Total produced or injected flowrate of all fluids across the well-reservoir contact with the volumes measured at the sandface temperature and pressure conditions.
Usually abbreviated as q_t or qB.
The concept applies both to producing and injecting wells.
The main purpose of describing the intakes and offtakes in terms of the Total sandface flowrate q_t is that it measures the actual flowing volumes in porous formations and as such directly relate to reservoir pressure.
For volatile oil fluid model the total sandface flowrate is related to surface flowrates of fluid components as:
(1) | q_t = q_w + q_o + q_g = B_w \, q_W + (B_o - R_s \, B_g) \, q_O + (B_g - R_v \, B_o) \, q_G |
where
q_w, \, q_o, \, q_g | water, oil and gas sandface flowrates |
q_W, \, q_O, \, q_G | water, crude oil and natural gas surface flowrates |
B_w, \, B_o, \, B_g | formation volume factors between separator and sandface pressure/temperature conditions |
R_s, \, R_v | Solution GOR and Vaporized oil ratio at sandface pressure/temperature conditions |
(2) | q_t = \left[ B_w Y_w + \left[ (B_o - R_s B_g] + (B_g - R_v B_o) \, GOR \right] \cdot (1-Y_w) \right] \cdot q_L |
\displaystyle Y_w = \frac{q_W}{q_L} | Production Water Cut |
---|---|
\displaystyle GOR= \frac{q_G}{q_O} | Production Gas-Oil-Ratio |
It simplifies for the Black Oil model to:
(3) | q_t = q_w + q_o + q_g = B_w \, q_W + \left( B_o + \left( \frac{GOR}{R_s} -1 \right) \cdot R_s \, B_g \right) \, q_O |
(4) | q_t = B_w \, q_W + (B_o - R_s \, B_g) \, q_O + B_g \, q_G = B_w \, q_W + B_o \, q_O + B_g ( q_G - R_s \, q_O ) |
and simplifies further down to production from undersaturated reservoir as:
(5) | q_t = B_w \, q_W + B_o \, q_O |
and even simpler for single-phase fluid (water, dead oil or dry gas) with surface flow rate q and formation volume factor B as below:
(6) | q_t = q \cdot B |
See Also
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Well Testing (WT) / Flowrate Testing / Flowrate
[ Well & Reservoir Surveillance ]
[ Sandface flowrates ] [ Oil sandface flowrate ] [ Gas sandface flowrate ] [ Water sandface flowrate ]
[ Surface flowrates ] [ Oil surface flowrate ] [ Gas surface flowrate ] [ Water surface flowrate ] [ Liquid production rate ]
[ Non-linear multi-phase diffusion derivation @model ]