A Model of Performance and Life of Diamond Drill Bits

The performance and life of diamond drill bits is presented with discussion of the analytical background, single point diamond studies, laboratory drilling performance tests, and field performance comparisons. The analytical basis of the diamond bit performance model is discussed with respect to the diamond-rock cutting mechanism, mathematical modeling of rock properties, factors affecting drilling efficiency, and the attrition wear model. Single point diamond tests are described, and the test results are used to determine a rock wear constant and to determine the velocity dependent exponent of the wear equation. Using the model, laboratory drilling test results are predicted for both petroleum and mining diamond drill bits. The location of wear and the bit life are predicted in both laboratory and field tests. The data presented shows the analytical model satisfactorily describes diamond bit performance and life over a wide range of drilling conditions and formations.