MULTIPLE HYDRAULIC FRACTURING OF FORMATION IN WELL HORIZONTAL SHAFT Russian patent published in 2015 - IPC E21B43/267 

FIELD: oil-and-gas industry.

SUBSTANCE: proposed method comprises drilling the well horizontal shaft in oil-saturate section of production bed, cementing of annulus between casing and bed rock. Casing pipe is perforated in said well shaft oriented in azimuth by intervals with the help of slot perforator lowered in the well on string in a single trip. String with packer is lowered in the well to fit the packer in place. Fracturing fluid is injected via said string for hydrofracturing in said horizontal well shaft. Well shaft us drilled in the bed parallel with direction of minimum main strain. Plug is fitted at string lower end and two packers are arranged at flexing pipe string. Note here that through holes are made at the latter. Said flexing pipe string with packers is lowered into well shaft for hydraulic fracturing via perforated intervals by cutting of every interval of perforation on both sides. Bed fracturing is started from horizontal well interval nearby the bottom and fluid is forced via flexible pipe string via through holes at flow rate of 2 m³/min to produce transverse fractures from perforation interval relative to well shaft. Note here that fracturing fluid is composed of hydrocarbon-based cross-linked gel. Made fractures are secured by injection of proppant of 12/18 mesh fraction with cross-linked gel, a carrier fluid. Packers are removed to displace flexible pipe string for hydraulic fracturing of the bed in the next perforation interval. Then, above jobs are reiterated. Then, flexible piper string with packers is withdrawn from the well to lower pipe string therein. Packer is fixed at well vertical part for hydraulic fracturing by injection of fluid via horizontal well shaft to produce lengthwise fractures at flow rate of 8 m³/min. Linear gel is used as fracturing fluid. Said lengthwise fractures are secured by injection of ground quartz with linear gel as carrier fluid.

EFFECT: higher efficiency of fracturing.

2 dwg