Size and configuration of mud motor drilling affects the optimum power outputs

Abstract

The present invention provides a modular drilling assembly having a module for contactless power and data transfer over a nonconductive gap between rotating and non-rotating members of a steering module. The gap usually application data contains a non-conductive fluid, such as drilling fluid, or oil for operating hydraulic devices in the down-hole tool. The down-hole tool in one embodiment is a modular drilling assembly wherein a drive shaft is rotated by a down-hole motor to rotate a drill bit attached to the bottom end of the drive shaft. Generally, there are two main sections on mud motor which are bearing section and power section. The power section generally includes a housing which houses a motor stator within which a motor rotor is rotationally mounted. The power section converts hydraulic energy into rotational energy by reverse application of the Moineau pump principle. The stator has a plurality of helical lobes which define a corresponding number of helical cavities. The rotor has a plurality of lobes which number one fewer than the stator lobes and which define a corresponding plurality of helical cavities. Generally, the greater the number of lobes on the rotor and stator, the greater the torque generated by the motor. Fewer lobes will generate less torque but will permit the rotor to rotate at a higher speed. Based on torque and rotate speed, determine the optimum power can be produced by power section configurations.

Study of the Relationships among the Reverse Torque, Vibration, and Input Parameters of Mud Pumps in Riserless Mud Recovery Drilling

“…Therefore, the relationship between the useful work per unit time and the single-stage mud pump rotational speed, n, can be determined, as shown in Columns 1 and 2 in Table 3. Based on Equation ( 5) [39] of the relationship between the torque exerted by mud on the single-stage mud pump and the useful work per unit time, and according to the data of the useful work and rotational speed shown in Columns 1 and 2 in Table 3, the relationship between the calculated torque T and the rotational speed n can be obtained, as shown in Columns 1 and 3 in Table 3. Fluent is a computational fluid dynamics software that utilizes numerical methods to solve fluid mechanics problems.…”