Lubricant level detection system for sealed mud motor bearing assembly

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. The position of the floating piston is thus detected by the receivers and sent to the surface, generally through the measurement-while-drilling (MWD) sub, so that rig personnel at the surface known at any given time the position of the floating piston and, thus, the remaining lubricant level in the reservoir. The signal source can be a magnetic component mounted in the bearing housing reservoir area where the surrounding components are nonmagnetic such that the receiver responds to the magnetic field created by the magnetic signal source. The signal source can also be powered by a stored electrical supply which can generate through a signal source a signal which can be measured, either over the air or by a hand-held receiver held by rig personnel, or by a connection to the bearing housing for a direct reading of the signal generated.