Black Gold Chronicles 2: Advanced Artificial Lift Systems

  admin    August 18, 2021    0


The systematics of petroleum production from a borehole shows that the rate of fluid flow is directly proportional to the reservoir pressure. Hence, flow rate in low reservoir pressure boreholes needs to be enhanced by an artificial system.

There exist several artificial lift systems, amongst which;

  1. The Electrical Submersible Pump
  2. The Sucker Rod Pump
  3. The Gas Lift
  4. The Plunger Lift
  5. The Progressive Cavity Pump
  6. Hydraulic Pump

Basic concepts and definition of terms

Wells never actually attain absolute flow potential due to the fact that for fluids to flow out of the well to the surface, the reservoir pressure (Pwf) must exceed the back pressure the producing fluids exert on the formation as it moves through the production system.

The back pressure or bottom hole pressure stops the fluid from moving up the surface. This pressure is served by the following components;

  1. The hydrostatic pressure of the producing fluid column
  2. Friction pressure caused by fluid movement through the tubing, wellhead and surface equipment.
  3. Kinetic or potential losses due to diameter restrictions, pipe bends or elevation changes.

Artificial Lift Systems: these are enhanced means of overcoming bottom hole pressure so that a well can be produced at a desired rate. Artificial lifting is achieved either by gas injection into the borehole fluids to reduce hydrostatic pressure and improve buoyancy or using down hole pumps to provide additional lift pressure.

Artificial lifting is mostly associated to mature, depleted fields where average pressure (Pavg) has declined such that the reservoir can no longer produce under its natural energy. Artificial lift systems are also used in younger fields to increase production rates and improve project economics.