Free Tool · Decline Curve Fit

Production Decline Analyzer

Enter 12+ months of monthly production data. The tool fits a hyperbolic decline curve (Arps), surfaces the initial rate, decline rate, and hyperbolic exponent, and projects forward production and EUR.

Setup

Production unit

Well type

Monthly production — Months 1 to 24

Fill at least 12 consecutive months. Leave trailing months blank if you have less data. Month 1 = first month of stabilized production.

Best-fit decline

qi (initial rate)

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Di (annual decline)

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Effective, year 1

b (hyperbolic exponent)

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0 = exponential, 1 = harmonic

R² (fit quality)

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1.0 = perfect fit

Actual production vs fitted decline curve

Actual production

Fitted curve / projection

Forward projection

Projected month-12 rate

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Projected month-24 rate

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Projected month-36 rate

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Cumulative — 36 months

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EUR estimate (30-year cap)

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Decline curves are one input. The bigger question: where is uplift available?

Type-curve performance vs offset wells, re-completion candidates, artificial-lift optimization, choke management — those are the levers that change the EUR output. A 30-minute conversation maps which ones apply to your situation.

Schedule a discovery call

Methodology & references

This tool fits a hyperbolic decline using Arps' equations (Arps, 1945; J.J. Arps, "Analysis of Decline Curves"). The fitting method:

Hyperbolic equation: q(t) = qi / (1 + b·Di·t)^(1/b), where t is time in years from month 1
Grid search over b ∈ [0, 2] with step 0.05; for each b, qi and Di solved by minimizing sum of squared log-residuals between actual rates and the model
Effective annual decline reported in year 1 = (q0 - q12) / q0
EUR computed by integrating the hyperbolic curve to 30 years (industry-standard economic limit) or to a terminal exponential decline of 6% per year, whichever comes first

Typical Appalachian b values from public well-level data: Marcellus 0.8 – 1.4; Utica 0.6 – 1.2; conventional verticals 0.0 – 0.5. b values above 1.5 are usually a fitting artifact from short time series and warrant skepticism.

This tool produces a directional fit, not a reserves report. A reserves-grade analysis includes type-curve normalization, GOR/CGR adjustments, and offset-well comparisons — none of which a single-well fitter can do.