RECOVERY METHOD FOR OIL-SOURCE RESERVOIRS BY THE CONTROLLED MULTI-STAGE HYDRAULIC FRACTURE Russian patent published in 2017 - IPC E21B43/26 E21B43/16 

FIELD: oil and gas industry.

SUBSTANCE: invention can be applied in the development of oil-source reservoirs managed using a controlled multi-stage hydraulic fracturing (MHF). To isolate high permeability zones and fractures, the method comprises applying in the wells of injection of mixture of surfactants, polyacrylamide (PAA), a stapler - chromium acetate, filler and water, well subjecting to process exposure, products selection from wells. According to the invention, a low-permeability reservoir is selected with an average absolute permeability of less than 2 mD, which are used for drilling, or already drilled horizontal sidetrack wells are used. In each of such wells, the first MHF is performed, during which the fracture propagation area is recorded by means of low-frequency seismic survey. Packers separate the horizontal wellbores into sections, then the wells with conducted MHF are injected, through each horizontal wellbore section, with insulating composition with the following component ratio, wt %: SAW - 0.2-5.0, PAA - 0.005-2.5, chromium acetate - 0.01-1.0, filler - 0.5-15.0, water with a salinity of less than 1.5 g/l - the rest. After the soak period during 1-10 days and colmatation of fractures after the first HF, the second HF is conducted in the same wells by the pumped insulation compound, during which fracture propagation is also recorded by means of the low-frequency seismic survey. Upon obtaining data on fractures distribution after the first and the second MHF, a decision is made on performance in these injection wells of subsequent phases of insulating composition injection and MHF conducting. Moreover, the number of subsequent MHF is determined based on the full reservoir coverage with MHF fracture zones both in plan and in profile around each horizontal wellbore. After all MHF, the reservoir is processed by separate injection in each stage of the horizontal wellbores of the insulating composition solvent in a volume of 0.8-2.0 from the total volumes previously pumped insulating compositions to this satge of the horizontal wellbore.

EFFECT: increasing of the coverage factor and oil production of the oil-source reservoirs.