Development of Nano and Micro Delivery Systems of Polymers for Water-Blocking

A serious problem in the extraction of crude oil is the presence of water, often in significant quantities, in the oil fields. During the extraction there is a gradual reduction of the pressure inside the reservoir which leads to a sharp decline in productivity. In order to keep the pressure constant, one possibility is creating a well used to inject water in the aquifer to obtain a thrust effect. During this operation, the volumetric fraction of water in the reservoir increases significantly, leading to a decrease in productivity. An oil reservoir is judged to be technically sold out when selling products is no longer able to cover the costs of production. In this situation, the quantity of hydrocarbons still present in the reservoir could be quite high. Therefore methods of water shut-off for blocking the production of water are welcome. In this work we developed new delivery systems for hydrophilic-viscosifier polymers. These polymers, based on carboxymethylcellulose, are nano and micro-organized in inverse emulsions. The possibility to organize these materials at the nano and micro-scale widespread the application of these solutions to both porous wells as well as fractureted ones. In this work, formulations with a stable dispersed phase up to 25% of the total massive amount have been optimized. The capacity of these solutions in increasing the water viscosity has been tested in water with different amounts of dissolved salts, from 25 up to 100 g/l. The dynamic viscosity of water after the application of these inverse emulsions is enhanced of about three orders of magnitude.