Time-dependent cuttings transport modeling considering the effects of eccentricity, rotation and partial blockage in wellbore annuli

This paper presents a new cuttings transport model that captures the time-dependent effects of pipe rotation, drillpipe eccentricity and annulus blockage on hole cleaning. By integrating the time-dependent model with well construction data, the level of cuttings deposition along the trajectory of the wellbore can be simulated in real-time. The model recalculates its hole cleaning assessment at every time-step, and can use real-time drilling data at pre-determined time/depth intervals for calibration purposes. The integrated, real-time hole cleaning model was applied to a field case. Field data from an actual stuck pipe event was used to calculate the behavior of the cuttings profile in time along the wellbore. The data show that a high rate of penetration whilst sliding with a directional motor in the near-horizontal section of the well resulted in a significant amount of cuttings buildup around the bottom hole assembly (BHA). Unsurprisingly, the drillstring packed off and became stuck on the final trip out of the hole. Moreover, the casing-hole annulus packed off and caused induced losses while cementing because of the cuttings bed left in the hole. If the proposed time-dependent cuttings transport model had been utilized, these well problems and associated non-productive time (NPT) could have been better predicted and possibly avoided. •A novel time-dependent cuttings transport model is proposed.•A case study with a stuck pipe incident is analyzed with the proposed model.•The results from the model are in good agreement with the case study.•The proposed method is practical to implement and algorithmically efficient.•Cuttings deposition profile along the wellbore, with time, can be calculated.