Abstract
One of the biggest ongoing challenges to the successful production of many hard, interbedded and abrasive applications is the ability to improve drilling efficiency. In many of these applications, the use of PDC drill bits has been sporadic as many formations have been labeled ‘not PDC drillable’. As a result, these intervals often include several trips to change out drill bits (both rollercone and PDC drill bits of different types) in an attempt to maximize drilling performance. While PDC drill bits have generally proven to drill with higher ROP than rollercone bits, in these difficult drilling environments, the ROP differential can be very small, and the durability differential can be very large.
A new line of steel bodied drill bits has recently been introduced that has shown dramatic improvements in drilling efficiency in highly difficult Western Canadian drilling applications. These new steel bodied drill bits incorporate a second row of PDC cutters to add durability to the bit while still remaining aggressive enough to drill at a high ROP. The use of steel as a body material makes it possible to have the best of both worlds – a bit with very high diamond volume for excellent durability (two rows of PDC cutters per blade) while also achieving a high void volume and large junk slot area for excellent cleaning. New techniques have also been developed to protect the steel body from the typical erosion and wear that has historically been seen in highly abrasive applications.
Recent runs with this new line of drill bits have been recorded in intervals and through formations previously only drilled with rollercone bits. The new technology developed for these bits allows higher ROP and longer runs in demanding applications. In one challenging well in British Colombia, a series of these new steel multi-row bits drilled nearly twice as fast and over 30% more footage per bit than a direct offset well – saving days off the drilling curve.
