A physical model test method for the extension law of natural cracks and artificial cracks

Abstract

The invention belongs to the technical field of yield increase of oil-gas wells and particularly relates to a physical model test method for extension rules of natural cracks and artificial cracks. The method comprises the following steps: acquiring three-dimensional terrestrial stress and rock mechanics parameters of a real geological rock core under stratum conditions; establishing a physical model of a real reservoir interlayer in a simulated mode, and prefabricating natural cracks in the physical model; loading confining pressure on the physical model according to the three-dimensional terrestrial stress parameters, performing a hydraulic fracture test on the physical model, and acquiring data until the model fractures; sectioning and scanning the fractured model; and performing quantitative analysis on the crack morphology of the model, and researching the influence of the natural cracks on the extension rules of the artificial cracks. The method provided by the invention solvesthe problems that an existing model is a homogeneous model, only one crack is prefabricated in the model, and the crack problems of quantity, positions, sizes and the like of the natural cracks are not considered. The method provided by the invention can master the major factors of the natural cracks on the extension influence of the artificial cracks, provides a theoretical basis for reservoir reformation, and greatly improves the development effect of the oil reservoir.

Description

technical field

[0001] The invention belongs to the technical field of increasing production of oil and gas wells, and in particular relates to a physical model test method for the extension law of natural fractures and artificial fractures. Background technique

[0002] The Ordos Basin generally has reservoir characteristics of poor permeability and developed natural micro-fractures. In some blocks, the reservoirs are tight, and faults and fractures are developed. Mud and calcareous interlayers are developed in the layers, and the characteristics of thin interbeds are obvious, especially the development of fractures. It is easy to cause artificial fractures to get out of control. In recent years, the idea of ​​"volume fracturing" has been used for tight reservoirs. The large-scale fracturing operation has formed a complex fracture network in which natural fractures and artificial fractures are intertwined. The injected water is easy to flow along. The fracture advances, cau...

Examples

Embodiment 1

[0025] Such as Figure 1-3 Shown, a kind of natural crack and artificial crack extension rule physical model test method, comprises the following steps:

[0026] Obtain the three-way stress value and rock mechanics parameters of the real geological core under formation conditions, the rock mechanics parameters include density, uniaxial compressive strength, tensile strength, Poisson's ratio and modulus of elasticity; the step 1) The shape of the real geological core is a cylinder, the height of the cylinder is 50mm, and the diameter is 25mm; the three-dimensional stress value interprets the relative coordinates of fractured wells, initial fracturing data, logging data and The relationship between rock mechanics parameters and in-situ stress is obtained; in isotropic rocks, the in-situ stress in all directions is equal; according to the actual measurement results of the in-situ stress field, it is concluded that the stress in the stratum is not equal in all directions in the ho...

Embodiment 2

[0036] In 2017, for fracture-developed reservoirs in the Yanchi area, the natural fracture and artificial fracture extension law physical model test method was used to optimize the parameters of the key factors that high-angle fractures affect artificial fractures, including the following steps:

[0037] 1) Obtain the three-dimensional in-situ stress value and rock mechanics parameters of the real geological core under formation conditions, and the rock mechanics parameters include density, uniaxial compressive strength, tensile strength, Poisson's ratio and elastic modulus; according to the in-situ stress field According to the actual measurement results, it is concluded that the stress in the horizontal direction of the formation is not equal, and the three-dimensional stress value in the physical model test is set as σ V -σ H -σ h =18-12-6 / MPa; The real geological core shape is a cylinder in the step 1), the height of the cylinder is 50mm, and the diameter is 25mm;

[003...

technical field

[0001] The invention belongs to the technical field of increasing production of oil and gas wells, and in particular relates to a physical model test method for the extension law of natural fractures and artificial fractures. Background technique

[0002] The Ordos Basin generally has reservoir characteristics of poor permeability and developed natural micro-fractures. In some blocks, the reservoirs are tight, and faults and fractures are developed. Mud and calcareous interlayers are developed in the layers, and the characteristics of thin interbeds are obvious, especially the development of fractures. It is easy to cause artificial fractures to get out of control. In recent years, the idea of ​​"volume fracturing" has been used for tight reservoirs. The large-scale fracturing operation has formed a complex fracture network in which natural fractures and artificial fractures are intertwined. The injected water is easy to flow along. The fracture advances, cau...

Examples

Embodiment 1

[0025] Such as Figure 1-3 Shown, a kind of natural crack and artificial crack extension rule physical model test method, comprises the following steps:

[0026] Obtain the three-way stress value and rock mechanics parameters of the real geological core under formation conditions, the rock mechanics parameters include density, uniaxial compressive strength, tensile strength, Poisson's ratio and modulus of elasticity; the step 1) The shape of the real geological core is a cylinder, the height of the cylinder is 50mm, and the diameter is 25mm; the three-dimensional stress value interprets the relative coordinates of fractured wells, initial fracturing data, logging data and The relationship between rock mechanics parameters and in-situ stress is obtained; in isotropic rocks, the in-situ stress in all directions is equal; according to the actual measurement results of the in-situ stress field, it is concluded that the stress in the stratum is not equal in all directions in the ho...

Embodiment 2

[0036] In 2017, for fracture-developed reservoirs in the Yanchi area, the natural fracture and artificial fracture extension law physical model test method was used to optimize the parameters of the key factors that high-angle fractures affect artificial fractures, including the following steps:

[0037] 1) Obtain the three-dimensional in-situ stress value and rock mechanics parameters of the real geological core under formation conditions, and the rock mechanics parameters include density, uniaxial compressive strength, tensile strength, Poisson's ratio and elastic modulus; according to the in-situ stress field According to the actual measurement results, it is concluded that the stress in the horizontal direction of the formation is not equal, and the three-dimensional stress value in the physical model test is set as σ V -σ H -σ h =18-12-6 / MPa; The real geological core shape is a cylinder in the step 1), the height of the cylinder is 50mm, and the diameter is 25mm;

[003...

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