DYNAMIC MODELING OF PERMEABILITY AND SMALL-SCALE TEXTURES IN CORE USING A SYSTEMS APPROACH

THE RELATIONSHIPS BETWEEN SMALL-SCALE STRATIGRAPHY AND THE PERMEABILITY DISTRIBUTION IN ROCKS HAVE NOT BEEN ESTABLISHED. THIS PROJECT WILL BUILD A SYSTEMS DYNAMICS COMPUTER MODEL TO TEST THE RELATIVE IMPORTANCE OF SMALL- SCALE STRATIGRAPHY TO THE PERMEABILITY DISTRIBUTION IN A SANDSTONE CORE. PERMEABILITY CHANGES AS DIAGENETIC EVENTS CEMENT SAND INTO SANDSTONE; DIAGENETIC TEXTURES SUCH AS CEMENT DISTRIBUTION AND PORE GEOMETRY ARE CONSIDERED PARTOF THE STRATIGRAPHY. THE MODEL WILL HANDLE BOTH QUANTITATIVE AND QUALITATIVE (DESCRIPTIVE) DATA. A SYSTEMS DYNAMICS APPROACH USES A SYSTEM'S FEEDBACK BEHAVIOR TO EVALUATE THE RELATIVE IMPORTANCE OF ITS ELEMENTS IN CREATINGA GIVEN CONDITION OVER TIME. FOR SANDSTONE CORE, THESE ELEMENTS INCLUDE TYPE AND ARRANGEMENT OF BEDS AND LAMINAE, GRAIN SIZE, SORTING AND SHAPE, MINERALOGY, CLAY DISTRIBUTION, CEMENT TYPE AND ARRANGEMENT, POROSITY, AND PORE GEOMETRY. FINAL CONDITIONS ARE DERIVED DIRECTLY FROM CORE MEASUREMENTS. INITIAL CONDITIONS ARE PARTLY DERIVED FROM THESE MEASUREMENTS AND PARTLY ASSESSED FROM SIMILAR MEASUREMENTS ON MODERN, ANALOGOUS SEDIMENTS. THE MODEL WILL BE CONSIDERED READY WHEN PRESENT CORE PLUG PERMEABILITIES ARE OBTAINED FROM EQUATIONS THAT DESCRIBE THE INTERACTIONS OF THE INITIAL CONDITIONS OVER TIME. PHASE II WILL EXAMINE MANY DIFFERENT CORE PLUGS TO EVALUATE THE UNIVERSALITY OF THE FINDINGS IN PHASE I AND WILL EXAMINE THE PROBLEM OF SCALING STRATIGRAPHIC DATA ON CORE PLUGS TO THE CORE LEVEL.