Presented By Dr. Youness El Fadili January 31th 2016 · Dr. Youness El Fadili January 31th 2016....
Transcript of Presented By Dr. Youness El Fadili January 31th 2016 · Dr. Youness El Fadili January 31th 2016....
Presented ByDr. Youness El Fadili
January 31th 2016
Outline
Introduction
Objective
Critical rate definition
Theory and development of New model
Application and comparison of the New model
Experimental setup
Experimental results
Conclusion and Recommendations
What is Liquid Loading
3
CR
Loading
Intermitting
Loaded
Flowing
Pro
du
ctio
n R
ate
Time
Effects of Liquid Loading
Potential EUR 700 MMscf.Potential revenue $2.1MM
P&A candidate
Unstable production
Ga
s (M
scf/
d)
Ga
s (M
scf/
d)
TP
, C
P,
Psc
(psi
g)
Psc
(psi
g)
Potential EUR 234 MMscf. Potential revenue $0.71M.
Basis of Droplet Model
5
Force Balance
Drag
Gravity
Droplets fall at below critical velocity condition
Vertical Flow Patterns
𝑊𝑒 =𝜌𝑔 𝑑𝑝 𝑉𝑐
2
𝜎 × 𝑔𝑐
𝑞𝑐 =3.067 𝑃 𝐴 𝑉𝑐
𝑇 × 𝑍
𝑉𝑐 = 4
3 𝑔
l− 𝜌𝑔
𝜌𝑔 𝑑𝑝
𝐶𝑑
𝑉𝑐 = 1.593 𝜌𝑙 − 𝜌𝑔
𝜌𝑔2
𝜎
14
Droplet Model and its Evolution
30 Coleman
60 Turner
lbf/ft=6.852 10-5
dyne/cm
• Particle Terminal Velocity
• Critical Gas Velocity, ft/sec
• Critical Gas Rate MMscf/d
Particle Reynolds Number (NRep)
Cd
Modified Droplet Model, Horizontal Wells
Belfroid et al. (2008): Turner and Fiedler shape function
Veeken et al. (2009): observed rate and Turner Ratio, TR
where, a = -2.17 x 10-6, b = 3.09x10-3, and c = 1.02
𝑞𝑐 = 1 − 𝑏𝑄𝑇𝑢𝑟𝑛𝑒 𝑟 − 𝑏𝑄𝑇𝑢𝑟𝑛𝑒𝑟 − 1 2 + 4𝑎. 𝑐.𝑄𝑇𝑢𝑟𝑛𝑒𝑟
2 0.5
2𝑎.𝑄𝑇𝑢𝑟𝑛𝑒𝑟
𝑉𝑐 = 1.593 𝜌𝑙 − 𝜌𝑔
𝜌𝑔2
𝜎
14
× 𝑠𝑖𝑛 1.7𝜔
0.38
0.78
Horizontal Wells Geometry
Effect of Geometry on Flow
BUR 2
BUR 1
Liquid droplets entrained
in gas stream
Flow conduit
Liquid droplets
Fractional Energy Loss
y = 0.0406x0.7537
R² = 0.982
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 10 20 30 40 50 60 70 80 90
(Vi2 -
Vb
2 )/V
i2
Angle of Impact (qi)
Jayaratne and Mason (1964)
Regression Curve
Maximum Limit
0.95
Fd,mup = Fd,befo re − Fd,after = (1 − 𝛼2)Fd,before
𝑉𝑏𝑉𝑐
= 𝛼 𝑜𝑟 𝑉𝑏 = 𝛼𝑉𝑐
𝑉𝑐2 − 𝑉𝑏
2
𝑉𝑐2
= 0.0406 ∗ 𝜃𝑖0.7537
Model Development
1. Determine the fractional energy loss
2. Calculate the restitution velocity
3. Makeup Drag
Fd,after =1
2𝑔𝑐𝑔𝐶𝑑𝐴𝑑(𝛼𝑉𝑐)2
hence,
Model Development Cont.
