Optimized PDC Point-Loading Cutter Placement Drives Higher Performance in Anhydrite

Abstract

Abstract Shaped cutters have been popular in the PDC cutter development realm. However, the optimum placement of those shaped cutters in a drill bit remains wide field to be explored. This paper illustrates how placement of the point-loading cutters drove higher performance in Anhydrites minimizing the need for multiple bits to complete the 8.5" section in the Unconventional Gas unit in The Middle East. Formations rich in anhydrites and carbonates present a challenge to successfully drill given the hardness of the anhydrite and interbedding with carbonates. To assure consistent success with this application, a detailed application study was carried out to determine cutter failure modes. After that, multiple bit designs have been evaluated using Tetrahedron, a drilling simulator software, having variable position of the shaped cutter. Once the shaped cutter position has been optimized, the bit was tested in a lab environment. It was then deployed in the field after successful lab results. Lab testing showed promising results for field deployment. Once the bit is run in the field, ROP improvement of 33% was achieved. Then, more field deployment followed with higher performance compared to other PDC bits. This bit consistently drills the entire section in one run replacing 2 bits. The field deployments resulted in significant cost savings for the operator as well as reductions in well delivery time. This repeatable performance proved that optimizing the position of point-loading shaped cutters leads to a higher performance drilling anhydrite. This higher performance results in enormous savings to the operator in terms of time and economics.