Prediction method for variable space-time diversion capacity of fractures of coal-bed gas well

Abstract

The invention discloses a prediction method for a variable space-time diversion capacity of fractures of a coal-bed gas well. The prediction method comprises the following steps: S1, collecting related parameters of reservoir rock of the target coal-bed gas well; S2, calibrating spatial distribution of a global diversion capacity of a prop fracture at an initial moment after fracturing; S3, establishing a mechanism expression about the influence of pulverized coal deposit, proppant embedding and time on diversion capacity of the fracture filled with a proppant; S4, performing spatial dispersion on the global diversion capacity calibrated in the step S2 according to a built diversion capacity change mechanism model to obtain diversion capacity values of each discrete unit at different moments; S5, repeating the steps S3-S4 until the global diversion capacity is completely computed on the basis of computing results of the step S4 as a starting point. According to the prediction method, the defects of diversion capacity prediction by existing indoor experiments are overcome, damage to the diversion capacity by pulverized coal deposit and proppant embedding are taken into account afterthe coal-bed gas well is fractured, and the global variable space-time diversion capacity of the fracture filled with the proppant can be effectively predicted.

Description

technical field [0001] The invention relates to the technical field of coalbed methane production stimulation and transformation, in particular to a method for predicting the variable time-space conductivity of coalbed methane well fracturing fractures. Background technique [0002] my country is rich in coalbed methane resources, the geological resources rank third in the world, and the prospect of development and utilization is broad. Due to its unique occurrence state and reservoir physical properties, establishing an effective fracture network through hydraulic fracturing is the key to the development of coalbed methane. However, in the mining practice of coalbed methane wells after fracturing, coal powder will settle and block the coal seam fracture system, which will significantly reduce the coal seam permeability, resulting in a significant decrease in water production and slow desorption of coalbed methane, which will seriously affect the formation of industrial prod...

AI Technical Summary

Problems solved by technology

After coal rock fracturing, as the production process proceeds, coal powder will also gradually deposit in the proppant filling layer and block the fractures, reducing the porosity and permeability of the fractures, resulting in the loss of fracture conductivity.

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