Development And Properties Of Anti-high Temperature Coating Agent For Drilling Fluids

As the depth of drilling in the exploration of oil and gas resources continues to increase,the complexity of drilling encounters with the formation and it has much chance encounters the shale-prone formation.In order to the drill smoothly,the inhibition of the drilling fluid is particularly important.The macromolecular coating inhibitor,as one of the key treatment agents for providing the inhibition of the drilling fluid,is faced with the increasingly complex high-temperature environment.The development of a high-efficiency coating inhibitor which perform at high-temperature and has significant practical significance.In this paper,acrylamide,N-vinyl pyrrolidone and dimethyl diallyl ammonium chloride were selected as the reaction monomers.After radical copolymerization,partial hydrolysis of amide groups by potassium hydroxide was used to synthesize anti-high temperature coating agent HPAND.By observing the changes of product inhibition under different synthesis conditions,the reaction conditions of the reaction system were optimized: monomer ratio,degree of hydrolysis,amount of initiator,reaction time,etc.,and the optimal synthesis conditions for the preparation of HPAND were determined.The synthesized product was analyzed by infrared spectroscopy,which proved that the target product was successfully synthesized.The viscosity average molecular weight of the product was 8.28 million.Thermogravimetric analysis showed that the polymer had good thermal stability and the decomposition temperature was 232℃.The HPAND’s coating inhibition and rheological fluid loss performance evaluation results show that the HPAND high temperature coating performance is excellent,and the rolling recovery of drill cuttings in the 0.2% HPAND solution at 150℃ is 95.56%,and 80.85% at 180℃;0.4% concentration of HPAND solution linear expansion anti-expansion rate of 52.8%;at 30% salt content,drill cuttings in 0.2% HPAND solution at 150 ° C rolling recovery was 81%;its inhibition Clay slurry has excellent performance and can improve the viscosity of the base slurry and reduce its fluid loss.In the anti-high temperature water-based drilling fluid,HPAND,with good compatibility,can improve the system viscosity and inhibition capacity,and reduce its fluid loss.Scanning electron microscope,laser particle size analyzer and specific surface area analyzer were used to analyze the mechanism of action of HPAND.The analysis results show that: HPAND can adsorb different clay particles,playing as a bridge,making the clay particles larger,the dispersion becomes worse;through the multi-point adsorption package attached to the surface of drill cuttings,the formation of a protective film or into the pores of drill cuttings plugging The porosity reduces the porosity of drill cuttings,reduces the contact between cuttings and moisture,and inhibits the dispersion of drill cuttings.