Experimental study on hydraulic fracturing properties of elliptical boreholes

Liu, Chao1,2,3; Zhang, Dongming3; Zhao, Honggang3; Li, Minghui3; Song, Zhenlong3,4

2022

10.1007/s10064-021-02531-9

Bulletin of Engineering Geology and the Environment   影响因子和分区

1435-9529

1435-9537

Subsurface rocks are in the in situ stress state prior to drilling. The original and intact borehole subjected to stress redistribution can be deformed during field operations, and elliptical boreholes will be generated. Most laboratory scale hydraulic fracturing experimental specimens were predrilled in the center without considering lateral and axial pressure. In order to investigate the hydraulic fracturing characteristics of boreholes with non-circular appearance commonly seen in the field, hydraulic fracturing experiments were performed on boreholes with elliptical morphology. These experiments provide a comparison of elliptical and circular boreholes, and indicated that the horizontal in situ stress difference and borehole shape affect the breakdown pressure together. When the horizontal stress difference exists, the breakdown pressure reduces with the increase of the short-axis of elliptical boreholes. At zero horizontal stress difference, the situation is just the opposite. The analytic solutions of the stress fields near the elliptical borehole were obtained by employing the complex variable function. The fracture initiation conforms to the maximum tensile stress criterion. Whether the borehole is elliptical or circular, the damage process during hydraulic fracturing will cause fractures to eventually curve to the major stress direction.

Elliptical borehole Hydraulic fracturing Maximum circumferential stress Fracture initiation

SCI ; EI

英语

其他

National Natural Science Foundation of China[51874053,52108386,51734009] ; Fundamental Research Funds for the Central Universities[2021QN1027]

Engineering ; Geology

Engineering, Environmental ; Engineering, Geological ; Geosciences, Multidisciplinary

WOS:000730246900002

SPRINGER HEIDELBERG

20215111366200

Boreholes ; Fracture ; Stresses

Petroleum Deposits : Development Operations:512.1.2 ; Materials Science:951

Web of Science

1.China Univ Min & Technol, State Key Lab Geomech & Deep Underground Engn, Xuzhou 221116, Jiangsu, Peoples R China
2.China Univ Min & Technol, Sch Mech & Civil Engn, Xuzhou 221116, Jiangsu, Peoples R China
3.Chongqing Univ, State Key Lab Coal Mine Disaster Dynam & Control, Chongqing 400030, Peoples R China
4.Southern Univ Sci & Technol, Dept Earth & Space Sci, Shenzhen 518055, Guangdong, Peoples R China

Liu, Chao,Zhang, Dongming,Zhao, Honggang,et al. Experimental study on hydraulic fracturing properties of elliptical boreholes[J]. Bulletin of Engineering Geology and the Environment,2022,81(1).

Liu, Chao,Zhang, Dongming,Zhao, Honggang,Li, Minghui,&Song, Zhenlong.(2022).Experimental study on hydraulic fracturing properties of elliptical boreholes.Bulletin of Engineering Geology and the Environment,81(1).

Liu, Chao,et al."Experimental study on hydraulic fracturing properties of elliptical boreholes".Bulletin of Engineering Geology and the Environment 81.1(2022).