| 摘要 |
In the course of completing a production well in a heavy oil or tar sand reservoir arranged for frontal displacement, thermal drive from at least one injection well, the well is divided into separate, non-communicating lower and upper zones. The lower is connected with the reservoir by perforations; the upper by a large gravel packed zone and preferably a sand screen. The completion process involves starting a local combustion drive adjacent to the bottom of the well by injecting compressed air through the perforations while preventing upward migration of the combustion zone in the vicinity of the well by injection of water or dilute aqueous soap solution through the screen and gravel packed zone. After a suitable time, generally of the order of a month or less, air injection is stopped. Production is started through the screen (no workover or killing operation needed). After producing some or all of the combustion product gas and locally heated oil, the well is still hot, with a region of high permeability adjacent to the gravel packed zone, ready to produce fluids and/or gas from a distant injection well. Should further heating be needed later in the life of this well, the annular space normally used for production can be displaced with a soap solution after which the local heating step is repeated.
|
