Progress in Development and Testing of Anchoring Technology for Hard and Abrasive Drilling Conditions

Abstract

Over the last two decades there has been a significant advance in Polycrystalline Diamond Composites (PDC) bit technology, but PDC cutters still wear out when drilling hard and abrasive formations. Laboratory tests investigating Depth of Cut (DoC) of PDC cutters indicate that using low Revolutions Per Minute (RPM) but high DoC could significantly improve economics of drilling hard rock. However, Low RPM / High DoC is difficult to achieve in practice because of a damaging torsional vibration called Stick-Slip. If we can eliminate Stick-Slip and generally improve downhole stability, we will be able to apply more weight to a PDC drill bit and improve drilling economics. The authors of this paper are involved in the development of plasma drilling technology. In parallel to this development, they invented a downhole anchoring system which can work not only with plasma drilling but also with conventional rotary drilling. Combining the anchoring technology with PDC bits and a downhole motor enables consistent drilling without stick slip, enabling longer lifetime of the drill bit and Bottom Hole Assembly (BHA) components. Using the anchor with High Torque / Low RPM downhole motors enables more rock to be drilled with the same bit, reducing the number of trips and the number of consumed drill bits. Also, since the anchoring module is in contact with the formation, it provides a platform for direct measurements of different drilling parameters. The technology was for the first time tested in April/May 2023 at the testing site of leading drilling contractor in Houston, TX. The more advanced prototype is now under design with further testing expected throughout 2024 on a testing site in Norway.