Drilling the hard, abrasive and interbedded Travis Peak and Cotton Valley formations in East Texas creates a problem for polycrystalline diamond compact (PDC) bits. Historically, conventional PDC cutting elements failed quickly due to formation abrasiveness, impact damage and thermal fatigue. These cutter limitations are the major factor restricting further advancement of PDC drilling in East Texas.
New cutter technology and manufacturing processes have yielded a highly abrasion resistant PDC bit enabling faster drilling, increased footage and improved dull condition in the basin. Furthermore, intervals that normally require multiple PDC bits/runs to reach TD are now being drilled in some cases with one bit saving the operator trip time and bit cost.
In spite of the advancements the majority of bits were repeatedly lacking favorable dull grades, typically a 1-2-WT or worse. Further improvements were necessary to advance the cutter's abrasion resistance for these applications. To achieve the objective and improve PDC cutter performance to save the operator additional cost, engineers refined and implemented new procedures to increase abrasion resistance. This technology platform used to produce the next generation premium cutters included:
Tighter diamond packing
Diamond table synthesized under extremely HP/HT for enhanced abrasion resistance
Refined post-pressing process to reduce residual stress and improve thermal stability
In laboratory experiments, the next generation cutter (O2) has shown a 15% improvement in abrasion resistance in wear index comparisons against the previous generation (O1) premium cutters. The tests were performed on a vertical turret lathe under cooling and non cooling conditions. Field testing of the new cutter was done in limited quantities across East Texas. In these tests the new cutter has achieved an average ROP increase of approximately 15% while producing improved dull bit condition. The next generation O2 cutters are expected to have a positive economic impact in the East Texas region and in other hard and abrasive applications worldwide.