Increased ROP by 18% in Norway and in Other Applications through Optimizing Cutter Geometry from Laboratory Tests, Numerical Models and Field Tests

Abstract

Abstract The oil-and-gas drilling industry has been utilizing modified PDC cutter geometry for improving performance. One of the first reinforcements of beliefs in positive effects of edge geometry changes was in report by Lin et al. in 1992 from conducting laboratory experiments on cutters. Currently, certain geometries are being favored based on limited testing and analysis of the design space. The detailed effect of geometry on attributes such as strength, cutting, wear and the tie to performance has not been fully understood. This paper reports results of laboratory studies, numerical models, and field runs towards building such understanding. Single cutter edge-loading tests, pressurized cutting and wear tests were carried out alongside full-scale PDC bit tests and field runs. Improved analysis techniques were utilized to extract meaningful information from the tests. Numerical models were used to exploit the design space for the geometry. The optimized geometry was selected with greater than 50% strength improvement as indicated by the numerical model. For the optimized geometry, pressurized single cutter lab tests indicated greater than 25% performance improvement in several aspects. Of the field runs in various applications, the largest dataset was in Norway with an ROP increase of 18% among greater than 187 bits run. This study is part of a holistic approach to understanding the thermo-mechanical behavior of PDC cutter drilling as it applies to improving design as demonstrated and drilling practices. The improved cutter geometry has helped customers drill further and faster, which has helped reduce the cost of drilling. There are still improvements that can be made to cutter geometries that will push performance even further. The methods discussed in this paper will help expedite the learning process and help build better insights.