METHOD OF MULTILAYER HYDRAULIC FRACTURING DOWN HOLE Russian patent published in 2015 - IPC E21B43/26 

FIELD: oil and gas industry.

SUBSTANCE: invention is referred to mining and may be used for multilayer hydraulic fracturing down the hole. Due to the method in a subsurface structure there are formed permeable channels in two or more layers around the borehole. The above channels are separated from each other by the length of a certain section of the borehole. The permeable channels in each zone have different characteristics considering the orientation of each channel in two or more layers and in regard to the selected direction of hydraulic fracturing as well as a difference in pressure before commencement of hydraulic fracturing for each of the two layers or more layers. A breakdown agent is injected to the borehole during the process of hydraulic fracturing. The injected breakdown agent is supplied at a pressure higher than the pressure before commencement of one of the two or more layers. It speeds up fracturing of the above layer; at that the pressure remain less than the pressure before commencement of hydraulic fracturing for the other one layer or more layers not affected by hydraulic fracturing. The process is repeated for at least one or more layers not affected by hydraulic fracturing or for two or more layers.

EFFECT: improved efficiency of hydraulic fracturing of the layers down the hole.

15 cl, 8 dwg