Decline curve analysis
Paste a rate history and get an Arps fit — qi, Di and b — with the time to the economic limit, remaining reserves and an EUR.
Production & lift
IPR curve
One well test turned into an inflow performance curve, a productivity index and an absolute open flow.
Loading the calculation…
This calculation ran in your browser. No value you entered was sent anywhere, and nothing was stored.
How it is calculated
- Straight-line PI: q = J(P̄ − Pwf), valid while the whole drainage area stays above the bubble point.
- Vogel: q/qmax = 1 − 0.2(Pwf/P̄) − 0.8(Pwf/P̄)², for a saturated reservoir.
- Composite: a straight line above the bubble point and Vogel below it, joined at qb = J(P̄ − Pb) so the curve and its slope are continuous.
- J is back-calculated from the test point under the model you choose, not assumed.
Standards it speaks
Where this stops being true
One test point fixes one constant, so the shape of the curve is entirely the model you picked — two models through the same test point can differ by thirty per cent at high drawdown. It is also a snapshot: reservoir pressure falls with depletion, skin changes with every job, and an IPR built on a test from last year describes last year. Multi-rate tests exist precisely because a single point cannot distinguish between a low PI and a high one with turbulence.
Related tools
Gas-lift injection optimisation
Fit a gas-lift performance curve through your injection tests and find both the technical peak and the point where the next MSCF stops paying for itself.
Static gradient & bottom-hole pressure
Bottom-hole pressure from a wellhead reading — a liquid gradient for oil and water, and a stepwise gas-column integration for gas.
Build-up test — permeability & skin
A Horner plot from your shut-in pressures, with the semilog slope turned into permeability, skin, p* and flow efficiency.