Abstract
The paper presents the results of theoretical and hydrodynamic substantiation of shockwave stimulation parameters for dynamic near-wellbore treatment and skin-factor reduction in tight reservoirs. The study is based on actual geological and technical data from production wells No. 45 and No. 47 of the Lower Visean substage at the «Х» field. A two-dimensional axisymmetric finite element model based on the Biot-Frenkel dynamic poroelasticity theory was developed, which accounts for the radial change in fluid viscosity and density within the zone of deep invasion of heavy mud filtrate (1.90 g/cm³). Through numerical simulation, the optimal frequency range of the shock pulse (10–15 Hz) was determined. It was established that the pressure wave with an amplitude of up to 4.5 MPa generated by the hydraulic impulse system exceeds the tensile strength of the rock (σt = 2.8 MPa) and ensures the opening of a microfracture network according to Coulomb’s cubic law at a distance of up to 2.0 m from the wellbore wall at a frequency of 10 Hz. The practical significance lies in the elimination of the mud cake screen formed under high overbalance conditions during the primary disclosure of an ultra-tight formation (porosity up to 0.15%, permeability from 0.001 mD). The implementation of the proposed regimes allows for a reduction in the calculated skin factor from critical 8.8 down to 0.4–1.5, which provides a 2.4 to 3.1-fold increase in the predicted well productivity index.