Testing the Performance Impact of Automation Applications on Different Drive Systems in Unconventional Well Development
Authors: Pink Tony , Coit Andrew , Smith Joseph , Nieto James 
Published: March 2015

Objectives/Scope

Today, during the development of unconventionals, lack of knowledge about the downhole dynamics environment creates a culture of conservatism where excessive safety margins need to be applied to prevent damage to the rig equipment, drill bits, drill string and sensitive drilling tools. By using a combination of high-speed downhole data, surface applications, and an automated control system, this risk can be reduced, drilling performance improved and non-productive time reduced. Unconventional wells are typically drilled with several different types of drive systems, so on this project the impact of the automated drilling system was methodically tested in combination with the following BHA drive types: Conventional motorsRotary steerable toolsDownhole motorized rotary steerable tools.

Methods, Procedures, Process

This paper discusses the test program implemented across a 6-well project drilling in the Eagle Ford unconventional shale formation in South Texas. It was essential at the pre-planning phase that key performance indicators were identified and a solid test plan was designed. A road map was put in place to fully analyze the performance benefits where the automated drilling applications were tested against drive system, formation type and wellbore geometry. The primary objectives were to identify which applications combined with which drive system delivered the largest, consistent performance gains and the greatest cost savings. The paper includes a detailed description of the various automated applications tested: A surface-located, active stick-slip mitigation deviceA closed-loop high-speed downhole weight on bit controllerAn automated closed-loop, high-speed downhole data driven autodriller, aimed at maximizing rate of penetration whist minimizing all modes of vibration.

Results, Observations, Conclusions

These technologies bring significant benefits to our industry, especially in the development of unconventional assets where it is becoming increasingly difficult to deliver step changes in performance with current crews and technology. The high-speed downhole-driven control of the rig equipment allowed the driller and the customer representatives to maximize the performance of the rig without compromising safety or the reliability of the equipment. Drilling with automated motor BHAs and automated non-motorized rotary steerable BHAs allowed for repeated improvements in drilling performance of 37%, well on well. The fact that this performance increase is repeatable offers significant bottom line value for operators, by allowing reliable well delivery, forecasting and overall reduced well cost.

Novel/Additive Information

Downhole-automated drilling control described within this case study is a powerful tool to be used by existing drillers and directional drillers. The drilling crew must use the automated control system in partnership with specialized automated drilling applications to realize higher performance, without sacrificing safety margins or tool life. Even with an automated drilling system, optimum performance is measurably more difficult to achieve without optimal BHA design and drive type.