FORMATION HYDRAULIC FRACTURING METHOD Russian patent published in 2015 - IPC E21B43/267 E21B34/10 

FIELD: oil industry.

SUBSTANCE: method involves lowering to a well of a tubing string with a packer, seating of the packer above the roof of the formation subject to hydraulic fracturing, pumping of fracturing fluid to the formation via the tubing string through the well till a fracture is created in the formation, reinforcement of the created fracture by pumping of a propping agent, closure of the well and expectation of pressure drop, relief of residual wellhead pressure till atmospheric pressure, depressurisation of the wellhead, removal of the packer and lifting of the tubing string out of the well. At the wellhead, the tubing string is provided in an upward direction with a bottom-hole pulsator, a knock-off valve and the packer. The tubing string is lowered into the well so that the bottom-hole pulsator can be arranged in the middle of the formation subject to hydraulic fracturing, and the packer can be arranged above the roof of this formation. Annular space of the well is sealed by setting of the packer; total volume of helium-saturated liquid is determined; total volume of helium-saturated liquid is divided into three equal parts, out of which 1/3 part is represented by helium-saturated liquid on water base for formation and development of a fracture in the formation, 1/3 part is represented by helium-saturated liquid on water base - the liquid carrying the propping agent, 1/3 part is represented by helium-saturated liquid on the basis of merchantable oil - the liquid carrying the granulated lime. A formation hydraulic fracturing process is started by pumping via the tubing string through the bottom-hole pulsator in a pulsing mode of 1/3 part of helium-saturated liquid on water base for formation and development of a fracture in the formation; after that, for reinforcement of the created fracture in the formation in a pulsing mode there performed is alternating pumping of granulated lime with the carrying liquid - helium-saturated liquid on the basis of merchantable oil and the propping agent with the carrying liquid - helium-saturated liquid on water base with 15 equal portions each. With that, each of 15 equal portions of helium-saturated liquid on the basis of merchantable oil includes granulated lime based on 800 kg/m³, and at pumping of 15 equal portions of helium-saturated liquid on water base of the liquid carrying the propping agent there increased concentration and a fraction of the propping agent and pumped: from the first to the fifth portion - the propping agent with concentration of 600 kg/m³ and with fraction of 20/40 mesh, from the sixth to the tenth portion - the propping agent with concentration of 800 kg/m³ and with a fraction of 20/40 mesh is pumped; from the eleventh to the fourteenth portion - the propping agent with concentration of 1000 kg/m³ and with a fraction of 20/40 mesh is pumped; the last fifteenth portion - the propping agent with concentration of 1000 kg/m³ and with a fraction of 16/20 mesh is pumped. Then, pumping of an acid solution is performed in a pulsing mode; water solution (24%) of chlorhydric acid is used as the above acid solution in the volume of the carrying liquid pumped into the formation - helium-saturated liquid on the basis of merchantable oil for decomposition of the formed caustic lime and destruction of gel residues. After that, the well is closed to expect pressure drop and acid reaction; after that, residual wellhead pressure is relieved to atmospheric pressure, the wellhead is depressurised and the well is developed by swabbing via the tubing string till there is oil inflow from the formation; after that, the packer is removed and the tubing string is lifted out of the well.

EFFECT: improving efficiency of formation hydraulic fracturing.

1 dwg, 1 tbl