Geostatistical Modeling and Reservoir Simulations of Reservoirs in the Greater Monument Butte Region, Uinta Basin, Utah: ABSTRACT

Abstract

The reservoir simulation and history matching of the successful water flood in the Monument Butte unit revealed that the reservoirs extended well beyond unit boundaries. A 12-section area around the Monument Butte unit was targeted for analysis. Porosities and water saturations at two-feet resolution were obtained using digitized logs. Permeabilities were generated using porosity-permeability cross plots. Alternate three-dimensional reservoir images were generated using three dimensional varlogram models and sequential Gaussian simulations. These three-dimensional reservoir images were used in a three-dimensional, three-phase black-oil simulator to examine reservoir performance. Four different and distinct sands, D1, B2, C and A were analyzed. The reservoir images clearly reflected the fluvial-deltaic nature of the deposits. The reservoir performance in primary production and during a water flood was evaluated. The pressure decline in an undeveloped section due to primary production activity in neighboring sections was not significant. However, the water flood performance was governed by reservoir connectivity. It was observed that as much as 30% of the water injected into the Monument Butte unit migrated outside of unit boundaries. Thus, water flood responses in unitized regions can be expected to be affected significantly by water flood activity in units in the vicinity. Similar trends were observedmore » through the analysis of a larger 45-section geostatistical and reservoir model.« less