Difference between revisions of "Decline Curve Analysis"

Revision as of 14:45, 9 July 2018

Decline Curve Analysis (DCA) is an empirical method for rate decline analysis and rate forecasting published by Arps in 1945 ^[1].

DCA is applied for Wells and Reservoirs production forecasting.

E&P Portal has DCA available as one of it's engineering tools.

DCA in the E&P Portal

Note <refname = DDA/>	Rate	Cumulative
Hyperbolic decline 0 < b < 1, b > 1	$q(t) = \frac{q_i}{(1+b\ D_i\ t)^{1/b}}$	$Q = \frac{q_i}{D_i\ (b-1)} \left ( (1+b\ D_i\ t)^ \left ( 1-\frac{1}{b} \right ) -1 \right )$
Exponential decline b = 0	$q(t) = {q_i}\ e^{-D_i\ t}$	$Q = \frac{q_i}{D_i}(1-e^{-D_i\ t})$
Harmonic decline b = 1	$q(t) = \frac{q_i}{1+D_i\ t}$	$Q = \frac{q_i}{D_i} ln{(1+D_i\ t)}$

If one has a need to convert decline factor D_i to the actual annual decline in %:

if\ b > 0, a = (1 - (1 + b\ D_i)^{- 1 / b}) \times 100

if\ b = 0, a = (1 - e^{-D_i}) \times 100

DCA tool at the E&P Portal

a

= annual decline, %

b

= decline curve parametr, dimensionless

D_i

= decline factor per time t, dimensionless

q_i

= initial rate, any rate units applies

q(t)

= rate at time t, any rate units applies

Q

= cumulatve rate at time t, any rate units applies

t

= forecast time, days

↑ Arps, J. J. (1945). "Analysis of Decline Curves". Transactions of the AIME. Society of Petroleum Engineers. 160 (01).

Cite error: <ref> tag with name "DDA" defined in <references> is not used in prior text.

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-<th>Note</th>
+<th>Note <refname = DDA/></th>
 <th>Rate</th>
 <th>Cumulative</th>