A novel sensor system, integrated into a rotary steerable system (RSS), has led to a new level of drilling optimization by providing the concurrent real-time measurement of near-bit borehole caliper and near-bit vibration. This new sensor system gathers all the information 2 to 3 meters above the drill bit, whereas conventional MWD/LWD sensor measurements are made 20 to 40 meters away from the bit.

Integration of these sensors with an RSS resulted in consistent measurements of borehole caliper and the three principal types of downhole vibration (torsional, lateral, and axial), which has helped facilitate comparative analysis of drill bit and BHA performance for different BHAs and wells. Additionally the real-time drilling data was available to a multi-disciplinary drilling optimization team consisting of engineers and researchers. Remote satellite communication and Internet technologies enabled the team to monitor the downhole drilling conditions around the clock and to provide critical feedback to rig site engineers for minimizing vibration-related failures and for improving drilling efficiencies.

This paper will discuss the application of real-time near-bit caliper and vibration measurements while drilling with various hole-size RSS. One unique feature of this particular RSS is a shop-configurable point-the-bit or push-the-bit mode, depending upon the application. This paper also shows a comparison of borehole conditions and vibration between point-the-bit and push-the-bit modes using an identical RSS, having consistency in stiffness, weight, force applying capability and control system.

Through the integrated sensor and team approach, the ability to detect borehole washout conditions and/or BHA instability due to vibration allows RSS operators to take timely remedial action before the occurrence of downhole RSS failure. As a result, the performance and survivability of the RSS has been remarkably improved.

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