Page 103 - Petroleum Production Engineering, A Computer-Assisted Approach

Guo, Boyun / Computer Assited Petroleum Production Engg 0750682701_chap07 Final Proof page 95 3.1.2007 8:47pm Compositor Name: SJoearun

FORECAST OF WELL PRODUCTION 7/95
tarner, j. How different size gas caps and pressure main- 7.3 For the oil reservoir described in Problem 7.2, predict oil
tenance programs affect amount of recoverable oil. Oil production rate and cumulative oil production over the
Weekly June 12, 1944;144:32–34. time interval during which reservoir pressure declines from
bubble-point pressure to abandonment reservoir pressure
of 2,000. The following additional data are given:
Problems (4:5S g þ0:3)
k ro ¼ 10
7.1 Suppose an oil reservoir can produce under transient k rg ¼ 0:75S 1:8
flow for the next 1 month. Predict oil production rate g
and cumulative oil production over the 1 month using
the following data: 7.4 Assume that a 0.328-ft radius well in a gas reservoir
drains gas from an area of 40 acres at depth 8,000 ft
through a 2.441 inside diameter (ID) tubing against a
wellhead pressure 500 psia. The reservoir has a net pay
of 78 ft, porosity of 0.14, permeability of 0.17 md, and
Reservoir porosity (f): 0.25 water saturation of 0.27. The initial reservoir pressure
Effective horizontal 50 md is 4,613 psia. Reservoir temperature is 180 8F. Gas-
permeability (k): specific gravity is 0.65. The total system compressibility
1
Pay zone thickness (h): 75 ft is 0:00015 psi . Both Darcy and non-Darcy skin are
Reservoir pressure (p i ): 5000 psia negligible. Considering both transient and pseudo–
Oil formation volume 1.3 rb/stb steady-state flow periods, generate a gas production
factor (B o ): forecast until the reservoir pressure drops to 3,600 psia.
Total reservoir 0.000012 psi 1 7.5 Use the following data and develop a forecast of a gas
compressibility (c t ): well production during the transient flow period:
Wellbore radius (r w ): 0.328 ft
Skin factor (S): 0 Reservoir depth: 9,000 ft
Well depth (H): 8,000 ft Initial reservoir pressure: 4,400 psia
Tubing inner diameter (d): 2.041 Reservoir temperature: 1708F
Oil gravity (API): 35 API Pay zone thickness: 60 ft
Oil viscosity (m o ): 1.3 cp Formation permeability: 0.25 md
Producing gas–liquid ratio: 400 scf/bbl Formation porosity: 0.15
Gas specific gravity (g g ): 0.7 air ¼ 1 Water saturation: 0.30
Flowing tubing head 500 psia Gas-specific gravity: 0.7 air ¼ 1
4
pressure (p hf ): Total compressibility: 1:6 10 psi 1
Flowing tubing head 120 8F Darcy skin factor: 0
temperature (T hf ): Non-Darcy flow coefficient: 0
Flowing temperature at 160 8F Drainage area: 40 acres
tubing shoe (T wf ): Wellbore radius: 0.328 ft
Water cut: 10% Tubing inner diameter: 2.441 in.
Interfacial tension (s): 30 dynes/cm Desired flowing bottom-hole
Specific gravity of water (g w ): 1.05 pressure: 1,100 psia
7.6 Use the following data and develop a forecast of a gas
well production after transient flow until the average
7.2 Suppose the reservoir described in Problem 7.1 begins reservoir pressure declines to 2,000 psia:
to produce oil under a pseudo–steady-state flow con-
dition immediately after the 1-month transient flow. If Reservoir depth: 8,000 ft
the bubble-point pressure is 4,000 psia, predict oil Initial reservoir pressure: 4,300 psia
production rate and cumulative oil production over Reservoir temperature: 1608F
the time interval before reservoir pressure declines to Pay zone thickness: 50 ft
bubble-point pressure. Formation permeability: 0.20 md
Formation porosity: 0.15
Water saturation: 0.30
Gas-specific gravity: 0.7 air ¼ 1
4
Total compressibility: 1:6 10 psi 1
Reservoir Darcy skin factor: 0
pressure Non-Darcy flow coefficient: 0
(psia) B o (rb/stb) B g (rb/scf) R s (rb/scf) m g (cp) Drainage area: 160 acres
Wellbore radius: 0.328 ft
4,000 1.300 6.80E 04 940 0.015 Tubing inner diameter: 1.995 in.
3,800 1.275 7.00E 04 920 0.015 Desired flowing bottom-hole
3,600 1.250 7.20E 04 870 0.015 pressure: 1,200 psia
3,400 1.225 7.40E 04 830 0.015 7.7 Use the following data and develop a forecast of a gas
3,200 1.200 8.00E 04 780 0.015 well production after transient flow until the average
3,000 1.175 8.20E 04 740 0.015 reservoir pressure declines to 2,000 psia:
2,800 1.150 8.50E 04 700 0.015
2,600 1.125 9.00E 04 660 0.015 Reservoir depth: 8,000 ft
2,400 1.120 9.50E 04 620 0.015 Initial reservoir pressure: 4,300 psia
2,200 1.115 1.00E 03 580 0.015 Reservoir temperature: 1608F
2,000 1.110 1.10E 03 540 0.015 Pay zone thickness: 50 ft
Formation permeability: 0.20 md