Synthesis And Oil Displacement Performance Evaluation Of Low Hydrolysis Polyacrylamide

The traditional polymer has poor temperature and salt resistance,which leads to the unsatisfactory effect of enhanced oil recovery.In the recent study,the new type of polymer with temperature and salt resistance has become a hotspot.The domestic research focuses on the synthesis of new polyacrylamide,while pay little attention on hydrolysis.Therefore,it is of practical value to study the temperature and salt resistance of polymers with different low hydrolysis degrees.Through homopolymerization posthydrolysis process,the polyacrylamide with different low degree of hydrolysis was synthesized from acrylamide.According to the study on the amount and type of hydrolyzer as well as various additives on the hydrolysis degree of polyacrylamide,the optimum experimental formula was determined finally as follows,the concentration of monomer was 23%while the ammonia was 0.2%,the initiator system was APS(0.08%)-PMS(0.08%),the temperature was 40°C,the polymerization time was 8h,as well as the pH was 10.Three low hydrolysis polymers with molecular weight of about 14 million were obtained by controlling the amount of alkali.The effects of metal cations and reaction temperature on the viscosity and viscosity retention of polyacrylamide solution with low hydrolysis degree under different salinity was measured by Brinell viscometer.The evaluation of temperature and salt resistance of polyacrylamide with low degree of hydrolysis can be used to determine the adaptability of them under the different reservoir conditions.The rheological properties of self-synthesized low-hydrolysis polyacrylamide were measured,and the flow experiments were carried out with artificial cylinder cores.The resistance coefficient and residual resistance coefficient of low-hydrolysis polyacrylamide at different permeability were determined,and the matching relationship between low-hydrolysis polyacrylamide and different reservoir permeability was determined.The effect of salinity,metal cation,polymer concentration,temperature and complexing agent on the oil displacement efficiency of low hydrolysis degree polyacrylamide were studied by using artificial homogeneous rectangular cores.It was concluded that the low hydrolysis degree polyacrylamide and complexing agent complex system could further improve oil and gas recovery in high temperature and high salinity reservoirs.