METHOD FOR TEMPORARILY BLOCKING A PRODUCTIVE FORMATION UNDER CONDITIONS OF ABNORMALLY LOW FORMATION PRESSURES Russian patent published in 2023 - IPC E21B43/32 C09K8/42 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry, in particular to the killing of gas and gas condensate wells with temporary blocking of productive formations during repair work under conditions of abnormally low reservoir pressure (ALRP) and above ALRP. The method includes successive injection into a well equipped with a tubing string of killing fluid, blocking fluid and displacement fluid. A flexible pipe is lowered into the tubing string and a killing fluid is pumped through it in the filling volume of the wellbore from the bottom to the upper boundary of the perforation interval, then the annulus is opened and the killing fluid is pumped into it in volume to create back pressure on the reservoir when the condition of one and a half times excess of hydrostatic pressure is met above the reservoir, after which the flexible pipe is lowered to the roof of the productive formation, the annulus is closed and blocking fluid is pumped through the flexible pipe into the productive formation with a pressure determined by calculation. At the same time, a three-phase foam prepared on the basis of a foaming liquid of the following composition is used as a killing fluid and a squeezing fluid, wt.%: biopolymer Gammaksan 0.2-0.5; sulfonic acid 0.5-1.2; mustard powder 0.1-0.5; water the rest; and as a blocking liquid, a composition of the following composition is used, wt.%: biopolymer Gammaxan 0.30-0.60; LSTP 0.45-0.90; FHLS-M 0.15-0.30; chromium nitrate 9-water 0.50-1.30; ammonium nitrate 0.5-10.0; water the rest, at a mass ratio of the biopolymer Gammaxan : LSTP : FHLS equal to 1:1.5:0.5. The blocking liquid may additionally contain organo-mineral filler "OM-2C" in the amount of 5-10% by weight of the latter.

EFFECT: increasing the efficiency of temporary blocking of the productive formation, in the formation of a shield of increased strength in the bottomhole formation zone and the possibility of its complete destruction, as well as the possibility of controlling hydrodynamic processes in the bottomhole formation zone, preventing the destruction of the reservoir and ensuring the preservation of its reservoir properties.

2 cl, 5 tbl