Synthesis And Properties Of Cationic Acid Gelling Agent

Acidizing treatment is one important measure for hydrocarbon reservoir to increase production,the performance of acidizing working liquids and acidizing fluid additives directly affect the effect of acidizing treatment,especially for deep wells with high temperature and low permeability.At present,under the deep well condition with high temperature,the routine acidizing fluid has limited ability of slowing rate,and can not form the longer acid etching fracture that has some sustaining ability.In this paper,considered the pratical application of acid fluid system with improved temperature resistant,compatibility and reduced potential resevior damage, methylacryloyloxyethyltrimethyl ammonium chloride(DMC) is chosed as raw material according to documents investigation,and a kind of new acid fluid gelling agent P(DMC) is synthesized with both of aqueous solution polymerization and inverse phase emulsion polymerization;on the basis of homopolymerization,methylacryloyloxyethyltrimethyl ammonium chloride (DMC) and acrylamide (AM) binary copolymer P(DMC-AM) is prepared through free radical aqueous solution copolymerization;meanwhile,the influences of reaction conditions such as monomer concentration,monomer ratio,initiator amounts,temperature,pH value etc.on the intrinsic viscosity of polymer are also discussed,and as a result,the optimum synthesis scheme are proposed,and under which their intrinsic viscosities are respectively 672ml/g,236ml/g and 723ml/g.The properties of polymer P(DMC-AM)solution are explored,and the model of the effect of added salts on the viscosity of dilute polymer solution are also put forward.At last,through theoretical derivation, some doubts about the conventional adsorption-bridging theory are raised.In laboratory tests,the above synthesised homopolymers and copolymers are estimated as gelling agent in acid fluids. Evaluation standard of acid fluid gelling agent refers to the People Republic of China petroleum natural gas profession standard(SY/T6214-1996).The experimental result shows that the two kinds of polymers P(DMC) and P(DMC-AM) both have good properties in thermal stability,shear thinning,corrosion inhibition and salts resistant,good compatibility with other kinds of acid fluids additives, the content of polymer gelling agnet is droped from 2.5 wt % to 1.0 wt % in common acid fluid,so the potential damage of polymer residues is also reduced. We believe they have a broad researching and application prospect in petroleum industry and some other fields.