METHOD FOR OIL POOL DEVELOPMENT WITH HORIZONTAL WELLS Russian patent published in 2006 - IPC E21B43/20 

FIELD: oil production, particularly enhanced recovery methods for obtaining hydrocarbons.

SUBSTANCE: method involves drilling main horizontal or inclined conveying bore in productive reservoir roof part; drilling descending additional branch bores from the main one so that additional bore bottoms extend towards main conveying bore bottom. Height of horizontal part of the last additional branch bore is selected from ratio of distance between bore bottom and oil-water contact to distance between main conveying bore and oil-water contact, wherein the ratio is to be equal to 0.6-0.8. Height of horizontal section of additional branch descending bore is selected from ratio of distance between bore bottom and oil-water contact to distance between main conveying bore bottom and oil-water contact, wherein above ratio is to be equal to 0.1-0.2. Heights of horizontal sections of additional branch bores located between the first and the last bores are selected from ratio of distance between bore bottom and oil-water contact to distance between main horizontal bore and oil-water contact, wherein the ratio is to be equal to 0.2-0.6. Then the wells are brought into operation for oil production. In the case of increased water content in produced oil because of oil-water interface elevation watered descending bores are put out of well operation.

EFFECT: increased oil recovery.

1 ex, 1 dwg