Wellbore Nodal Analysis (IPR vs VLP) Calculator

Determine equilibrium well flow rate (q_op) and bottomhole flowing pressure (Pwf_op) by solving the intersection of Inflow and Outflow (VLP) curves.

Inflow (IPR) & Tubing (VLP) Inputs

Reservoir Pressure P_R (bar):

Productivity Index PI (STB/d/bar):

Well True Vertical Depth TVD (m):

Tubing Size (Internal Diameter):

Wellhead Pressure P_wh (bar):

Average Fluid Gradient (bar/m): Aerated multiphase column: 0.035 - 0.055

Nodal Equilibrium Point

Operating Flow Rate (q_op):

—

Flowing BHP (Pwf_op):

—

Total Well Drawdown:

—

Tubing Friction Loss:

—

Nodal Flow Regime:

—

Recommended Tools & Equipment

Tested hardware and components for high reliability

100% Free Tool Zero Sign-Up

Frequently Asked Questions

What is Nodal Analysis in petroleum production engineering?

Nodal analysis evaluates an entire production system by selecting a key node (typically the bottomhole sandface) and plotting inflow deliverability from the reservoir (IPR) against outflow capability through the tubing string (VLP). The intersection gives the well’s operating rate.

Why does oversized tubing cause a well to stop flowing?

Oversized tubing reduces superficial gas velocity below the critical liquid-lifting threshold. Liquid accumulates inside the wellbore, increasing hydrostatic gradient until the well "loads up" and ceases flowing.

How does wellhead pressure Pwh affect deliverability?

Higher wellhead separator backpressure shifts the entire VLP curve upward, requiring higher bottomhole flowing pressure, which slashes well drawdown and drops production rate.