NUMERICAL SIMULATION RESEARCH ON THE SPIRAL VELOCITY DISTRIBUTION OF HERSCHEL-BULKLEY FLUID IN ECCENTRIC ANNULAR USING IN OIL AND GAS DEVELOPMENT.

In the drilling and production process of the petroleum industry, the research on the flow of nonNewtonian fluids in eccentric annulus is of great significance. At present, drilling fluids are mainly based on Bingham fluids and power law fluids. However, the research on the distribution law of the spiral flow velocity field of eccentric annulus H-B fluid is insufficient. Based on the actual situation of drilling fluid flowing between drill pipe and casing in eccentric annulus, a physical model of eccentric annulus with different eccentricity is established through CREO three-dimensional modeling software, and the eccentric annulus is analyzed. The control equation and solution method of the Herschel-Bulkley (H-B) fluid spiral flow are simulated and analyzed by ANSYS fluid analysis software. Through numerical simulation analysis, it is concluded that due to the eccentricity, the wide gap in the eccentric annular spiral flow field will form a turbulent constant velocity flow area, and there will be a low-speed flow area around the narrow gap. The greater the deviation angle of the spiral flow field, the more uneven the flow field velocity distribution, which is not conducive to the migration of drilling cuttings. The deviation angle of the spiral flow field gradually increases with the increase of drill pipe speed, annulus eccentricity, and drilling fluid fluidity index, and gradually decreases with the increase of annulus flow velocity. The consistency coefficient of drilling fluid and dynamic shear force has no effect on the deviation angle of the spiral flow field. [ABSTRACT FROM AUTHOR]