Enrichment conditions and exploration potential of shale gas in continental lake basins in Qikou Sag, Bohai Bay Basin

被引：0

作者：

Zhou L. ^{[1
]}

Chen C. ^{[1
]}

Han G. ^{[1
]}

Yang F. ^{[1
]}

Shi Q. ^{[1
]}

Fu D. ^{[1
]}

Dong Y. ^{[1
]}

Zhao Y. ^{[1
]}

Sun L. ^{[1
]}

Liang C. ^{[1
]}

机构：

[1] PetroChina Dagang Oilfield Company, Tianjin

来源：

Natural Gas Industry | 2021年 / 41卷 / 05期

关键词：

Bohai Bay Basin; Continental shale gas; Exploration potential; Hydrocarbon accumulation pattern; Paleogene; Qikou Sag; The third Member of Shahejie Formation;

D O I：

10.3787/j.issn.1000-0976.2021.05.001

中图分类号：

学科分类号：

摘要：

To further evaluate the shale gas enrichment conditions and exploration potentials of the continental lake basin in Qikou Sag of the Bohai Bay Basin, this paper studies the Es3(the third Member of Paleogene Shahejie Formation) shale in this area comprehensively from the aspects of sedimentary environment, lithology and its combination characteristics, hydrocarbon generation conditions, reservoir space, rock brittleness and gas bearing property by using seismic, wireline logging, mud logging and core analysis data. In addition, the shale gas accumulation pattern in this area is established and shale gas exploration potential is evaluated. And the following research results were obtained. First, the Es3 shale in this area is of great cumulative thickness and large distribution area, and in the middle-low slope area of Qikou Sag it has entered the stage of a large amount of gas generation, so it has the hydrocarbon generation conditions for scale shale gas reservoirs. Second, speaking of the shale in this area, the content of felsic minerals is dominant, and matrix pores and micro fractures are more developed to provide some reservoir spaces. Moreover, the content of brittle minerals is high, and the total content of illite and illite/montmorillonite interlayer in clay minerals is 94%. The shale of low expansion and brittle can be fractured easily. Third, fluid expansion generated in the process of continuous hydrocarbon generation is the main cause of overpressure in Es3. The shale interval with pressure coefficient higher than 1.2 presents an obvious anomaly in while-drilling gas logging and has the conditions for shale gas accumulation. Fourth, when the burial depth of Es3in Qikou Sag is 3 100-4 400 m, shale gas and shale oil are associated mainly in the form of dissolved gas; when it is 4 400-4 850 m, wet gas is dominant; and when it is greater than 4 850 m, dry gas is dominant. In conclusion, the middle-low slope area in Qikou Sag is a favorable target area for shale gas exploration, whose favorable exploration area is about 1 476 km2 and shale gas resource is more than 1×1012 m3, indicating greater shale gas exploration potential. © 2021, Natural Gas Industry Journal Agency. All right reserved.

引用

页码：1 / 10

页数：9

共 29 条

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