TECHNOLOGY FOR HIGH YIELD IMPROVEMENT IN PRODUCED WATER QUALITY
1. Andy Little
Lead Sales Engineer - Low Shear
High Yield Improvement in
Produced Water Quality &
Separation Efficiency
(without additional treatment)
2. Why develop a low shear control system
(produced water)
Water produced during oil and gas extraction operations
constitutes the industry’s most important waste stream on
the basis of volume. The oil and gas industry produces
approximately 14 billion bbl. of water annually.
Produced water is most often considered a waste.
Water handling practices must also be environmentally
protective or the operator could face regulatory action.
Source ALL Consulting LLC – Argonne National Laboratory & US D.O.E. 2004
What do we do with all this water?
• Offshore = water overboard, re-injection
• Onshore = evaporation ponds, agriculture, re-injection
3. Regulation (cleaner production)
Best Available Techniques Guidance Document on upstream hydrocarbon
exploration and production
(ISBN: 978-92-76-01443-0 / doi: 10.2779/607031 / KH-04-19-262-EN-N) Feb 2019
EPL - Environmental performance level
• Table 15.1 EPLs for Discharge to Surface Water or Land
Parameter Unit EPL
Total hydrocarbon content mg/l 10
• Table 23.1 EPLs Associated with the Application of BAT for the Management of Produced Water
Discharges Containing Hydrocarbons
New facilities EPL
Zero discharge* of oil in produced water or, where not appropriate**, minimisation of discharges as
defined for existing facilities
Existing facilities (monthly average) EPL
Minimisation of discharges to < 15 mg/L dispersed oil or, where not appropriate** < 30 mg/L
• Table 24.1 EPLs for Discharges to Sea of Hydrocarbons
Parameter EPL
Oil in water (OIW) discharged (monthly average) [8] 30 mg/L *
Oil in water (OIW) discharged (Machinery Space drainage) [1] 15 mg/L
* Per OIW discharge EPL for produced water, refer to Offshore Activity 7 (table 23.1)
4. Gravity Based Separation (Stokes Law)
• ddroplet influences terminal velocity (vt), of dispersed droplet
• ddroplet influences separation efficiency (performance) of existing vessels
• ddroplet influences retention time (by definition of vt)
Increased vt, = reduced retention time = increased capacity
𝑣𝑣𝑡𝑡 =
𝑔𝑔�𝑑𝑑2
𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑
�(|ρc – ρ d|)
18�µ𝑐𝑐
[m/s]
𝐻𝐻/𝑣𝑣𝑣𝑣 = Leff/𝑣𝑣h[m/s]
Mokveld Typhoon Valve System slide 13
5. ε = Mean energy dissipation rate per unit mass
ε = Ē/m where Ē is the turbulent energy dissipation rate, the rate at which the
turbulence energy is absorbed by breaking the eddies down into smaller and
smaller eddies until it is ultimately converted into heat by viscous forces (shear
forces exerted on the fluid)
Kundu 1990: Ē = Δ𝑃𝑃 ∗ 𝑄𝑄
Droplet breakup caused by energy dissipation
(viscous and inviscid/inertial shear forces)
Hinze (1955)
dmax = (Wecrit)3/5 * (σinterface/ρc)3/5 * ε -2/5
Davies (1985)
dmax = C*((4 * σinterface + ηd * µin) / ρc)3/5 * ε -2/5
Kolmogorov scale (1949)
λ0 = (η3/4 *ρc
3/4 ε -1/4 )
slide 5
Anne Finborud, Mark Faucher, Erik Sellman - SPE 56643 - 1999
6.9 13.8 20.7 27.6 34.5 41.3 48.3
bar
6. Droplet size reduced by shear forces
• Energy dissipation droplets breakup
• Main energy dissipation developed in valves (dP)
• Choke and control valves degrade oil-water separation and yet…
Mokveld Typhoon Valve System slide 6
8. Standard valve(s)
drilled hole cage
Other valve(s)
