Study On Synthesis And Property Evaluation Of Resistance To High Tempreature And High Salt Dispersible Latex

This paper summarizes the research progress and application status of domestic and foreign nanomaterials in drilling fluids,and it states the mechanism of nanomaterials in drilling fluids and the principle and application used as drilling fluids agents as well.Further,it analyzes the disadvantage of the current nano-sealing agents.Aim at the poor performance of chemical stability of nanomaterials under high temperature and high salt conditions,and the problems of easy to coagulating and difficult to dispersing in drilling fluids system,the author of this paper selects to use the styrene,acrylate and sulfonated functional materials as monomers and the reactive surfactants as raw materials to successfully develop a new kind of high-temperature resistance and anti-salt-based drilling fluids polymer latex sealing agent named KY-SEAL,after which is dried and solidified and mixed together with rigid particles to generate the plugging while drilling agent named MSEAL.In addition,it is comprehensively evaluated the latex sealing agent performance in WBM and OBM and the performance of MSEAL in OBM,the main contents are as follows:1.From the perspective of molecular design,the styrene,acrylate and sulfonated functional materials are used as monomers,NT and FR are to be as emulsifiers,APS is used as initiator,a temperature-resistant and salt-resistant latex sealing agent KY-SEAL is synthesized,which is characterized with core-shell structure by emulsion polymerization.Through the investigation towards a single variable,it is determined the optimal reaction conditions for the polymerization below:the total added amount both for NT and FR is 3%,in which the percentage of NT occupies 35%;MAIS is 3%,APS is 0.8%,NaHCO3 is 0.2%,the reaction temperature is 75?,and the stirring speed is 250 rpm.2.The result of infrared spectroscopy indicates that the synthesized polymer is determined to be ST/BA/MAIS polymer.3.The salt-resistance evaluation results show that the synthesized polymer latex sealing agent has good temperature resistance and salt resistance.The temperature resistance is not lower than 150? simulated in 20%NaCl water-based brine drilling fluids.4.The porosity pressure transfer experiments demonstrate that the nano-latex particles can effectively seal micro-cracks in shale after adding KY-SEAL into water-based drilling fluids,thereby reducing pore pressure transmission rate and improving wellbore stability.5.The oil-based drilling fluid with adding KY-SEAL can also effectively reduce the oil-based drilling fluid filtration loss and improve the oil-based drilling fluid sealing performance,and the temperature resistance is also not less than 150?.6.The generated OBM plugging while drilling agent MSEAL is made from the dried and solidified KY-SEAL and rigid particles at a mass ratio of 1:1,which has excellent performance of temperature resistance.In addition,it can increase the bearing pressure capacity of the OBM from 5?6 MPa to 18 MPa at 176?.Similarly,it shows that MSEAL can effectively improve the performance of bearing pressure sealing capacity under the 2%concentration by the both drilling fluids HTHP sand bed leakage test and PPT experiment.