Experimental study of hydraulic fracture initiation and propagation in deep shale with different injection methods
文献类型：期刊论文
| 作者 | Chang, Xin1,4; Xu, Ersi3; Guo, Yintong1,4; Yang, Chunhe1,4; Hu, Zhiwen2; Guo, Wuhao1 |
| 刊名 | JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
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| 出版日期 | 2022-09-01 |
| 卷号 | 216期号:-页码:- |
| ISSN号 | 0920-4105 |
| 关键词 | Deep shale gas Hydraulic fracturing Injection methods Cyclic fluid injection Acoustic emission (AE) X-ray CT scanning |
| 英文摘要 | Deep shale gas reservoirs, compared to shallow and intermediate shale gas reservoirs, usually exhibit lower fracture complexity, smaller stimulated volume, poorer conductivity, and faster production decline when the same injection scheme and construction parameters are used. As a result, specific injection scenarios for deep shale reservoirs must be investigated. In this paper, a series of laboratory fracturing tests were conducted to investigate the influence of injection scenarios on deep shale hydraulic fracture initiation and propagation. The black shale of the Lower Silurian Longmaxi formation in the Sichuan Basin was adopted, and four different injection schemes (constant fluid rate injection, cyclic injection, shut-in intermittent injection, and low-frequency pulse pressurization injection) were utilized in these experiments. The energy evolution during hydraulic fracturing with different injection schemes was analyzed by an array of acoustic emission (AE) sensors. Furthermore, the internal fracture geometry of the shale specimens after failure was determined using high-resolution CT scanning. Two parameters, fracture bulk density and fractal dimension were defined to quantitatively characterize the post-pressure fracture complexity. The results indicate that the rock breakdown pressure rises rapidly as the injection rate increases, for conventional monotonic rate injection. Although increasing the injection rate can serve the purpose of increasing the net pressure in the seam and enhancing the fracture complexity, it makes it easier to approach the equipment pressure limit. Unlike conventional hydraulic fracturing, which mainly induces tensile fractures near the wellbore, cyclic fracturing is more likely to cause fatigue damage to the rock, resulting in the formation of subcritical microcracks, which gradually grow into macroscale fractures. In addition, the cyclic injection method can reduce the rock breakdown pressure by approximately 24% compared with the conventional continuous injection method. The shut-in intermittent injection method can also reduce the breakdown pressure of shale by 22%, but this method is not conducive to enhancing the fracture complexity. Pulse fracturing creates the most complex fracture morphology among the four injection schemes tested. The rapid changes in wellbore pressure over a short time can easily result in the formation of multiple fractures around the borehole. Our experimental results and theoretical analysis can provide theoretical support for the optimization of injection schemes for deep shale hydraulic fracturing. |
| 学科主题 | Energy & Fuels ; Engineering |
| 语种 | 英语 |
| 出版者 | ELSEVIER |
| WOS记录号 | WOS:000837977400001 |
| 源URL | [http://119.78.100.198/handle/2S6PX9GI/35188]  |
| 专题 | 中科院武汉岩土力学所 |
| 作者单位 | 1.State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China 2.State Key Laboratory of Coal Mine Disaster Dynamics and Control, College of Resources and Environmental Sciences, Chongqing University, Chongqing, 400044, China 3.Shale Gas Research Institute, PetroChina Southwest Oil & Gas Field Company, Chengdu, Sichuan, 610051, China 4.Hubei Key Laboratory of Geo-Environmental Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China |
| 推荐引用方式 GB/T 7714 | Chang, Xin,Xu, Ersi,Guo, Yintong,et al. Experimental study of hydraulic fracture initiation and propagation in deep shale with different injection methods[J]. JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING,2022,216(-):-. |
| APA | Chang, Xin,Xu, Ersi,Guo, Yintong,Yang, Chunhe,Hu, Zhiwen,&Guo, Wuhao.(2022).Experimental study of hydraulic fracture initiation and propagation in deep shale with different injection methods.JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING,216(-),-. |
| MLA | Chang, Xin,et al."Experimental study of hydraulic fracture initiation and propagation in deep shale with different injection methods".JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING 216.-(2022):-. |
入库方式： OAI收割
来源：武汉岩土力学研究所
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