Intermittent Gas LiftEdit
Intermittent gas lift is a practical method of artificial lift used in oil and gas production to increase the flow of fluids from a well. It relies on cyclic injections of gas to reduce the weight of the fluid column in the production string, making it easier for reservoirs to push oil and water to the surface. This approach sits within the broader family of gas-lift techniques and is typically contrasted with continuous gas lift, rod pumping, and electric submersible pumps in terms of cost, complexity, and applicability to different well conditions.
In many fields, intermittent gas lift provides a flexible, scalable solution for aging or marginal wells, especially where oil viscosity or high water cut would otherwise suppress production. It is commonly deployed on both onshore and offshore installations and often serves as a bridge technology—maintaining production while more capital-intensive projects are planned or while reservoir conditions evolve. As with other artificial lift methods, the choice to implement intermittent gas lift reflects a balance between capital expenditure, operating costs, and the economics of sustained production.
Principles of operation
Basic concept: Gas is injected into the annulus or tubing string to create gas pockets that reduce the hydrostatic pressure of the produced fluid column. The reduced density allows reservoir fluids to rise more readily to the surface. In intermittent gas lift, the injection is cyclic, producing periods of gas entry and periods of no gas entry.
Downhole components: Central to the system are gas-lift valves and associated packers or tubing fittings that regulate when gas can enter the production string. These devices can be mechanical, hydraulic, or pressure-responsive, enabling controlled slug generation of gas and liquid.
Surface and subsurface integration: A gas source—often a compressor and gas handling system—feeds the downhole apparatus. Controls may be automated or manually adjusted to match changing production rates, reservoir pressure, and gas availability. The configuration links to gas lift theory and practice, and it interacts with other wellbore and surface equipment such as the wellhead, controls lines, and surface separators.
Operational cycles: The cycle period depends on factors such as oil viscosity, gas quality, well depth, casing pressure, and desired production rate. Shorter cycles can be used for lighter oils or higher gas supply, while longer cycles may suit heavier oils or limited gas. Proper cycling helps avoid gas breakthrough that could lead to gas locking or slug instability.
Design considerations: Operators assess reservoir performance, tubing size, packer placement, gas-injection rate, and the pressure differentials needed to open and close the downhole valves. Wellbore integrity and sand production are also considerations, since solids can affect valve seating and cycle reliability.
History and development
Intermittent gas lift emerged as part of the broader evolution of artificial lift in the mid-20th century. Early gas-lift concepts were refined as downhole valve technology improved, enabling more reliable control over when and where gas entered the production string. Over time, the approach adapted to a wider range of well conditions, including deep wells, heavy oil, and fields with fluctuating gas supplies. Today, intermittent gas lift remains a common option alongside continuous gas lift and other artificial lift methods such as rod pumping and electric submersible pumps Electric submersible pump.
Applications and field implementation
Onshore fields: Widely used in mature or marginal onshore wells where conventional production methods underperform. It is particularly suitable when oil is viscous, gas is readily available, and a flexible production plan is desirable.
Offshore platforms: In offshore contexts, intermittent gas lift can be used to manage variable production while limiting capital expenditure compared with more complex systems. It is compatible with existing risers, subsea trees, and surface gas handling infrastructure.
Heavy oil and high water cut: The method can help lift oil in formations where heavy oil or significant water production would otherwise limit flow, enabling more economical recovery without resorting to more aggressive or expensive lift techniques.
Lifecycle management: Operators frequently employ intermittent gas lift as part of a field’s life-cycle strategy—extending well life, deferring costly redevelopment, or stabilizing production during reservoir management adjustments.
Advantages and limitations
Advantages:
- Lower upfront capital relative to some alternatives, with scalable deployment across many wells.
- Flexibility to adapt to changing production targets and well conditions.
- Ability to salvage marginal wells and extend field life without major new drilling.
- Can be integrated with existing surface gas handling and control infrastructure.
Limitations:
- Dependence on a reliable gas source and suitable gas quality.
- Control complexity and the need for ongoing monitoring and maintenance of downhole valves.
- Potential for gas venting or emissions if gas recovery and handling are not optimized.
- Performance can be sensitive to reservoir changes, oil viscosity, and gas pressure fluctuations.
Economic considerations
Intermittent gas lift tends to strike a balance between capital expenditure and operating cost. It often requires less initial investment than full-scale electric submersible pumps or extensive re-completions, while still delivering meaningful improvements in production rates. The economics hinge on gas supply reliability, gas pricing, well productivity targets, facility constraints, and the costs of controls and monitoring. In many cases, operators evaluate intermittent gas lift as part of a broader optimization strategy that includes other lift methods and field redevelopment plans Oil wells and field infrastructure are typically managed with a view toward maximizing return on investment over a multi-year horizon.
Environmental and safety considerations
Emissions and venting: Gas handling during intermittent gas lift must minimize methane emissions and venting. Efficient gas capture, reuse, or flaring practices are relevant considerations in regulatory and corporate environmental programs.
Reservoir integrity and wellbore safety: Downhole valves and packers must maintain integrity under cycling pressure, and sand management remains important to prevent valve sticking or wear.
Regulatory context: Operators operate within frameworks that govern gas handling, emissions, and safety standards. These frameworks influence design choices, monitoring requirements, and reporting obligations.
Controversies and debates
Energy security and domestic production: Proponents emphasize that intermittent gas lift supports existing production, reduces the need for immediate new drilling, and can contribute to domestic energy supply when deployed prudently. They argue that maintaining and optimizing current wells is a cost-effective way to balance energy output with market demand and employment, especially in regions with mature oil basins.
Environmental concerns and climate policy: Critics point to methane emissions and the broader climate footprint of fossil-fuel extraction. They argue that even with efficient gas handling, continuing production—especially for longer field lifetimes—perpetuates fossil-fuel use. From this perspective, some advocate for faster transitions to low-carbon alternatives and more aggressive deployment of renewables.
Woke criticisms and industry responses: Debates around climate policy and social responsibility sometimes frame fossil-fuel technologies as out of step with broader environmental goals. A practical industry view notes that technologies like intermittent gas lift can reduce waste by keeping production economical from existing assets, potentially lowering per-unit emissions by avoiding more energy-intensive redevelopment. Proponents might argue that blocking or delaying such technologies can raise short- and medium-term costs, reduce energy independence, and slow economic growth. Critics may challenge these claims by urging stricter performance standards, methane-reduction commitments, and transparency about externalities. In policy discussions, the emphasis often centers on balancing reliability and affordability with environmental stewardship, rather than treating the technology as inherently good or evil.