Summary Gas drilling is a promising technique for developing tight sandstone reservoirs. Cuttings accumulation in horizontal and deviated gas drilling impairs wellbore cleaning, reducing drilling efficiency and elevating operational risks. A novel model for predicting cuttings bed height in horizontal and deviated gas drilling is proposed. Based on particle dynamics theory, mechanical equilibrium equations are derived for three distinct cuttings initiation mechanisms—sliding, rolling, and lifting—to solve for the critical frictional velocity. Combined with wellbore geometric relationships, the cuttings bed height is predicted using an iterative method. This model is validated by computing the critical annular gas velocity and comparing the results with previous experimental data, yielding average prediction errors of 12.1% and 11.1%. Based on the model, the effects of key parameters, including wellbore inclination, equivalent particle diameter, particle sphericity, exposure level, and gas injection rate, on cuttings bed height are analyzed. The results indicate that wellbore inclination exerts a threshold effect on cuttings bed height. Specifically, cuttings bed height rises as inclination increases up to the 60–65° range, where the bed height peaks and declines as inclination continues to rise beyond this interval. This trend holds across different equivalent particle diameters. Cuttings initiation mode is also consistent across different equivalent particle diameters, adopting the lifting mode at inclinations below 60° and shifting to the rolling mode at inclinations around 60° and above. Equivalent particle diameter also affects cuttings bed height, with particularly pronounced effects in the range of 1–5 mm. Higher particle sphericity promotes accumulation, while higher exposure level and gas injection rate reduce it. This model provides a reliable tool for optimizing drilling parameters to mitigate cuttings bed accumulation, thereby supporting the efficient development of tight sandstone reservoirs.
Li et al. (Sun,) studied this question.