| This dissertation presents several new techniques for the analysis of long term production performance of gas wells producing at constant flowing bottomhole pressure, pwf, and subjected to periodic shut-ins. The presence of these shut-in periods causes severe scatter in the production rate and hinders the analysis using conventional techniques (specialized plots, deconvolution, etc.).;In this work, I propose a novel application of the principle of superposition to filter out the scatter in the production rate data and establish the production trend without the effects of shut-ins. The superposition (convolution) principle is used to determine an analytical reservoir model that matches the production and pressure history of the well. The analytical model provides estimates for reservoir permeability, distance to boundaries, and original gas in place. A computer program (EXCEL spreadsheet based) is presented to automate the analysis process.;A new closed-form analytical solution for the production rate following a shut-in period is also presented. The analytical solution is used to establish a correlation between the production data above and below the trend of the well capacity. This correlation is used to filter out the scatter in production data resulting from the periodic shut-in. A similar correlation and filtering technique is also developed using the principle of superposition.;Although the concepts presented in this dissertation are quite general and applicable to a wide variety of reservoir flow conditions, the focus is on wells producing at constant flowing bottomhole pressure from tight gas reservoirs exhibiting linear flow. |
