production control chokes - george e king petroleum...
TRANSCRIPT
![Page 1: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/1.jpg)
Production Control Chokes
• Types
• Reasons
• Basics of Operations
• Application
3/14/2009 1George E. King Engineering
GEKEngineering.com
![Page 2: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/2.jpg)
Adjustable Restriction
“Needle and Seat” for this type of choke.
Rough schematic of an adjustable choke
A choke is a restriction in a flow line that causes a pressure drop or reduces the rate of flow. It commonly uses a partially blocked orifice.
3/14/2009 2George E. King Engineering
GEKEngineering.com
![Page 3: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/3.jpg)
Most Common Chokes
• Positive:– Fixed orifice
– Shut in well (or divert flow) and disassemble choke housing to change the restriction or “flow bean”
• Adjustable– Provides variable orifice size through external
adjustment without choke disassembly.
3/14/2009 3George E. King Engineering
GEKEngineering.com
![Page 4: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/4.jpg)
Variable Chokes - good for bringing wells on gradually.
Prone to washouts from high velocity, particles, and even droplets or bubbles in severe cases.
Solutions - hardened chokes (diamond and carbide), chokes in series, dual chokes.
3/14/2009 4George E. King Engineering
GEKEngineering.com
![Page 5: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/5.jpg)
Beans are fixed (non adjustable) orifices – ID size is in 64ths of an inch.
This type of choke is used on wells that require almost no adjustments to flow.
ID
3/14/2009 5George E. King Engineering
GEKEngineering.com
![Page 6: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/6.jpg)
Choke Uses
• Control Flow – achieve liquid lift
• Maximize use – best use of gas (lift?)
• Protect equipment – abrasion and erosion
• Cleanup – best use of backflow energy
• Control circulation – holds a back pressure
• Control pressures at surface (during flow)
• Control injection – on injection line
3/14/2009 6George E. King Engineering
GEKEngineering.com
![Page 7: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/7.jpg)
What Happens as Choke Provides a Pressure Drop and What Happens to the pressure?
Energy from pressure drop is lost in:
• Increased velocity (from gas expansion)
• Vaporization (flashing) of light (short carbon chain) hydrocarbon liquids to gas
• Vaporization of water
• Cavitation
• Heat production (usually liquid friction)
3/14/2009 7George E. King Engineering
GEKEngineering.com
![Page 8: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/8.jpg)
Detriments
• Flashing – hydrocarbon light ends lost (value lost)
• Cavitation – erosion of surfaces in and around choke
• Erosion– solids, droplets and bubbles in high velocity flow
• Freezing – expansion of gasses cools the area – refrigeration principle
3/14/2009 8George E. King Engineering
GEKEngineering.com
![Page 9: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/9.jpg)
Pressure around the choke
Inlet or well pressure, P1
Pressure drop through the orifice
Pressure “recovery” , P23/14/2009 9George E. King Engineering
GEKEngineering.com
![Page 10: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/10.jpg)
Distance Flow Traveled
Delta P
Recovery
P1
P2
Pressure
VENA Contracta Phenomenon
The consequences of the low pressure region in the choke can lead to severe problems with cavitation and related flashing (vaporization).
3/14/2009 10George E. King Engineering
GEKEngineering.com
![Page 11: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/11.jpg)
Problems
• The larger the difference between the inlet and outlet pressures, the higher the potential for damage to the internals of the choke.
• When delta P ratio (i.e., (P1-P2)/P1) rises above 0.6, damage is likely. Changes in choke type, materials of construction, or choke arrangement may be needed (multiple chokes in series for high pressure drops?)
3/14/2009 11George E. King Engineering
GEKEngineering.com
![Page 12: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/12.jpg)
Cavitation During Liquid Flow
Ultra low pressure region in and immediately below choke causes bubble to form from vaporizing liquid, Recovery of pressure causes bubble to collapse; i.e., cavitation
The rapid collapse of the bubbles causes high velocity movement of liquid and damage around the site.
Pressure recovery line – limit of damage
Imploding bubbles and shock waves
3/14/2009 12George E. King Engineering
GEKEngineering.com
![Page 13: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/13.jpg)
Flashing During Liquid Flow
Vaporization of light ends, but no significant damage in this region since pressure recovery not above vapor pressure, hence bubbles don’t collapse.
Pressure recovery occurs downstream, damage location?
3/14/2009 13George E. King Engineering
GEKEngineering.com
![Page 14: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/14.jpg)
Freezing
• Expansion of gas (and solutions containing gas) cools the surroundings. Can form an ice plug and block flow.
Press
Distance Traveled
RecoveryRecovery
Freezing PtTemperature
dP
P1 T1
T2 P2
3/14/2009 14George E. King Engineering
GEKEngineering.com
![Page 15: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/15.jpg)
P2 is outlet pressure
P1 is inlet pressure
Flow rate through the choke
dP is press drop thru the choke
Measurements used in Choke Calculations
3/14/2009 15George E. King Engineering
GEKEngineering.com
![Page 16: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/16.jpg)
Calculations
• delta P = P1 – P2
• delta P ratio = delta P/P1
• These values are use to measure the capacity and recovery of the choke
3/14/2009 16George E. King Engineering
GEKEngineering.com
![Page 17: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/17.jpg)
Throttling Methods
• Needle and seat
• Multiple orifice
• Fixed Bean
• Plug and Cage
• External Sleeve
3/14/2009 17George E. King Engineering
GEKEngineering.com
![Page 18: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/18.jpg)
Needle and Seat
• Simplest and least expensive adjustable
• Best for pressure control
• High Capacity
3/14/2009 18George E. King Engineering
GEKEngineering.com
![Page 19: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/19.jpg)
Multiple Orifice
• Quick open and close
• Good rate and pressure control
• An in-line instrument – not usually used on the wellhead
3/14/2009 19George E. King Engineering
GEKEngineering.com
![Page 20: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/20.jpg)
Fixed Bean
• Best when infrequent change needed
• Used mostly on trees
3/14/2009 20George E. King Engineering
GEKEngineering.com
![Page 21: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/21.jpg)
Plug and Cage
• High capacity
• Good control
3/14/2009 21George E. King Engineering
GEKEngineering.com
![Page 22: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/22.jpg)
External Sleeve
• Superior Erosion Resistance
• Minimizes Body Erosion
3/14/2009 22George E. King Engineering
GEKEngineering.com
![Page 23: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/23.jpg)
Choke Sizing
• Control the flow – maximize production
• Minimized vibration damage
• Minimize erosion damage
3/14/2009 23George E. King Engineering
GEKEngineering.com
![Page 24: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/24.jpg)
Choke Selection
• Based On:– Application (lift, deliquifying the well, erosion
control, solids production prevention, etc.)
