METHOD FOR MULTIPLE HYDRAULIC FRACTURING OF FORMATION IN HORIZONTAL SHAFT OF WELL Russian patent published in 2014 - IPC E21B43/267 

FIELD: oil and gas industry.

SUBSTANCE: method includes identification of natural fracturing of rocks and its maximum primary stress, isolation of the burst interval in a horizontal well bore, performance of hydraulic fracturing in the isolated interval, fixing of the fracturing. A horizontal well with a bore length equal to at least 200 m is either selected or drilled in the direction being the bisector of the least angle between the vector of natural fracturing and the vector of the maximum primary stress. When length Ln of each interval is exceeded along the well borehole per more than 50 m, at this section N=Ln/100 steps of hydraulic fracturing is performed where N is rounded off to an integer number. Initially hydraulic fracturing step is made within the interval with the lowest permeability, the breaking fluid is injected at the flow rate of 1-3 m³/min and crosslinked gel and linear gel is used in the ratio of 2:1 respectively, flushing of fluid with a proppant is made by the process fluid with density equal to the density of stratal water in this stratum. At that fractures in each interval are fixed by fractions of the proppant which are selected on the condition that equality is ensured for processing duration of the stratum intervals with different permeability as per the theoretical dependency.

EFFECT: improving efficiency of hydraulic fracturing for zonal and non-uniform reservoirs.

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