Fracture form prediction method considering interlayer weak plane

Abstract

The invention discloses a fracture form prediction method considering an interlayer weak plane. The method comprises the following steps: establishing a three-dimensional geologic model according to acquired stratum parameters of an actual interaction stratum; establishing a rock seepage-stress coupling model based on a stress balance equation, a continuity equation and boundary conditions; determining a crack extension rule; inputting fracturing well parameters of a target well area, and establishing a fracturing three-dimensional full-coupling model; and simulating the influence of different geological factors and engineering factors on the fracture form. Based on a finite element method, a full-three-dimensional seepage-stress coupling model is established, two fracture surfaces are preset by using a Cohesive pore pressure unit, an interlayer weak surface or a bedding weak surface is considered, the influence of different geological factors and engineering factors on the fracture form is researched, the fracture form of the reservoir containing the interlayer weak surface during fracturing can be quickly predicted, and fracturing construction parameter design is guided.

Description

technical field [0001] The invention relates to the technical field of oil and gas exploration and development, in particular to a fracture shape prediction method considering weak planes between layers. Background technique [0002] As the exploration and development of global oil and gas resources gradually turns to unconventional oil and gas development, hydraulic fracturing technology, as a kind of production stimulation measures for unconventional oil and gas wells, has been widely used in my country. Unconventional oil and gas reservoirs have strong vertical heterogeneity. For example, there are sand-shale interbeds and mudstone interbeds in tight sandstone, and shale-sandstone interbeds and shale-carbonate interbeds in shale. Interbeds lead to complex and unpredictable fracture patterns during hydraulic fracturing. How to predict the fracture shape according to the actual interaction between strata and to guide the optimization of construction parameters is one of th...

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Problems solved by technology

[0004] In terms of two-dimensional model research: the patent document with application number 202010545763.X discloses a multi-cluster fracturing fracture shape prediction method based on discrete element fluid-solid coupling, which can effectively consider the influence of interlayer weak planes on fracture shape, but The flow of liquid in the third dimension is not considered, and there is a certain gap with the actual three-dimensional formation, which has certain limitations

[0005] In terms of 3D model research, the patent document with application number 201910470372.3 discloses a method for constructing a layer-crossing fracturing plate. This method establishes a 3D model to study the fracture height extension law of sand-mudstone interactive reservoirs, but does not take into account the weak interlayer fractures. shape influence

[0006] Existing methods that can consider the fracture morphology of interlayer weak planes are limited to 2D models, which have a certain gap with the actual 3D formation, and the 3D model is difficult to consider the influence of interlayer weak planes on fracture morphology

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