RESEARCH ON THE BLOCKING CAPACITY OF JUMPING FLUIDS IN THE CONDITIONS OF CAPITAL AND CURRENT REPAIR OF WELLS

Abstract

Key to increasing the carbon efficiency of productive formations is ensuring the preservation of reservoir properties during major and routine well repairs. The filtration characteristics of wells in challenging mining and geological conditions are most effectively preserved using clay-free polymer and emulsion flushing systems. However, the use of biopolymer systems at great depths, where formation pressures and temperatures are high, is limited due to their low blockage breakthrough pressures, which are a result of their heat resistance and density. One solution to this problem is to develop heat-resistant systems that increase their blocking characteristics as the temperature rises. The breakthrough pressures of the main jamming solutions were determined and the most effective composition for preserving the productive characteristics of productive horizons was selected on a specially designed installation. It was found that most of the killing fluids used do not meet the geological and technical characteristics of the wells. Namely, they cannot withstand the temperature regime at the bottom of the well, have low breakthrough pressures and reduce viscosity, thereby increasing filtration into the pore space. The change in the main physicochemical characteristics of killing solutions under the influence of high temperatures, as well as the effect of the main components of killing fluids on breakthrough pressures and the conditions for removing killing fluids from wells, were considered. Based on the research conducted, a recipe for a killing system based on magnesium and ammonium salts is proposed. Under conditions of high reservoir pressures and temperatures, this system provides the highest possible breakthrough pressures of up to 45 MPa, due to a sharp increase in density and minimised filtration. It was determined that the main factor in maintaining reservoir productivity is ensuring high breakthrough pressures and high rates of killing fluid removal from the well bottom.