MULTIPLE SCALE VALLEY-FILL RESERVOIR HETEROGENEITIES AND GEOLOGIC AND ENGINEERING RESERVOIR CHARACTERIZATION

WE PROPOSE TO DEVELOP A NEW AND QUANTATIVE MODEL AND VERIFY IT WITH RESERVOIR SIMULATION. QUANTATIVE MODELS HAVE NOT BEEN DEVELOPED FOR VALLEY-FILL RESERVOIR OIL FIELDS SINCE THEY ONLY RECENTLY HAVE BEEN IDENTIFIED AS HAVING SIGNIFICANT PRODUCTION. MORE THAN 20 VALLEY-FILL FIELDS NOW PRODUCE. THE VARIOUS TYPES AND SCALES OF RESERVOIR HETEROGENEITIES WITHIN RESERVOIR FLOW UNITS AND BETWEEN THE VALLEY-FILL AND PRE-VALLEY FILL SEDIMENTS HAVE NOT BEEN DOCUMENTED AND QUANTIFIED. VALLEY-FILL RESERVOIRS ARE FORMED DURING PERIODS OF RISING SEA LEVEL WHEN RIVERINE, MARINE OR MIXED MARINE/RIVERINE SANDSTONES ARE DEPOSITED IN A PREVIOUSLY CUT VALLEY. ABRUPT LATERAL AND VERTICAL CHANGES OCCUR BOTH WITHIN AND AT THE MARGINS OF VALLEY-FILL RESERVOIRS. TO EVALUATE AND ANALYZE THE HETEROGENEITIES OF VALLEY-FILL RESERVOIRS LITHOLOGIC GEOLOGICAL INTERPRETATION OF FLOW UNITS AND PORE TYPES AND PORE DISTRIBUTION WILL BE COMPARED TO PERMEABILITY AND POROSITY DISTRIBUTIONS IN 10-12 CORES FROM TWO OIL FIELDS. ISOPACH MAPS AND SELECTED CROSS SECTIONS, TIED TO GEOLOGIC ANALYSIS OF CORES, WILL BE CONSTRUCTED TO SHOW FIELD SCALE HETEROGENEITIES. TO DETERMINE MICROHETEROGENEITIES, THIN SECTION ANALYSIS, X-RAY DIFFRACTION MINERALOGY, AND SCANNING ELECTRON ANALYSISWILL BE CONDUCTED. OUTCROPS NEARBY TO, AND EQUIVALENT IN AGE TO, ONE OF THE VALLEY-FILL RESERVOIRS, WILL BE INTERPRETED IN PREPARATION FOR A MINIPERMEAMETER SURVEY. PHASE II WILL RELY ON THE FINDINGS OF PHASE I TO DETERMINE WHICH PORTION OF THE FIELDS ARE MOST SUITABLE FOR RESERVOIR SIMULATION. KREIGING WILL BE USED AND DYKSTRA PARSON COEFFICIENTS WILL BE CALCULATED. THE RELATIVE IMPORTANCE OFEACH TYPE OF RESERVOIR HETEROGENEITY WILL BE EVALUATED FOR PRIMARY, SECONDARY AND TERTIARY PRODUCTION. SIMULATION ON THE MOST IMPORTANT SCALES WILL BE CARRIED OUT AND TECHNIQUES FOR SCALING-UP OF GEOLOGICAL VARIABLES WILL BE DEVELOPED AND IMPLEMENTED INTO AN OVERALL VALLEY-FILL RESERVOIR MODEL.