EUR and time-to-limit for Arps decline curves

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Description

Evaluate estimated ultimate recovery and time to economic limit for Arps decline curve objects.

Usage

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arps.eur(decl, q.limit)
arps.t.el(decl, q.limit)

Arguments

decl

an Arps decline object as returned by arps.decline or curtail.

q.limit

economic limit rate [volume / time] in same units as decl.

Value

arps.eur returns the total production for decl at the point in time when the economic limit q.limit is reached; that is, arps.Np(decl, arps.t.el(decl, q.limit)), in the same units as q.limit.

arps.t.el returns the time until the economic limit q.limit is reached for decline decl.

See Also

arps, curtail.

Examples

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## exponential decline with
## qi = 1000 Mscf/d, Di = 95% effective / year
## EUR with economic limit 10 Mscf/d
decline <- arps.decline(1000,
    as.nominal(0.95, from.period="year", to.period="day"))
arps.eur(decline, 10)

## hyperbolic decline with
## qi = 500 bopd, Di = 3.91 nominal / year, b = 1.5,
## time to reach economic limit of 3 bopd
decline <- arps.decline(rescale.by.time(500, from="day", to="year"),
    3.91, 1.5)
arps.t.el(decline, rescale.by.time(3, from="day", to="year"))