Features оf Carrying оut Repair аnd Restoration Works in Gas Wells of Western Siberia Fields at the Stage of Falling Production

Introduction. The article discusses the features of carrying out repair and restoration work in gas wells of Western Siberian fields that are at the stage of declining production. The compositions of process fluids used to block the bottomhole formation zone during well killing, to isolate the inflow of formation waters in various mining and geological conditions are given. The compositions of process fluids used in repair and restoration work in certain fields of Western Siberia are presented. They are easily removed when inducing inflow from the formation, and allow providing the required pressure at the bottomhole, as well as maintaining the reservoir properties of the productive formation and preventing its destruction.

Materials and research methods. Based on the generalization of field experience in killing wells, fields at the stage of declining production, the results of their own theoretical, laboratory and bench studies.

Research results and their discussion. When killing wells with temporary blocking of the bottomhole formation zone, the choice of the composition of process fluids with high stability, low filtration, in a wide range of adjustable density and rheological properties, allows creating the necessary repression on the formation and carrying out various operations in the well without complications. Technological fluids for killing wells, which are direct-type emulsion systems based on a composite reagent, are pseudo-plastic systems in terms of rheological parameters, where the density range is 900-1000 kg/m3. The properties of the emulsion solution based on the kill fluid reagent are determined by the complex effect of the reagents included in its composition. Filler-based blocking fluids are used to temporarily block the bottomhole formation zone of wells, and are prepared by introducing the calculated amount of the reagent into the required volume of killing fluid based on the killing fluid reagent. As a water-insulating composition for creating an insulating barrier in the reservoir, a formulation of a gel-forming composition based on a reagent – a dry mixture for carrying out repair and restoration work and a gelforming reagent – is considered.

Conclusions. Based on the study, it was determined that the most promising technology for killing wells under conditions of abnormally low formation pressures is the technology of preliminary blocking of the bottomhole formation zone using blocking fluids with filler. To ensure high efficiency of repair and restoration work, preliminary calculations of the process fluids used are necessary, taking into account the mining and geological conditions of the reservoir and the geometric parameters of the well.

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