Hydraulic Optimization of PDC Bits by Visualization Methods

Abstract

ABSTRACT The number of ways in which cutters are distributed, and the number of shapes of Polycristalline Diamond Compact (P.D.C.) bits are increasing every day. These bits can be fitted with either nozzles or crowfoot fluid outlets. The fluid will spread around the bit in a more or less complex manner depending on these outlets and on the geometry of the annulus encountered. This fluid distribution will have an influence on the efficiency with which the cuttings are evacuated and on the cooling action on the cutters, i.e. the capability to drill faster and for longer. The methods by which flow structures can be determined, are high-performance numerical methods and visualization experiments. This paper describes a testing sequence for flow visualization, which has been developed in the laboratory, plus the necessary equipment. These tests reveal the hydraulic structures, and those most frequently encountered will be described. A concrete example showing the application of our studies will be given: the case of bit profile improvement used by one of our subsidiaries on an oil field under development. The limitations of our experiments, allowing for the tests run and the equipment available, will be discussed, as well as future lines of research.