Synthesis and Performance of D230 Polyether Ammonium Salts Mixed with Cationic Gemini Surfactant as Clay Stabilizer for Water Injection Reservoirs

Cationic Gemini surfactants which were synthesized from long carbon chain alkyl tertiary amines and 1,3-dibromopropane, and polyether ammoniums as clay stabilizers which were synthesized by the reaction of polyether ammine (D230) with formic acid and hydrochloric acid, named as D230FA and D230HC, respectively, were used to preclude hydration expansion and migration of clay minerals in low permeability oilfields, hence facilitating the water injection and oil recovery from the tight reservoirs. The surface tension and interfacial tension (IFT) of surfactants, anti-swelling property of clay stabilizers and the injection performance of the composite system were evaluated in this study. The experimental results show that C14-3-C14 has high interfacial activity and solubility, and the composite system of C14-3-C14 and polyether ammonium salt has good clay stability. The anti swelling rate of Na-clay treated by the solution of 1.5% KCl + 0.1% C14-3-C14 after 10 times of washing with distilled water decreased from 72.6% to 28.0%. While 1% D230FA and 1% D230HC mixed with 0.1% C14-3-C14 + 0.5% KCl have the initially anti swelling rates of 72.1% and 68.3%, and the anti swelling rates after flushing with distilled water  reach 61.2% and 58.3%, respectively, indicating good anti-swelling durability . Core flooding experiments show that the injection performance of the composite system depends on the contact angle ( θ ) and the surface tension ( γ ), and the composite system contained 1% D230HC with lower value of γ cos θ has better injection performance than that of 1% D230FA. XRD analysis shows the lower interlayer spacing of clay minerals treated with clay stabilizer solution containing polyether ammonium salts.