Abstract:
Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.
Abstract:
A downhole dynamometer for a rod pumping unit is provided. The downhole dynamometer includes a shell within which a plurality of sensors, a non-transitory memory, and a dynamometer controller are located. The shell is configured to be coupled to a sucker rod string of the rod pumping unit and disposed in a well opposite a wellhead of the well. The plurality of sensors is configured to measure downhole accelerations of the sucker rod string and to measure a downhole load on the sucker rod string. The dynamometer controller is coupled to the plurality of sensors and the non-transitory memory. The dynamometer controller is configured to periodically collect measurements from the plurality of sensors and store the measurements in the non-transitory memory.
Abstract:
A lift apparatus and method for driving a downhole reciprocating pump is disclosed. The apparatus includes a hydraulic cylinder having a piston and a hydraulic fluid port, the piston being coupled to a rod for driving the reciprocating pump, the piston being moveable between first and second ends of the cylinder in response to a flow of hydraulic fluid through the hydraulic fluid port. The apparatus also includes a variable displacement hydraulic pump coupled to receive a substantially constant rotational drive from a prime mover for operating the hydraulic pump, the hydraulic pump having an outlet and being responsive to a displacement control signal to draw hydraulic fluid from a reservoir and to produce a controlled flow of hydraulic fluid at the outlet. The apparatus also includes a hydraulic fluid line connected to deliver hydraulic fluid from the outlet of the hydraulic pump through the hydraulic fluid port to the cylinder for causing the piston to move through an upstroke away from the first end and toward the second end of the cylinder. The apparatus further includes a valve connected between the hydraulic fluid port and the reservoir, the valve being responsive to a valve control signal for controlling discharge of hydraulic fluid from the hydraulic fluid port of the cylinder back to the reservoir to facilitate movement of the piston through a downstroke away from the second end toward the first end of the cylinder. The valve is operable to prevent flow of hydraulic fluid through the valve during the upstroke and the hydraulic pump is operable to prevent flow of hydraulic fluid back into the outlet of the hydraulic pump during the downstroke.
Abstract:
A controller for operating a prime mover of a rod pumping unit includes a processor configured to operate the prime mover over a first stroke and a second stroke. The controller is further configured to compute a first motor torque imbalance value for the first stroke and engage adjustment of a counter-balance. The controller is further configured to estimate a second motor torque imbalance value for the second stroke. The controller is further configured to disengage adjustment of the counter-balance during the second stroke upon the second motor torque imbalance value reaching a first imbalance range.
Abstract:
An artificial lifting system is disclosed. The artificial lifting system comprises an elongated cylinder fixed to a base or ground. The elongated cylinder receives a piston rod axially movable therein. The piston rod engages a downhole rod pump for driving the rod pump reciprocating uphole and downhole to pump downhole fluid to the surface. A control unit controls the axial movement of the piston rod, and automatically adjust the system operation to adapt to drift of the top and bottom stop positions of the piston rod. In an alternative embodiment, the system further comprises a dump valve controlled by the control unit to prevent over-stroke. In another embodiment, the system further comprises a chemical injection unit for injecting treatment fluid to a wellbore under the control of the control unit.
Abstract:
A pump apparatus has a downhole pump disposed in a wellbore and has a motor at the surface, and a rod string operatively moved by the motor reciprocates the downhole pump in the wellbore. Downhole data indicative of load and position of the downhole pump is generated using surface measurements and a wave equation model having a damping factor. Actual fluid load lines are determined from the downhole data for upstrokes and downstrokes of the downhole pump, and calculated fluid load lines for from the strokes are determined from the distribution of the load values in the downhole data. The actual fluid load lines are compared to the calculated fluid load lines to determine if the downhole data is over or under-damped. Then, the damping factor of the wave equation model can be adjusted so that new downhole data can be generated with appropriate damping.
Abstract:
Rod Float Mitigation (RFM) methods for rod-pumped oil wells having a variable frequency drive which controls the speed of the motor for the pump. Each method monitors rod loads or a similar condition and takes action only when rod load drops below a predefined minimum load. A first method reduces the speed of the motor to a preset level. A second method fixes the torque level on the pump downstroke by adjusting motor speed based on a calculated gearbox torque compared to a programmed fixed limit. Another method includes a program in the variable frequency drive which includes a preferred RFM Torque Curve for the pump to follow on its downstroke. When rod float occurs, the program monitors gearbox torque and adjusts the speed to follow the predetermined RFM Torque Curve thereby mitigating rod float with minimum decrease in production.
Abstract:
An apparatus and method for monitoring a reciprocating member of a reciprocating piston compressor is presented. The apparatus and method provide a means for measuring parameters of the reciprocating member, such as road load or cross-head temperature and the like, and wirelessly transmitting the data to a receiver. A mobile assembly is attached to a reciprocating member of the compressor, the mobile assembly having a sensor assembly, a wireless transmitter and a power generation assembly. The sensor assembly measures a parameter of the reciprocating member and generates a representative sensor signal. The wireless transmitter wirelessly transmits a corresponding data signal to a stationary assembly mounted nearby. The power assembly powers the transmitter and sensor assembly. The measured data is used, in conjunction with other measurements, such as a crankshaft encoder, to calculate the work performed by the compressor, the power used by the compressor and other information. The compressor utilization is then optimized based on the gathered information.
Abstract:
The present invention generally provides apparatus and methods of operating a pumping system. The pump control apparatus includes a first sensor for measuring strain on a structure of the well pumping system and a second sensor for measuring a position of the structure. The apparatus also has a controller configured to control the well unit by receiving output signals from the first and second sensors and generating control signals according to a motor control sequence. This controller may be mounted to the structure of the pumping system to measure the strain experienced by the structure. The control signals may be transmitted to a motor control panel using a cable-less communications system. Preferably, the first sensor, the second sensor, and the controller are integrated into a single unit. In another embodiment, the pump control apparatus may be self-powered.
Abstract:
An apparatus and method for monitoring a reciprocating member of a reciprocating piston compressor is presented. The apparatus and method provide a means for measuring parameters of the reciprocating member, such as road load or cross-head temperature and the like, and wirelessly transmitting the data to a receiver. A mobile assembly is attached to a reciprocating member of the compressor, the mobile assembly having a sensor assembly, a wireless transmitter and a power generation assembly. The sensor assembly measures a parameter of the reciprocating member and generates a representative sensor signal. The wireless transmitter wirelessly transmits a corresponding data signal to a stationary assembly mounted nearby. The power assembly powers the transmitter and sensor assembly. The measured data is used, in conjunction with other measurements, such as a crankshaft encoder, to calculate the work performed by the compressor, the power used by the compressor and other information. The compressor utilization is then optimized based on the gathered information.