Influence of the relative opening of the gas-bearing formation on the process of watering wells in reservoirs with bottom water

Purpose. The research aims to study the influence of gas-bearing reservoir relative opening on the patterns of well water-flooding process in deposits with bottom water. Methods. Using the Petrel&Eclipse software, the influence of different values of the relative reservoir opening (0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9) on the deposit mining indicators in the 5th, 10th and 15th years of mining has been studied. The paper examines options for operating wells with a reservoir depression of 1.25 MPa (5% of the initial pressure) and 2.5 MPa (10% of the initial pressure). Findings. The research results are presented in the form of tables and graphical dependences of the studied parameters on the relative reservoir opening in the 5th, 10th and 15th years of deposit mining at different reservoir depressions. According to the research results, at a reservoir depression of 1.25 MPa, the optimal value of the relative reservoir opening is 0.6. In the 15th year of deposit mining, the reservoir pressure decreases from the initial value of 25 to 3.2 MPa, gas flow rate changes from 133.2 to 36.35 thousand m3/day, and gas recovery factor is 85.66%. At a reservoir depression of 2.5 MPa, the optimal value of the relative reservoir opening is 0.4. In the 15th year of deposit mining, the reservoir pressure decreases from 25 to 2.5 MPa, gas flow rate changes from 178 to 27.46 thousand m3/day, and gas recovery factor is 90.46%. Thus, the choice of opening and depression parameters significantly influences the efficiency of deposit mining. Originality. Based on the results of the conducted research for the conditions of the analyzed example, the optimal value of the relative reservoir opening has been obtained, which varies within 0.4-0.6 at a reservoir depression of 1.25-2.5 MPa (5 and 10% of the initial pressure). Practical implications. Using the conducted research results, it will be possible to select the optimal parameters of relative reservoir opening to minimize water-flooding of the well and increase gas recovery efficiency. This will help to prolong the water-free period of well operation and substantiate the feasibility of using technologies for joint mining of gas and water from wells in difficult hydrogeological conditions.