摘要
为明确有机质及矿物成分对鄂尔多斯盆地延长组7段(长7段)泥页岩储层孔隙结构的影响,利用氩离子抛光—场发射扫描电镜、低压氮气吸附实验,表征长7段泥页岩储层孔隙结构特征,并结合全岩矿物组分及有机地球化学实验,分析长7段泥页岩孔隙结构的主控因素。结果表明:长7段泥页岩主要发育黏土矿物晶间孔、粒间孔,可见少量有机质孔、溶蚀孔及微裂缝,其氮气吸附等温线均为Ⅱ型等温线,兼具有H3及H4型滞后环特征,表明泥页岩孔隙的中孔较为发育,孔隙形态呈平行片状及墨水瓶状。泥页岩孔隙结构受控于有机质、黏土矿物、石英、长石和黄铁矿,其中黏土矿物相转化在其矿物晶体层间形成大量微孔及中孔,是研究区泥页岩孔隙的主要来源;有机质生成的液态烃和固体沥青及自形单晶黄铁矿充填无机矿物孔隙,一定程度上减少了长7段泥页岩的孔隙空间。研究结果可以为认识长7段泥页岩孔隙结构特征及控制因素提供新的参考。
In order to clarify the influence of organic matter and mineral composition on the pore structure of shale reservoir in the seventh member of Yanchang Formation(Chang 7 Member),Ordos Basin,the pore structure characteristics of Chang 7 Member shale reservoir were analyzed by Argon Ion Polishing-Field Emission Scanning Electron Microscopy(FE-SEM)and Low-pressure Aitrogen adsorption(LP-N2A),and the controlling factors of pore structure were analyzed in combination with whole-rock mineral composition and organic geochemistry experiment.The results show that the Chang 7 Member shale mainly develops intercrystalline pores of clay minerals and intergranular pores,and a few organic matter pores,dissolution pores and microfractures can be seen.The LP-N2A isotherms of shale are all typeⅡisotherms,with H3and H4hysteresis loop characteristics,indicating that the mesopore are relatively developed,and the pore morphology is parallel lamellar and"ink bottle"shape.The pore structure of shale is controlled by the organic matter,clay minerals,quartz,feldspar and pyrite.The clay mineral phase transformation forms a large number of micropores and mesopores between the mineral crystal layers,which is the main source of pores in shale in the study area.Liquid hydrocarbon,solid asphalt and monoidiomorphic pyrite generated from organic matter filled the pores of inorganic minerals,which reduced the pore space of shale in Chang 7 Member to a certain extent.These results can provide a new cognition for understanding the pore structure characteristics and controlling factors of Chang 7 Member shale.
作者
黄伟凯
周新平
刘江艳
贺彤彤
马晓峰
陶辉飞
李树同
郝乐伟
HUANG Weikai;ZHOU Xinping;LIU Jiangyan;HE Tongtong;MA Xiaofeng;TAO Huifei;LI Shutong;HAO Lewei(Northwest Institute of Eco⁃Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;Key Laboratory of Petroleum Resources,Gansu Province,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China;National Engineering Laboratory for Exploration and Development of Low Permeability Oil&Gas Fields,Xi’an 710018,China;Exploration&Development Research Institute,PetroChina Changqing Oilfield Company,Xi’an 710018,China;No.9 Oil Production Plant,PetroChina Changqing Oilfield Company,Yinchuan 750001,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2022年第12期1951-1968,共18页
Natural Gas Geoscience
基金
国家自然科学青年基金(编号:41802160)资助
关键词
鄂尔多斯盆地
泥页岩
孔隙结构
场发射扫描电镜
低压氮气吸附
Ordos Basin
Shale
Pore structure
Field emission scanning electron microscopy
Low pressure nitrogen adsorption
