%。
In order to systematically explore the deep coal-rock reservoir characteristics and the enrichment law of coal-rock gas in the eastern part of Ordos Basin,this paper carried out a study on the characteristics of deep coal-rock accumulation characteristic and gas occurrence pattern from the aspects of geology,coal quality,coal body structure,geochemical characteristics,pore structure and gas-bearing properties.The results indicate that the coal seams in the eastern Ordos Basin exhibit a structurally controlled planar distribution pattern characterized by north south zonation and west-deeper/east-shallower trends.Vertically,over ten coal-bearing strata are developed,with the No.5 coal seam of the Shanxi Formation and No.8 coal seam of the Benxi Formation serving as the primary productive layers,deposited in continental and marine-influenced peat swamp environments,respectively.The coal lithotypes transition gradually from dull to bright coal eastward,with bright coal in the Benxi Formation accounting for 75.3%of the total.Pore systems are dominated by cellular pores,vesicular pores,and cleat fractures.Deep coal reservoirs predominantly consist of intact primary-structured coal with well-developed fracture networks,exhibiting an average matrix permeability of 0.339×10^(-3)μm^(2),favorable for dual gas storage(adsorbed and free states).The pore structure is mesopore-dominated(42.94%incremental pore volume),displaying strong continuity with micropores,collectively contributing 74.41%of the total specific surface area.Experimental results indicate that reservoir pressure exerts limited influence on gas adsorption capacity,whereas adsorption behavior is predominantly temperature-dependent.The reservoirs exhibit"dual-high"characteristics of high gas saturation(average 125.04%)and substantial free gas content(27.41%proportion in deep coal seams).
作者
张荣军
张喆
白亚萍
窦雨刚
屈乐
钟新宇
孙健
苗芷芃
陈朝兵
ZHANG Rongjun;ZHANG Zhe;BAI Yaping;DOU Yugang;QU Le;ZHONG Xinyu;SUN Jian;MIAO Zhipeng;CHEN Zhaobing(School of Petroleum Engineering,Xi′an Shiyou University,Xi′an,Shaanxi 710065,China;Xi′an Key Laboratory of Tight Oil(Shale Oil)Development,Xi′an Shiyou University,Xi′an,Shaanxi 710065,China;No.2 Gas Production Plant,Changqing Oilfield Company,Xi′an,Shaanxi 710020,China;School of Earth Sciences and Engineering,Xi′an Shiyou University,Xi′an,Shaanxi 710065,China)
出处
《钻采工艺》
北大核心
2025年第3期181-188,共8页
Drilling & Production Technology
基金
国家自然科学基金“致密油储层人工裂缝网络形成机制及其流体多场耦合渗流理论研究”(编号:52074226)
国家自然科学基金“基于多源随钻信息与机器学习的储层岩性实时智能识别研究”(编号:52304036)。
关键词
深层煤岩气
成藏特征
储层特征
煤岩含气性
鄂尔多斯盆地东部
deep coal-rock gas
accumulation characteristics
reservoir characteristics
coal rock gas occur⁃rence
east Ordos basin
