Abstract
Abstract
Vibration and drilling dysfunction continue to be a limiting factor to drilling performance. Minimizing vibration lowers the failure rate of downhole tools from short term catastrophic failures to longer term fatigue failures. Minimizing dysfunction reduces bit and BHA damage which reduces bit trips and improves performance as optimal operating parameters can be applied for longer. In onshore operations, short well cycle times strain logistics and asset availability. Rerunning assets, such as rotary steerable and MWD tools, is a significant cost saving to both the operator and service company. Mitigating vibration can be achieved through BHA design, bit design, and manipulating drilling parameters. However, these can be uneconomical, because they require a lot of trial and error, along with, multiple combinations and iterations. Using downhole vibration mitigation tools can be a more cost-effective method of reducing vibration while achieving economic drilling performance.
This example from the D.J. Basin, Colorado, used two different downhole vibration mitigation tools to try and reduce the magnitude of vibration, specifically, tangential vibration, which posed a higher risk of failure to the directional drilling tools. Four wells on a single pad were selected for the trial to ensure similar geology and well design. Four wells that had comparable geological and well profiles, were selected as offsets. The aim was to reduce vibration and successfully rerun the directional drilling tool on at least two consecutive wells, while maintaining the offset well's ROP.
The paper will outline the design of the two technologies and the results from each well. Changes in vibration magnitude will be explained and the effect on ROP. The paper will compare the four trial wells to the four offsets and contrast the performance of the two tools in the trial wells. The paper will also discuss mechanisms unaffected by the technology and how that provided insight into the interrelationship of vibration mechanisms.
During the technology evaluation process, it became apparent that the run history with vibration mitigation tools was relatively low for the D.J. Basin. Of the two technologies, only one had previous experience in the basin with less than 50 runs over the previous 10 years. This was the first application of this type of downhole technology for this operator in this basin. The results have identified vibration as a performance founder point and helped demonstrate the change in performance that can be achieved by reducing drilling dysfunction.