Definition - What does Drilling Rate mean?
Drilling Rate is the speed at which a drill bit can crush or cut a rock under it to deepen the borehole. The speed is normally measured in meters per hour or feet per minute and in minutes per foot at times. The drilling rate generally increases in the fast drilling formations like sandstone and decreases in the slow drilling formations like shale. It decreases in shale because of overburden stresses and diagenesis. It decreases with increase in plastic velocity.
Petropedia explains Drilling Rate
An accurate analysis of drilling rate is complicated by the difficulty of entirely separating the variable. There are numerous factors that affect drilling rate. It can be affected by the properties of drilling fluid and by hydraulic factors only when they influence the efficiency of drilling. If it is normalized to rotatory speed, weight on bit, bit tooth wear, depth, and bit hydraulic, as a result, drilling rate is not affected by any of these variables except by the properties of drilling fluid. Some over-pressured zones result in twice of drilling rate as expected which indicates well kick.