Characteristics and controlling factors of organic pores in the 7th member of Yanchang Formation shale in the Southeastern Ordos Basin

被引：0

作者：

Cai Z. ^{[1
,2
]}

Lei Y. ^{[1
]}

Luo X. ^{[1
,2
]}

Wang X. ^{[3
,4
,5
]}

Cheng M. ^{[1
]}

Zhang L. ^{[3
,4
,5
]}

Jiang C. ^{[3
,4
,5
]}

Zhao Q. ^{[3
,4
,5
]}

Yin J. ^{[3
,4
,5
]}

Zhang L. ^{[3
,4
,5
]}

机构：

[1] Key Laboratory of Petroleum Resource Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing

[2] University of Chinese Academy of Sciences, Beijing

[3] Shaanxi Yanchang Petroleum (Group) Co., Ltd., Xi'an, 710075, Shaanxi

[4] Shaanxi Engineering Technology Research Center of Shale Gas Exploration and Development, Xi'an, 710075, Shaanxi

[5] Shaanxi Key Laboratory of Lacustrine Shale Gas Accumulation and Exploitation, Xi'an, 710075, Shaanxi

来源：

Oil and Gas Geology | 2020年 / 41卷 / 02期

关键词：

Ordos Basin; Organic pore; Shale; Type of solid organic matters; Yanchang Formation;

D O I：

10.11743/ogg20200213

中图分类号：

学科分类号：

摘要：

Recent studies have shown that organic pores are developed in the medium-to-low-maturity shale of the 7th member of Yanchang Formation in the Southeastern Ordos Basin, but the influencing factors on the development of organic pores in the continental shale reservoir need to be further understood. With the aid of argon ion polishing and FE-SEM observation, we observed the characteristics of organic pores in Chang 7 shale in the Southeastern Ordos Basin. Statistical analysis was made on the organic pore sizes in kerogen of different maturity and different types of migrated solid organic matters, and also on the ratio of organic pore area to the total organic matter area (SR) of these organic matters. Thereaf-ter, main factors affecting the development of organic pores were discussed. The results indicate that organic pores were widely developed in shales of diverse maturity (Ro: 0.5%-1.25%) in the Chang 7 member, but there were significant differences in the development of organic pores in kerogens and migrated solid organic matters. Sedimentary organic matter (kerogen) occurs mainly in the form of enrichment along beddings, isolated dispersion and combination with clay minerals in shale and has relatively lower degree of organic pore development. The ratio of the organic pore area to the total organic matter area ranges from 0% to 44.13%, averaging at 6.03%, but generally less than 10%. The majority of organic pores ranges from 10 nm to 40 nm in size. The migrated solid organic matters mainly occurs in inorganic mineral pores, including inter-particle pores/inter-particle dissolution pores in rigid particles, inter-particle pores/inter-particle dissolution pores between rigid particles and clay minerals, intercrystalline pores in pyrite of shale. These organic matters have relatively higher degree of organic pore development. The ratio of the organic pore area to the organic matter area varies from 0% to 46.51%, averaging at 23.05% and generally less than 30%. In addition, the pore size is larger, mainly ranging from 50 nm to 100 nm. The development of organic pores in the Chang 7 member shale is mainly controlled by the organic matter type, the abundance of migrated solid organic matters and the maturity of organic matter: positively correlated with higher content of migrated solid organic matters and more maturity of the organic matters. © 2020, OIL & GAS GEOLOGY Editorial Board. All right reserved.

引用

页码：367 / 379

页数：12

共 48 条

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