Water production is a major concern for oil companies because it involves not only a high cost for handling the water on surface, but also issues related to scale and corrosion in tubulars, and an overall decrease of hydrocarbon production. Finding the right solutions for each case is a challenge because there is no one solution that fits all. Chemical treatments for water shutoff are cheaper than mechanical treatments and can offer more targeted and customized design, but they often come with higher operational risks.
A new water control system based on a single particulate additive was extensively evaluated under laboratory conditions and then successfully implemented in the field. The fluid is easy to prepare using traditional field mixers and does not need curing after it is pumped into the formation, thus saving time and cost compared to most conventional water shutoff systems. The fluid was evaluated in the laboratory with a wide range of formation permeabilities and injection conditions using the fluid loss apparatus, permeameter, and formation response tester. The viscosity and stability of the fluid in different water salinity and concentrations were also investigated.
Overall, it was found that the new fluid system was very efficient in shutting-off formations greater than 50 md up to a few darcies. Those results were consistent with the nature of the plugging mechanism, which relies on physical pore plugging alone. The system could be further tuned depending on the formation permeability. In the presence of oil saturation, the penetration of the particulate system was found limited as compared to a single-phase, water-saturated core.