Numerical simulation of casing deformation during volume fracturing of horizontal shale gas wells

Guo, Xuqiang; Li, Jun; Liu, Gonghui; Xi, Yan; Zeng, Yanjun; He, Miao; Hui, Yan

doi:10.1016/j.petrol.2018.08.067

Cited by 65 publications

(24 citation statements)

References 24 publications

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“…13,20 Vast engineering practice indicated that 78% of the microseismic events had a strike-slip failure mechanism in Southern Simonette, Canada. Recent studies showed that fault activity occurred during multistage fracturing appeared to be associated with a strike-slip stress regime (S Hmax > S Vertical > S Hmin ) in Sichuan basin, China.…”

Section: Slippingmentioning

confidence: 99%

“…Recent studies showed that fault activity occurred during multistage fracturing appeared to be associated with a strike-slip stress regime (S Hmax > S Vertical > S Hmin ) in Sichuan basin, China. 13,20 Vast engineering practice indicated that 78% of the microseismic events had a strike-slip failure mechanism in Southern Simonette, Canada. Thus, it could be inferred that the strike-slip fault sliding was the main reason of casing shear deformation.…”

Section: Analysis Of Fault Slippingmentioning

confidence: 99%

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A new numerical method for evaluating the variation of casing inner diameter after strike‐slip fault sliding during multistage fracturing in shale gas wells

Liu

et al. 2019

Energy Science & Engineering

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Casing shear deformation has become a prominent problem in the process of completion in shale gas wells. It was believed that the slide of strike‐slip fault induced by multistage fracturing was the main reason. This paper presented a new numerical investigation for evaluating the casing inner diameter after strike‐slip fault sliding based on the microseismic data. A 3D finite element model, considering the mechanical anisotropy of shale and heat‐fluid‐solid coupling effect during multistage fracturing, was developed to calculate the variation of casing inner diameter after fault sliding under different engineering and geological conditions. The calculation result was verified by comparison with the measurement result of the multi‐finger caliper survey. Sensitivity analysis was carried out and the results showed that decreasing the sliding distance, maintaining high pressure, increasing the casing thickness, and increasing the elasticity modulus and decreasing the Poisson ratio of cement sheath were beneficial to protect the casing integrity. Finally, the engineering verification demonstrated that the numerical method has an accuracy up to 85.9%. Numerical model in this study was expected to provide a better understanding of casing shear deformation and an evaluation method of casing inner diameter after fault sliding during multistage fracturing in shale gas wells.

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Section: Slippingmentioning

confidence: 99%

Section: Analysis Of Fault Slippingmentioning

confidence: 99%

A new numerical method for evaluating the variation of casing inner diameter after strike‐slip fault sliding during multistage fracturing in shale gas wells

Liu

et al. 2019

Energy Science & Engineering

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“…Therefore, hydraulic fracturing technology is required to achieve higher yields. 1 , 2 However, this method can seriously threaten the sealing integrity of the cement sheath as a result of the large displacement, high pump pressure, and cyclic loading. 3 , 4 During the shale gas development process for the Fuling shale gas block in Sichuan Basin, China, there has been a significant sustained casing pressure (SCP) phenomenon after staged fracturing.…”

Section: Introductionmentioning

confidence: 99%

Sealing Failure Mechanism and Control Method for Cement Sheath during Hydraulic Fracturing

