Difference between revisions of "Oil Material Balance"
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| + | Equating all underground withdrawals to the sum of the volume changes: | ||
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| + | Np * Bo + Np * (Rp - Rs) * Bg = N * (Bo - Boi) + N * (Rsi - Rs) * Bg + m * N * Boi * (Bg / Bgi - 1) + (Pi - Pres)* N * (1 + m) * Boi * (cw * Swc + cf) / (1 - Swc) - (Wp * Bw - Wi * Bw - Ggi * Bgi - We * Bw) | ||
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)) | 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)) | ||
Revision as of 12:25, 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:
Np * Bo + Np * (Rp - Rs) * Bg = N * (Bo - Boi) + N * (Rsi - Rs) * Bg + m * N * Boi * (Bg / Bgi - 1) + (Pi - Pres)* N * (1 + m) * Boi * (cw * Swc + cf) / (1 - Swc) - (Wp * Bw - Wi * Bw - Ggi * Bgi - We * Bw)
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))
See also
Nomenclature
= gas formation volume factor, ft3/scf
= initial gas formation volume factor, ft3/scf
= gas initially in place, scf
= cumulative gas produced, scf
References
- ↑ Dake, L.P. (1978). Fundamentals of reservoir engineering. Amsterdam, Hetherlands: Elsevier Science. ISBN 0-444-41830-X.
