Determination of predictive technological indicators for the development of a two-seam gas field in the gas mode by a common well grid and their operation with constant wellhead pressure

Methods for predicting technological indicators for the development of a single-layer gas field for the gas regime and operation of wells with constant wellhead pressure are presented. For a two-layer gas field with different permeability, hydrodynamically isolated layers, developed by a single network of wells with constant wellhead pressure, there are no available engineering calculation methods that allow one to quickly predict technological indicators of gas production with sufficient accuracy. A methodology has been developed to determine predictive technological indicators for the development of a two-layer gas field in gas mode, using a common well pattern and operating at constant wellhead pressure. Studies were carried out on a hypothetical (model) two-layer gas field with different permeability, hydrodynamically isolated layers, developed together by a single well grid, using mathematical modelling methods, in particular the method of sequential changes in steady states. The proposed methodology is based on the joint solution of the material balance equation for each gas-bearing formation for the gas regime, the two-term formula for gas inflow in each formation to the average well, the equation for gas movement in vertical well pipes and the equation establishing the relationship between bottomhole pressures in each layer. Dependencies have been obtained that make it possible to determine the current values of reservoir and bottomhole pressures in each formation, the gas flow rate from each formation and the �average� well, annual and cumulative gas production from each formation and field. The methodology presented is implemented in Mathcad software and tested on a hypothetical field. The proposed methodology for determining the predicted technological indicators of development of a two-layer gas field for the gas regime with a common well pattern and their operation at constant wellhead pressure allows you to quickly calculate the technological indicators of gas production using widely available computer programs