STEAMING PROCESS, INVOLVING A PAIR OF HORIZONTAL WELLS, FOR USE IN HEAVY OIL RESERVOIR

摘要

"STEAMING PROCESS, INVOLVING A PAIR OF HORIZONTAL WELLS, FOR USE IN HEAVY OIL RESERVOIR" A pair of horizontal parallel co-extensive wells, one spaced closely above the other, are completed so that they extend through a heavy oil reservoir in close proximity to its base. The upper well is referred to as the injector and the lower a the producer. Each well has a screened liner and an inner tubing string extending the length of the well. Steam is circulated separately through each of the wells to heat by conduction the span of formation extending between the wells and establish fluid communication between them. The circulation is conducted in through the tubing and out through the annulus at an elevated pressure that is less than fracture pressure. The rate of production of effluent from each well is controlled to maintain its temperature just below saturated steam temperature. Once communication is established, steam circulation in the producer is discontinued and the well is produced through the tubing. Steam is then injected through both the annulus and tubing of the injector. Condensate and oil are produced through the lower well. Steam-assisted gravity drainage is the mechanism thereafter used to heat the reservoir and produce the oil. Production rate is controlled to maintain the temperature and pressure of the produced fluid just below saturated steam conditions.