A New Approach to Stick-Slip Management Integrating Bit Design andRotary-Steerable-System Characteristics

摘要

North Sea fields continue to benefit from improvements inPDC bit and rotary steerable technology. There are, however,ongoing issues in these fields relating to very hard inter-beddedformations that result in stick-slip, bit and bottom holeassembly (BHA) wear, shocks / vibration, tool failures, andshort run lengths.Rotary steerable systems (RSS) are essential to drill thechallenging well paths. Push-the-bit RSS tools were firstemployed along with early versions of point-the-bit systems; allsuffered premature tool failures due to tool wear and extremeshocks and vibration attributable to excessive stick-slip. Tooland BHA modifications to increase ruggedness, have led tolonger runs and reduced shocks / vibrations in the harsh drillingenvironments.PDC bits are utilized and there has been an evolution in cuttertechnology and bit design. The PDC cutters have higher wearresistance and are able to drill formations that were previouslynot PDC drillable. Bit designs evolved as RSS tools havechanged: point vs. push-the-bit systems. The new point-the-bitsystems require modifications to bit gauge designs. High stick-slipand vibration are the main constraints to performance butare greatly reduced by designing the bit to complement theRSS.This paper will build on previously published data showinghow modifications to bit designs (based on the steeringcharacteristics of RSS tools), and modifications to operatingparameters of the RSS tools (based on the characteristics ofPDC bits) have been brought together for the first time to yielda significant improvement in drilling performance. Resultsfrom initial test runs in one field were then incorporated in theplans for another field yielding similar improvements inperformance.This paper will offer both the specific details of how theintegration of the bit and RSS characteristics was achieved inthis example as well as more generic principles for widerapplication.