Analysis of tight gas well performance

This study is a collection of models and solutions useful in analyzing pressure and production data of tight gas reservoirs. Emphasis has been placed on linear flow because many tight gas wells produce predominantly under linear flow conditions for long times. The objectives of this research are (1) to develop a catalog of linear flow causes, models, and solutions; (2) to develop new solutions for models that can be used in analyzing tight gas wells production data; (3) to develop a systematic procedure to analyze production data of these wells.;Several models that can be used to describe production of tight gas reservoirs were reviewed. Combination of analytical, semi-analytical (numerically inverted Laplace space solutions), and numerical solutions were used to achieve our objectives.;A catalog for linear flow was developed. This catalog includes models, solutions, and analysis equations or type curves. Solutions were provided for homogeneous and dual porosity linear reservoirs, homogeneous and dual porosity radial reservoirs, homogeneous and dual porosity channel reservoirs (wells between two parallel no-flow boundaries), and wells near fractures. Some new solutions were added to the catalog. These new solutions include: (1) dual porosity solutions for linear reservoirs, (2) constant ;The new semi-analytical solutions were verified with numerical simulation. A procedure was developed to use "tricks" (input data modifications) to model dual porosity behavior for any two-dimensional problem with a conventional simulator.;A general procedure for analyzing production data of tight gas wells was also developed. This procedure uses diagnostic plots and the Excel Solver program (minimization routine) to history match production data. All analytical and semi-analytical solutions collected and developed in this work were programmed in Visual Basic for Excel. An example field case was analyzed using this procedure.;Causes of linear flow in tight gas reservoirs are numerous. Among these are: linear reservoirs, high permeability streaks, wells between two no-flow boundaries, transient dual porosity behavior for radial reservoirs, wells intercepted by vertical, horizontal, or diagonal fractures, horizontal wells, and horizontal wells with fractures.