Study of the efficiency of well repair at the Karachaganak field

Abstract

The assessment of the effectiveness of the choice of formulations of clay-free inhibited salt solutions, recommended for washing when drilling side shafts and horizontal sections, based on the study of biopolymers, in the conditions of the Karachaganak deposit, is considered. The duration of the fountaining of production wells at the Karachaganak field depends both on the methods used to increase the oil yield of layers (primary and secondary) and on the dimensional characteristics of the fountain system for lifting well production. As a result of a gradual decrease in reservoir pressure and water inflow into the downhole zone of the well, its stability is significantly reduced, the filtration characteristics of the reservoir deteriorate, the formation of mineral deposits, sand and gas hydrate plugs increases, and the corrosion activity of production increases. And as a result, the production capacity of producing oil and gas condensate wells is significantly reduced. The character of the composition of the reservoirs of the deposits of the Karachaganak deposit, in the overwhelming majority, contain clayey cement. At the same time, the "swelling" of clay rocks is a significant reason for the decrease in productivity of production wells. Collectors with low permeability with practically irreversible "internal clogging" are especially sensitive to this effect. The use of technological fluids has been found to be the most effective – solutions containing a biopolymer as the main component, possessing pseudo-plasticity and contributing to high-quality cleaning of the bottom hole from mud, as well as the maximum removal of mud residues from the well system, which have a minimal polluting effect on reservoir reservoir systems, since biopolymer the substance entering the collector is enzymatically decomposed after a certain time. The use of the composition of the inhibitory biopolymer salt solution based on the KCl complex salt (potassium chloride-electrolyte) will allow to fully preserve the properties of the productive layer. For maximum isolation of the watered downhole zone of the formation, the authors propose to use a tamping solution on an adhesive basis with properties sufficient for reliable isolation. Injection of tamping solution under pressure into the layer will increase the strength of the cement stone by an average of 1.5 times.