METHOD OF GAS WELL KILLING WITH PRESSURE MONITORING ON THE BOTTOMHOLE Russian patent published in 2020 - IPC E21B43/12 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and is intended for killing of gas wells during repair works. Proposed method consists in determination of dependence of change of wellhead pressure on height of solution level rise providing pressure at bottomhole in conditions of absence of solution absorption and pickup of gas packs. This condition is ensured by compliance with mathematical inequality. At the stage of preparation for well killing, well head pressure is measured, formation pressure, density of solution, volumes of pipe and annular spaces are calculated. Further, the downhole pressure value is determined, which ensures absence of solution absorption and pickup of gas packs. Knowing the required pressure at the downhole, the remaining values are calculated. For convenience of using obtained results, information is reduced to a table. Well is killing in three stages. At first stage tubular space of well and sump is filled, required volume of solution is determined beforehand, solution is pumped with maintenance of required pressure in annular space at wellhead, if necessary, gas is released from it. At the second stage without stopping after the first one, the solution is pumped into the well tubular space by blowing gas from the annular space, maintaining the required pressure value defined by the table depending on the volume of the solution pumped into the well. At the third stage, after lifting solution through annular space at wellhead, well is washed in volume of one well volume with clean solution, gas solution is changed to clean solution, shutoff valve is closed, and the well is left to process sediment. Well is killed.

EFFECT: absence of colmatation of bottom-hole zone, reduction of well killing time from several days to several hours, exclusion of excess chemical consumption for preparation of additional volume of solution lost as a result of absorption, reducing the number of used cementing and pumping units to one unit, avoiding the need for intensification of influx, reducing the risk of gas and oil aquifers, emergencies.

1 cl, 6 dwg