In-situ hydrocarbon formation and accumulation mechanisms of micro- and nano-scale pore-fracture in Gulong shale, Songliao Basin, NE China  

作　　者：WANG Xiaojun CUI Baowen FENG Zihui SHAO Hongmei HUO Qiuli ZHANG Bin GAO Bo ZENG Huasen 

机构地区：[1]National Key Laboratory of Continental Shale Oil,Daqing 163002,China [2]PetroChina Daqing Oilfield Co.,Ltd.,Daqing 163002,China [3]PetroChina Daqing Oilfield Exploration and Development Research Institute,Daqing 163712,China [4]PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China

出　　处：《Petroleum Exploration and Development》2023年第6期1269-1281,共13页石油勘探与开发（英文版）

基　　金：Supported by the Central Guiding Local Science and Technology Development Special Project(ZY20B13)。

摘　　要：By conducting experimental analyses, including thermal pyrolysis, micro-/nano-CT, argon-ion polishing field emission scanning electron microscopy (FE-SEM), confocal laser scanning microscopy (CLSM), and two-dimensional nuclear magnetic resonance (2D NMR), the Gulong shale oil in the Songliao Basin was investigated with respect to formation model, pore structure and accumulation mechanism. First, in the Gulong shale, there are a large number of pico-algae, nano-algae and dinoflagellates, which were formed in brackish water environment and constituted the hydrogen-rich oil source materials of shale. Second, most of the oil-generating materials of the Qingshankou Formation shale exist in the form of organo-clay complex. During organic matter thermal evolution, clay minerals had double effects of suppression and catalytic hydrogenation, which expanded shale oil window and increased light hydrocarbon yield. Third, the formation of storage space in the Gulong Shale was related to dissolution and hydrocarbon generation. With the diagenesis, micro-/nano-pores increased, pore diameter decreased and more bedding fractures appeared, which jointly gave rise to the unique reservoir with dual media (i.e. nano-scale pores and micro-scale bedding fractures) in the Gulong shale. Fourth, the micro-/nano-scale oil storage unit in the Gulong shale exhibits independent oil/gas occurrence phase, and shows that all-size pores contain oils, which occur in condensate state in micropores or in oil-gas two phase (or liquid) state in macropores/mesopores. The understanding about Gulong shale oil formation and accumulation mechanism has theoretical and practical significance for advancing continental shale oil exploration in China.

关 键 词：micro- nano-scale oil storage unit hydrocarbon occurrence phase organo-clay complex in-situ hydrocarbon accumulation Gulong shale oil Cretaceous Qingshankou Formation Songliao Basin 

分 类 号：TE31[石油与天然气工程—油气田开发工程] P618.13[天文地球—矿床学]