How to Select PDC Bit for Optimal Drilling Performance

Selecting bit when you have multiple bit vendors giving their proposal can be a challenge for the operator. To justify the bit selection can be hard for the drilling engineer in a multiple vendor situation. The purpose of this paper is to show a systematic approach on how to select PDC bit based on quantitative measure by using a simple scorecard. When the drilling organization has agreed on the overall drilling objective for the well a scorecard is used as decision criteria for selecting bits. To quantify the input for each bit a drilling simulator was used. The simulator can, based on a rock strength prognosis for a well, predict the rate of penetration and bit wear for each bit based on the bit design. For other criteria which are more difficult to obtain e.g. ability to create dog leg a qualitative ranking was used. In the two field examples shown from the North Sea the method has worked well to give a reliable and transparent bit selection method. Using a scorecard also reduced the ambiguity among the bit company representatives on how the selection process was done