Synthesis Of New Polymer Suitable For High Temperature And High Salinity Reservoir And Development Of Its Gel System

EOR is an effective method of high temperature and salinity oil reservoirs recovery and the heat and salt resistant polymers are the key technologies for chemical flooding and chemical profile control. At present, Chinese high quality reserves,which are for the development,is becoming less, and high temperature and salinity reservoirs are the main object for future exploitation. Polyacrylamide are widely used in enhanced oil recovery, but it has some shortcomings at high temperature and salinity conditions, which limits its application. Therefore, it is significant to synthesis the heat and salt resistant acrylamide-based polymer and the heat and salt resistant polymer gels for the development of high temperature and salinity reservoirs.In this paper, the raw materials for the heat and salt resistant poymer were acrylamide (AM) as a main monomer and 2-acrylamido-2-methylpropane sulfonic acide (AMPS), methacryloyloxyethyl trimethyl ammonium chloride (DMC),2-vinylpyridine (2-VP) as functional monomer. It calculated the interaction energy of each monomer at different pitches with the Gaussian program MP2 algorithm, theoretically proven interaction between four momnomers and polymerization reaction.A new amphoteric hydrophobic quadripolymer P(AM-AMPS-DMC-2-VP) was synthesized with aqueous solution radical poymerization. Through single factor experiment, the obtained optimum reactiom conditions were as follows:total monomer concentration is 30%, AM, AMPS, DMC, hydrophobic monmer 2-VP urea additive, EDTA mass fraction of 70%,20%,10%,0.1%,5%,0.5%, initiator ((NH4)2S2O4-NaHSO3:V50) ratio of 1:2,0.1% of the amount of initiator, pH value 6, initiation temperature of 45?. The structure of the synthesized polymers were chracterized by Fourier transform infrared spectrometer Tensor-27, AVAVCE500 nuclear magnetic resonance spectroscopy, Raman spectroscopy LabRAM HR Evolution and CE440 elemental analyzer that the resulting polymers as the target product.The solution property of the poymers was studied. The results show that the poymer P(AM-AMPS-DMC-2-VP) has a good heat and salt resistance, shear stability and long-term aging stability, when compared with PAM. The flooding experiment results show that when the polymer concentration is greater than 1500 mg/L, P(AM-AMPS-DMC-2-VP) of resistance coefficient and residual resistance coefficient were higher than PAM, and when the polymer solution concentration was 1500 mg/L, P(AM-AMPS-DMC-2-VP) of oil recovery is 12.5% largerer than PAM.On the condition of temperature of 80?,90?,100?,110?, and salinity of 39059.23 mg/L, through the comparison of the crosslinking agents with P(AM-AMPS-DMC-2-VP) of the gel time, gelation stability and gelation strength, the organic phenolic crosslinker was selected; the obtained polymer crosslinking system formuations were as follows:polymer concentration is 2000?4000 mg/L, crosslinker concentration is 2500?4000 mg/L, thiourea concentration is 500 mg/L. At the temperature of 90?, the polymer crosslinking system has good gelling properties, long-term thermal stability, shear resistance and can effectively bock the high permeability layer, the higher rate of closure, and effectively impoves the ultimate recovery.