A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Initiation Pressure and Location of Fracture Initiation in Elliptical Wellbores
https://orcid.org/0000-0001-5449-8420
Abstract Due to the shear failure caused by the compressive stress concentration in the wellbore wall and the non-isotropy of the in situ stresses, the actual shape of the wellbore cross-section is oval instead of what is usually considered a circle. The purpose of this paper is to find the fracture initiation pressure and the initiation location in elliptical wellbores. For this purpose, a simple analytical model is used. This model is obtained by combining analytical relations of stress distribution around elliptical wellbores and material tensile strength criterion to predict crack initiation. According to the results, if the in situ stresses are isotropic, the fracture initiation location is in the direction of the longest diameter of the wellbore, and the initiation pressure decreases with the increase of the shape parameter. In the case that the in situ stresses are non-isotropic, a critical shape parameter is defined. If the shape parameter is less than the critical value, the fracture initiation in the wellbore wall is along the maximum in situ stress and the initiation pressure increases with the increase of the shape parameter, and if the shape parameter is greater than the critical value, up to 0.33, the fracture initiation in the wellbore wall occurs in the direction of the minimum in situ stress and the initiation pressure decreases with the increase of the shape parameter. This model can be used in estimating the fracture initiation pressure and determining the fracture initiation position in elliptical cavities in the field and laboratory.
Initiation Pressure and Location of Fracture Initiation in Elliptical Wellbores
https://orcid.org/0000-0001-5449-8420
Abstract Due to the shear failure caused by the compressive stress concentration in the wellbore wall and the non-isotropy of the in situ stresses, the actual shape of the wellbore cross-section is oval instead of what is usually considered a circle. The purpose of this paper is to find the fracture initiation pressure and the initiation location in elliptical wellbores. For this purpose, a simple analytical model is used. This model is obtained by combining analytical relations of stress distribution around elliptical wellbores and material tensile strength criterion to predict crack initiation. According to the results, if the in situ stresses are isotropic, the fracture initiation location is in the direction of the longest diameter of the wellbore, and the initiation pressure decreases with the increase of the shape parameter. In the case that the in situ stresses are non-isotropic, a critical shape parameter is defined. If the shape parameter is less than the critical value, the fracture initiation in the wellbore wall is along the maximum in situ stress and the initiation pressure increases with the increase of the shape parameter, and if the shape parameter is greater than the critical value, up to 0.33, the fracture initiation in the wellbore wall occurs in the direction of the minimum in situ stress and the initiation pressure decreases with the increase of the shape parameter. This model can be used in estimating the fracture initiation pressure and determining the fracture initiation position in elliptical cavities in the field and laboratory.
Initiation Pressure and Location of Fracture Initiation in Elliptical Wellbores
https://orcid.org/0000-0001-5449-8420
Abstract Due to the shear failure caused by the compressive stress concentration in the wellbore wall and the non-isotropy of the in situ stresses, the actual shape of the wellbore cross-section is oval instead of what is usually considered a circle. The purpose of this paper is to find the fracture initiation pressure and the initiation location in elliptical wellbores. For this purpose, a simple analytical model is used. This model is obtained by combining analytical relations of stress distribution around elliptical wellbores and material tensile strength criterion to predict crack initiation. According to the results, if the in situ stresses are isotropic, the fracture initiation location is in the direction of the longest diameter of the wellbore, and the initiation pressure decreases with the increase of the shape parameter. In the case that the in situ stresses are non-isotropic, a critical shape parameter is defined. If the shape parameter is less than the critical value, the fracture initiation in the wellbore wall is along the maximum in situ stress and the initiation pressure increases with the increase of the shape parameter, and if the shape parameter is greater than the critical value, up to 0.33, the fracture initiation in the wellbore wall occurs in the direction of the minimum in situ stress and the initiation pressure decreases with the increase of the shape parameter. This model can be used in estimating the fracture initiation pressure and determining the fracture initiation position in elliptical cavities in the field and laboratory.
Initiation Pressure and Location of Fracture Initiation in Elliptical Wellbores
Jolfaei, Somaie (author) / Lakirouhani, Ali (author)
2023
Article (Journal)
Electronic Resource
English
BKL:
57.00$jBergbau: Allgemeines
/
38.58
Geomechanik
/
57.00
Bergbau: Allgemeines
/
56.20
Ingenieurgeologie, Bodenmechanik
/
38.58$jGeomechanik
/
56.20$jIngenieurgeologie$jBodenmechanik
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