Characteristics of shale gas enrichment in tectonically complex regions -A case study of the Wufeng-Longmaxi Formations of Lower Paleozoic in southeastern Sichuan Basin

被引：0
|
作者：
Lu Z. [1 ,2 ]
He Z. [2 ,3 ,4 ]
Yu C. [5 ]
Ye X. [2 ,3 ,6 ]
Li D. [2 ,3 ,6 ]
Du W. [2 ,3 ,6 ]
Nie H. [2 ,3 ,6 ]
机构：
[1] School of Energy Resources, China University of Geosciences (Beijing), Beijing
[2] State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing
[3] Key Laboratory of Shale Oil & Gas Exploration & Production, SINOPEC, Beijing
[4] Department of Science and Technology, China Petroleum & Chemical Corporation, Beijing
[5] Chongqing Institute of Geology and Mineral Resources, Chongqing
[6] Petroleum Exploration and Production Research Institute, SINOPEC, Beijing
来源：
Oil and Gas Geology | 2021年 / 42卷 / 01期
关键词：
Graptolite belt; High-quality shale; Lower Paleozoic; Reservoir space; Shale gas; Southeastern Sichuan Basin; Tectonic uplift; Wufeng-Longmaxi Formations;
D O I：
10.11743/ogg20210108
中图分类号：
学科分类号：
摘要：
The Dingshan area in southeastern Sichuan Basin is one of the focal points for shale gas exploration and development in China.Despite some promising test results achieved from several wells drilled in the area, the subsequent rapid production decline rate and low EUR estimations make their development uneconomical.To tackle the problem, efforts were exerted to the characterization of shale gas accumulations and predication of potential exploration targets in such areas.The representative Wufeng-Longmaxi Formation shale in the Dingshan area was chosen to conduct analyses of the shale rock types, distribution characteristics, reservoir types and gas content by means of core observation, identification and correlation of graptolite belts and scanning electron microscope (SEM) observation.The results show that there are four types of shale: siliceous shale, lime-calcareous shale, clayey shale and silty shale.Among them, the siliceous shale in the graptolite belt of the second member of the Wufeng Formation and the fourth member of the Longmaxi Formation (WF2-LM4) is potentially high-quality shale rocks with a thickness of 6 m to 10 m.The reservoir space is mainly organic-matter pores, mineral pores and micro-fractures.The dissolution pores that are well developed near the margin of the basin are found to be no signs of asphalt, indicating a poor preservation condition for shale gas.Compared with the Fuling shale gas field, the siliceous shale rocks in the graptolite belts in the Dingshan area are thinner, with those buried shallow in the faulting zone near the edge of the basin containing shallow normal-pressure gas reservoirs of low formation pressure coefficients, and those distributed basinward having deep, over-pressure gas reservoirs of high pressure coefficient.It is suggested that the exploration of shale gas should be focused on parts with large thickness, moderate burial depth and good preservation conditions in the WF2-LM4 zones of southeastern Sichuan Basin. © 2021, OIL & GAS GEOLOGY Editorial Board. All right reserved.
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页码：86 / 97
页数：11
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