1097 yessica prieto - flomeko2019flomeko2019.lnec.pt/proceedings/1097 yessica prieto.pdffigure...
TRANSCRIPT
1
Outline
I – Background
II – Electrical Capacitance Measurement (ECT)
III – Experimental results
IV – Conclusions
2
Multiphase flow measurement in the Oil & Gas Industry
Oil & Gas industry
Multiphase Flow Measurement
Electrical Tomography
ECT
• Advanced oil and gas production techniques
• Challenges:o Marginal Fields o Development costs o Energy efficiency
Figure source: EIA (2019, pg.1), IEA (2017, pg.1), Rodrigue, J. (2016, pg. 1.), & BP (2018, pg.14.)
3
0
5
10
15
20
25
30
35
40
0
20
40
60
80
100
120
140
160
Ba
rre
l p
ric
e i
n U
SD
YearR
eso
urc
es
in t
ho
usa
nd
s o
f m
illio
n b
arr
els
Pro
du
cti
on
in m
illio
n b
arr
els
Discovered Resources WTI oil price World Annual Oil Production
100
120
140
160
Re
sou
rce
s in
th
ou
san
ds
of
mill
ion
ba
rre
ls
Pro
du
cti
on
in m
illio
n b
arr
els
Ba
rre
l p
ric
e i
n U
SD
Oil & Gas industry
Multiphase Flow Measurement
Electrical Tomography
ECT
1993 1998 2003 2008 2013 2018 2023
0
2000
4000
6000
8000
10000
12000
0
2000
4000
6000
8000
10000
12000
Nu
mb
er
of
MFM
un
its
Glo
ba
l Ma
rke
t (U
SD M
illio
n)
Global MFM market Installed MFM units
Adapted from Falcone, G and Harrison, B 2011:4 and kbv research [online: https://www.kbvresearch.com/flow-meters-market]
• Mitigation role of technology
• MFM solutions:o Production allocationo Deep water meteringo Real time well monitoringo Survey reservoir life o Small footprint
Flow separation prior to
measurementDirect measurement
of phase fraction and velocity
• Full separation
• Partial Separation• Tomography
Multiphase flow measurement in the Oil & Gas Industry
4
Oil & Gas industry
Multiphase Flow Measurement
Electrical Tomography
ECT
Opportunities:• Non-intrusive• Non-radioactive• No moving parts• Fast• Low cost
Multiphase flow measurement in the Oil & Gas Industry
5
Source: International Society for Industrial Process Tomography [online: https://www.isipt.org/]
0%
5%
10%
15%
20%
25%
30%
35%
2002 2004 2006 2008 2010 2012 2014 2016 2018 2020
Re
sea
rch
orie
nte
d t
o M
FM
in t
he
fie
ld o
f So
ft T
om
og
rap
hy
Year
Oil & Gas industry
Multiphase Flow Measurement
Electrical Tomography
ECT
Soft-field tomography technology based on measurement of the electric properties of the fluid phases.
Industrial experiences:• flow pattern identification• volumetric rates, • velocity measurement • hydrocarbon phase separation• tankers loading, • Collapse of oil foams.
Multiphase flow measurement in the Oil & Gas Industry
6
Photograph courtesy of Atout Process Ltd
ECT: Principle of operation
Figure adapted from Process Tomography Ltd. PTL300e operating manual (2018, AN1-22)
7
Method
Tx1
Rx2
M1Rx3
M2
Rx4
M3
Rx5
M4
Rx6
M5Rx7
M6
Rx8
M7
Oil
Water
ECT-8
• Working fluids: oil → εr=2.2
water → εr=80
• Water cuts → 25% - 75%
• Flow direction: Horizontal
• Full ECT system vs. capacitance measurements from a single sensor pair
• Water cut determination from capacitance metering (for the first time!)
8
Illustration of the ECT sensor positions around a horizontal pipe
Tx1
Rx2
M1Rx3
M2
Rx4
M3
Rx5
M4
Rx6
M5
Rx7
M6
Rx8
M7
Oil
Water
ECT-2
Experimental facilities
9
Photograph courtesy of iPhase Ltd
ECT-8: Single-phase and low water cut measurements
• The results show two clear different levels of relative permittivity for single-phase
flows (air and oil)
• As the water content increases in the oil-
water flow from 25% to 35%, the measured relative permittivity also increases.
• The multiphase flow measurements show relative permittivity larger than the single-
phase flows, with an increasing difference as the water cut increases.
10
ECT-8: Multi-phase flow measurements
Tx1
Rx2
M1Rx3
M2
Rx4
M3
Rx5
M4
Rx6
M5Rx7
M6
Rx8
M7
Oil
Water
ECT-8
• Increase in water cut results in a higher overall mixture permittivity
and inter-electrode capacitance for water cuts between 25% and 45%.
• For water contents above 45%, the trend shifts and a slight decrease is evident as the water content
continues to increase.
11
ECT-2: Multi-phase flow measurements
Tx1
Rx2
M1Rx3
M2
Rx4
M3
Rx5
M4
Rx6
M5
Rx7
M6
Rx8
M7
Oil
Water
ECT-2
• Consistent increase in capacitance with increasing water cut throughout
all oil-water ratios.
• Capacitance measurements show
improved signal to noise ratio with decreasing water content.
12
ECT: Multi-phase flow measurements
13
���
Water cut determination
��� � 2931 � 73570
�
�
• It was determined that for oil flow rates ranging from 3 to 9m3/hr, the
capacitance varied with water cuts at a ratio given by:
where ��� is the capacitance in pF measured from the electrode pair Tx1-Rx4 and � is the water volumetric fraction
expressed in percentage.
• The developed correlation describes over
96% of the variability of the measurement with an overall fitting inside the ±10% deviation range.
14
Conclusions
• The 8-sensor ECT meter was able to recognise changes in liquid-liquid concentration for low water ratios.
• Electric capacitance meters are sensitive to changes in flow concentrations regardless of the conductive properties of one of the phases or its volumetric fraction.
• Water cut prediction from single-electrode pair measurements provides an uncertainty range below 10% over a spectrum of water cuts from 25% to 75%.
15
