Abstract: In a measuring while drilling or similar system, a pressure balance drive cylinder exhaust valve is driven by a toggling sense piston. Reset of the sense piston creates a pressure balance across the exhaust valve such that, as the pressure within the drive cylinder regeneratively increases, this pressure is applied to both sides of the exhaust valve. The pressure balance thus created greatly reduces the force necessary to close the exhaust valve. Once the sense piston is driven past the toggle allowing the drive cylinder pressure to have an offset pressure equal to the downstream main valve pressure, the drive cylinder forces the exhaust valve open thus decreasing the drive cylinder pressure. The pressure reduction allows the sense piston to reset, thereby restarting the process.

Abstract: An oscillating valve driven by the pressure in a mud pulser develops a pressure variation in the mud pulse signal that is at a frequency that is different than the frequencies of the mud system. The oscillating valve is coupled to or integral with the pulse drive cylinder, whether the drive means for operation of the pulser is upstream or downstream from the orifice. A bistable valve improves performance of the transmitting element at low flow rates by providing a toggle mechanism which assures positive seating of the bistable valve.

Abstract: An oscillating valve driven by the pressure in a mud pulser develops a pressure variation in the mud pulse signal that is at a frequency that is different than the frequencies of the mud system. The oscillating valve is coupled to or integral with the pulse drive cylinder, whether the drive means for operation of the pulser is upstream or downstream from the orifice, or whether or not the drive means and the poppet are on the same side or opposite sides of the orifice. The oscillating valve is a bistable valve which preferably forms one wall of the drive piston of the pulser. Pressure from the drive cylinder behind the drive piston is directed in such a way as to unseat the bistable valve. When the bistable valve unseats, pressure is bled from within the drive cylinder, which also bleeds the pressure that unseated the bistable valve in the first place.

Abstract: An oil well pumping system includes a small positive displacement pump below the fluid interface in a low volume oil well which pumps at a rate to maintain approximately constant fluid level in the well. The system includes at least a pair of sensors in a sensor array that is positioned above the pump and near the fluid interface to unambiguously determine liquid level. By maintaining the pumping rate of the positive displacement pump below that required to lower the liquid level to the pump, the pump will not unload and pump power requirements are reduced to a nearly constant low rate. In addition, the pump off control function is accomplished by a microprocessor which is mounted adjacent to the downhole sensor array. This location allows simple direct control of the downhole electric motor and eliminates the requirement that a control element be placed on the surface far from the pump.

Abstract: An oscillating valve driven by the pressure in a mud pulser develops a pressure variation in the mud pulse signal that is at a frequency that is different than the frequencies of the mud system. The oscillating valve is coupled to or integral with the pulse drive cylinder, whether the drive means for operation of the pulser is upstream or downstream from the orifice, or whether or not the drive means and the poppet are on the same side or opposite sides of the orifice. The oscillating valve is a bistable valve which preferably forms one wall of the drive piston of the pulser. Pressure from the drive cylinder behind the drive piston is directed in such a way as to unseat the bistable valve. When the bistable valve unseats, pressure is bled from within the drive cylinder, which also bleeds the pressure that unseated the bistable valve in the first place.

Abstract: An oil well pumping system includes a small positive displacement pump below the fluid interface in a low volume oil well which pumps at a rate to maintain approximately constant fluid level in the well. The system includes at least a pair of sensors in a sensor array that is positioned above the pump and near the fluid interface to unambiguously determine liquid level. By maintaining the pumping rate of the positive displacement pump below that required to lower the liquid level to the pump, the pump will not unload and pump power requirements are reduced to a nearly constant low rate. In addition, the pump off control function is accomplished by a microprocessor which is mounted adjacent to the downhole sensor array. This location allows simple direct control of the downhole electric motor and eliminates the requirement that a control element be placed on the surface far from the pump.