ANALYSIS OF GLOBAL PRACTICES OF FORMATION WATER INTAKE PROFILE STABILIZATIONS BASED ON CROSS-LINKED POLYMER GELS

Abstract

Due to a growing number of wells being in late stages of operation, there is an increasing demand for introduction of new integrated solutions reducing wellbore fluid watercut. Eventually, watercut reduction enables a prolonged operation of encroached wells and improves recovery of residual oil reserves. Polyacrylamide is the most available and industrially applicable reagent stabilizing formation water intake profiles. Based on the review of international and native experience, the study analyses the effectiveness of a variety of methods using polyacrylamide to reduce the wellbore fluid watercut. The paper discusses such injection technologies as conventional polymer water flooding, in situ gels, colloidal dispersion gels, and precrosslinked gels. Cross-linked polymer gels are three-dimensional structures where polymer chains are cross-linked by either ionic or covalent polar bonds. Depending on particle sizes, they are divided into macrogels (100 µm to several cm) and microgels (0.1 to 30 µm). Compared to in situ compounds, the use of macro-and microgels substantially reduces the risk of polymer chain destruction by mechanical, chemical or thermal factors. Based on the analysis, recommendations were developed for application of various polymer injection methods taking into account the geological and technological conditions of the production site development. It is recommended to use macrogels to reduce the wellbore fluid watercut in fields with the reservoir permeability above 500 mD; while it is advisable to use microgels with the reservoir permeability from 100 to 500 mD; and colloidal dispersion gels can be used with the reservoir permeability from 10 to 100 mD. In order to improve the development effectiveness, advanced technologies need to be adapted in due time to the geological and process conditions. Also pilot production operations need to be conducted in the native fields.