Lian

Qian

et al. 2020

ACS Omega

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This study focused on the sealing failure mechanism and control method for a cement sheath during hydraulic fracturing. Taking a shale gas well as an example, whole wellbore numerical models of the casing-cement sheath-formation assembly were established, failure modes of the cement sheath at different depths were clarified, and control methods were proposed based on the calculation results. The following conclusions were drawn. (1) The maximum radial/tangential stress of the cement sheath increased/decreased with an increase in the depth, and the cement sheath above the intermediate casing shoe posed the risk of tangential tensile failure, resulting in tensile cracks. The cement sheath below the intermediate casing shoe produced a micro-annulus under a cyclic casing pressure, and the tensile cracks and micro-annulus constituted passages for the sustained casing pressure. (2) The swelling stress of the expansion cement slurry could offset the circumferential tensile stress and increase the radial compressive stress. Because a cement sheath with a high Young’s modulus usually exhibits high tensile and compressive strengths, it is recommended to use a high Young’s modulus cement slurry system above the intermediate casing shoe and optimize the free expansion ratio. (3) In comparison with ordinary cement stone, low residual strain cement stone exhibited a larger elastic deformation interval. The cumulative residual strain caused by cyclic loading was smaller, and the Young’s modulus demonstrated a lesser decrease. The results of an equivalent physical experiment demonstrated that an ordinary cement sheath lost its integrity after 13 loading cycles with a maximum casing pressure of 60 MPa. A low residual strain cement sheath could guarantee integrity after 30 loading cycles when the maximum casing pressure was 90 MPa, and sealing failure occurred after 11 loading cycles when the maximum casing pressure was 130 MPa. It is recommended to use a low residual strain cement slurry below the intermediate casing shoe to prevent a micro-annulus.

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“…Chen et al [16] presented a mathematical model for establishing the relationship between microseismic moment magnitude and degree of casing sheared deformation. Guo et al [24] developed a numerical model and calculated the influences of slip distance, slip angle, and the mechanical parameters of cement sheath on casing stress. But few of the above studies analyzed the difference between measurement results and actual deformation, and have not put forward solutions to casing shear deformation and showed their validity in engineering in practice.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms and Influence of Casing Shear Deformation near the Casing Shoe, Based on MFC Surveys during Multistage Fracturing in Shale Gas Wells in Canada

Liu

et al. 2019

Energies

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Casing shear deformation has become a serious problem in the development of shale gas fields, which is believed to be related to fault slipping caused by multistage fracturing, and the evaluation of the reduction of a casing’s inner diameter is key. Although many fault slipping models have been published, most of them have not taken the fluid-solid-heat coupling effect into account, and none of the models could be used to calculate the reduction of a casing’s inner diameter. In this paper, a new 3D finite element model was developed to simulate the progress of fault slipping, taking the fluid-solid-heat coupling effect during fracturing into account. For the purpose of increasing calculation accuracy, the elastoplastic constitutive relations of materials were considered, and the solid-shell elements technique was used. The reduction of the casing’s inner diameter along the axis was calculated and the calculation results were compared with the measurement results of multi-finger caliper (MFC) surveys. A sensitivity analysis was conducted, and the influences of slip distance, casing internal pressure, thickness of production and intermediate casing, and the mechanical parameters of cement sheath on the reduction of a casing’s inner diameter in the deformed segment were analyzed. The numerical analysis results showed that decreasing the slip distance, maintaining high pressure, decreasing the Poisson ratio of cement sheath, and increasing casing thickness were beneficial to protect the integrity of the casing. The numerical simulation results were verified by comparison to the shape of MFC measurement results, and had an accuracy up to 90.17%. Results from this study are expected to provide a better understanding of casing shear deformation, and a prediction method of a casing’s inner diameter after fault slipping in multistage fracturing wells.

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Numerical simulation of casing deformation during volume fracturing of horizontal shale gas wells

Cited by 65 publications

References 24 publications

A new numerical method for evaluating the variation of casing inner diameter after strike‐slip fault sliding during multistage fracturing in shale gas wells

A new numerical method for evaluating the variation of casing inner diameter after strike‐slip fault sliding during multistage fracturing in shale gas wells

Sealing Failure Mechanism and Control Method for Cement Sheath during Hydraulic Fracturing

Mechanisms and Influence of Casing Shear Deformation near the Casing Shoe, Based on MFC Surveys during Multistage Fracturing in Shale Gas Wells in Canada

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