Effect Of The Functional Monomers With Different Structures On The Performance And Mechanism Of Oil Well Cement Latex

Due to the advancement of modern social science and technology,the demand for oil is increasing.In order to increase oil production,it is necessary to mine oil layers in more complex geological environments.However,the complex situation of these underground environments makes the performance of oil well cement unable to meet the needs of cementing.Therefore,it is necessary to use various additives to improve the performance of oil well cement to meet the requirements of cementing and ensure the smooth progress of oil exploration.Styrene-butadiene latex is a commonly used admixture,which can improve the mechanical properties of cement stone,improve the toughness of cement stone,and prevent cracking and fracture.However,styrene-butadiene latex has problems such as poor temperature and salt tolerance and poor dispersibility,and it needs to be modified to make up for its defects.In this work,two functional monomers,sodium p-styrene sulfonate(SSS)and 2-acryloylamido-2-methylpropionic sulfonic acid(AMPS),were copolymerized with styrene(St)and liquid polybutadiene(LPB)to prepare two kinds of latex(called SSS latex and AMPS latex),and their properties were compared in order to optimize functional monomers.Infra-red spectrum,thermogravimetry,particle size,salt resistance and transmission electron microscopy were used to test the two latexes.The results showed that the product had the target structure,uniform particle size distribution,core-shell structure and good heat and salt resistance.The temperature resistance of SSS latex was about 30°C higher than that of AMPS latex.The content of free liquid,settlement stability,fluidity,rheological property,flexural strength,compressive strength and triaxial mechanical strength of two latex modified cement were tested.The results show that after adding SSS latex,the free liquid content of cement slurry decreases from 0.541% to 0.153%,settlement stability increases by 66%,and the fluidity of cement slurry increases from 190 mm to 280 mm.The rheological properties of cement slurry are good,and the flexural strength of cement stone increases from 4.63 MPa to 6.28 MPa.It also makes up for the defect that latex reduces the mechanical properties of cement and controls the strength loss within 10%.Compared with AMPS latex,the fluidity of SSS latex is about 50-80 mm higher and the loss of compressive strength is about 5% less than that of AMPS latex.The interaction between the two latexes and cement was investigated by cement hydration exothermic rate,Zeta potential,scanning electron microscopy,BET and other tests.The results show that latex retards cement hydration and plays a dispersive role through adsorption,and the addition of latex fills the pore structure of cement paste,thus improving the mechanical properties of cement paste.Because the adsorption capacity of SSS latex is about 30% higher than that of AMPS latex,the adsorption performance of SSS latex is stronger than that of AMPS latex,thus SSS latex modified cement has better fluidity and mechanical properties.