– Rate or flow and range of flow rate
– Presence of solids
– Maximum velocity
– Total pressure drop
3/14/2009 24George E. King Engineering
GEKEngineering.com
![Page 25: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/25.jpg)
Choke Selection (continued)
• Fluid – liquid, gas, or GOR of mix.• Pressure – both pressure drop and total
pressure• Temperature – range of acceptable
temperatures during service• Occurance and timing of solids in flow• Droplets, bubbles• Scale and organic deposit potential
3/14/2009 25George E. King Engineering
GEKEngineering.com
![Page 26: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/26.jpg)
How would you set a choke with minimum monitoring equipment?
• One way is by measuring temperature at the surface……– Producing a well at maximum rates means lifting
more liquids. Using the high heat capacity of liquids (3 to >10x most gas heat capacities), the max lift in a well would be achieved very near the maximum wellhead temperature.
3/14/2009 26George E. King Engineering
GEKEngineering.com
![Page 27: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/27.jpg)
Choke Sizing
• Cv = coefficient value– Number of gallons of water per minute that will
pass through a restriction with a pressure drop of 1 psi at 60oF.
– Used as the “flow capacity index”
– Does not correspond to a specific throttling method.
3/14/2009 27George E. King Engineering
GEKEngineering.com
![Page 28: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/28.jpg)
3/14/2009 28George E. King Engineering
GEKEngineering.com
![Page 29: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/29.jpg)
3/14/2009 29George E. King Engineering
GEKEngineering.com
![Page 30: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/30.jpg)
Choke Size (inches)
Bore Diam (inches)
Choke Coefficient MCF/D/PSIA
4/64 0.0625 0.08 6/64 0.0938 0.188 7/64 0.1094 0.261 8/64 0.1250 0.347 9/64 0.1406 0.444
10/64 0.1563 0.553 12/64 0.1865 0.802 16/64 0.2500 1.470 24/64 0.3750 3.400 32/64 0.5000 6.260
Example: a well is flowing through a 10/64 choke at 2175 psig WHP. What is the dry gas flow rate? (This is a very rough estimate!)2175 psig = 2190 psia. Choke coeff. for 10/64 = 0.553Gas rate = 2190 x 0.553 = ~1200 mcf/d
Choke Calculation Example
Note: for accuracy – the upstream press must be twice downstream press.
3/14/2009 30George E. King Engineering
GEKEngineering.com
![Page 31: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/31.jpg)
Choke Operations
• Problems with Erosion
• Solutions
3/14/2009 31George E. King Engineering
GEKEngineering.com
![Page 32: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/32.jpg)
Erosion is damage caused by impingement of particles, droplets, bubbles and even liquid on any solid surface at high velocity.
To reduce erosion, slow down the velocity.
3/14/2009 32George E. King Engineering
GEKEngineering.com
![Page 33: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/33.jpg)
Erosion in a positive of bean choke from micron sized fines and high velocity gas flow.
3/14/2009 33George E. King Engineering
GEKEngineering.com
![Page 34: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/34.jpg)
Typical flow patterns (and erosion) in a bean choke.
3/14/2009 34George E. King Engineering
GEKEngineering.com
![Page 35: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/35.jpg)
Advanced corrosion is often in the exit end of the choke from higher gas velocities after gas has expanded.
3/14/2009 35George E. King Engineering
GEKEngineering.com
![Page 36: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/36.jpg)
Erosion at the exit flange
JPT, March 1998
3/14/2009 36George E. King Engineering
GEKEngineering.com
![Page 37: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/37.jpg)
The velocity profile and pressure drop across a choke with a large pressure drop – opportunity for erosion is very high.
JPT, March 19983/14/2009 37
George E. King Engineering GEKEngineering.com
![Page 38: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/38.jpg)
One solution to the problem is to take the pressure drop in series and hold a slight backpressure. For example, a 1000 to 0 psi pressure drop produces a 68 fold expansion in gas volume, while a 1500 to 500 psi pressure drop produces a 3 fold gas volume expansion.
JPT, March 19983/14/2009 38
George E. King Engineering GEKEngineering.com
![Page 39: Production Control Chokes - George E King Petroleum ...gekengineering.com/Downloads/Free_Downloads/Production...Production Control Chokes • Types • Reasons • Basics of Operations](https://reader031.vdocument.in/reader031/viewer/2022021510/5aae3a477f8b9a25088bfc1d/html5/thumbnails/39.jpg)
Choke Conclusions
• Production chokes help unload and produce the well through pressure management.
• Choke setting requirements change as pressure drops, rate changes and fluid composition varies.
• Good production engineering requires regular design and setting checks for production chokes.
3/14/2009 39George E. King Engineering
GEKEngineering.com