HYDRAULIC FRACTURING METHOD Russian patent published in 2020 - IPC E21B43/26 C09K8/80 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and can be used in hydraulic fracturing of productive formation (HFF) using proppant in wells with weakly cemented bottom-hole zone in the presence of nearby flooded interlayers. Method of hydraulic fracturing of a formation includes pumping fluid into the formation with addition of a proppant – polydicyclopentadiene (PDCPD). Before performance of hydraulic fracturing in the well there determined is current oil saturation of the formation, in the zone with maximum oil saturation there performed is selective perforation of the formation, distance from perforation interval to water-flooded interlayer is determined. At distance from lower perforation interval to lower flooded interlayer, equal to 3 m and less, prior to pumping liquid with PDCPD, the cross-linked gel is in-series injected in volume equal to 1/5 of the total volume of cross-linked gel with weighted proppant, weight equal to 1/5 of total weight of proppant filler, and cross-linked gel in volume equal to 3/5 of part of total volume of cross-linked gel, pumping of liquid with PDCPD is carried out by weight of PDCPD equal to 3/5 of total weight of propping filler, wherein the liquid used is commercial oil with density less than density of PDCPD, and upon completion of the fracture cracks attachment, the cross-linked gel is pumped in the volume equal to 1/5 of the total volume of the cross-linked gel with the resin-coated proppant by weight equal to 1/5 of the total weight of the proppant filler, wherein the resin-coated proppant before pumping is heated at the wellhead to temperature of 55–60 °C. At a distance from the upper perforation interval to the upper water-flooded interlayer, equal to 3 m and less, prior to pumping liquid with PDCPD, the cross-linked gel is in-series injected in volume equal to 1/5 of the total volume of the cross-linked gel with the lightweight proppant, weight equal to 1/5 of the total proppant fill weight, and the cross-linked gel in the volume equal to 3/5 parts of total volume of cross-linked gel, pumping of liquid with PDCPD is carried out by weight of PDCPD equal to 3/5 of total weight of propping filler, wherein the liquid is industrial water with density greater than PDCPD density, and upon completion of the fracture cracks attachment, the cross-linked gel is pumped in the volume equal to 1/5 of the total volume of the cross-linked gel with the resin-coated proppant by weight equal to 1/5 of the total weight of the proppant filler, wherein the resin-coated proppant before pumping is heated at the wellhead to temperature of 55–60 °C. At a distance from the lower and/or from the upper perforation intervals to the corresponding flooded interlayers of more than 3 m, prior to pumping liquid with the PDCPD, a linear gel is pumped in a volume equal to 4/5 parts of total volume of linear gel, pumping of liquid with PDCPD is performed by weight equal to 4/5 of total weight of proppant filler, wherein the liquid is industrial water with density equal to PDCPD density, and upon completion of the fracture cracks attachment, a linear gel is injected in volume equal to 1/5 of the total volume of the linear gel with resin-coated proppant, by weight equal to 1/5 of the total mass of the propping filler pumping, wherein resin-coated proppant before pumping is heated at wellhead to temperature of 55–60 °C.

EFFECT: method provides higher oil recovery of the formation after HFF, reduced risk of uncontrolled development of the HFF crack along the height, higher reliability of attachment of the fracture of PDCPD, higher efficiency of HFF in weakly cemented rocks of the productive formation.

1 cl, 3 dwg