Jeffrey R. Bailey

Field Trial Results of a Drilling Advisory System

Field tests of a real-time Drilling Advisory System (DAS) have demonstrated value in several drill well surveillance applications. This system receives drilling data and transmits recommended operating parameters to the driller using existing rig systems and Wellsite Information Transfer Specification (WITS) data records. Using this industry standard, DAS can be deployed to any suitable data acquisition system on the diverse rig equipment available in the industry. The DAS computer may also be connected to a company network to enable desktop viewing of the drilling recommendations in the office. The method embodied in the software comprises both a learning mode and an application mode. In learning mode, systematic changes in parameters are recommended to explore the operating space, and calculation of an objective function determines results. Complex decisions to change operating parameters such as weight on bit, rotary speed, and flow rate can also be made with the assistance of DAS via early detection of drilling dysfunctions which change with depth and formation. The operator’s ROP (Rate of Penetration) management process is focused on MSE (Mechanical Specific Energy) surveillance, and the DAS process extends this methodology to a real-time operating system. DAS is designed to assist the driller by capturing and organizing real-time data without imposing on their judgment and control. It is intended to be a digital helper that enhances the driller’s ability to interpret current drilling conditions and make effective decisions. Remote access capabilities and customized output to the driller’s display were demonstrated in field trials, and key lessons from field trials have been implemented. The field trials included multiple hole sections in onshore and offshore wells across a wide variety of drilling conditions. In one example provided in this paper, the use of DAS provided 35% higher ROP when DAS was used to avoid drilling dysfunctions.

Managing Drilling Vibrations through BHA Design Optimization

Significant performance improvement has been achieved by successfully managing drilling vibrations through bottomhole assembly (BHA) redesign. This effort has resulted in increased footage per day and reduced tool damage. Prior literature has described improvements in operating practices to manage vibrations(1,2) as a key component of this ROP (rate of penetration) management process. In a parallel work activity, the redesign efforts have provided additional performance improvements of approximately 36% in one drilling application. Dynamic modeling of the BHA has identified the key design changes leading to these improvements. The redesigned BHA has lower calculated vibration indices than the standard BHA.