A method for determining optimum drilling techniques

Abstract

This report develops a simple method for determining the combination of weight-on-bit, rotary speed and hydraulic horsepower which produces minimum drilling cost. Empirical relationships are developed to show the influence on penetration rate of weight-on-bit, rotary speed and hydraulic horsepower. Optimum weight-on-bit is shown in relation to formation drillability, and optimum rotary speed is related to weight-on-bit. These five relationships are then combined into a chart for determining optimum drilling techniques from a minimum of field test data. Secondary issues discussed are: (l) Advantages of the jet bit over the regular bit and minimum nozzle fluid velocity requirements for jet bit use relative to formation drillability; and (2) distribution of pump horsepower into nozzle fluid velocity and circulating volume.