Preservation of filtration and capacity properties of productive formations during their temporary isolation

Abstract

The article considers the preservation of the filtration-capacitive properties of the productive formation during well killing – during temporary isolation, which is part of the technological process aimed at stopping the flow of formation fluid into the wellbore. This procedure is carried out as part of well workover operations. The features of choosing the type and rheological parameters of the killing fluid are studied, taking into account the features of the structure of the pore space of the reservoir. Criteria for choosing well killing technologies with temporary isolation of the productive formation under abnormally low reservoir pressures are proposed to maintain reservoir permeability. The features of the fluid for blocking the bottomhole zone of the formation during well killing under conditions of abnormally low formation pressures were systematized. Compositions of blocking fluids with filler for well killing are proposed, the main rheological parameters and main characteristics for practical application are given. The technical and economic features of well killing with preliminary blocking of the bottomhole formation zone under conditions of abnormally low formation pressures are studied. Also, the paper considers the technical and economic aspects of the proposed compositions. The aim of the research is to study and select the composition of blocking fluids used for well killing under conditions of abnormally low formation pressures, ensuring the preservation of the filtration-capacitive properties of productive formations during their temporary isolation, while assessing their technical and economic feasibility. The results of laboratory and field studies were studied, generalized and abstracted using the theoretical level method, allowing us to draw conclusions and theoretical generalizations. Physicochemical, rheological and filtration studies of the considered process fluids were carried out, including an assessment of the blocking, filtration and gas-retaining properties of the killing fluids. Results. Based on the analysis and generalization of the research results, compositions of blocking fluids for temporary isolation of the productive formation during well killing under conditions of abnormally low formation pressures are proposed. The technical and economic aspects of the recommended fluid compositions were determined.