Use of Compositional Simulation in the Management of Arun Gas Condensate Reservoir

Abstract

ABSTRACT This paper describes the simulation of the Arun gas condensate reservoir using Mobil's fully compositional simulator, COSMOS (Compositional System Mobil Oil Simulator). The reservoir is a Miocene carbonate reef complex which occurs at a depth of approximately 10,000 feet, and is up to 1.000 feet thick in some areas. The Arun reservoir is a ccmpositionally dynamic system. The purpose of this simulation study was to predict future reservoir performance under various demand scenarios and optimize gas and NGL recovery. The simulation model utilizes the Peng-Robinson equation of state to account for the compositionally dynamic behavior of the reservoir in predictions of future performance; The equation of state was modified by Mobil to incorporate-special features for Arun such as water vaporization in the reservoir under high temperature conditions. A significant amount of time was spent on the geologic description of the field and initial data preparation, which contributed to a good match of the historical data. The simulation model will serve as a reservoir, management and planning tool to evaluate future operating strategies in the field. The technology presented in this paper is applicable to the management of other gas condensate reservoirs which exhibit physical phenomena such as retrograde condensation, revaporization, and water vaporization.