Preparation And Properties Of Multicomponent Copolymer Thermo-sensitive Gel Profile Control Agent

With the long-term water drive development of the reservoir,the characteristics and environment of oil reservoir are changing constantly,which makes the development contradiction more complicated.Especially for high temperature reservoirs deep in the formation,it is difficult for the existing profile control agent to meet the site construction requirements.Therefore,in order to meet the requirements of high reliability and stability of oilfield fracturing development and high performance of profile control agent,it is urgent to develop a thermo-sensitive expansion functional gel profile control agent matching with high-temperature reservoir conditions,so as to realize its"intelligent profile control and control"in reservoir development.In this paper,acrylamide and acrylic acid copolymers are used as basic functional gel materials,supplemented by specific temperature sensitive polymer materials and a series of has a specific function,gel water plugging function smart controllable composite gel profile control agent were prepared by template layer-by-layer assembly technology,microfluidic technology,ion gelation method and reverse phase microemulsion polymerization.The water absorption,thermal stability,salt resistance and aging resistance of gel microspheres can be controlled by changing the type and dosage of the functional materials and the variation of water absorption ratio of gel microspheres with time,temperature and salinity in simulated reservoir environment was studied.The main research contents and results are as follows:?1?Combining microfluidic technology with emulsion polymerization method,using water-in-oil?W/O?emulsion template,and the droplets were used as micro reaction vessel to prepare P?AA-AM?gel particles by free radical polymerization.And by using the layer by layer assembly technology and the ionic gelation reaction between sodium alginate and CaCl₂ solution,the P?AA-AM?gel particles were coated with a layer of calcium alginate film to prepare the gel particles profile control agent P?AA-AM?@SA with core-shell structure.The structure of the gel microsphere was characterized by SEM,FTIR,and TGA.And the variation of water absorption ratio of gel microspheres with time,temperature and salinity in simulated reservoir environment was studied,the results show that when the concentration of the coated calcium alginate film was 2%,the preparation of the gel particles has good thermal property and high water absorption rate,good salt resistance and thermal stability.?2?Using layer-by-layer assembly technology and combining inorganic silica particles with organic polymers and then acrylic and acrylamide copolymers and SA are coated on the surface of SiO₂ layer by layer by means of reverse phase emulsion polymerization and solution polymerization and the profile control agent P?AA-AM-SA?@SiO₂ with core-shell structure was prepared,and then it was modified in the ethanol solution of calcium chloride?CaCl₂?.The gel microspheres prepared not only have the characteristics of high compressive strength and good dispersion of inorganic SiO₂ particles,but also have the swelling and deformation ability of organic polymers.The structure of the gel microsphere was characterized by SEM,FTIR,and TGA.And the variation of water absorption ratio of gel microspheres with time,temperature and salinity in simulated reservoir environment was studied.The result shows that:When m?SA?:m?AA+AM?is 30%,the water absorption performance of the gel microsphere is the best.And the prepared gel microspheres have good temperature sensitivity,and the prepared gel microspheres have good salt tolerance and thermal stability.?3?Using layer-by-layer assembly technology and combining inverse emulsion polymerization with precipitation polymerization,using SiO ₂,acrylamide and acrylic acid as raw material,octadecyl dimethyl allyl ammonium chloride(C₁₈DMAAC)as a temperature sensitive functional monomer material designed and prepared Gel microsphere profile control agent of P(AA-AM-C₁₈DMAAC)@SiO₂ with multi-layer assembly structure.The structure of the gel microsphere was characterized by SEM,FTIR,and TGA.Further,the influences of C₁₈DMAAC dosage in P(AA-AM-C₁₈DMAAC)@SiO₂ at different temperatures of simulated reservoir environment on the water absorption ratio of the gel microsphere was studied and concluded that when m(C₁₈DMAAC):m?P?AA-AM?@SiO₂?was 1.25:1,the water absorption performance of the profile control agent was optimal and had the best temperature sensitivity.Because the introduced monomer C ₁₈DMAAC is a cationic monomer containing a long alkyl chain,the prepared polymer exhibits hydrophobicity at room temperature and hydrophilicity at high temperature,serving as a functional temperature-sensitive and water absorbing material.Therefore,the prepared polymer gel microsphere profile control agent has the temperature sensitivity of water absorption under different temperature conditions,and at the same time has certain salt resistance and stability.?4?Using reverse phase microemulsion polymerization,acrylamide and acrylic acid copolymers as the water plugging profile control material,C₁₈DMAAC as the temperature sensitive monomer material and styrene as the auxiliary polymer monomer material,a new profile control agent HWSP?Hydrophobic Water-Soluble Polymer?for temperature sensitive polymer gel microspheres was designed and prepared.The structure of the gel microsphere was characterized by SEM,FTIR.And the variation of water absorption ratio of gel microspheres with time,temperature and salinity in simulated reservoir environment was studied.The result shows that when the styrene content was 0.25g and m(C₁₈DMAAC):m?AA+AM?was 1:5,the HWSP had the best water absorptionbest temperature sensitivity and water absorption.Because of the monomer material C₁₈DMAAC,the gel microspheres have better stability and because the addition of functional monomer styrene provides a rigid group,so the HWSP prepared have better salt resistance and aging resistance,which are suitable for high alkali reservoir environment.