labyrinth type
Typical Droplet Distribution by Valves
Typhoon® Valve System
9. Mokveld Typhoon Valve System slide 9
Separator Type Technology Droplet Size Removal
API separator Gravity ~ min. 150 µm
Corrugated Plate / Tilted
Plate Interceptor
Gravity with coalesce ~ min. 40 – 50 µm
Horizontal IGF Gas flotation
(no flocculants)
~ min. 20 – 25 µm
Hydro-cyclones Centrifugal Force ~ min. 10 – 15 µm
Horizontal IGF Gas flotation
(with flocculants)
~ min. 5 µm
Filtration Adsorption / Barrier < 0.01 – 5 µm
Typical Droplet Distribution by Valves
10. Design Features
Mokveld Typhoon Valve System slide 10
Cage & Venturi:
• Increases volume engaged in energy dissipation
resulting in reduced shear forces
Flow Conditioner:
• Prevents rotation flow downstream of the valve
o Prevents erosion of the downstream piping
o Allows installation of instruments downstream the valve
Erosion Resistant:
• Angle & axial Typhoon Valve System tested at DNV-GL
• Design & correct material selection make valve suitable for severe
service
• Same erosion resistance as conventional Mokveld Choke Valve
Low shear trim
11. Typhoon Valve System (Laboratory Testing)
slide 12
Typhoon Valve System was tested with produced water made up of 13 different North Sea
crudes grades ranging from grades API 19 - 45
Conclusions:
• Systematic reduction of droplet break-up with all crudes
• Dv(x) on valve outlet typically 2 - 3 times larger with Typhoon Valve System
12. Prototype produced water testing
Mokveld Typhoon Valve System slide 13
Typhoon Valve System (Laboratory Testing)
Dv(10): Droplet size measurements for Inlet,
Typhoon Valve System and Standard Valve used
with 500 ppm crude oil in saltwater at 60°. The
flow rate is constant at 800 l/h giving a
pressure drop of 6.9 bar across the valves.
Dv(10) on valve outlet typically 2 - 3 times
larger with Typhoon Valve System
Dv(50): Droplet size measurements for Inlet,
Typhoon Valve System and Standard Valve used
with 500 ppm crude oil in salt water at 60°. The
flow rate is constant at 800 l/h giving a
pressure drop of 6.9 bar across the valves.
Dv(50) on valve outlet typically 2 times larger
with Typhoon Valve System
13. Typhoon Valve System Performance
Multiphase Flow Loop
• Systematic improvement of
water quality; by 60-90%
• Robust technology
Mokveld Typhoon System slide 14
Offshore Installation
• Challenging conditions (70 bar dP),
free gas
• Systematic improvement of
water quality; by 45%
14. Typhoon Valve System Performance
Offshore Installation
• 7months production
• Process conditions:
- 15-20 bar (218 – 290 psi)
differential pressure
- Low water cut
- High gas content (~97%)
• Systematic improvement
of water quality; 60%
Mokveld Typhoon System slide 15
Courtesy of Øyvind Hagen/Equinor
15. Typhoon Valve System Performance
Mokveld Typhoon System slide 16
Typhoon® Valve
System
Conventional
Globe valve
Flow rate [m³/hr] 52
Inlet pressure [bar-g] 4.5 - 5
Outlet pressure [bar-g] 2.3
Temperature [degC] 55
OiW out valve [ppm] 113 107.3
OiW out CFU [ppm] 38.6 49.8
PPM Removed: 74.4 57.5
Efficiency Improvement CFU ~ 23%
Measured by an operator in the Exmouth Sub-Basin
Western Australia , May 2019
“The Mokveld valve appeared to perform better, delivering a lower OiW ppm out of the CFU, for the same conditions.
This may be attributed to the reduced shear through the Mokveld valve and larger OiW droplet sizes allowing improving
separation.”
