Down Hole Pressure Variation Due to Axial Stick Slip Motion Effect on Drill String

Zhao, Dapeng; Sangesland, Sigbjørn

doi:10.2118/173624-ms

Cited by 4 publications

References 14 publications

(12 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

Drill Rig Control Systems: Debugging, Tuning, and Long Term Needs

Pastusek

Owens

Barrette

et al. 2016

Day 3 Wed, September 28, 2016

View full text Add to dashboard Cite

This paper documents some of the key findings on the data required and methods used to detect and correct issues with drilling control systems such as auto drillers, top drive active torsional damping systems, and heave compensation systems. It has been found that the rig control systems and how they are tuned can have a significant impact on drilling dynamics. Issues related to drilling dynamics have varied widely among rigs, even among those that are in the same field and that have the same equipment and specifications. The standard answer has been that drilling is different on the ‘other side of the road, river, or anticline', or that one rig crew is better than the other. While there are significant differences in the drilling environment and between crews, recognition of the effects of the control systems employed can explain many of these differences and expand the tools and techniques available to improve drilling performance and reduce dysfunctions. Once the fundamental elements of a control system are understood, the performance limiters identified can often be applied to other rigs in the fleet with different systems via effective documentation of the changes made and their results. Opportunities abound for improvement in oilfield drilling control systems, their basic design, and documentation on how they should be tuned and best used. There are also opportunities in crew training catered to different audiences: Drilling Engineers, Rig Supervisors, Drillers, Directional Drillers, and Rig Electricians. Lastly, there is often a knowledge and communication gap between the software/control/user experience and engineers designing the control systems. Since rig control systems are not usually identified as the source of drilling dysfunction, requests for software or interface redesign have not often been initiated in the past. Not surprisingly, the best progress has been made when four way work groups were formed with all key stakeholders involved: the operator's drill team, internal technical experts, rig contractor and crew, and OEM control systems experts. Investing the time and personnel in this process and establishing group trust has helped prevent gaps in understanding of overall system performance. It also allows each stakeholder to contribute their expertise, raise concerns, and get buy in from their extended teams. This process takes commitment from all parties to change the way work is done, but the performance improvements are immediate and can be clearly seen. Challenges for the future are to continue to upgrade rig site manuals, arrange for more crew training, upgrade the control system design, and to incorporate the control system response as part of the topside boundary condition for future drilling dynamics models.

show abstract

Drill Rig Control Systems: Debugging, Tuning, and Long Term Needs

Pastusek

Owens

Barrette

et al. 2016

Day 3 Wed, September 28, 2016

View full text Add to dashboard Cite

show abstract

Reducing Stick-Slip by Avoiding Auto-Driller Control Dysfunction

Adam

2018

Day 3 Thu, March 08, 2018

View full text Add to dashboard Cite

Analysis of historical drilling data in the Delaware Basin revealed stick-slip was being initiated by the rig control system. It was determined that a weight-on-bit (WOB) road map with calibrated range values delivered near-maximum rate of penetration (ROP) and reduced stick-slip. This was achieved by simplifying the auto-driller's parameter limits and avoiding differential pressure control. Details of the statistical analysis process and results from field trials is presented and compared to historical performance. The road map was developed using data from top performing offset wells. The standard deviation of the auto-driller's active control limiters was cross-plotted against the standard deviation of the ROP. Intervals in which the differential pressure was the primary control or the ROP range was excessive displayed a high standard deviation, indicating unstable control behavior. Data from the non-dysfunctional areas determined the WOB and ROP ranges to be targeted through an interval. Use of these range limits steadied the application of WOB and reduced the need to control the auto-driller via differential pressure. Wells using the parameter road map were compared to high-performing offsets. The comparative analysis focused on ROP, mechanical specific energy (MSE), downhole accelerations, and bit damage. Performance in formations known to cause dysfunction are highlighted. Benefits have been observed in the rotary steerable control collar RPM data. Depth-of-cut (DOC) through the Brushy Canyon was improved by use of the road map. Traditional auto-driller limiters (torque and differential pressure) were avoided due to the limits of the drilling system embedded within the road map's setpoints. Data are presented showing that differential pressure control can result in stick-slip. This dysfunction is avoidable with the use of a road map employing accurate range values for WOB and ROP to control the auto-driller. Improved auto-driller range management addressed a specific source of dysfunction and positively impacted performance at the bit. The visual road map conveyed WOB and ROP guidance directly to the driller, which accelerated the rig's learning curve. When combined, the product of these data-driven concepts increased bit life and ROP.

show abstract

Theoretical Study of Tool-Face Disorientation Mechanisms During Slide Drilling and Correction by Surface-Rotation Pulses

Wang

et al. 2018

SPE Drilling &Amp; Completion

View full text Add to dashboard Cite

Summary Tool-face control is an important issue when drilling directional wells with steerable motors. Although extensive knowledge about tool-face orientation is available, the mechanisms of tool-face disorientation during slide drilling are not completely understood. Surface-rotation pulses can correct tool-face orientation (Maidla and Haci 2004), but the underlying mechanism, in our view, remains unclear. This paper proposes a drillstring model to analyze the mechanisms underlying tool-face disorientation and correction. Our drillstring model is based on the finite rigid-body assumption with a mixed friction model that incorporates Stribeck's friction curve. The simulation results indicate that tool-face hysteresis caused by the difference in the higher loading rate and lower unloading rate of reactive torque is an essential factor in tool-face disorientation. In addition, a harder formation is more prone to inducing tool-face disorder. The process of tool-face correction can be divided into three stages, and the position of the vanishing point of reactive torque determines the effectiveness of the surface-rotation pulse. The tool face turns clockwise only if the applied rotation pulse drives the vanishing point of reactive torque downward to the bit. The simulation results and analysis are useful for understanding drillstring behavior during slide drilling and further improving the efficiency of tool-face control.

show abstract

Down Hole Pressure Variation Due to Axial Stick Slip Motion Effect on Drill String

Cited by 4 publications

References 14 publications

Drill Rig Control Systems: Debugging, Tuning, and Long Term Needs

Drill Rig Control Systems: Debugging, Tuning, and Long Term Needs

Reducing Stick-Slip by Avoiding Auto-Driller Control Dysfunction

Theoretical Study of Tool-Face Disorientation Mechanisms During Slide Drilling and Correction by Surface-Rotation Pulses

Contact Info

Product

Resources

About