A Novel Polysaccharide Friction Reducer That can be Used with Water of All Salinity Levels

Abstract

This work was carried out to compare a new system with synthetic polyacrylamide friction reducers used in the oil and gas industry. The most common friction reducers used for fracturing are anionic, and hence have limited use in high TDS brines especially in brines containing di and trivalent metal ions. When the new system is properly optimized, we were able to achieve a very efficient and low-cost carrier fluid that can give maximum friction reduction and effectively suspend proppant during a fracturing treatment. The new technology for unconventional fracturing is a versatile and multifunctional product that can be pumped with the traditional frac equipment used in the industry for pumping powdered dry guar gum on the fly. The main objective of this work is to develop a new friction reducer formulation to aim to reduce cost and improve retained conductivity. This product is shown to be Gulf of Mexico green and biodegradable. Conventional breakers can be used to break these fluids and give excellent retained permeability on cores. The new system gives good friction reduction even at a very small dosage of 1ppt to 4ppt or 0.25-1.0 gpt, and it can be used similarly to guar gum as a linear gel or can be crosslinked with boron to yield better viscosity and proppant transport. The presence of iron in water can seriously affect the rheology and friction of traditional friction reducers, high viscosity friction reducers, and even guar systems. Laboratory studies have shown that this new product is very effective even in water containing very high concentrations of Ferric iron. Case histories from wells treated with this system containing high divalent and trivalent metal ions confirm the laboratory findings. In countries where equipment to pump on the fly is not available, the new system can be used as a slurry also. This paper will present laboratory test results of using a new polysaccharide friction reducer with similar friction reduction to a Polyacrylamide Friction reducer and the proppant suspension of a crosslinked guar system. This system can be used with fresh or saline waters containing high concentrations of divalent and trivalent metal ions. This gives the operator the flexibility of using any water, and the water analysis step before a frac job can be eliminated.