Patent Number: 6,167,966

Title: Toe-to-heel oil recovery process

Abstract: In an underground oil reservoir, an injection well is completed low in the reservoir and a production well is provided having a horizontal leg completed relatively high in the reservoir and a vertical leg completed low in the reservoir. Water is injected with the vertical leg open and the horizontal leg closed, so that a displacement front advances in an under-riding manner between the wells and oil is produced through the vertical leg. Once the water break-through in the vertical leg occurs, it is closed and the horizontal leg is opened. A rising, horizontal, gravity-stable displacement front then advances upwardly toward the horizontal leg, through which oil is produced. The open horizontal leg acts as a low pressure sink to induce the horizontal displacement front to advance up toward it. This two-stage process is characterized by a good vertical and lateral sweep. In a slightly modified version, water is injected with the vertical leg closed and the horizontal leg open so that a gravity-stable displacement front advances both laterally and vertically with a relatively upright position of a displacement front. In this version (one stage process) the process is also characterized by a good vertical and lateral sweep.

Inventors: Ayasse; Conrad (Calgary, CA), Turta; Alex (Calgary, CA)

Assignee: Alberta Research Council, Inc.

International Classification: E21B 43/16 (20060101); E21B 43/30 (20060101); E21B 43/00 (20060101); E21B 43/20 (20060101); E21B 043/20 ()

Expiration Date: 01/02/2018