𝑉𝑒𝑓𝑓 = 𝑉𝑐 + 𝑉𝑚𝑢𝑝
𝑉𝑚𝑢𝑝2 = (1 − 𝛼2)𝑉𝐶
2
𝑉𝑚𝑢𝑝 = 𝛽𝑉𝐶
𝛽 = (1 − 𝛼2)
where, b the effective velocity factor
𝑞𝑒𝑓𝑓 =3.067𝑃𝐴𝑉𝑒𝑓𝑓
𝑇𝑍
4. Makeup velocity
5. the effective velocity is:
6. Finally, the effective rate to keep the well from loading up is:
Example
It is desired to determine the effective gas rate for a horizontal well with the following
characteristics:
-Tubing pressure = 100 psi
-Temperature = 80 oF
-Tubing size = 2 7/8”
- Maximum BUR = 20 o/100 ft
- Water gravity1.07
- Gas gravity = 0.64
-Z factor = 0.95
-Surface tension= 60 dynes/cm
𝑉𝑏 = 0.78𝑉𝑐 ∴ 𝑉𝑔 → 0.78𝑉𝐶
𝑉𝑐2 − 𝑉𝑏
2
𝑉𝑐2
= 0.0406 ∗ 200.7537 = 0.388
Example
Determine the fractional energy loss
Calculate the restitution velocity
Makeup velocity
Makeup Drag
Thus, the effective velocity and rate to keep the well from loading up is:
1 −𝑉𝑏
2
𝑉𝑐2 = 0.388
Fd,mup = Fd,before − Fd,after = 0.392Fd,before
𝑉𝑒𝑓𝑓 = 1.6258𝑉𝑐
𝑉𝑒𝑓𝑓 = 35.47 𝑓𝑡/𝑠𝑒𝑐
𝑞𝑒𝑓𝑓 = 689 𝑀𝑠𝑐𝑓/𝑑
For comparison,
- Coleman rate is 425 Mscf/d
- Turner rate is 505 Mscf/d
Compressor Performance Analysis
3306 TAA Gas Rate in Mscf/d at different P discharge
Psuc @ Pd 1200 psi @ Pd 1100 psi @ Pd 1050 psi
60 650 650 650
50 546 550 550
50 657 650 647
40 550 520 517
40 619 625 629
16
3306 NA Gas Rate in Mscf/d at different P discharge
Psuc @ Pd 1200 psi @ Pd 1100 psi @ Pd 1050 psi
60 518 522 523
50 435 438 440
50 549 565 575
40 433 453 452
40 526 532 546
Spacer
400
450
500
550
600
650
700
60 50 50 40 40
Ga
s R
ate
(m
scf/
d)
Suction Pressure (psig)
3306 NA vs. TAA
@ Pd 1200 psi
@ Pd 1100 psi
@ Pd 1050 psi
@ Pd 1200 psi
@ Pd 1100 psi
@ Pd 1050 psi
600
700
800
900
1000
1100
1200
40 45 50 55 60 65
Ga
s R
ate
(m
scf/
d)
Suction Pressure (psig)
Volumetric Efficiency Comparison
'@ Pd 600 psi
'@ Pd 1050 psi
3306 TAA Gas Rate in Mscf/d at different P discharge
Psuc '@ Pd 600 psi '@ Pd 1050 psi
60 1121 650
50 983 647
40 805 629
- BPV: Back Pressure Valve. BV: Ball Valve MV: Motor Valve. CV: Check Valve. FRV: Fuel Recycle Valve. CTB: Central Tank Battery.
Experimental Setup
Formation
Bypass
CTB
Sales line MeterLP ~ 30 psi
Compressor
CV
Suction Controller Valve set at 40 psi
Liquids line from compressor scrubber to CTB
CV
MV 70 psi
CV
CV
FRV25 psi
Gas R
ecycle Lin
e
BPV
CV BV
BV
BV
BV
BV
BV
BV
Supply Gas
CV
BV 3 Phase Separator
BV
Injection Meter
Casing
Tubing
Byp
ass
Choke
3 Phase Test Separator with recycle line
Injection Gas Meter
3 Stages Dual Reciprocating Compressor: Front View
3 Stages Dual Reciprocating Compressor: Side View
Common Operational Issues
Causes Solutions
Max discharge- The volume of liquid accumulated in the wellbore is high.- Malfunctioning discharge valve.
- Reduce liquid volume in the well, i.e.swabbing, pushing fluid back to formation- Check the discharge valve for proper functioning.
Low suction
- Low gas supply to compressor. - Malfunctioning suction valve.- Suction line leak.
