Multiparameter Autodrilling Capabilities Provide Drilling/Economic Benefits
Authors: Bybee Karen 
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 119965, "Multiparameter Autodrilling Capabilities Provide Drilling/ Economic Benefits," by Fred Florence, SPE, Michael Porche, Randall Thomas, SPE, and Ryan Fox, SPE, NOV M/D Totco, originally prepared for the 2009 SPE/IADC Drilling Conference and Exhibition, Amsterdam,17–19 March. The paper has not been peer reviewed.
Recent field data have shown significant economic benefits are achievable when using electronic autodrilling technology. 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 improved control of drilling parameters such as weight on bit (WOB) and ROP.

Introduction
Automatic drillers, or autodrillers, have been used since the early 1970s, although it was not until relatively recently that they could outperform an experienced driller on conventional rigs. The development of the modern autodriller has been supported by the development of more-sophisticated mechanical-braking and electronic-control systems, resulting in systems with substantial capability. Recently, improvements in signal processing and electronic control have allowed 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 as many as 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 US. The full-length paper outlines the historical development of automated-drilling technology, its operational capabilities, and its economic benefits demonstrated in the field.

History
The development of automatic drilling controls began well over a century ago, with the earliest method invented in the early 1860s. They typically were referred to as drilling feed controls, describing the mechanism whereby a device would drill or feed the bit into the formation rock to create a wellbore. Early automatic drillers supplied inconsistent feed and nonuniform progress toward the target well depth. After the turn of the 20th century, better braking mechanisms allowed smoother feed and greater control over the bit feed. Through the 1920s and 1930s, many different automatic drilling methods were used, consisting mainly of purely mechanical devices, from various hydraulic-feed rotary-table designs to torque-based automatic-feed-control machines. By the 1940s, brake performance improved further, leading to the use of band-brake controls for drilling-feed machines. The majority of these feed-control devices were actuated pneumatically, their drilling feed maintained according to the rig's standard weight indicator.