DOUBLE-HOLE WELL OPERATION METHOD Russian patent published in 2015 - IPC E21B43/00 

FIELD: oil and gas industry.

SUBSTANCE: according to the method a removable whipstock is installed. Then a window is cut in boring case. An offshoot is drilled from the main borehole. Offshoot drilling is made with running in of the boring case, its continuous cementing, perforation and provision of required reliability of attachment in the area of offshoot tracking. At that behind-the-casing flows of gas and liquid mixture are excluded. To this end upon window cutting a cement ring is cut in the boring casing and adjoining soil is cut as well in direction of offshoot drilling forming a cavern with diameter exceeding diameter of the offshoot. The cavern is poured with solid sealing compound and offshoot is drilled through the cavern. Downhole pumping equipment is placed in the main borehole and oil is extracted from the main borehole and offshoot.

EFFECT: increased oil extraction from offshoot at operated main borehole.

3 cl, 2 dwg