Characteristics and exploration potential of unconventional Middle Triassic Lei32 reservoirs in the central Sichuan Basin

被引：0

作者：

Yang Y. ^{[1
]}

Xie J. ^{[1
]}

Zhang J. ^{[2
]}

Wen L. ^{[1
]}

Zhao L. ^{[1
]}

Zhang H. ^{[2
]}

Tian H. ^{[2
]}

Wang Z. ^{[2
]}

Fu X. ^{[2
]}

Li W. ^{[2
]}

Sun H. ^{[1
]}

Xie Z. ^{[2
]}

Hao Y. ^{[2
]}

Xin Y. ^{[2
]}

机构：

[1] PetroChina Southwest Oil and Gas Company, Sichuan, Chengdu

[2] PetroChina Research Institute of Petroleum Exploration & Development, Beijing

来源：

Natural Gas Industry | 2022年 / 42卷 / 12期

关键词：

Argillaceous limestone and limy mudstone; Central Sichuan Basin; Exploration potential; Lagoon facies; Lei[!sub]3[!/sub][!sup]2[!/sup; Leikoupo Formation; Middle Triassic; Unconventional reservoir;

D O I：

10.3787/j.issn.1000-0976.2022.12.002

中图分类号：

学科分类号：

摘要：

Well CT1 in the central Sichuan Basin recently obtained a high yield of oil and gas flows from the argillaceous limestone and limy mudstone of the second sub-member of the third member of Triassic Leikoupo Formation (Lei32), making it a possible important strategic petroleum successor system in the Sichuan Basin. Based on the analysis data of drilling cores and cuttings, the characteristics of the Lei32 argillaceous limestone and limy mudstone reservoirs are studied, the favorable reservoir areas are predicted according to well–seismic data, and the petroleum exploration potential in the study area is analyzed with consideration to the geological conditions for hydrocarbon accumulation. The results show that the Lei32 argillaceous limestone and limy mudstone reservoirs have a storage space mainly composed of nano- to micron-scale inorganic pores, organic pores and micro-fractures, with a porosity of 2.00%–8.51% (2.7% on average) and a permeability of 0.000 76–1.680 00 mD (0.190 mD on average), indicating low-porosity and low-permeability unconventional reservoirs. The content of clay minerals and gypsum is a key factor controlling the porosity of reservoirs, and the reservoir porosity is high in areas with a high content of clay minerals and gypsum. Fractures are a key factor controlling the permeability of reservoirs. Reservoirs of lagoon facies are widely distributed in central Sichuan Basin. Two favorable reservoir areas, Xichong–Yilong and WD6–MX3, are recognized. The Xichong–Yilong area contain reservoirs with a thickness of 30–50 m and an area of 4 700 km2. The WD6–MX3 area contains reservoirs with a thickness of 10–30 m and an area of approximately 4 000 km2. It is concluded that the widespread argillaceous limestone and limy mudstone of lagoon facies in Lei32 strata serve as both source rocks and reservoir rocks, with the roof and floor sealed and capped by gypsum rocks, where hydrocarbons are generated, stored and sealed in situ, forming a new type of unconventional gas accumulation system. Therefore, the Lei 2 reservoirs in the central Sichuan Basin have a great exploration potential and can be considered as a new target of exploration. © 2022 Natural Gas Industry Journal Agency. All rights reserved.

引用

页码：12 / 22

页数：10

共 30 条

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