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Reservoir EngineeringWaterflooding and EOR

In-Situ Combustion Oil Production - Nelson and McNeil Formula

Np=7758ϕ[Vr(SiSf)+0.4(VpVr)Si]N_p=7758\phi\left[V_r(S_i-S_f)+0.4(V_p-V_r)S_i\right]

In-Situ Combustion Oil Production - Nelson and McNeil calculates cumulative oil production for waterflooding and eor workflows in reservoir engineering.

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How engineers use this formula

Use this formula when the listed inputs (V_r, S_i, S_f, V_p, phi) are known and the assumptions behind the cited waterflooding and eor relationship match the engineering case being checked.

Assumptions

  • Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
  • The declared units match the field-unit constants used in the formula.
  • The cited formula applies to the selected petroleum engineering workflow.

Limitations

  • The calculation does not replace a full engineering model or operating procedure.
  • Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.

Common mistakes

  • Mixing unit systems without converting the inputs.
  • Using default example values as field recommendations.
  • Applying the formula outside the source assumptions.

Default example

Using the default inputs, N_p equals 107,836.2 bbl.

V_racre-ft

100

S_ifraction

0.65

S_ffraction

0.25

V_pacre-ft

160

phifraction

0.25

Inputs

V_r

acre-ft

Volume of Reservoir Burned

S_i

fraction

Initial Oil Saturation

S_f

fraction

Oil Saturation After Combustion

V_p

acre-ft

Pattern Volume

phi

fraction

Porosity

Outputs

N_p

bbl

Cumulative Oil Production

phi

fraction

Porosity

V_p

acre-ft

Pattern Volume

V_r

acre-ft

Volume of Reservoir Burned

S_i

fraction

Initial Oil Saturation

S_f

fraction

Oil Saturation After Combustion

Source and review

reviewed

Enhanced Oil Recovery, Green, D.W., Willhite, G.P.

Green, D.W. and Willhite, G.P. Enhanced Oil Recovery, Page 395.

Source

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