Page 210 - Petroleum Production Engineering, A Computer-Assisted Approach

Guo, Boyun / Computer Assited Petroleum Production Engg 0750682701_chap13 Final Proof page 206 3.1.2007 9:07pm Compositor Name: SJoearun

13/206 ARTIFICIAL LIFT METHODS
data, calculate the required output pressure of the 13.12 Size port for the data given below:
compression station:
Upstream pressure: 950 psia
Gas-specific gravity (g g ): 0.75 Downstream pressure
Base temperature (T b ): 60 8F for subsonic flow: 550 psia
Base pressure ( p b ): 14.7 psia. Tubing ID: 1.995 in.
13.4 An oil field has 32 oil wells defined in Problem 13.2. Gas rate: 1,500 Mscf/day
The gas lift gas at the central compressor station is Gas specific gravity: 0.70 (1 for air)
first pumped to four injection manifolds with 4-in. Gas specific heat ratio: 1.3
ID, 1.5-mile lines and then distributed to the well- Upstream temperature: 80 8F
heads with 4-in. ID, 0.4-mile lines. Given the fol- Gas viscosity: 0.03 cp
lowing data, calculate the required output pressure Choke discharge coefficient: 0.6
of compression station: Use Otis Spreadmaster Valve
Gas-specific gravity (g g ): 0.70 13.13 Design gas lift valves using the following data:
Base temperature (T b ): 60 8F
Base pressure ( p b ): 14.7 psia Pay zone depth: 5,500 ft
Casing size and weight: 7 in., 23 lb
3
13.5 For a reciprocating compressor, calculate the theo- Tubing 2 ⁄ 8 in.,
retical and brake horsepower required to compress 4.7 lb (1.995-in. ID):
50 MMcfd of a 0.7-gravity natural gas from Liquid level surface:
200 psia and 70 8F to 2,500 psia. If intercoolers Kill fluid gradient: 0.4 psi/ft
cool the gas to 90 8F, what is the heat load on the Gas gravity: 0.65
intercoolers and what is the final gas temperature? Bottom-hole temperature: 150 8F
Assuming the overall efficiency is 0.75. Temperature surface flowing: 80 8F
13.6 For a reciprocating compressor, calculate the theo- Injection depth: 5,300 ft
retical and brake horsepower required to compress The minimum tubing pressure 550 psi
30 MMcfd of a 0.65-gravity natural gas from 100 psia at injection point:
and 70 8F to 2,000 psia. If intercoolers and endcoolers Pressure kickoff: 950 psi
cool the gas to 90 8F, what is the heat load on the Pressure surface operating: 900 psi
coolers? Assuming the overall efficiency is 0.80. Pressure of wellhead: 150 psi
13.7 For a centrifugal compressor, use the following data Tubing pressure margin at surface: 200 psi
to calculate required input horsepower and polytro- Casing pressure margin: 0 psi
1
pic head: Otis 1 ⁄ 2 -in. OD valve with
Gas-specific gravity: 0.70 1 ⁄ 2 -in. diameter seat: R ¼ 0:2562
Gas-specific heat ratio: 1.30
Gas flow rate: 50 MMscfd at 13.14 Design gas lift valves using the following data:
14.7 psia and 60 8F Pay zone depth: 7,500 ft
Inlet pressure: 200 psia Casing size and weight: 7 in., 23 lb
Inlet temperature: 70 8F Tubing 2 ⁄ 8 -in.,
3
Discharge pressure: 500 psia 4.7 lb (1.995 in. ID):
Polytropicefficiency: E p ¼ 0:61 þ 0:03 log (q 1 )
Liquid level surface:
Kill fluid gradient: 0.4 psi/ft
13.8 For the data given in Problem 13.7, calculate the
Gas gravity: 0.70
required brake horsepower if a reciprocating com-
Bottom-hole temperature: 160 8F
pressor is used.
13.9 Only 1 MMscf/day of lift gas is available for the well Temperature surface flowing: 90 8F
described in Problem 13.3. If 1,000 psia is available Injection depth: 7,300 ft
to kick off the well and then a steady injection The minimum tubing pressure at 650 psi
pressure of 800 psia is maintained for gas lift oper- injection point:
ation against a wellhead pressure of 130 psia, design Pressure kickoff: 1,050 psi
locations of unloading and operating valves. As- Pressure surface operating: 950 psi
sume a casing pressure margin of 0 psi. Pressure of wellhead: 150 psi
13.10 An unlimited amount of lift gas is available for the Tubing pressure margin at surface: 200 psi
well described in Problem 13.4. If 1,100 psia is avail- Casing pressure margin: 10 psi
able to kick off the well and then a steady injection Otis 1-in. OD valve with
1 ⁄ 2 -in. diameter seat: R = 0.1942
pressure of 900 psia is maintained for gas lift oper-
ation against a wellhead pressure of 150 psia, design 13.15 Determine the gas lift gas requirement for the
locations of unloading and operating valves. following well data:
Assume a casing pressure margin of 50 psi.
Depth ¼ 7,500 ft
13.11 Size port for the data given below:
p so ¼ 800 psig
3
Upstream pressure: 950 psia 2 ⁄ 8 -in. tubing ¼ 1:995 in: ID
1
Downstream pressure 650 psia 5 ⁄ 2 -in., 20-lb/ft casing
for subsonic flow: No water production
Tubing ID: 2.259 in. g o ¼ 0:8762,30 API
Gas rate: 2,000 Mscf/day BHP (SI) ¼ 1,800 psig
Gas-specific gravity: 0.70 (1 for air) PI ¼ 0:125 bbl=day=psi
Gas-specific heat ratio: 1.3 p tf ¼ 50 psig

Upstream temperature: 100 8F t av ¼ 120 F
Gas viscosity: 0.02 cp Cycle time: 45 minutes
Choke discharge coefficient: 0.6 Desired production: 150 bbl/day
Use Otis Spreadmaster Valve g g ¼ 0:70