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Arps qi, Di, b — rate, cumulative, and EUR to an economic limit.
Arps hyperbolic decline: qi, nominal decline Di (1/month), and b-factor. Estimate rate, cumulative production, and EUR to an economic rate limit.
Use b = 0 for exponential (Di ≈ monthly % decline as decimal).
Results
Rate at time
393 /mo
Cumulative Np
15,827 units
Instant decline
2.93%/mo
EUR to limit
40,838 units
Months to limit
228.7
After 24.0 months: q ≈ 393 units/month, Np ≈ 15827 cumulative units. EUR to 50 units/mo limit ≈ 40838 over 228.7 months. Tie to pressure and operating constraints before reserves booking.
engineeringEngineering screening only. Engineering screening calculator only — not a substitute for licensed professional engineering, API/ASME/code-compliant design, certified reserves audits, regulatory well approvals, or field-measured PVT and flow data. Verify all inputs, units, and correlations against your facility standards and qualified sign-off before operations or design decisions.
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Hyperbolic Arps with b < 1 is the default language of unconventional and many conventional forecasts. Di sets early steepness; b controls how long the tail bends.
EUR to an economic limit is more honest than infinite-time integrals — always tie cutoff rate to operating cost and facility constraints.
This tool is single-segment screening. Spreadsheet Studio is where multi-segment history matches and type-curve libraries live.
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