Possible negative influence of cationic polymers on borehole stability in clay rocks

Abstract

Introduction. At present, cationic polymers are increasingly used in drilling practice. This trend is directly related to the exceptional properties, which are quite reasonably attributed to these polymers by specialists in the field of drilling and drilling fluids. However, during when evaluating the model cationic polymer performance, an undesirable effect of its influence on a model clay sample was discovered. In this regard, the purpose of the work was the case study of discovered effect in the context of available scientific and technical data, as well as an assessment of its possible impact on the technical and economic indicators of drilling. 40 "Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal". No. 8. 2020 ISSN 0536-1028 Methodology and results. The research methodology includes experiments on comparative evaluation of capillary impregnation rate of clay rock samples in various media including the ones with the model cationic polymer, as well as analyzing and comparing the results with the available scientific and technical data. The cationic polymer negative influence effect on the model clay rock is described and an assumption about its causes and mechanism is made. A possible scenario of negative effect implementing during drilling, as well as its consequences, is given. Summary. The results obtained made it possible to establish that the main significant aspects which determine the observed effect are the cationic nature of the polymer and the specificity of its adsorption on the surface of clay minerals