Development and verification of a physical simulation experiment system for initiation and propagation of multiple clusters of hydraulic fractures

被引:0
|
作者
Bi Z. [1 ]
Wang L. [2 ]
Yang H. [1 ]
Guo Y. [2 ]
Zhou J. [2 ]
Chang X. [2 ]
Yang C. [1 ,2 ]
机构
[1] State Key Laboratory for Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing
[2] State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan
基金
中国国家自然科学基金;
关键词
Multi-cluster hydraulic fracturing; Multiple fractures propagation; Physical simulation experiment system; Rock mechanics; Strain monitoring;
D O I
10.13722/j.cnki.jrme.2021.0058
中图分类号
学科分类号
摘要
Horizontal well segmented multi-cluster fracturing technology is a core technical means for the development of shale gas reservoirs. For truly simulating the multi-cluster fracturing progress to reveal the propagation law and mutual interference mechanism of multiple fractures within the segments, a physical simulation experiment system for the initiation and propagation of multi-cluster hydraulic fractures was developed based on an existing large triaxial hydraulic fracturing experiment system, by designing a multi-channel fracturing wellbore and composite wrapped layered artificial specimens and equipping a multi-cluster shunt and monitoring system and a strain monitoring system. The advantages and innovations of the test system include that: (1) a number of independent fracture positions can be set in the multi-channel fracturing wellbore to guarantee the sufficient fracture propagation at each perforation cluster, (2) composite wrapped layered artificial fracturing cube samples with a side length of 500 mm can be prepared by considering the maximum allowable sample size of the testing machine, the maximum fracture propagation path, the stress interference between fractures, the pressure maintenance after fracture initiation and propagation, the influence of bedding and other factors, (3) the multi-cluster shunt and monitoring system can monitor the instantaneous flow rate, the pressure and the cumulative injection volume of each cluster channel in real time, which is helpful to understand the flow competition and allocation mechanism, (4) the strain monitoring system can monitor and record the deformation characteristics of the rock mass around each perforation cluster and fracture propagation path in real time during the fracturing process, which could be used for explaining the propagation behavior of hydraulic fractures, and (5) the system can not only simulate the initiation and propagation of multiple clusters of fractures, but also imitate the ball-sealer in-stage diversion technology and re-fracturing after the initial fracturing by selectively shutting a number of channels with sufficient fluid intake. A true triaxial multi-cluster fracturing test was carried out to verify the effectiveness of the system. The test results show that the breakdown pressure of the subsequent perforation clusters gradually increases while the corresponding stimulated area decreases. The developed experiment system provides a new method for the study of multi-cluster fracturing, which can promote the in-depth study of the initiation and propagation of multi-cluster hydraulic fractures and the stress interference mechanism between the fractures. © 2021, Science Press. All right reserved.
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页码:2273 / 2285
页数:12
相关论文
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