Predicting Reservoir Quality and Diagenetic History in the Frio Formation (Oligocene) of Texas
Published:January 01, 1984
Principles of equilibrium thermodynamics were applied and found useful in evaluating aspects of Frio diagenesis. Solutionmineral equilibria as predictors of reservoir quality and diagenetic history were tested by comparing formation waters from regions of good and poor reservoir quality, the upper and lower Texas coast, respectively. Comparison among waters from these regions was made on activity diagrams of 16 diagenetic reactions such as calcite = ferroan calcite, kaolinite = chlorite, and Ca-montmorillonite = Na-montmorillonite. Relative position of tested waters, with respect to the stability field of authigenic minerals occluding permeability and porosity, was related to reservoir quality. Solution-mineral equilibria...
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Clastic diagenesis has evolved from a very descriptive science to a much more process-oriented study. This evolution has been driven by the realization that many hydrocarbon reservoirs have significant diagenetic compotents directly affecting porosity and permeability characteristics. The prediction in time and space of reservoir characteristics affected by diagenesis can greatly reduce the risk in the search for hydrocarbon accumulations, particularly in subtle targets lacking pronounced structural expression. This publication contains three sections designed to increase understanding in the processes controlling clastic diagenesis: Conepts and Principles; Aspects of Porosity Modification; and Applications of Clastic Diagenesis in Exploration and Production. The first two sections deal with processes controlling various aspects of clastic diagenesis, and the third section applies these principles and observations to specific examples. Altogether, the three sections contain 22 chapters.