- Increase supply gas by adding a recirculation line - Check the suction valve for proper functioning.- Check suction line for leaks- Add fuel recycle valve
22
Horizontal Wells Examples
Horizontal
Well 1
Horizontal
Well 2
Pro
duct
ion D
ata
qo (BO/d) 2.39 61.50
qw (BW/d) 19.52 2.00
qg (Mscf/d) 273 181
FTP (psia) 110 92
Tsurface (oF) 80 60
Tformation (oF) 223 130
OGR (bbls/MMscf) 3.3 90
WGR (bbls/MMscf) 27 3
WOR 8.18 0.03
Tubula
r D
ata
Tubing OD (in.) 2.875 2.875
d (in.) 2.441 2.441
Casing OD (in.) 5.5 7
Casing ID (in.) 4.892 6.276
Liner Top (ft) 12,950 8,177
Liner OD (in.) 3.5 4.5
Liner ID (in.) 2.992 4
Absolute roughness (in.) 0.0006 0.0006
Depth (ft) 12,863 8,306
Max BUR o/100 ft 12.34 18.34
PV
T
API 65 40
N2 Mol % 0 1.686
CO2 Mol % 0 0.843
H2S Mol % 0 0.003
Specific gas gravity 0.65 0.7
Specific water gravity gw 1.02 1.02
Specific oil gravity go 0.72 0.83
Identifying Critical Gas Rate: Horizontal Well 1
0
5
10
15
20
25
30
35
40
45
50
240
245
250
255
260
265
270
275
280
285
290
0 5 10 15 20 25 30 35 40
Inje
cte
d G
as
(Msc
f/d
), W
ate
r (B
WP
D)
Pro
du
ced
Ga
s (M
scf/
d)
Time (Days)
Gas (Mscf/d)
Injected Gas * 10
Water (BWPD)
Actual Lift Rate, Mscf/ d 730
Absolute Percent
Deviation, %
Coleman model Mscf/ d 455 38
Turner model, Mscf/ d 541 26
New Model, Mscf/ d 692 5
Belfroid model, Mscf/ d 495 32
Veeken model, Mscf/ d 579 21
Observed critical gas rates and percent deviation for horizontal well 1
Horizontal Well 1
26
40
45
50
55
60
65
70
400
450
500
550
600
650
700
750
800
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
To
tal
Flu
id (
BF
PD
)
To
tal
Ga
s (M
scf/
d)
Days
Total Gas (Mscf/d)
Fluid (BFPD)
Identifying Critical Gas Rate: Horizontal Well 2
Observed critical gas rates and percent deviation for horizontal well 2
27
Actual Lift Rate, Mscf/ d 684
Absolute Percent
Deviation, %
Coleman model Mscf/ d 404 41
Turner model, Mscf/ d 481 30
New Model, Mscf/ d 648 5
Belfroid model, Mscf/ d 506 26
Veeken model, Mscf/ d 512 25
Horizontal Well 2
Gradient
28
400
500
600
700
800
900
1000
1100
400
410
420
430
440
450
460
470
480
490
500
8:24:00 9:36:00 10:48:00 12:00:00 13:12:00 14:24:00 15:36:00 16:48:00 18:00:00
To
tal
Ga
s (M
scf/
d)
FB
HP
(p
sig
)
Time
FBHP (psig)
Total Gas (mscf/d)
650 to 720 Mscf/d rate yield lowest BHFP
Compressor
shut downs
Unstable BHP indicating
subcritical condition even at
rates proposed by other models
Don’t Set and Forget: Dynamic Operation
Don’t Set and Forget: Dynamic Operation
Conclusions & Recommendations
1. The new model accounts for the effects of wellbore geometry on liquid loading and predicts
the critical gas rate for horizontal and deviated wells.
2. Experimental work with 2 horizontal wells showed the new model prediction is within 5%
from actual.
3. Conventional vertical models should not be used for horizontal and deviated wells.
4. In vertical wells, the new model collapses to Coleman model.
5. The new model yields best results for gas rates less than 10,000 Mscf/d and for BUR’s
between 3o and 30o/100 ft.
6. Don’t set and forget. Optimization through surveillance with good automation setup.
References
Questions??
Youness El Fadili, Subhash Shah “A new model for predicting critical gas rate in horizontal and deviated wells”, Journal of Petroleum Science and Engineering, December 3rd 2016. http://dx.doi.org/10.1016/j.petrol.2016.11.038