Shale gas reservoir physical property inversion

In response to the limitations of traditional well-test methods that require shut-in and impact production, this paper proposes an inversion method for shale gas reservoir physical properties based on a productivity model. The method involves constructing a trilinear flow model for shale gas fractured horizontal wells, comprehensively considering the linear flow and desorption-adsorption effects in the matrix, fracture network, and main fracture. Dynamic productivity equations are derived. Utilizing deconvolution techniques, actual variable production pressure data is transformed into constant pressure variable production data, which is then matched with established production decline curve templates to achieve reservoir type identification and parameter inversion. Case study analysis demonstrates that the method can effectively invert key parameters such as permeability, porosity, and desorption volume, accurately predicting production trend changes. The research findings provide a shut-in-free, low-cost technical means for efficient shale gas reservoir development, holding significant engineering application value.