Abstract: A downhole motor operated by circulating mud fluid in the wellbore is revealed. The motor has nested rotors and is geared to a bit drive. The motor is a dual-rotor pump that is operated as a motor with mud flow through the rotor housing on end connections. The structures of the rotor housing and the rotors can be made of the same material. An angular offset can be incorporated between the centerline of the output of the motor and the bit drive. In the preferred embodiment, the motor output is through a gear located within a bigger gear connected to the bit so as to provide a speed reducer. The gear on the bit shaft is preferably made of spaced rods to mesh with the gear on the motor output shaft. The drive between the rotors and the bit can accommodate angular offsets of a predetermined amount for directional drilling. The design is compact and can be used to drill wellbores as small as about 2½″ in diameter, or even smaller.

Abstract: A simple torque-testing tool, particularly for downhole progressing-cavity motors, easily bolts on to the bearing housing on one end and the bit box on the other end. The assembly is first screwed together where a predetermined amount of preload is applied to opposing clutch surfaces. Opposite ends of the housing are affixed to the bearing housing uphole and the bit box downhole and a predetermined amount of flow is run through the stator housing. If the downhole motor is close to its design operating parameters for a given flow rate, it should be able to drive the bit box despite the drag applied by the opposing clutch surfaces. Failure of the downhole motor to be able to overcome the resistance from the device at the predetermined flow rate indicates that the motor is worn. Torque resistance is applied preferably by stacked Belleville washers which can be stacked in a number of arrangements to alter the amount of force.

Abstract: An improved lubricant cooling system for a sealed bearing section used in drilling with downhole motors comprises a radial bearing or bearings which preferably contain internal and external spiral grooves such that rotation of the central hollow shaft which supports the drillbit forces lubricant up the external grooves toward the upper seal and then back down in the internal grooves along the cooled hollow shaft which has drilling mud flowing through it. Similarly, the rotation of the hollow shaft forces lubricant through an internal spiral in a lower radial bearing or bearings until it reaches the lower seal at which time it is forced into the external spirals past the thrust bearings in the bearing section. This axial circulation effect allows the removal of heat efficiently from the lubricant by virtue of circulating drilling mud in the hollow shaft and in the outer annulus returning to the surface.

Abstract: An apparatus and method for detecting lubricant reservoir levels, particularly in bearing sections for downhole mud motors, is revealed. This allows rig personnel to more exactly ascertain the remaining bearing life of the assembly. In one embodiment, the assembly is pulled out of the hole and comprises of a signal source. A hand-held device is placed next to the bearing housing and the location of the strongest signal is a direct measurement of the position of the floating piston in the lubricant reservoir. The rig personnel can then readily obtain a level reading on the fluid level in the reservoir. An alternative design is also revealed where the position of the floating piston is sensed in real-time by receivers mounted at spaced locations in the lubricant reservoir.

Abstract: A rotary fluid converter having sloping exterior shoulders at one end, a hollow bore at the center, and a downwardly sloping fluid orifice extending from said sloping exterior shoulders at a tangent to said interior bore such that turbulence caused by said fluid flow is reduced thereby reducing the erosion and wear of said rotary fluid converter.

Abstract: A waterjet machining process and system applied to a heat-treated hollow device for cutting a predetermined pattern therein. The hollow device is mounted in the holder that applies rotational, axial, and transverse movements to the hollow metal device as needed in relation to an abrasive water cutting jet stream to cut a predetermined pattern therein. The pattern may be digitized and stored in a computerized numerical controller for moving the holder as necessary to cut the predetermined pattern therein. Inserts may be provided within the hollow device when cutting asymmetrical patterns to protect the inside diameter wall opposite the waterjet from erosion.