Application Of Modified Nanoparticles With Different Shapes In Oil-based Drilling Fluid

The continuous oil phase,the dispersed brine phase,and appropriate additives such as emulsifiers,wetting agents,rheology modifiers,and weighting materials together form an oil-based drilling fluid.Compared with water-based drilling fluids,oil-based drilling fluids have stronger temperature resistance,shale suppression,and corrosion resistance,enabling better recycling of drilling fluids.Traditional polymer additives such as emulsifiers and rheology modifiers tend to decompose at high temperatures,which greatly affects the overall performance of drilling fluids.After decades of development,conventional oil and gas fields have been gradually exploited,and unconventional oil and gas fields have been gradually increased to meet actual demand.Then,the demand for the development of new and efficient drilling technologies has increased.Due to their smaller diameter,larger specific surface area,morphological diversity,and easily adjustable surface properties,nanoparticles have shown great advantages in improving the high temperature and high pressure performance of drilling fluids.In this paper,two kinds of nanoparticle additives for oil-based drilling fluids,fibrous sepiolite particles and spherical silica particles were selected and prepared,and their dispersibility,rheological properties and emulsifying ability in non-polar media were studied.The drilling fluid system was prepared.In the first part,organic soil has the function of increasing viscosity and cut shearing force in oil-based drilling fluids because of its structural characteristics.In this part,we use the same alkyl chain length,different chain number,and different amino modifiers octadecylamine,dimer diamine,octadecyl trimethyl ammonium chloride,dioctadecyl dimethyl ammonium chloride,and oligomeric quaternary ammonium salts are used as preparations for the preparation of organic modified sepiolite.The sepiolite modified by the dioctadecyl dimethyl ammonium chloride showed a strong resistance to high temperature,and the dispersion stability of its GTL dispersible system was hardly affected by temperature,and it had a strong viscosification ability at high temperatureIn the second part,the particulate emulsifier can be more firmly adsorbed on the oil-water interface,effectively solving the problem of traditional polymer additives that are easily degraded at high temperatures.In this section,a methyl-modified silica nanoparticle R974 was used to successfully prepare a water-in-oil emulsion.The particle addition was determined to be 2.0 wt%,the oil-water ratio was 8:2,and the GTL was a continuous phase,25 wt%CaC12 brine is the dispersed phase of an emulsion system model.The prepared drilling fluid which is based on the emulsion has flat rheological properties after aging at a low temperature of 65 ℃.The addition of organic sepiolite which is modified by the dioctadecyl dimethyl ammonium chloride effectively enhances the viscosity and shearing force of the drilling fluid after high temperature.