IPO Unloading Valve Technology Developments
and
The Associated Benefits
Alan Brodie, Feb 2011
IPO unloading valve technology developments
Introduction
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IPO Unloading valve operation reminder
What the industry wanted in tomorrows unloading valves
What’s different about PTC unloading valves
The benefits these differences are delivering
IPO Unloading valve operation reminder
Pressure
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•
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Required during gas lift well commissioning
– Where lift gas pressure can’t facilitate deep lift
During unloading they should have:
– Predictable operating characteristics
( opening and closing pressures)
– High as possible throughput
After unloading they should:
– Stay reliably closed for the life of the well
– Not be a weak link in the primary well barrier envelope
– Not allow shallow lift gas entry or multi-pointing
Unless .............well conditions change or are unpredictable:
– And lift gas via the operating valve becomes unachievable
– Then the unloading valve should be capable of:
• Reliably acting as an operating valve
Open
Open
Open
Open
Depth
Pressure
Closed
Closed
Closed
Open
Depth
IPO Unloading valve operation reminder
• Ball and seat valve set in side pocket mandrel
• Also incorporates a check valve ( not shown here):
– To provide tubing > casing integrity
• Held closed by an N2 charged dome
• Annulus (P1) and Tubing (P2) pressure trying to open it
• P1 acts on large bellows area P2 acts on the valve port:
– When pressures are high enough valve opens
– Injection pressure dominates
P
• ....but tubing pressure still has an impact
Pb
Pressured
Dome
Ab
P1
1
Ap
P2
The industry wish list
for tomorrows unloading valves
• Improved Integrity:
– Well barrier performance in line with packers and plugs
• Improved Reliability:
– Life of well longevity
– Fail safe architecture
• Reduced well commissioning costs
• Higher throughput for faster unloading
• Ability to pressure test tubing and annulus with live valves in the well
• Improved Performance:
– High pressure rating to enable deeper installations
– Reduced valve throttling and chattering
– Flexibility to use as an operating valve if well conditions change
• Without compromising integrity or reliability
What’s different about PTC unloading valves
Well Integrity
• Incorporates well barrier accredited check valve module:
– Optimised flow paths and long valve travel
– Minimal erosion
– Patented orifice check dart linkage
• Chattering virtually eliminated:
What’s different about PTC unloading valves
Well Integrity
What’s different about PTC unloading valves
Well Integrity
• Incorporates well barrier accredited check valve module:
– Optimised flow paths and long valve travel
– Minimal erosion
– Patented orifice check dart linkage
• Chattering virtually eliminated:
– Spring location (around dart) & size
• Robust and requires 25 psi dp to open
• Achieved V1( <20 cc /10 mins based on ISO 14310) , even:
– As part of an unloading valve
– After flowing erosive fluid through the valve
• A well barrier is for life not just to pass a FAT
What’s different about PTC unloading valves
Reliability
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In addition to well barrier accredited check valves.........
The PTC IPO valves use a revolutionary bellows design
All dome seals and inflation valves are metal / metal:
– Reduces likelihood of dome pressure leakage:
Bellows rated to 10000 psi
– Usually operating well within range
No dp across bellows
– Tested up to 35000 cycles without failure:
Very low load rate ( flexible even at 10000 psi )
– Long stem travel / large valve opening
– Little throttling / erosion / chattering
Valve held closed by spring
– Not by bellows pressure as is more common
– Active fail safe closure mechanism in the event of
• dome pressure leak
• bellows failure
– No multi-pointing
Pb
Pressured
Dome
Ab
P1
P1
Ap
P2
What’s different about PTC unloading valves
Reduced well commissioning costs
• Faster unloading rates
– Long stem travel in both unloading and check valve modules:
– Designed using computational fluid dynamics
• Faster completion pressure testing
– Shearable unloading valves
– Avoids the need to run dummy valves for tubing and annulus testing
– Patented shear mechanism external to valve
• Works even with multiple valves in the well
What’s different about PTC unloading valves
Improved performance
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Bellows area larger than in most unloading valves:
– Low R factor ......less tubing pressure sensitive
• More predictable performance
Bellows load rate ( stiffness) lower than in most unloading valves:
– Even at 10000 psi ......
– Valve fully opens quickly with long stem travel
• Less throttling / chattering:
– Ideal where conditions are uncertain or may change
• Unloader module becomes “practically invisible”
• Unloader can be used as a shallow operating valve
– Without compromising well integrity or reliability
10 k psi pressure rating:
P
– Valves can be used in deep or high pressure applications
• Deeper lift depth results in higher production
Pb
Pressured
Dome
•
Ab
P1
1
Ap
P2
Conclusions
• A new generation of IPO valves are now available:
– Their design is revolutionary and in many ways unique
• They are now delivering a step change in:
– Well integrity
• Unique well barrier capability even after erosion testing
– Reliability
• Unique high pressure low load rate bellows
– Commissioning costs reduction
• Unique shearable unloaders
– Performance
• Unique flexibility to use as an operating valve
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