Research And Application Of Organic Amine Inhibitors For Drilling Fluids

When the water-based drilling fluid was used to drill,there would be a lot of problems because of the hydration expansion and dispersion of the mud shale,like wellbore instability,bit packing and poor drilling fluid rheology,which increased the difficulty of drilling.Therefore,higher requirements were put forward for drilling fluid additives,especially inhibitors.In this paper,an organic amine inhibitor named RS-712 was synthesized,and the reaction conditions such as fatty acid,reactant ratio,reaction temperature and reaction time were studied by measuring the rolling recovery rate of synthetic inhibitors.The best reaction conditions were as follows:hexadecanoic acid was used as fatty acid,the monomer ratio of hexadecanoic acid:hydroxyethylethylene diamine was 1:1.2,the reaction temperature was 155 C,and the reaction time is 5 h.Under the optimum reaction conditions,the recovery rate of the inhibitor was 93.34%,and the morphology of the inhibitor was yellow viscous liquid.The results of scratch rolling recovery experiment,clay suppression pulping test,cuttings immersion experiment,core linear expansion rate experiment and the evaluation of three different water-based drilling fluid system showed that the prepared organic amine inhibitor RS-712 could inhibit mud bentonite clay slurry and the hydration and dispersion of cuttings.The effect of the organic amine inhibitor on the viscosity change of drilling fluid system was small,and the cuttings roller recovery of drilling fluid system was about 94%.The organic amine inhibitor RS-712 showed good compatibility with various treatment agents,and the rheological properties of three kinds of basic drilling fluid systems have not been greatly affected.The micro-mechanism of organic amine inhibitor RS-712 was studied via clay particle size,Zeta potential measurement,SEM and contact angle test and so on.The results indicated that the organic amine inhibitor RS-712 was adsorbed onto the negative surface of clay with electric attraction and hydrogen bond,and the electrostatic repulsion and surface water film the repulsion between the clay surface was weakened.The amino monolayer of the inhibitor molecule adsorbed on the clay surface to bound adjacent clay layers to form dense structure,and the fatty acid carbon chain in inhibitor molecules composed of a hydrophobic barrier in the clay surfac to prevent the hydration of clay.The organic amine inhibitor RS-712 was successfully tested in Changning area.Field tests showed that the organic amine inhibitor could significantly improve the inhibition of the drilling fluid and improve the stability of the borehole wall.In addition,the organic amine inhibitor RS-712 had good compatibility with drilling fluid system and had wide adaptability to meet the requirements of drilling engineering.