Study On High Temperature Protector And Water Reducer For Water - Based Drilling Fluids

High-temperature resilient water-based drilling fluid is pivotal in deep or ultra-deep dri lling engineering. This paper started from the mechanism of a typical drilling fluid loss addi tive,and focused on the synthesis of novel high-temperature capable agent and temperature enhancementof existing fluid loss control agent.Firstly, the paper explored the cross-linking mechanism of sulfonated phenolic resin. SEM was employed to analyze the self-assembly of sulfonated phenolic resin and sulfonated lignite in aqueous solution and their synergistic effect, along with the adsorption of clay particles on the polymer morphology. By analyzing the effect of temperature protective agent on the sulfonated drilling fluid particle size distribution and Zeta potential, it was concluded the addition of temperature protective agent should be controlled at a certain range, given the equilibrium between the crosslinking and the protective colloid ability.By analyzing the fluid loss control agent previous research and present utilization weakness, combined with their molecular structure design, the paper firstly chose four kinds of monomer (AM, AMPS, NVP, APEG)to synthesizewater-soluble polymer fluid loss additive, which exerted small effect on drilling fluid viscosity. Comparison experiment was conducted to determine the preferred reaction conditions.Properties of AM/AMPS/NVP/APEG synthesized under the optimum synthetic condition were characterized in many ways. FT-IR and NMR were utilized to testify the molecular structure of the polymer and monomer reactions coincided with the object desin.Thermal Gravimetric Analysis(TGA) was employed to study the polymer’s thermal weight loss, and the results showed that the good thermostability of the product. It was resulted from the Intrinsic Viscosity and Gel Filtration Chromatography that polymer presented a suitable molecular weight and reasonable weight distribution.Performance evaluation of AM/AMPS/NVP/APEG reached good results. The polymer was good at filtration loss control and was resistant to temperature at180℃and high concentration of calcium and salt. It had small effect of the drilling fluid viscosity, even after the addition of barite to raise density. Viscosity effect was lower than SY-3and JT888. Centered on the AM/AMPS/NVP/APEG as main filtration loss agent, mixed with other necessary agents, the paper formed a set of water-based drilling fluid resistant to high temperature, salt and calcium and with good inhibition capability.By virtue of SEM, Zeta Potential Analyzer and Particle Size Analyzer and other modern analytical instruments, this paper conducted the in-depth analysis of function mechanism in drilling fluid. Results showed that the addition of polymer sustained a certain amount of fine particles and made more reasonable size distribution. High temperature aging and electrolytes could affect the particle size distribution, yet still was in controlled within a certain range.SEM was utilized to study the AM/AMPS/NVP/APEG self-assembly in aqueous solution, the adsorption of clay particles, and the morphology of clay cake. The results displayed that because of the two kind of hydrogen bond, self-assembly of polymer displayed more compact film-like structure, and the clay particles adsorb on the edge and internal of the film. Even after temperature aging structure remained, so that polymer possessed great adsorptive and dispersive capacity. Furthermore, polymer could change the density of the filtrate cake, and wrap the clay particles. No obvious cracks and holes on the cake after the temperature aging.