Deep shale gas reservoir fracturing optimization method based on compressibility evaluation

Abstract

The invention discloses a deep shale gas reservoir fracturing optimization method based on compressibility evaluation. The method comprises the following steps: obtaining geological parameters, and building a three-dimensional geological model; carrying out gridding subdivision on the geological model, and calculating comprehensive compressibility indexes of all geological grids respectively; dividing all the geological grids into three levels according to the comprehensive compressibility index, and classifying the geological grids at the same level into a compressibility fracturing section at the same level; carrying out production simulation on each stage of compressible fracturing section under the conditions of fixing liquid strength and different sand adding strength, and obtaining different stages of construction curves, wherein the highest inflection point of the curve is an optimal fracturing design parameter; and calculating a to-be-researched well to obtain the stage number of the layer sections of the to-be-researched well, and directly selecting the optimal fracturing design parameters of the stage determined in the previous step as the optimal construction parameters according to the calculated stage number. More comprehensive compressibility characterization of the fractured interval is obtained, finer fracturing design parameter optimization is carried out for each fractured interval, the optimization result is more reliable, and the method has practical significance.

Description

technical field

[0001] The invention relates to the technical field of gas reservoir exploitation, in particular to a fracturing optimization method for deep shale gas reservoirs based on compressibility evaluation. Background technique

[0002] With the deepening of the burial depth, the three-dimensional stress of the shale gas reservoir increases, the horizontal stress difference increases, the plasticity of the rock increases, the reservoir compressibility is poor, and the fracture extension is difficult, which is not conducive to the formation of a complex fracture network.

[0003] According to domestic and foreign literature research, after staged fracturing of shale gas horizontal wells, the gas production of gas wells basically conforms to the "three-three-three" principle, that is, the gas production contribution rate of about one-third of the segments and clusters reaches 70%. About one-third of the segment clusters contribute about 30% to gas production, and the ...

Examples

Embodiment Construction

[0038] The present invention will be further described in detail below with reference to the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0039] S1. Obtain the geological parameters of the target block. There are many parameters extracted, and only the scope is listed here;

[0040] Table 1 Range of geological parameters of target blocks

[0041]

[0042] (1) Parameter normalization processing:

[0043] For the positive correlation parameters such as brittle mineral content, brittleness index (Young's modulus), TOC content, gas content, porosity, and formation pressure coefficient, the parameter normalization equation is as follows:

[0044]

[0045] For negative correlation parameters such as clay mineral content, Poisson's ratio, stress difference, tensile strength, compressive strength, fracture toughness, and shale density, the parameter normalization equation is as follows:

[0046]

[0047] ...

technical field

[0001] The invention relates to the technical field of gas reservoir exploitation, in particular to a fracturing optimization method for deep shale gas reservoirs based on compressibility evaluation. Background technique

[0002] With the deepening of the burial depth, the three-dimensional stress of the shale gas reservoir increases, the horizontal stress difference increases, the plasticity of the rock increases, the reservoir compressibility is poor, and the fracture extension is difficult, which is not conducive to the formation of a complex fracture network.

[0003] According to domestic and foreign literature research, after staged fracturing of shale gas horizontal wells, the gas production of gas wells basically conforms to the "three-three-three" principle, that is, the gas production contribution rate of about one-third of the segments and clusters reaches 70%. About one-third of the segment clusters contribute about 30% to gas production, and the ...

Examples

Embodiment Construction

[0038] The present invention will be further described in detail below with reference to the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0039] S1. Obtain the geological parameters of the target block. There are many parameters extracted, and only the scope is listed here;

[0040] Table 1 Range of geological parameters of target blocks

[0041]

[0042] (1) Parameter normalization processing:

[0043] For the positive correlation parameters such as brittle mineral content, brittleness index (Young's modulus), TOC content, gas content, porosity, and formation pressure coefficient, the parameter normalization equation is as follows:

[0044]

[0045] For negative correlation parameters such as clay mineral content, Poisson's ratio, stress difference, tensile strength, compressive strength, fracture toughness, and shale density, the parameter normalization equation is as follows:

[0046]

[0047] ...

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