Artificial Lift (AL)

Artificial Lift (AL)

What is Artificial Lift (AL)?

Artificial lift is a method used to enhance the production of oil or gas when natural reservoir pressure is insufficient to push fluids to the surface.

Why use Artificial Lift?

• The well ceases to flow naturally.
• The well is not producing economically.

Types of Artificial Lift

1. Pumping Method:
   Uses mechanical motion to impart energy to fluids, lifting them to the surface.

2. Gas Lifting:
   Utilizes compressed gas energy to lift fluids to the surface.

Common Artificial Lift Techniques

• Gas Lift: Utilizes injected gas to lower fluid density, enabling efficient lifting in wells with adequate gas supply.
• Pumps:
  • Electric Submersible Pumps (ESP): Ideal for high-flow, deep wells requiring continuous electrical power.
  • Progressing Cavity Pumps (PCP): Perfect for handling viscous and abrasive fluids in challenging well conditions.
  • Sucker Rod Pumps (SRP): Traditional and reliable choice for shallow to medium-depth wells with moderate production.
  • Jet Pumps: Suitable for shallow, gas-free wells with low to medium flow rates using the Venturi effect.
  • Plunger Pumps: Effective in high-pressure wells with high gas-to-oil ratios and fluctuating pressures.
  • Hydraulic Piston Pumps: Versatile for various depths where electrical power is limited, using hydraulic energy.

Selection Criteria for Artificial Lift Methods

1. Well Completion & Profile:
   Suitability based on well depth and type (vertical, horizontal, etc.).
2. Geophysical & Environmental Conditions:
   Consider the operating environment and potential challenges like high temperatures or harsh fluids.
3. Reservoir Characteristics:
   • Liquid Production Rate: A key factor; high rates require methods capable of handling larger volumes.
   • Water Cut: Methods must handle varying levels of water production, with high water cuts requiring special considerations.
   • Gas-Liquid Ratio (GLR): High gas production can lower pump efficiency and impact selection (e.g., gas lift is more effective at high GOR).
   • Viscosity: High-viscosity fluids may require specific methods like PCP or jet pumps for efficient lifting.
   • Bubble Point: Lift methods should be chosen based on whether the reservoir operates below or above the bubble point.
   • Oil Gravity: API gravity affects the suitability of methods (e.g., ESP for >12 API, Jet Pump for 8-45 API).
4. Reservoir Pressure & Well Productivity:
   The current reservoir pressure and expected production rates must be matched to the method's capability, especially as pressure depletes.
5. Characteristics of Fluid:
   The fluid's viscosity, density, and other characteristics (such as paraffin or scale content) play a crucial role in the selection process.
6. Surface Constraints:
   Physical constraints at the surface, such as available space and power, should be considered when selecting AL methods (e.g., ESP needs significant surface power).
7. Service Availability:
   The availability of specialized services for installation, maintenance, and repair impacts the choice of AL method.
8. Economic Consideration:
   Economic feasibility must be considered in terms of initial costs, operating costs, and expected return on investment.
9. Operational Ease:
   Ease of installation, operation, and maintenance should be prioritized to minimize downtime and increase operational efficiency.
10. Other Reservoir Problems:
    Issues such as sand, scale, or gas coning can affect the efficiency of certain AL methods. These should be accounted for during the selection process.

Read the pdf attached below for more selection criteria