A Compositional Simulation Evaluation of the Santa Rosa, Colorado EF Reservoir, Eastern Venezuela

Abstract

ABSTRACT This report presents the results of a simulation study of the Santa Rosa Colorado EF, RG-14 reservoir located in Eastern Venezuela. The objectives of this study were to determine the quality of the hydrocarbon gas accumulated in the reservoir and to predict oil recoveries under a variety of operating modes. The reservoir contains a condensate gas cap that overlies an oil leg. Depth of the reservoir varies from 6560 ft (1999 m) subsea, at the crest of the dome to 11150 ft (3399 m) subsea on the northern flank. In order to match field performance history, a significant effort was made in developing a geological model based on the depositional environment concept. A fluid characterization model was also constructed for both, reservoir oil and gas condensate using the Peng-Robinson equation of state. A satisfactory history match for 36 years of reservoir performance was achieved using a three dimensional, three phases, multicomponent, compo-sitional simulator. The results at the end of the reservoir history match, indicated that the gas present in the reservoir is mainly methane. A total of five prediction cases were then studied, all intended to provide performance data for technical and economic analysis. The main effects analyzed were: higher gas-oil ratio limit, additional wells, partial and full pressure maintenance and reservoir blowdown. The main conclusions drawn from the results of this reservoir simulation study were that drilling and reactivating wells in the oil leg and re-locating the injection wells would increase the cumulative production of oil by approximately 9.1 × 106 bbl (1.447 × 106 m3).