Synchronized dual well variable stroke and variable speed pump down control with regenerative assist

摘要

A dual well pumping unit (12) has two hydraulic ram units (26), one for each well (preferably with each ram unit (26) having three hydraulic rams). Each hydraulic ram units is connected to first ram pump (18) and a second ram pump (20). The drive shaft (40) of the first ram pump (18) is coupled to the drive shaft (38) of the second ram pump (20) and to a rotor of a drive motor (16). The ram pump (18) and the ram pump (20) are preferably variable displacement piston pumps which are controlled by a microprocessor based controller (44), such that during the downstroke of the hydraulic ram (26) the ram pump (18) operates as an hydraulic motor powering the ram pump (20) and during the up stroke of the hydraulic ram (26) the ram pump (20) operates as a hydraulic motor to provide assist to the ram pump (18).

主权项

1. A dual well hydraulic pumping unit for removing well fluids from a first well and a second well, comprising:
a prime mover having a rotary drive shaft for turning in a first angular direction; a reservoir for a hydraulic fluid; a first sucker rod assembly disposed in the first well for removing the well fluids from the first well; a first ram connected to said first sucker rod assembly for moving in an upstroke and moving said first sucker rod assembly from a downward position to an upward position, and moving in a downstroke with said first sucker rod assembly moving from said upward position to said downward position; a second sucker rod assembly disposed in the second well for removing the well fluids from the second well; a second ram connected to said second sucker rod assembly for moving in an upstroke and moving said second sucker rod assembly from a lowered position to a raised position, and moving in a downstroke with said second sucker rod assembly moving from said raised position to said lowered position; a first ram pump connected to said rotary drive shaft, said first ram pump having a first ram pump suction port connected to said reservoir and a first ram pump discharge port connected to said first ram for during the upstroke of said first ram transferring the hydraulic fluid into said first ram and moving said first ram from a downward position to an upward position, and during the downstroke of said first ram pump transferring the hydraulic fluid into said reservoir; a second ram pump connected to said rotary drive shaft, said second ram pump having a second ram pump suction port connected to said reservoir and a second ram pump discharge port connected to said second ram for during the upstroke of said second ram transferring the hydraulic fluid into said second ram and moving said second ram from a lowered position to a raised position, and during the downstroke of said second ram pump transferring the hydraulic fluid into said reservoir; and at least one control unit adapted for controlling flow rates of the hydraulic fluid through said first ram pump and said second ram pump, and adapting said first ram pump for pumping the hydraulic fluid into said first ram during the upstroke and during the downstroke passing the hydraulic fluid from said first ram into said reservoir and turning said rotary shaft in said first angular direction to power said second ram pump in response to pressures within said first ram provided by the weight of said first sucker rod assembly in combination with said prime mover, and adapting said second ram pump for pumping the hydraulic fluid into said second ram during the downstroke of said first ram and the upstroke of said second ram and turning said rotary shaft in said first angular direction to power said second ram pump in response to pressure within said second ram provided by the weight of said second sucker rod assembly in combination with said prime mover.