Difference between revisions of "Oil Material Balance"

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(References)
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<ref name=DakeP>{{cite book
 
<ref name=DakeP>{{cite book
 
  |last1= Dake |first1=L.P.
 
  |last1= Dake |first1=L.P.
  |title=The practice of reservoir engineering
+
  |title=The Practice of Reservoir Engineering
 
  |date=1994
 
  |date=1994
 
  |publisher=Elsevier Science
 
  |publisher=Elsevier Science

Revision as of 12:39, 28 March 2018

Brief

The general form of the Oil Material Balance equation was first published by Schilthuis in 1941[1].

Math & Physics

Equating all underground withdrawals to the sum of the volume changes[1]:

N_p B_o + N_p (R_p - R_s) B_g = N (B_o - B_{oi}) + N (R_{si} - R_s) B_g + m N B_{oi} (\frac{B_g}{B_{gi}} - 1) + (P_i - P_{res}) N (1 + m) B_{oi} \frac{c_w S_{wc} + c_f}{1 - Swc}- (W_p B_w - W_i B_w - G_{gi} B_{gi} - W_e B_w)

For use in the code to find Pres:

Pres = Pi - (Np * Bo + Np * (Rp - Rs) * Bg + (Wp * Bw - Wi * Bw - Ggi * Bgi - We * Bw) - (N * (Bo - Boi) + N * (Rsi - Rs) * Bg + m * N * Boi * (Bg / Bgi - 1))) * (1 - Swc) / (N * (1 + m) * Boi * (cw * Swc + cf))

For use in the code to find Np:

Np = (N * (Bo - Boi) + N * (Rsi - Rs) * Bg + m * N * Boi * (Bg / Bgi - 1) + N * (1 + m) * Boi * (Pi - Pres) * (cw * Swc + cf) / (1 - Swc) - (Wp * Bw - Wi * Bw - Ggi * Bgi - We * Bw)) / (Bo + (Rp - Rs) * Bg)

Discussion

One of the consistently best correlations ...
— Michael Economides et al[2]

See also

P/Z plot

Nomenclature

 B_g = gas formation volume factor, ft3/scf
 B_{gi} = initial gas formation volume factor, ft3/scf
 GIIP = gas initially in place, scf
 G_p = cumulative gas produced, scf

References

  1. 1.0 1.1 Dake, L.P. (1978). Fundamentals of Reservoir Engineering. Amsterdam, Hetherlands: Elsevier Science. ISBN 0-444-41830-X. 
  2. Dake, L.P. (1994). The Practice of Reservoir Engineering. Amsterdam, Hetherlands: Elsevier Science. ISBN 0-444-88538-2.