16. Separator Debottlenecking
• Conventional approach:
• Modification of separator internals
• Use of compact inline separation equipment
• Low Shear approach:
• Low Shear Choke valve/Level Control Valve
• Case study Brown Field:
• OiW and WiO d/s separator is as is
• Conservative 10 to 15% increase in
droplet size
• 20 to 30% increase in liquid flow rate
• Case study Green Field:
• 15 to 20% reduction in liquid
separation volume
0 5 10 15 20
OiW
[ppm]
Retention Time [min]
Water Quality as function of Retention Time
10% WC, 5 bar dP, GLR 12
Standard
Typhoon
0 5 10 15 20
OiW
[ppm]
Retention Time [min]
Water Quality as function of Retention Time
50% WC, 5 bar dP, GLR 12
Standard
Typhoon
17. Benefits – More oil recovered
Typhoon® Valve
System
Conventional
Globe valve
Flow rate [m³/hr] 52
Inlet pressure [bar-g] 4.5 - 5
Outlet pressure [bar-g] 2.3
Temperature [degC] 55
OiW out valve [ppm] 113 107.3
OiW out CFU [ppm] 38.6 49.8
PPM Removed: 74.4 57.5
Efficiency Improvement CFU ~ 23%
Measured by an operator in the Exmouth Sub-Basin
Western Australia , May 2019
slide 18
Input Imperial units (SG)
Water volume flow [bwpd] 144000
Oil density [SG] 0.940 19 [API]
OiW reduction [ ppm] 16.9 mg/L or mg/kgH2O
Crude oil price [US$/bbl] 100
Savings [bpd] 2.59 852.61 [lbs/d]
Savings [bbl/yr] 944.76
Savings [US$/yr] 94,476.14
$
18. Typhoon Valve System Benefits
• Increased production, extended
production, cleaner production,
smaller footprint
• Cost efficient way to improve separation,
increase separation capacity and/or
debottleneck separation systems
• Robust technology, enhanced separation
for a wide range of process and operating
conditions:
• High to low WC
• High to low dP
• High to low API
• Reduced requirements for chemicals or
heat
Mokveld Typhoon valve slide ‹#›
Produced water quality after bulk separation
Red – standard valve
Blue – Typhoon Valve System
19. Regulation (cleaner production)
Best Available Techniques Guidance Document on upstream hydrocarbon
exploration and production
(ISBN: 978-92-76-01443-0 / doi: 10.2779/607031 / KH-04-19-262-EN-N) Feb 2019
15.3 Best Available Techniques
The following techniques are considered BAT for produced water handling and management:
Treat produced water to reduce constituents with potential environmental impacts to below acceptable EPLs:
Consider technology to prevent shearing of oil droplets during treatment, such as low shear valves and low shear
pumps, since larger oil droplets are easier to separate.
23.3 Best Available Techniques
The following techniques are considered BAT for produced water handling and management in line with the
hierarchy of options addressed in Section 21.2 above:
Treat produced water to reduce constituents with potential for environmental impact to below acceptable EPLs:
Prevent prior formation of stabilised emulsions in produced water, which are typically the most difficult to treat
with produced water technologies. Formation prevention can be reduced through selection of production chemicals and
optimisation of chemical dosage.
Consider technology to prevent shearing of oil droplets during treatment, such as low shear valves and low
shear pumps, since larger oil droplets are easier to separate.
20. Mokveld Typhoon Valve System slide 21
Typhoon System Applications
Choke Valves
Level Control Valves
21. Typhoon Valve System
Other Publications relating to low shear
OTC-20029-MS
OTC-28660-MS
SPE OGF - SAVVY SEPARATOR SERIE, PART 5
https://www.typhonix.com/learn-more-about-low-shear
“Best Available Techniques Guidance Document on upstream
hydrocarbon exploration and production”
070201/2015/706065/SER/ENV.F.1 (Feb2019)
“Reviewing Cyclonic Low-Shear Choke and Control Valve Field Experiences”
SPE -205016-PA
Andy Little
Lead Sales Engineer - Low Shear
andy.little@mokveld.com
Mokveld Typhoon Valve System slide 22