Coiled Tubing Drilling Advancement with Smallest Shaped Diamond Cutting Element

Abstract

This paper describes an innovative concept for the smallest polycrystalline diamond compact (PDC) cutter size with non-planar diamond table used on a fixed cutter drill bit. This unique PDC cutter significantly increases durability, enhancing the bit life to drill more footage in multi-lateral applications driven by motor or turbine in two different challenging formations. Collaboration between a national oil company and a drill bits provider resulted in achieving consistent records in footage while maintaining good rate of penetration (ROP). This 8.2 mm diameter PDC cutter equipped with unique geometry was used on a 3.625 in. fixed cutter (PDC) drill bit design. Main objective of the unique geometry on this non-planar diamond table is to improve cooling efficiency compared to the standard diamond table of a PDC cutter. Traditionally, PDC cutter technology relies on the cutter's thermal stability and abrasion resistance. Often, those two properties may not provide sufficient durability in abrasive formations. Initially, this unique geometry was used on bigger PDC cutters including 13 mm and 16 mm where a performance improvement was achieved, leading to the decision to scale-down to the smallest PDC cutter size. Two different 3.625 in. fixed-cutter drill bit designs were used with non-planar diamond table PDC cutters and successfully passed the client requirement and trial testing criteria. Based on the field deployment results, drilling performance in the field was monitored and compared to standard diamond table PDC drill bit designs also used in the past as the benchmark. Shaped non-planar diamond table bit designs surpassed the footage of standard diamond table PDC cutter bit designs by 12% and 36% respectively with two different bit designs. Other performance aspect including dull condition were also monitored and showed similar wear progression as seen with other bit designs used in the application. This innovative concept demonstrates that the non-planar diamond table PDC cutter successfully delivers more footage per bit run. This led to increase overall performance with deployments on coiled tubing drilling rigs across this difficult drilling environment in the challenging wells drilled in the Middle East. The novel technology achieves all drilling objectives with fewer drill bits and fewer trips, delivering the target footage at improved ROP.