Steamflood process employing horizontal and vertical wells
AssigneeTexaco Inc.
InventorsYick M. Shum, Margaret A. Hight, Alfred Brown
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Abstract
An oil recovery process employing a well pattern having a horizontal well located along each of the four sides of a substantially rectangular well pattern, a vertical injection well located at the center of the well pattern, and four vertical infill wells located midway between the central injection well and the four corners of the rectangular well pattern. Steam is initially injected through the central injection well and production taken at the four infill walls. After the injection of about 0.5 to about 1.0 pore volumes of steam through the central injection well, central injection is converted to water, the infill production wells are converted to steam injection, and production is taken from the horizontal wells.
Claims5
A method of recovering hydrocarbons from an underground formation by employing a modified five-spot pattern, which comprises:
- drilling and completing four substantially horizontal wells, each horizontal well approximately located along each of the four sides of a substantially rectangular well pattern;
- said substantially rectangular well pattern containing a substantially vertical central injection well and four substantially vertical infill wells located approximately midway between the central well and each of the four corners of the rectangular well pattern;
- injecting steam into the formation through the central injection well;
- producing hydrocarbons at the four infill wells;
- after injecting enough steam through the central injection well to fill about 0.5 to about 1.0 pore volumes of the formation located within a pattern formed by the four infill wells, converting the infill production wells to injection wells;
- injecting water instead of steam into the formation through the central injection well;
- injecting steam into the formation through the infill wells;
- and
- producing hydrocarbons from the horizontal wells.
Dependencies are inferred from the claim text.