Achieving Optimum and Dynamic Backreaming Rates for Real-Time Well Engineering
Authors: Samuel Robello 
Published: February 2025

The industry has explored various backreaming rate calculation methods, often facing challenges with optimization due to uncertainties in downhole conditions. Traditional mathematical models, while accurate, may yield suboptimal rates and prove impractical for real-time use due to non-convergence deadlocks. This paper addresses the persistent challenges encountered in optimizing backreaming rates owing to the uncertainties prevalent in downhole conditions. By introducing a pioneering time-optimal batch methodology grounded in opto-satisficing principles, the aim is to delineate a viable solution space for the safe execution of backreaming operations, thus mitigating the limitations associated with traditional models and offering a more pragmatic solution for real-time applications.

Through the integration of various engineering and data science models via microservices, the methodology enables multiple calls during calculations, facilitating enhanced dynamic constraints and discretized subintervals to optimize outcomes. This comprehensive approach accommodates considerations such as bit wear, hole cleaning, force analysis, and vibration, thereby enabling the determination of optimal backreaming rates at specified intervals, while adapting to evolving formation conditions and drilling depths. To address conservatism, dynamic constraints enhance the model for optimal outcomes. Additional limits within discretized subintervals account for factors like bit wear, hole cleaning, force analysis, and vibration. Optimal backreaming rates are determined at specified intervals, considering changes in formation, depth, and various parameters. Continuous backreaming rate calculations become necessary due to evolving conditions. Discretization involves dividing the drilling interval into subintervals, integrating over each discrete interval. Within each subinterval, an overpull-RPM domain is identified, ensuring dynamic stability.

Analysis reveals the fast convergence of optimal backreaming parameters in real-time, ensuring predictability and optimal results under uncertainty, particularly in test wells. Moreover, these results establish a reasonable threshold even with augmented well drilling data. The study identifies that severe chaotic or stochastic oscillation during backreaming is infrequent, except in the presence of hole-opening tools, which may lead to phase reversal. The avoidance of severe vibrations, a common issue in neighboring wells, is highlighted, accompanied by straightforward guidelines for estimating effective backreaming rates. The findings underscore that as long as the rig operates within its range, the established parameters yield satisfactory results, equating to nearly standard technical solutions for backreaming. This methodology, integrating theoretical engineering models with real-time measurements, offers effective adjustments to operating conditions. Leveraging results from multiple wells, this approach surpasses traditional backreaming estimates, delivering comprehensive insights substantiated by real-time well drilling examples. The presented results affirm its efficacy in satisfying drilling engineers’ requirements.