We evaluated a new cross-linking system using nonionic polyacrylamide and an organic cross-linker in the lab for water control applications in high-permeability wells. The thin gel was not very sensitive to salinity and was stable up to 70°C. The reaction was optimal at a pH between 6 and 8.5, and thus under usual reservoir conditions. In this pH range, it was slow enough for the polymer/cross-linker mixture to be injected easily for several hours. After a shut-in time of one day, the thin gel formed in-situ. We compared the thin gel’s performance to that of the single polymer, and ran two-phase flow experiments in high-permeability sandpacks. The thin gel induced a considerable drop in the relative permeability to water (with krw values divided by a factor of 100 and more), while it remained fairly permeable to oil. Selective reduction of krw with respect to kro was an order of magnitude greater with the thin gel than with the single polymer.

You can access this article if you purchase or spend a download.