Vibrations are inevitable in drilling. However, the severity of vibrations and their detrimental influence on the drilling process depends on bit and Bottom Hole Assembly (BHA) design, the formation being drilled and, most importantly, the choice of drilling parameter such as WOB and RPM. When adjusting the drilling parameters the driller very often relies solely on his experience which (in the best case) is gained on offset wells.
A new Measurement-While-Drilling (MWD) based service significantly improves this situation by providing real-time feedback about the drilling process to the driller. A downhole tool containing various dynamics sensors, and a high speed data acquisition and processing system, continuously monitors BHA vibrations and diagnoses the occurrence of vibration related problems such as stick-slip, whirl, bit bounce etc. The type and severity of the diagnosed vibration are transmitted to the surface and displayed on a rig floor monitor. This allows the driller to take immediate remedial action by changing drilling parameters and, more importantly, optimize the entire drilling process.
This paper presents both the downhole tool and the surface display as well as the overall service concept. The downhole processing algorithms are also outlined. Several results from first downhole runs show how dynamic dysfunctions are identified and assessed downhole.
P. 649
