Estudo do processo de combustão in situ aplicado a um reservatório de óleo pesado através do processo Toe-to-Heel Air Injection (THAI)

Abstract

Much of the world's oil is made up of heavy oil. Due to its high viscosity the primary energy contained in the reservoir is not sufficient for extraction of this type of oil. In this way, special advanced oil recovery methods are required, in which thermal methods are inserted. Thermal methods are basically aimed at reducing the viscosity of the oil by supplying heat to the reservoir. One such method is in situ combustion, a process in which oxygen (air) is injected into the reservoir so that part of the oil contained in it burns to produce heat. In situ combustion techniques include the Toe-To-Heel Air Injection, in which the air is injected through a vertical well and the oil is extracted by a horizontal well. The objective of this work is to carry out a study of this technique, through numerical computational simulation, applied in a reservoir of synthetic heavy oil in order that, by varying operational parameters of flow, extension of the producing well and percentage of O2 in the injected air, the best oil recovery factor possible. Through the simulations made using the STARS (Steam, Thermal, and Advanced Processes Reservoir Simulator) program developed by the company CMG, it was verified that the in situ combustion technique employed is effective, so that a recovery factor of less than 0, 01% in the primary recovery was raised to about 59% in the best configuration obtained: 200,000 m3/d of air (21% of O2) injected, producing well with 162 m extension.