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

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 w...

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Main Authors: Xiaojun WANG, Baowen CUI, Zihui FENG, Hongmei SHAO, Qiuli HUO, Bin ZHANG, Bo GAO, Huasen ZENG
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2023-12-01
Series:Petroleum Exploration and Development
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1876380424604659
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author Xiaojun WANG
Baowen CUI
Zihui FENG
Hongmei SHAO
Qiuli HUO
Bin ZHANG
Bo GAO
Huasen ZENG
author_facet Xiaojun WANG
Baowen CUI
Zihui FENG
Hongmei SHAO
Qiuli HUO
Bin ZHANG
Bo GAO
Huasen ZENG
author_sort Xiaojun WANG
collection DOAJ
description 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.
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spelling doaj.art-4555ef10e8734e6197269a21d6887b802023-12-20T07:34:00ZengKeAi Communications Co., Ltd.Petroleum Exploration and Development1876-38042023-12-0150612691281In-situ hydrocarbon formation and accumulation mechanisms of micro- and nano-scale pore-fracture in Gulong shale, Songliao Basin, NE ChinaXiaojun WANG0Baowen CUI1Zihui FENG2Hongmei SHAO3Qiuli HUO4Bin ZHANG5Bo GAO6Huasen ZENG7National Key Laboratory of Continental Shale Oil, Daqing 163002, China; PetroChina Daqing Oilfield Co., Ltd., Daqing 163002, China; Corresponding author.National Key Laboratory of Continental Shale Oil, Daqing 163002, China; PetroChina Daqing Oilfield Co., Ltd., Daqing 163002, ChinaNational Key Laboratory of Continental Shale Oil, Daqing 163002, China; PetroChina Daqing Oilfield Exploration and Development Research Institute, Daqing 163712, ChinaNational Key Laboratory of Continental Shale Oil, Daqing 163002, China; PetroChina Daqing Oilfield Exploration and Development Research Institute, Daqing 163712, ChinaNational Key Laboratory of Continental Shale Oil, Daqing 163002, China; PetroChina Daqing Oilfield Exploration and Development Research Institute, Daqing 163712, ChinaPetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, ChinaNational Key Laboratory of Continental Shale Oil, Daqing 163002, China; PetroChina Daqing Oilfield Exploration and Development Research Institute, Daqing 163712, ChinaNational Key Laboratory of Continental Shale Oil, Daqing 163002, China; PetroChina Daqing Oilfield Exploration and Development Research Institute, Daqing 163712, ChinaBy 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.http://www.sciencedirect.com/science/article/pii/S1876380424604659micro-/nano-scale oil storage unithydrocarbon occurrence phaseorgano-clay complexin-situ hydrocarbon accumulationGulong shale oilCretaceous Qingshankou Formation
spellingShingle Xiaojun WANG
Baowen CUI
Zihui FENG
Hongmei SHAO
Qiuli HUO
Bin ZHANG
Bo GAO
Huasen ZENG
In-situ hydrocarbon formation and accumulation mechanisms of micro- and nano-scale pore-fracture in Gulong shale, Songliao Basin, NE China
Petroleum Exploration and Development
micro-/nano-scale oil storage unit
hydrocarbon occurrence phase
organo-clay complex
in-situ hydrocarbon accumulation
Gulong shale oil
Cretaceous Qingshankou Formation
title In-situ hydrocarbon formation and accumulation mechanisms of micro- and nano-scale pore-fracture in Gulong shale, Songliao Basin, NE China
title_full In-situ hydrocarbon formation and accumulation mechanisms of micro- and nano-scale pore-fracture in Gulong shale, Songliao Basin, NE China
title_fullStr In-situ hydrocarbon formation and accumulation mechanisms of micro- and nano-scale pore-fracture in Gulong shale, Songliao Basin, NE China
title_full_unstemmed In-situ hydrocarbon formation and accumulation mechanisms of micro- and nano-scale pore-fracture in Gulong shale, Songliao Basin, NE China
title_short In-situ hydrocarbon formation and accumulation mechanisms of micro- and nano-scale pore-fracture in Gulong shale, Songliao Basin, NE China
title_sort in situ hydrocarbon formation and accumulation mechanisms of micro and nano scale pore fracture in gulong shale songliao basin ne china
topic micro-/nano-scale oil storage unit
hydrocarbon occurrence phase
organo-clay complex
in-situ hydrocarbon accumulation
Gulong shale oil
Cretaceous Qingshankou Formation
url http://www.sciencedirect.com/science/article/pii/S1876380424604659
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