Change of the Properties of Steel Material of the Roller Cone Bit Due to the Influence of the Drilling Operational Parameters and Rock Properties

Abstract

The breakdown of the drill bit or rapid decrease of the rate of penetration during the drilling process results in a delay in the progress of drilling. Scientists and engineers are increasingly focusing on research to extend the bit life and improve the drilling rate. In our work, “in situ” drilling parameters were monitored during the drilling process with the roller cone drill bit IADC 136, diameter 155.57 mm (6 1/8"). After drilling, the bit was thoroughly examined to determine the damage and wear that occurred during drilling. The following modern and standardized investigative methods were used: an analysis of rock materials and an analysis of micro and macrostructure materials of the roller cone bit. Analyses were carried out using optical and electron microscopy, a simultaneous thermal analysis of materials of drill bit, analysis of the chemical composition of materials of drill bit, and a determination of the geomechanical parameters of rock materials. The resulting wear, local bursts, and cracks were quantitatively and qualitatively defined and linked to the drilling regime and the rock material. The results of our investigation of the material of the roller cone bit can serve as a good base for the development of new steel alloys, which can resist higher temperatures and enable effective drilling, without structural changes of steel material.

Dynamic Characteristics of Rock Holes with Gravel Sediment Drilled by Bit Anchor Cable Drilling

“…Yakym [12] conducted a metallographic analysis of several steel materials commonly used in drill bit production and discussed the methods to prevent premature loss of drill bit workability. Šporin [13] used an optical microscope to analyze the drill bit material's chemical composition and the rock material's mechanical parameters. The research results laid a good foundation for developing new alloy drill bits.…”