Field Q is a heavy and sour oil field characterized by a naturally fractured, dome-shaped carbonate reservoir with a compact structure. The recovery mechanism implemented is thermally assisted gas/oil gravity drainage (TA-GOGD). The steam injectors are shallow, deviated, openhole wells drilled at the top crest of the reservoir, penetrating a gas cap containing 3% hydrogen sulfide, which allows for the self-flow of sour gas when steam injection ceases. The complete paper describes the application of subsurface safety injection valves (SSSIV) in an extremely high-temperature environment.
Introduction
Field Q is a thermal enhanced oil recovery project producing heavy, viscous oil (16° API and 220 cp) from a shallow, naturally fractured carbonate reservoir at a depth of 210 m true vertical depth. It is a dual-porosity reservoir with extensive fractures, a matrix porosity of approximately 30%, and a matrix permeability varying between 5 and 20 md.
Field Q has been developed using the TA-GOGD recovery mechanism because of its highly fractured carbonate formation, high oil viscosity, shallow depth, gas cap, and thick oil column.
