Multi-Parameter Autodrilling Capabilities Provide Drilling, Economic Benefits

Abstract

Abstract Recent field data have shown significant economic benefits are achievable when utilizing electronic autodrilling technology in conjunction with surface sensors, wellsite computers and data acquisition systems. An electronic autodrilling system was developed to provide steady-state weight at the drill bit and/or differential pressure across the motors to produce a higher quality wellbore and faster rate of penetration (ROP). Recent field applications demonstrated conclusively that the electronic autodriller not only improved control of drilling parameters such as weight on bit (WOB) and ROP, but also provided other favorable drilling attributes like controlled reaming. Longer bit runs and shorter rotating times were also observed. This study outlines the results of an advanced electronic autodriller's field application, reviews the history of various autodrilling systems, and compares and contrasts each design with respect to practical application and economic benefit. While brake technology improvements historically have led advances in autodrilling development, recent progress in computers and programmable logic controllers (PLCs) have significantly increased the capability of automated drilling machines, culminating in multiparameter control algorithms that maximize drilling efficiency. More recently, signal processing capabilities and variable frequency drive (VFD) electronic control have been extended to allow modern digital control technologies to be combined with older band-brake type braking systems, enabling conventional drilling rigs to be equipped with a sophisticated level of control without brake replacement and the associated capital investment. The new electronic automatic drilling system, when combined with computing and data acquisition technology, optimized drilling by controlling the existing non-linear rig braking system while simultaneously examining multiple drilling parameters: WOB, ROP, differential pressure (also called delta P) and torque. Multiparameter control was proven demonstrably better than single parameter or manual control. Introduction Automatic drillers, or autodrillers, have been used since the early 1970s, although it was not until relatively recently that they could out perform an experienced driller on conventional rigs. The development of the modern autodriller has been supported with the rise of more sophisticated mechanical braking and electronic control systems, which has resulted in systems with substantial capability. However, a considerable capital investment was required to incorporate both components. Recently though, improvements in signal processing and electronic control have allowed the modern digital control to be implemented with early generation braking systems, making a sophisticated level of control available for conventional drilling rigs. Computerized autodrillers can monitor up to four drilling parameters simultaneously and continuously, adjusting line payout to optimize overall drilling performance. However, it is important to choose hardware and software that are both appropriate and compatible to provide smooth and accurate brake control. Such a system has been developed and deployed with considerable success on land rigs drilling throughout the USA. This paper outlines the history of automated drilling technology development, its operational capabilities and its economic benefits demonstrated in the field.