Method for judging the risk of wellbore casing damage in hydraulically fractured horizontal wells in naturally fractured shale formations

Abstract

The invention discloses a method for judging the casing failure risk of a horizontal well in a hydraulic fracturing horizontal well in a shale formation with natural fractures, and belongs to the technical field of shale gas fracturing. The present invention mainly overcomes the deficiencies in the prior art, and proposes a method for judging the risk of wellbore casing change in hydraulic fracturing horizontal wells in natural fractured shale formations, including: obtaining the in-situ stress, rock mechanics parameters, natural fracture occurrence, Wellbore parameters; respectively establish the force calculation model of the fracture not fully propped-casing system, and the fracture fully propped-casing system force calculation model; judge the state of the fracture and calculate the shear stress of the wellbore; finally, according to the wellbore parameters and the wellbore The shear stress is compared to determine whether there is a risk of casing deformation in the wellbore. The invention can quickly predict the risk of casing change in horizontal wells. In areas where the risk of casing change is judged to be high, measures such as optimizing wellbore orientation, strengthening cementing quality, appropriately reducing displacement, and adopting temporary plugging technology to reasonably control the fluid in the fracture can be considered. Pressure reduces the risk of set change.

Description

technical field [0001] The invention relates to a method for judging the casing change risk of a horizontal well in a hydraulically fractured shale formation with natural fractures, and belongs to the technical field of shale gas fracturing. Background technique [0002] During shale gas fracturing, casing deformation (hereinafter referred to as casing deformation) will affect the integrity of the wellbore, hinder downhole tool deployment, reduce the effectiveness of fracturing stages, and even cause some fracturing stages to abandon stimulation. One of the important factors in the development of gas fracturing. [0003] Many scholars have carried out research on casing deformation. At present, it is believed that fracture slipping and shearing the wellbore, wellbore wall yielding and collapse, and thermal stress are the main factors causing casing deformation. Regarding the research on casing deformation caused by fracture slipping and shearing wellbore, Liao Shimeng et al...

AI Technical Summary

Problems solved by technology

To sum up, the predecessors mostly used digital simulation software to carry out relevant research on the phenomenon of casing deformation, but the understanding of casing force and failure mechanism during fracturing is relatively insufficient.

[0004] In addition, on-site fracturing requires a method that can quickly judge the risk of casing change, and the digital-analog method has the limitations of complex modeling and slow calculation speed

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