| This dissertation presents a production analysis catalogue to study and interpret the long-term production performance of tight gas in homogeneous and dual porosity reservoirs.; The main objectives of this work are to: (1) present physical scenarios that cause long-term linear flow in tight gas reservoirs, (2) present an analytical matrix-parallel fracture flow model for a single-phase fluid, (3) develop a catalogue of reliable, straightforward, and stepwise methodologies to analyze production data of tight gas wells in order to provide estimates of reservoir properties, OGIP, and movable gas-reserves, (4) apply the production analysis methodologies in actual tight gas wells, and (5) validate the results estimated in actual tight gas wells using numerical simulation.; Three different physical scenarios that may cause long-term linear flow in tight gas reservoirs are presented. These scenarios are large anisotropy ratios in parallel natural fractures in tight matrix formations, linear flow perpendicular to the hydraulic fracture in fractured vertical wells in tight gas reservoirs, and vertical flow in a high permeability streak.; A systematic derivation of an analytical flow model that includes parallel natural fractures in a tight formation is presented.; The catalogue includes models, solutions, diagnostic plots, specialized plots, and interpretation formulas to estimate reservoir properties and OGIP. A series of models, analytical, semi-analytical, and numerical solutions for different flow geometries under a variety of boundary conditions are reviewed. Liquid solutions were adapted to gas flow using the real gas pseudopressure function.; Methodologies of production analysis for different flow geometries are provided for homogeneous and dual porosity reservoirs under either constant flowing bottomhole pressure or constant gas rate. A superposition time technique to plot and interpret production data is implemented.; Log-log diagnostic plots of pseudopressure drop/gas rate versus time to detect one or more flow geometries are discussed. Specialized plots of pseudopressure drop/gas rate versus specific functions of time which depend on the flow geometry are presented.; Reservoir properties, OGIP, and reserves using the methodologies developed are estimated for actual tight gas wells from U.S.A. and Mexico.; Finally, reservoir simulation to confirm or modify the analysis performed is accomplished. |
