Cationic Polymer Synthesis And The Impact On The Stability Of Clay

The clay mineral often exist in the most of reservoir. So how to stabilize the clay mineral become an important subject to the oil field development. The clay mineral in the reservoir mainly makes up of kaolinite, montmorillonite, illite, chlorite and so on. Among them, montmorillonite is easily swell while meeting water, and it is the principal reason of formation damage. The commonly used method to prevent from injuries is using clay stabilizer. The actions of clay stabilizer protecting oil bearing formation are preventing clay mineral from hydrating swelling and scattering migration which will block flowing porous canal, lead to permeability declining and influence the effectiveness of oilfield exploitation.The studying period on clay stabilizers can be divided into three stages. In the first stage, the inorganic salts are mainly used to stabilize clay from the 50s to the late 60s. In the second stage, inorganic multinuclear polymers and cationic surfactants are mainly used in the 70s. In the third stage, and the studying and experiments on cationic organic polymers stabilizing clay are mainly carried out after the 80s. In Chinese oilfield, application of clay stabilizers as a technical measure to protect oil bearing formation started from the early 90s, but generalized in the late 90s.According to the plenty of study in aboard and our homeland on the cationic polymer clay stabilizer with low molecular weight, three kinds of cationic polymer clay stabilizers with low molecular weight was synthesized by triethylamine, diethylamine, epichlorohydrin and redoxomorphic system.By laboratory experiments the optimum reaction condition have been identified. The optimum reaction time of the intermediate is 4h, temperture is 70℃, concentration is 40% and molar ratio of unit volume is 1:1. The optimum reaction time of the polymerization PETE is 5h, temperature is 60℃, amount of initiator is 0.8% and molar ratio of unit volume is 40%. The optimum reaction time of the polymerization PEDE-1 is 4h, temperature is 60℃, molar ratio of unit volume is 1:1 and molar ratio of unit volume is 40%. The optimum reaction time of the polymerization PEDE-2 is 5h, temperature is 50℃, amount of initiator is 0.6% ,molar ratio of unit volume is 50% and molar ratio of unit volume is 1.2:1.Through lab experiments anti-swelling analysis on the synthesis of quaternary clay stabilizer, the optimum used concentration is 1.0%. A law was found that the anti-swelling rate increase with the accretion of molecular weight or cationic degree. Through the mixture of cationic polymer PETE,PEDE-1,PEDE-2 and inorganic salts (NH4Cl, KCl) or inorganic polymer (hydroxyl aluminum), the anti-swelling get higher. The rate of binary mixture is 1:3, 1:2.5 and 1:3 respectively, and the rate of cationic polymer and hydroxyl aluminum is 1:1, the rate of ternary mixture is 1:3:1, 1:2.5:1 and 1:3:1 respectively, and it can reduce the cost and advance the efficiency of clay stabilizer at the same time by mixture.