Method for calculating non-steady state yield of volume fractured horizontal well of shale gas reservoir

Abstract

The invention discloses a method for calculating a non-steady state yield of a volume fractured horizontal well of a shale gas reservoir. The method comprises the following steps of dividing the reservoir into a volume fractured region and a non-transformed matrix region, and collecting basic parameters of the volume fractured region, the non-transformed matrix region and the horizontal well, wherein the volume fractured region is Darcy flow, and the non-transformed matrix region is Knudson flow; according to a mass conservation law, establishing a steady-state yield formula of the volume fractured horizontal well of the shale gas reservoir; based on a pressure propagation formula, the steady-state yield formula and a matter balance equation, calculating the non-steady state yield of the volume fractured horizontal well of the shale gas reservoir by applying a continuous quasi-steady method; and repeating the previous step, and performing calculation to obtain the non-steady state yield of the volume fractured horizontal well of the shale gas reservoir. The method fully considers a process that a pressure is propagated to a boundary gradually in a production process of the volume fractured horizontal well of the shale gas reservoir, different seepage laws of shale gas in a volume transformation region and the non-transformed matrix region, and adsorption and desorption effects of the shale gas, so that actual conditions are better met.

Description

technical field [0001] The application belongs to the field of oil and gas field development, and in particular relates to a method for calculating the unsteady-state production of a volume-fractured horizontal well in a shale gas reservoir. Background technique [0002] Shale gas reservoirs have nanoscale pore diameters and extremely low permeability, which belong to ultra-low permeability tight gas reservoirs. The occurrence states of shale gas mainly include dissolved gas, free gas and adsorbed gas. Forming a complex fracture network through volume fracturing of horizontal wells in shale gas reservoirs can significantly increase the overall permeability of the reservoir, thereby achieving a substantial increase in the production of horizontal wells in shale gas reservoirs. In the production process of volume-fractured horizontal wells in ultra-low permeability shale gas reservoirs, the permeability of the unreformed matrix area is extremely low, and the Darcy formula can...

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Problems solved by technology

[0004] The electrical simulation method and the analytical-semi-analytic method mainly take the average value of the permeability through the weighted average method of reservoir permeability, that is, the reservoir is regarded as a homogeneous reservoir, and the heterogeneity characteristics of the reservoir are not considered; the numerical simulation The method can consider the heterogeneity of the reservoir, but when using this method, a large amount of reservoir data is required, and the calculation speed is relatively slow

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