At the sharp end

Jarred Koenig and Michael Bouska, International Diamond Services, USA,

present the results from applications of new PDC cutter technology in challenging drilling formations.

Over the past 2 years International Diamond Services (IDS) has focused on accommodating changes in the PDC cutter market, the demands of the customer and the challenges of the application. In doing so IDS has tested, developed and successfully commercialised three product series: All-Terrain, Tactical and Elite. Each of these were developed through field trials and new proprietary pressing methods.

The All-Terrain series – with an updated press sintering method – has been specifically designed to tackle three performance aspects: thermal, abrasion and impact. Achieving a delicate balance between these three characteristics is crucial to successful downhole performance.

With a new press monitoring system, the Tactical series is designed with an emphasis on thermal, abrasion or impact while not ignoring the other key performance elements needed in a PDC.

Development of the Elite series entailed substantial hours of engineering and internal tests. The product line also includes a proprietary pressing method.

Case study: West Texas, US

For decades, West Texas has proven to have some of the most difficult drilling formations in the world. During a run in Midland County a customer was drilling the intermediate-vertical section of the well using the EL003 (Figure 1). While reaching total depth (TD), the customer also saw a rate of penetration (ROP) improvement of over 15% versus recent offsets, with a dull grade of 0-0-BT-G-X-I-CT-TD.

In Pecos County, a customer was drilling the deep-vertical section and also achieved notable results with the EL003 (Figure 2). The cutter is not just an improvement on thermal and abrasive characteristics, it has proven to hold together and stay sharp while drilling through conglomerates and challenging interbedded formations. This run not only drilled over 7000 ft, but also delivered an ROP improvement of just under 25% versus the incumbent cutter. The dull grade for this run was 1-1-BT-G-X-I-WT-TD.

Figure 1. ELOO3, Midland County, West Texas.

Figure 2. ELOO3, Pecos County, West Texas.

Case study: Algeria

This case study highlights the capabilities of the AT004 cutter, which utilises a diamond table that is thicker than 3 mm. The customer was looking for a cutter that could meet the challenge of drilling a formation that consisted of dolomite/shales/sandstone/pyrite but could also be economically viable. In this run, the customer saw a ROP of +90% versus field average and +20% versus best performer. The dull grade for this run was 1-1-WT-A-X-I-NO-TD.

Case study: Canada

A customer was struggling to find a cutter that was able to maintain structural integrity from the diamond layer through the carbide. The rigorous drilling conditions in the oilsands left many cutters unusable after one run, due to extreme carbide wear and undercutting at the diamond interface. IDS set out to design a carbide substrate that would overcome these obstacles. The end product was the AT005 cutter. The results of its application are further documented elsewhere.1

Following this success, the AT005 diamond layer and newly designed substrate were adopted across the company’s entire fleet of products. Coupled with a proprietary feed blend, IDS was able to create a cutter that was not only erosion and corrosion-resistant but had the propensity to withstand severe impact damage when the bit was introduced to any type of lateral, axial or torsional vibrations. The impact toughness not only translated into longer lifetime of the drill bit, but customers were also able to utilise this component in other areas of the drill string, such as rotary steerable pads, reamers, hole openers and, most recently, plug drill out bits and casing exit mills.

New shapes on the horizon

The standard PDC cutter cylinder is not the only shape for cutters on the market today. Shaped PDC cutters are evolving in every aspect of the drilling arena, with options available for operators looking for increased ROP, optimised cooling, better depth of cut and formation engagement, or better overall secondary cutting elements. The TC005 and TC010 are two possible shapes that could assist in multiple drilling applications by delivering higher depths of cut, while also allowing less heat build-up on the PDC diamond table. This could allow for a more aggressive approach downhole without jeopardising drill time.

Conclusion

The drill bit is an ever-evolving tool that is the working end on every bottomhole assembly (BHA) in every well drilled. As customer needs evolve, drilling practices change and materials advance; it is the task of PDC cutter developers to continue to deliver products that can remove rock efficiently and economically.

Reference

1. WONG, A., BELL, A., WILLIAMS, M., ISNOR, S., and HERMAN, J.J., ‘New Material

Technologies Reduce PDC Drill Bit Body and Cutter Erosion in Heavy Oil Drilling

Environments’, SPE-181196-MS, https://onepetro.org/SPELAHO/proceedingsabstract/16LAHO/2-16LAHO/D021S010R002/208081

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