Synthesis And Properties Of Thermo-thickening Salt-tolerant Polymer Based On Hydroxypropyl Methyl Cellulose

Petroleum is one of the important pillar energy sources for the economic development of various countries in the world.The output rate of crude oil has always been a topic of concern to researchers in various countries.Since China became a net importer of crude oil in 1993,the volume of crude oil imports has continued to rise.With the development of society,the importance of petroleum resources has become increasingly prominent,whether a stable oil supply can be provided is related to the stability of the development of country’s economic politicsWith the continuous exploitation of petroleum resources,the storage environment of crude oil has become more and more difficult,and the difficulty of mining continues to increase.The polymer flooding technology using polyacrylamide as the main oil displacement agent is prone to hydrolysis due to the unstable polyacrylamide main chain.The defects of the hydrolysate,such as poor salt tolerance,make it difficult to adapt to the development of high-temperature and high-salt oil reservoirs.The new polymer with thermo-viscosifying properties has great potential in the recovery of crude oil in unconventional oil reservoirs due to its excellent temperature resistance,salt resistance and shear resistance,so it has also been widely concerned by researchersThis article starts with the polymer backbone and uses hydroxypropyl methyl cellulose instead of polyacrylamide as the polymer backbone to avoid problems such as poor decomposition and stability of the polymer backbone.Two thermo-viscosifying and salt-resistant polymers were prepared by selecting reactive monomers that meet the requirements.By changing the proportion of the reactive monomers,the performance differences between different polymers were investigated,and effect on polymer properties of different factors such as temperature,salt ions,and shear rate were examined.1.Using hydroxypropyl methylcellulose(HPMC)as the polymer matrix,diacetone acrylamide(DAAM)as the thermo-viscosifying functional monomer,acrylamide(AM)as the hydrophilic monomer,through aqueous solution free radicals graft polymerization to prepare a series of ternary thermo-viscosifying polymers.The polymer was characterized by 1H NMR,FT-IR,TGA and SEM.The test results showed that a new type of thermo-viscosifying salt-resistant polymer(PHAD)was successfully synthesized,and a series of properties tests(viscosity,temperature resistance,salt resistance,shear resistance,shear recovery,viscoelasticity and displacement efficiency,etc.)The results show that compared with polyacrylamide,PHAD has obvious thermal thickening behavior in pure water or simulated mineralized water,and under high temperature conditions,the apparent viscosity of PHAD solution keeps increasing with the increase of salt ion concentration.Viscoelastic test results show that PHAD storage modulus is always higher than loss modulus at high temperature,showing classic elastic fluid behavior.2.Using hydroxypropyl methylcellulose(HPMC)as the polymer matrix,using sodium p-styrene sulfonate(SSSNa)as the salt-tolerant functional monomer,acrylamide(AM)as the hydrophilic monomer,diacetone Acrylamide(DAAM)as a thermo-thickening functional monomer,a series of quaternary temperature-resistant and salt-resistant thickening polymers were prepared by graft polymerization.The polymer was characterized by 1H NMR,FT-IR and TGA.The test results showed that a new type of thermo-viscosifying and salt-resistant polymer(PHADS)was successfully synthesized.Through the SEM test,the three-dimensional network structure in the molecule can be clearly observed from the test results.Through a series of properties tests on the PHADS solutions(viscosity,temperature resistance,salt resistance,shear resistance,shear recovery,viscoelasticity and displacement efficiency,etc.),the results show that the polymer has good rheolo gical properties and displacement capabilities.