Viscous oil recovery using controlled pressure well pair drainage
First Claim
1. A method of recovering viscous oil from a subsurface formation comprising the steps of:
- a. providing a first injection well and a first production well which extend into and communicate with said formation, said first injection well and said first production well being spaced laterally one from the other by a predetermined first distance, said first injection well and said first production well being electrically connected to each other by an electrically conductive metallic flow path;
b. injecting aqueous fluid into said first injection well at a predetermined first pressure in a manner such that said aqueous fluid flows from said first injection well through said formation and into said first production well, said first pressure being below the shut-in formation pressure of said first production well; and
c. passing electrical current from said first production well and said first injection well through at least a part of said formation.
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Accused Products
Abstract
A relatively closely spaced injection well and production well pair is used as a single electrode and is used in a way that significantly increases the effective radius of an electrode production location. This is achieved by appropriately spacing of the wells and flowing aqueous fluid between wells at a pressure below the pressure driving oil toward the production well. The controlled pressure flowing aqueous fluid forms a highly conductivity flow path for oil flowing toward the production well. The effectiveness of the increased well pair drainage radius is achieved or augmented by injecting aqueous fluid, preferably steam or hot water, into the formation at a pressure great enough to drive oil toward the well pair and using the formation injection well as an electrode for electrically heating the oil. More than one well pair may be used either as a separate or the same electrode. One injection well or one production well may be used to form two or more well pairs. Several well pairs may be used in a suitable producing and injection pattern.
47 Citations
11 Claims
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1. A method of recovering viscous oil from a subsurface formation comprising the steps of:
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a. providing a first injection well and a first production well which extend into and communicate with said formation, said first injection well and said first production well being spaced laterally one from the other by a predetermined first distance, said first injection well and said first production well being electrically connected to each other by an electrically conductive metallic flow path; b. injecting aqueous fluid into said first injection well at a predetermined first pressure in a manner such that said aqueous fluid flows from said first injection well through said formation and into said first production well, said first pressure being below the shut-in formation pressure of said first production well; and c. passing electrical current from said first production well and said first injection well through at least a part of said formation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification