Inversion method for fracture half-length of water production fracturing gas well in stress sensitivity storage layer

Abstract

The invention relates to an inversion method for the fracture half-length of a water production fracturing gas well in a stress sensitivity storage layer. The method comprises the following steps that(1) daily production data of the gas well, physical properties of the storage layer, physical properties of fluid and stress sensitivity data are collected and sorted out; (2) gas-water equivalent relative permeabilities under different pressure conditions are calculated; (3) improved simulation parameters considering gas-water two-phase complex seepage characteristics of the stress sensitivity storage layer are calculated; (4) an improved radical sign time curve is drawn and used for identifying a stratum linear flow; (5) data points at the stratum linear flow stage are subjected to linear regression, based on an obtained straight slope, calculation is conducted by using an inversion model, and inversion of the fracture half-length is achieved. According to the inversion method, complexseepage characteristics such as relative permeability curve stress sensitivity, absolute permeability stress sensitivity and slippage effect during gas-water two-phase seepage in the stress sensitivity storage layer can be comprehensively considered, errors caused by a traditional calculation method are removed, and the method can be widely applied to post-pressing evaluation of the water production fracturing gas well of the stress sensitivity storage layer.

Description

technical field [0001] The invention relates to the technical field of post-fracturing evaluation of hydraulic fracturing, in particular to a method for half-length inversion of fractures in water-producing fracturing gas wells in stress-sensitive reservoirs. Background technique [0002] During the production process of stress-sensitive reservoirs, due to the continuous change of formation stress conditions, the reservoir pore-throat structure will change accordingly. For water-producing gas wells in stress-sensitive reservoirs, the change of pore-throat structure with stress will lead to complex phenomena such as absolute permeability stress sensitivity, phase permeability curve stress sensitivity, and dynamic slippage effect in the gas-water two-phase seepage process. seepage characteristics. On the other hand, stress-sensitive reservoirs usually have low permeability and require fracturing to obtain industrial gas flow. The half-length of fractures formed by fracturing...

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Problems solved by technology

[0003] However, some existing fracture half-length inversion methods do not comprehensively consider the complex seepage characteristics of gas-water two-phase in stress-sensitive reservoirs, especially ignore the stress sensitivity of the gas-water phase permeability curve, and the obtained fracture half-length There is usually a certain difference between the value and the true value, so it is not suitable for fracture half-length inversion of water-producing fractured gas wells in stress-sensitive reservoirs

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