![]() ![]() ![]() This Jet optimization according to maximum hydraulic horsepower is based on the concept that the best condition to clean the well is when the hydraulic horsepower at the bit is the maximum. The above equation is developed if M is set equal to 2 so that P f = 1/3 P p. In addition, by observing that P F is proportional to the velocity: The total pump pressure (Pp) is equal to the sum of all friction pressures (PF) and the bit pressure drop (Pa): To optimize hydraulics, the pressure relationships throughout the well must be defined. Cross flow is maximum when an impact force is maximum. Laboratory and field studies have shown that cross-flow beneath the face of the bit is the most effective parameter in hole cleaning. Drilling Bit Jet Nozzles Optimization – Max Impact Force In some cases, any of these variables, when optimized, will clean the hole, whereas in other cases, one is more effective than the others. The variables most commonly optimized are impact force, hydraulic horsepower, and jet velocity. Many attempts have been made to optimize certain bit hydraulics variables to cause perfect hole cleaning. As yet, industry personnel does not agree on the perfect cleaning technique. For example, do high-impact forces clean the hole more effectively than maximum jet velocities? The critical point in this speculation is the attempt to develop the “perfect” cleaning mechanism such that a drilled rock fragment is removed virtually instantaneously after it is drilled. Much speculation has been made concerning hydraulics’ role in solids removal. ![]() In addition, features such as extended nozzles and varying the number of nozzles affected the drilling rate. Jet bits were developed to improve the jetting action of the high mud velocities at the drilling bit. This first became evident when larger mud pumps increased the drilling rate because more mud was being pumped through the large throat of the regular circulation bit. Engineering Guide: Broaching Series - How to Calculate the Cutting Forcesįor many years, drilling engineers have known that hydraulics play an essential role in cleaning the face of the formation so that a bit can drill faster. ![]()
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