Design of Simultaneous Enhanced Oil Recovery and Carbon Dioxide Storage Applied to a Heavy Oil Field Offshore Trinidad?

摘要

We have developed an injection strategy to recover moderately heavy oil and store carbon dioxide (CO2) simultaneously. Our compositional simulations are based on PVT-matched properties of oil found in an unconsolidated deltaic, sandstone deposit in the Gulf of Paria, offshore Trinidad. In this region oil density ranges between 940 and 1 010 kg/m3 (9-18 degrees API). We use counter-current injection of gas and water to improve reservoir sweep and trap CO2 simultaneously; water is injected in the upper portion of the reservoir and gas is injected in the lower portion. The two water injection rates investigated, 100 and 200m3/d, correspond to water gravity numbers 6.3 to 3.1 for our reservoir properties. We have applied this injection strategy using vertical producers with two injection configurations: single vertical injector and a pair of horizontal parallel laterals. Eight simulation runs were conducted varying injection gas composition for miscible and immiscible gas drives, water injection rate and injection well orientation. Our results show that water over gas injection can realize oil recoveries ranging from 17 to 30%. In each instance more than 50% of injected CO2 remained in the reservoir with less than 15% of that retained CO2 in the mobile phase.