Theoretical study of break down pressures and fracture initiation angles based on model containing wellbore and perforations

被引：5
作者：
Fan Y. [1 ,2 ]
Zhao Y. [1 ,2 ]
Zhu Z. [1 ,2 ]
Zhou C. [1 ,2 ]
Zhang X. [1 ,2 ]
机构：
[1] MOE Key Laboratory Deep Underground Science and Engineering, Sichuan University, Chengdu
[2] College of Architecture and Environment, Sichuan University, Chengdu
来源：
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | 2019年 / 50卷 / 03期
基金：
中国国家自然科学基金;
关键词：
Break down pressure; Hydraulic fracturing; Initiation angle; Perforation; Stress intensity factor;
D O I：
10.11817/j.issn.1672-7207.2019.03.021
中图分类号：
学科分类号：
摘要：
In order to study the influences of perforation parameters on break down pressures and hydraulic crack initiation angles, a 2D model containing perforations and wellbore was established to simplify the perforations as a crack. By conformal mapping techniques, the stress intensity factors at perforation tips were obtained. The theoretical method to calculate break down pressure and initiation angle was acquired according to the maximum tensile failure criterion. For validating the theoretical solutions, the experimental results and the in-situ test results were compared with the calculated results. The results show that they are in good agreement. The hydraulic crack initiation angles increase with the increase of two principal stresses, the perforation lengths and the perforation azimuths. The optimal perforation azimuth is between 0° to 15° with the major principal stress. The optimal perforation length is between 2 and 3 times wellbore diameter. © 2019, Central South University Press. All right reserved.
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页码：669 / 678
页数：9
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