Skid Mounted

Skid Mounted

Skid Mounted Pumping Units

In the sucker rod artificial lifting method, a pumping unit is a mechanism which imparts reciprocating motion to a polished rod to which is attached the rod string and the plunger of the bottom hole pump.

The beam type pumping units are limited to a stroke length of ±15 feet (or 4.5 m).

Beginning in the 1970s, the first vertical long stroke pumping unit appeared on the market: It was an electro mechanical unit capable of a stroke length up to 394”.

During the last decade the long stroke technology improved and the new generation is available as surface hydraulic long stroke pumping units capable of stroke length up to 336” (or 8.5 m) and completely assisted by VSD and PLC.

The SSiLift™ (Sure Stroke Intelligent Lifting System) is now the designer and the manufacturer of the innovative hydraulic surface (skid) mounted artificial lift system for oil and gases that are lighter, lower in cost and more energy efficient with greater lifting capacity compared to conventional lift systems.

How It Works

The SSiLift™ is a hydraulic surface-mounted artificial lift system that is used to extract fluids from both shallow and deep wells to produce crude oil or dewatering for natural gas production. It works in conjunction with a bottomhole pump and rod string. It is comprised of two main components:

  • pumping unit
  • power unit

The Pumping Unit:

  • Provides lift capacity from 15,000lbs to 80,000lbs
  • Determines stroke length based on model: Max stroke lengths from 168” to 372”
  • 7 models of units

The Power Unit:

  • Provides driving force and control for the pumping unit
  • Determines max speed which with the pumping unit it can run
  • 9 models of power units from 15hp to 200hp

Pumping Unit

Seven models of Pumping Unit are available ranging from a Model 150, with 15,000 lbs. lift capacity and a 168” stroke to a Model 800, with 80,000 lbs. lift capacity and a 360” stroke. The Pumping Unit is comprised of a triple chamber hydraulic cylinder, a heavy duty structural base, a counterbalance vessel containing nitrogen gas under pressure, and a pulley/wire rope lift mechanism which doubles sucker rod stroke relative to cylinder travel. The counterbalance can be adjusted at the well simply by adjusting the pressure of the gas in the storage vessel. The direction and speed of the pump is then controlled by sending hydraulic fluid under pressure to either the up or the down chambers of the cylinder. Since the pump is computer controlled, the speed and stroke limits can be independently established, thereby allowing for independent speeds for the up and down stroke.

Power unit

Multiple horsepower options per Pumping Unit model are available ranging from 15 Hp. to 200 Hp. The Power Unit provides the driving force and control for the Pumping Unit. It is comprised of a hydraulic system, variable speed drive (VSD) control and a computer control system (PLC). The system utilizes many sensor mechanisms to provide optimum stroke control and full monitoring of well and pump conditions. The self-monitoring system provides warnings of impending failure conditions, both at the surface and down-hole, and stops the pump prior to a catastrophic failure. The system includes a sealed hydraulic reservoir and various valves for precise control of the cylinder throughout the pumping cycle. The Power Unit is connected to the Pumping Unit by means of high-pressure hoses and electronic control circuitry. The electronics include computer controls that allow for the pump to be controlled by closed loop feedback for precise operation of stroke speed and position.


The next tables show the max stroke length and lifting capacity for the different models of Pumping Units:

Pumping Unit Model 150 250 350 400 400LS 600 800
Stroke Length 168" 240" 372" 288" 336" 336" 360"
Pumping Unit Model 150 250 350 400 400LS 600 800
Lift Capacity 15,000lbs 25,000lbs 35,000lbs 40,000lbs 40,000lbs 60,000lbs 80,000lbs

Benefits and Advantages


  • High Performance, Long Stroke & Intelligent
  • Rod Lift System
  • Optimized production
  • Reduced artificial lift costs
  • Maximizes revenue


  • An Intelligent system, with Programmable pump-off control
  • Long strokes
  • Soft turnarounds
  • A more efficient design
  • Adjustable accelerations and decelerations at the top and bottom of the stroke
  • Changes to stroke length and speed at the push of a button
  • Variable speed control on the up and down stroke
  • SCADA interface available on request for all adjustments
  • Lower energy consumption
  • Small foot print, visual profile and slow speeds are less disruptive
  • Reduced machine noise
  • Simpler transportation and installation
  • Light weight and fewer interventions
  • No heavy mechanical counterweight