Jet Mill Bit for Enhancing Cuttings Transportation and Decreasing Bottom-hole Pressure: What are the Characteristics of Internal Flow Field?

Abstract

Jet Mill Bit (JMB) is used to reduce the cuttings bed in horizontal drilling. In this paper, the internal flow field is simulated by computational fluid dynamics (CFD) modelling to analysing the pressure field, velocity field and turbulent energy field. At the same time, the DPM model is also used to simulate the particle field. The results show that the cuttings have good acceleration and pulverization performance in the accelerating tube. The drilling fluid generates high-speed injection when passing through the reverse nozzle outlet resulting in negative pressure in the acceleration tube, which generates suction force at the bottom of the well and accelerates the return of the cuttings and the maximum pressure drop is close to 0.5Mpa. The work done in this paper is instructive for the optimization design of Jet Mill Bit and it is expected to promote its field application.