Theory and method of temporary macrofracture plugging to prevent casing deformation in shale gas horizontal wells

被引：0

作者：

Tong H. ^{[1
,2
]}

Liu Z. ^{[3
]}

Zhang H. ^{[2
]}

Zhang P. ^{[3
]}

Deng C. ^{[3
]}

Ren X. ^{[3
]}

Xiao K. ^{[2
]}

Zhou Y. ^{[3
]}

机构：

[1] State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing

[2] College of Geosciences, China University of Petroleum, Beijing

[3] CNPC Chuanqing Drilling Engineering Company Limited, Chengdu

来源：

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

关键词：

Casing deformation; Casing deformation rate; Generalized shear activity criterion; Horizontal well; Hydraulic fracturing; Shale gas; Shear activity; Temporary macrofracture plugging;

D O I：

10.3787/j.issn.1000-0976.2021.05.010

中图分类号：

学科分类号：

摘要：

Since the industrial development of shale gas in China began at the end of 2013, many horizontal wells have undergone casing deformation, which seriously impacts the development efficiency and benefits of shale gas. In order to prevent and control casing deformation in shale-gas horizontal wells, this paper firstly confirms that casing deformation is caused by the shear activity of faults and macrofractures (referred to as fault-fracture) in the process of hydraulic fracturing. Then, according to the generalized shear activity criterion, the influences of the fluid pressure of hydraulic fracturing on fault-fracture shear activity are analyzed, the comprehensive criterion of preferred flow channel of fracturing fluid under the state of in-situ stress is established, and the factors influencing the flow capacity of natural fractures are quantitatively analyzed, so as to provide theoretical basis for temporary macrofracture plugging. Finally, fault-fracture risks are divided into three levels according to activity coefficient (fa) and fault-fracture scale, and the temporary plugging timing of faults-fractures of different risk levels is determined. And the following research results were obtained. First, macrofractures are the high-speed flow channels of fracturing fluid loss. Second, controlling the loss of fracturing fluid along macrofractures can effectively prevent casing deformation. Third, the combined temporary plugging can cut off or prevent the loss of fracturing fluid along macrofractures. Field tests of temporary macrofracture plugging were carried out in 19 wells, and the casing deformation rate decreased from 50.4% (before the test) to 15.8%. Great effects have been achieved, and significant progress has been made in the prevention of casing deformation. In conclusion, temporary macrofracture plugging is an effective method to prevent casing deformation in shale gas development, and is worthy of further popularization and application. © 2021, Natural Gas Industry Journal Agency. All right reserved.

引用

页码：92 / 100

页数：8

共 33 条

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