海相页岩成岩-成烃过程中孔隙结构的演变——来自热模拟实验的启示

doi:10.7623/syxb202005003

石油学报 ›› 2020, Vol. 41 ›› Issue (5): 540-552.DOI: 10.7623/syxb202005003

海相页岩成岩-成烃过程中孔隙结构的演变——来自热模拟实验的启示

罗文彬^1,2,3, 马中良^1,4,5, 郑伦举^4,5, 谭静强^1,2,3, 王张虎^1,2,3, 宁传祥^4,5

1. 中南大学地球科学与信息物理学院湖南长沙 410083;
2. 有色金属成矿预测与地质环境监测教育部重点实验室湖南长沙 410083;
3. 有色资源与地质灾害探查湖南省重点实验室湖南长沙 410083;
4. 中国石油化工股份有限公司石油勘探开发研究院无锡石油地质研究所江苏无锡 214126;
5. 页岩油气富集机理与有效开发国家重点实验室江苏无锡 214126

收稿日期:2019-06-10 修回日期:2019-09-25 出版日期:2020-05-25 发布日期:2020-06-08
通讯作者: 马中良,男,1984年12月生,2006年获中国石油大学(北京)学士学位,2009年获中国石油大学(北京)硕士学位,现为中国石油化工股份有限公司石油勘探开发研究院无锡石油地质研究所高级工程师、中南大学博士研究生,主要从事油气地球化学、石油实验地质学和油页岩原位开采技术研究。Email:mazl.syky@sinopec.com
作者简介:罗文彬,男,1994年3月生,2017年获华北科技学院地质工程专业学士学位,现为中南大学地球科学与信息物理学院硕士研究生,主要从事非常规油气地质研究。Email:lwblll@csu.edu.cn
基金资助:
国家自然科学基金项目（No.41872151）和国家科技重大专项（2017ZX05036-002-004，2017ZX05005-001-003）资助。

Evolution of pore structure during diagenesis and hydrocarbon generation of marine shale: the inspiration from thermal simulation experiments

Luo Wenbin^1,2,3, Ma Zhongliang^1,4,5, Zheng Lunju^4,5, Tan Jingqiang^1,2,3, Wang Zhanghu^1,2,3, Ning Chuanxiang^4,5

1. School of Geosciences and Info-Physics, Central South University, Hunan Changsha 410083, China;
2. Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education, Hunan Changsha 410083, China;
3. Hunan Key Laboratory of Nonferrous Resources and Geological Hazards Exploration, Hunan Changsha 410083, China;
4. Wuxi Institute of Petroleum Geology, Sinopec Petroleum Exploration and Production Research Institute, Jiangsu Wuxi 214126, China;
5. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Jiangsu Wuxi 214126, China

Received:2019-06-10 Revised:2019-09-25 Online:2020-05-25 Published:2020-06-08

摘要/Abstract

摘要：

页岩在沉积埋藏过程中，孔隙的形成、演变与成岩-成烃过程是同步的。为了揭示成岩-成烃作用对页岩孔隙结构的影响，以西加拿大盆地上白垩统海相未成熟页岩为研究对象，开展了地质条件约束下页岩从未成熟到过成熟阶段的成岩-成烃热模拟实验，并利用高分辨扫描电镜对热模拟后样品的微观结构进行分析，运用低温液氮吸附-脱附实验和Frenkel-Halsey-Hill （FHH）模型对实验样品的孔隙发育特征和分形维数进行定量分析。结果表明：①成岩-成烃过程中页岩的孔隙结构复杂多变，主要发育介孔和大孔，以楔状或平行板状狭缝型孔隙为主；②页岩中的孔隙比表面积主要为小于15 nm的微孔和介孔所贡献；③有机质丰度并非影响孔隙分形特征的主要因素，孔隙的结构分形维数与平均孔径存在明显的负相关关系，孔径越小孔隙间的连通性越差，孔隙结构越复杂；④不同演化阶段孔隙的分形特征差异明显，成熟阶段的生烃作用导致黏土矿物转化及矿物溶蚀可大大降低孔隙结构及表面的复杂程度，高过成熟阶段有机质孔的大量形成可增大孔隙表面的粗糙程度并使得页岩具有高的孔隙比表面积。

关键词: 海相未成熟页岩, 孔隙结构, 分形特征, 非均一性, 热模拟, 氮气吸附

Abstract:

During the deposition and burial of shale, pore formation and evolution are synchronized with the diagenesis and hydrocarbon generation processes. To reveal the effect of diagenesis and hydrocarbon generation on the pore structure of shale, taking the Upper Cretaceous marine immature shale in the Western Canada Basin as the research object, this study carries out the thermal simulation experiments on the diagenesis and hydrocarbon generation of shale from immature to over-mature stages under the geological conditions, analyzes the microstructures of samples after thermal simulation using the high-resolution scanning electron microscope, and quantitatively analyzes the pore development characteristics and fractal dimensions of experimental samples using the liquid nitrogen adsorption-desorption experiment and the Frenkel-Halsey-Hill (FHH) model. The results show as follows. (1) During diagenesis and hydrocarbon generation, the pore structures of shale are complex and changeable, mainly developing mesoporous and macroporous, with the shape of wedge or parallel plate. (2) The specific surface area of pore is mainly contributed by micropores and mesopores with the diameter smaller than 15 nm in shale. (3) Organic matter abundance is not the main factor affecting the fractal characteristics of pores. There is a clear negative correlation between the fractal dimension of pore structure and the average pore size, the smaller the pore size, the poor the pore connectivity, and the more complex the pore structure. (4) The fractal characteristics of pores in different evolutionary stages are obviously different.The clay mineral transformation and mineral dissolution caused by hydrocarbon generation in the mature stage can greatly reduce the complexity of pore structure and surface, while the formation of a large number of organic matter pores in the mature stage can increase the roughness of pore surface and make shale have a high pore specific surface area.

Key words: marine immature shale, pore structure, fractal characteristics, inhomogeneity, thermal simulation, nitrogen adsorption

中图分类号:

TE122.2

罗文彬, 马中良, 郑伦举, 谭静强, 王张虎, 宁传祥. 海相页岩成岩-成烃过程中孔隙结构的演变——来自热模拟实验的启示[J]. 石油学报, 2020, 41(5): 540-552.

Luo Wenbin, Ma Zhongliang, Zheng Lunju, Tan Jingqiang, Wang Zhanghu, Ning Chuanxiang. Evolution of pore structure during diagenesis and hydrocarbon generation of marine shale: the inspiration from thermal simulation experiments[J]. Acta Petrolei Sinica, 2020, 41(5): 540-552.

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海相页岩成岩-成烃过程中孔隙结构的演变——来自热模拟实验的启示

Evolution of pore structure during diagenesis and hydrocarbon generation of marine shale: the inspiration from thermal simulation experiments

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