High Frequency Downhole Dynamic Measurements Provide Greater Understanding of Drilling Vibration in Performance Motor Assemblies

Abstract

The use of downhole mud motors to improve drilling performance in vertical wells is becoming more common throughout the oil and gas industry. The additional torque provided by a downhole mud motor allows for a more aggressive drill bit design to be selected, and achieve a greater ROP. This paper will present a series of case studies where a near bit dynamics recorder has been used to determine the dynamic conditions below a motor. In several cases a dynamics recorder was also located above the motor, providing two discrete points of measurement.In the first case, near bit dynamic measurements allowed for BHA stick-slip to be identified as the cause for severe bit damage rather than difficult formation as was suspected. In the second case study, a near bit recorder coupled with a recorder above the mud motor identified that a significant level of vibration was generated by the motor. A different motor design was used on the following well and a reduction in vibration severity allowed for the section to be drilled in a shorter time. In the third case study, frequency analysis of near bit dynamic data conclusively identified backwards bit whirl as the cause for severe bit damage.In conclusion, the use of a near bit dynamics recorder has allowed for a greater understanding of the dynamics involved in performance motor assemblies. The application of this knowledge has helped to address the root cause of previously misunderstood vibration problems and improve drilling performance.

Vibration of drilling motors in unconventional oil and gas exploration with a miniature recorder

“…Drilling motors have been widely used in drilling applications due to the high dogleg capacity and relatively cheap cost. The additional torque provided by a downhole drilling motor allows for a more aggressive drill bit design to be selected and achieve a higher rate of penetration (ROP) [2]. Moreover, drilling motors can also be used for straight hole drilling, coring, under‐reaming, milling, vortex, and other operations.…”

Dynamic analysis of the longitudinal vibration on bottom drilling tools

“…The RSS exerts steer force while the drillstring is rotating during the directional drilling process, though the torque and drag are partially reduced, as a new problem, the weight on bit (WOB) and the torque transferred to the bit is reduced simultaneously. With more advanced measurement while drilling (MWD) technology appear successively, it has become the trend in recent years that the use of downhole measurement data to analyze the mechanical properties and vibration characteristics of the BHA [16]. Especially, we could obtain the data form the near-bit measurement [17], which is a technology that installs the measurement system near the drilling bit.…”

Chaotic Vibration Analysis of the Bottom Rotating Drill String

“…With the development of measurement while drilling (MWD) technology, in recent years the use of downhole measurement data to analyze the mechanical properties and vibration characteristics of the BHA has become the trend [13]. In particular, we could obtain the data form the near-bit measurement [14], which is the technology that installs the measurement system near the drilling bit.…”