Page 194 - Fundamentals of Enhanced Oil and Gas Recovery

182 Forough Ameli et al.

6
6
W s,eq 5 (2.854 3 10 26 ) (489.17 3 10 ) (993.83) 5 1.388 3 10 bbl.
F os 5 239198/1387500 5 0.172 bbl oil/bbl steam,
F so 5 5.81 bbl steam/bbl oil.

PROBLEMS

P1. Determine the heat loss from the wellbore from a 2-in. tube after 80 days of
injection. The depth of the formation is 900 ft.The steam quality is 83%. The

feed-water rate is 1000 B/D and the reservoir temperature is 390 F.
1. Determine the heat-loss rate from the tubing.
2. Calculate the heat-injection rate at surface.
3. How much heat is heat loss from the wellbore?
4. Determine the quality of the saturated steam applied for injection
(Table TP.1).
P2. The distribution line in Fig. P.1 is 3-in. [3.5-in. outer diameter (OD)]. The insu-
lation thickness is 2 in. of magnesia silicate covered by a layer of aluminum
(ε A1 5 0.77). The rate, pressure, and temperature of the stream injected are
350 B/D, 1650 psia, and 620 F. Mean ambient temperature is 100 F. The veloc-

ity of wind is 10 mi/h, and temperature of the subsurface is 70 F.
1. Determine the heat-loss rate of the distribution line.
2. Calculate the steam quality at wellhead as steam-generator quality is 0.85.

Table TP.1 Steam Injection Conditions
Mean subsurface temperature ( F) 70

Geothermal gradient ( F/ft) 0.02

Overall heat-transfer coefficient (Btu/D ft F) 33
Tubing ID (in.) 2
Drill hole diameter (in.) 7
Thermal conductivity of Earth (Btu/D ft F) 36

2
Thermal diffusivity of Earth (ft /D) 0.96

Figure P.1 Steam distribution system.