Evaluate Bearing Capacity and Mitigate Broaching Risks of Conductor Jetting by Combining Single-Phase CFD and Analytical Formula on Evacuation Depth

Abstract Current multiphase CFD on deepwater conductor jetting in cohesive soil is complicated, time-consuming and limited to simple geometries (either simplified drill bit or flow domain). To accurately evaluate the bearing capacity of conductor casing with real bits, a new approach combining single-phase CFD and analytical formula on evacuation depth is proposed. Polycrystalline diamond compact (PDC) and roller-cone (RC) bits in concentric and eccentric positions are compared to show the effect of nozzle layout and bit offset (or eccentricity) on impingement pressure and evacuation depth. In this work, only seawater is considered with the undisturbed soil surface treated as hole-bottom. Bit’s stick-out length, rotating speed, and nozzle layout are considered to obtain the impingement pressure on soil surface. By extending the analytical formula first developed by Wang et al. (2021), we could obtain the evacuation depth and deviation radius for each nozzle. This information is then used to evaluate the wellbore integrity to see if there are broaching risks.