Improved Water Management Through the Usage of Sulfonated Polymers

Abstract

Oil and gas production uses large volumes of water for injection during polymer flooding and hydraulic fracturing operations. The same operations generate large volumes of wastewater, of which produced formation water and flowback water make up the dominant volumes. The availability of fresh water is a growing challenge in many regions of the world and major oil companies take these challenges seriously and recognize their need to preserve fresh water. They report operations in water-scarce areas in their annual sustainability reports and they strive to reduce and ideally eliminate freshwater intake for their operations by increasing recycling capacity. Reusing high salinity water for hydraulic fracturing and polymer flooding applications is a challenge as high salinity water negatively impacts the economics and success rate of these treatments as the apparent viscosity of standard HPAM is affected by the high salinity. Desalination of these high salinity water sources can be executed by thermal desalination techniques which are not cost effective at these large water volumes. Altering the HPAM polymer by adding ATBS or AMPS monomer instead will enhance the viscosity and stability of the polymer solutions at high salinity. These sulfonated polymers showed excellent performance in using saline water in hydraulic fracturing operations, where friction reduction during injection and proppant carrying capacity are the main requirements. When using the right fraction of ATBS/AMPS monomers in the polymer, high salinity (even combined with high temperature) reservoirs can be flooded with sulfonated polymer solutions to obtain increased recovery as indicated by a field case.