Vertical Lift Performance (VLP)

 The Vertical Lift Performance curve illustrates the correlation between flow rate and pressure. It also shows how much pressure required to lift a certain amount of fluid to the surface at the given well head pressure. VLP curve is used in Well Nodal Analysis P vs Q plot software for production system design, analysis and optimization

There are factors influcing vertical lift performance, including fluid properties, wellbore conditions, and flow regimes. These include:

1. Fluid Properties:

-Density: The fluid's ability to flow to the surface is directly impacted by its weight. Higher pressure losses result from the need for more energy to lift higher-density fluids, such as water or oil with dissolved gas.

-Viscosity: Flow efficiency is influenced by the fluid's thickness or internal resistance. Higer friction losses in the tube from more viscous fluids, like heavy oil, results in lower output rates.

-Gas-Liquid Ratio (GLR): The flow regime is also influenced by the amount of gas in the fluid. Gas can improve fluid flow and lower flui flow and lower hydrostatic pressure while it expands as it rises in the well.

2. Tubing Size and Length:

Frictional and hydrostatic pressure losses are impacted by the production tubing's diameter and length. Although they amy result in higher capital expenditures, larger tubing diameters typically reduce frictional losses. The energy needed to raise fluids to the surface is also influenced by the well's overall vertical depth.

3. Wellbore Geometry and Deviation:

Whether the wellbore trajectory is horizontal, vertical or deviated, it affects how complex the flwo dynamics are. Compared to the vertical wells, deviated wells may less efficient due to increased friction and altered flow patterns.

4. Temperature and Pressure Conditions:

Temperature influences fluid parameters, such as viscosity and density, which then impacts the VLP. Furthermore, the pressure gradient in the wellbore alters as fluids rise, influencing gas expansion and overall flow behavior.

5. Flow Regime:

Depending on GLR, flow rates, and tubing size, fluid flow inside the tubing can alternate between bubble flow, slug flow, and annular flow. The flow regime has a substantial impact on frictional pressure losses.

VLP Curve Analyzing Flow Behavior:

The VLP curve is a graph that depicts the relationship between bottomhole pressure (BHP) and surface flow rate. It often slopes downward, indicating that higher flow rates result in larger pressure losses from friction and hydrostatic effects. This curve is a crucial aspect of the inflow performance relationship (IPR), allowing operators to determine how efficiently fluids are lifted to the surface.

Moreover, the VLP curve can be divided into two regions:

-Natural Flow Region: At greater reservoir pressures, the well may produce spontaneously without artificial lift, powered by the reservoir's energy. The VLP curve in this region demonstrates how much flow may ve achived using bottomhole pressure.