Improving the efficiency of production wells at the final stage of gas field development

Abstract

Purpose is to improve the efficiency of extraction of remaining hydrocarbons within the oil and gas fields at the final stage of their development while optimizing operational conditions of the production wells. Methods. Software package PipeSim by Schlumberger has been applied to improve the efficiency of the current well stock under the conditions complicated by liquid accumulation within a bottomhole. A hypothetic well has been used. Findings. The basic operational parameters of a production well have been calculated for different values of water coefficient (i.e. 50; 100; 150; 200; 250; 300; 350; 400 and 450 l/th.m3). The research has helped identify that increase in the water coefficient results in the increased rate of liquid as well as decreased gas rate. A nodal analysis method has been applied to identify the following: at the level of 450 l/th.m3, a production well stops flowing. The results of the studies support the idea that to activate a well efficiency at the level of 18 th.m3/day, it is required either to replace 62.0 tubing string with 50.3 mm one or reduce wellhead pressure from 10.16 down to 9.88 MPa or develop gas lift injection at the level of 1.9 th.m3/day. In addition, the results give the evidence of engineering efficiency as for the method implementation. However, expediency of the application depends upon the processing limits of industrial facilities as well as upon the ratio between the water-free and wet deposit areas. Originality. The correlation dependencies have been determined to forecast operational indices of highly watered wells. The research results help substantiate promptly the methods intensifying hydrocarbon output depending upon different types of geological and engineering limitations. Practical implications. Implementation of the results will help optimize operation of production wells under active edge and bottom water inflow into the productive pools and increase their hydrocarbon extraction respectively.