Oil recovery with fishbone wells and steam
The present disclosure relates to a particularly effective well configuration that can be used for steam-drive based oil recovery methods. Fishbone multilateral wells are combined with steam drive, effectively allowing drive processes to be used where previously the reservoir lacked sufficient injectivity to allow steam drive or cyclic steam based methods.
1. A method of producing heavy oils from a reservoir by steam drive, comprising:
a) providing a plurality of horizontal production wells at a first depth at or near the bottom of a hydrocarbon play;
b) providing a plurality of horizontal injection wells, each injection well laterally spaced at a distance D from an adjacent production well;
c) providing a plurality of open hole ribs originating from said plurality of horizontal production wells or said plurality of horizontal injection wells or both, wherein said plurality of open hole ribs cover at least 95% of said distance D;
d) cycling between injecting steam and producing through the laterals before injecting steam into said injection wells and steam driving heated heavy oils towards said production wells for production;
e) providing an open hole horizontal ghost hole above at least one injection well, wherein one or more open hole ribs slants towards said open hole horizontal ghost hole, and commencing a steam assisted gravity drainage process once a steam chamber encompasses said open hole horizontal ghost hole;
f) wherein said reservoir contains bitumen or heavy oil immobile for steam drive without the use of said plurality of lateral wells.
2. The method of claim 1 , wherein step d) includes alternating steam injection into said injection well and said production wells to improve steam injectivity before commencing steam drive step d).
3. The method of claim 1 , wherein said distanced D is 50-300 meters.
4. The method of claim 1 , wherein said distance D is at least 50 meters.
5. The method of claim 1 , wherein said distance D is at least 100 meters.
6. The method of claim 1 , wherein said distance D is at least 150 meters.