ECD Reduction Tool -...
Transcript of ECD Reduction Tool -...
1© 2007 Weatherford. All rights reserved.
ECD Reduction ToolR. K. Bansal, Brian Grayson, Jim StanleyControl Pressure Drilling & Testing
November 20, 2008Drilling Engineering Association, Fourth Quarter Meeting
© 2007 Weatherford. All rights reserved.
Description of the ECD Reduction Tool (ECD RT)
Lab test results
Field test results
Forward plan
Summary
Presentation outline
© 2007 Weatherford. All rights reserved.
ECD Reduction Tool (ECD RT)What?
• A downhole tool for reducing the equivalent circulating density (ECD), hence the bottomhole pressure, while drilling.
Why?• Wherever high ECD is a problem:
You want to drill with a lighter mud to minimize chances for mud loss but you risk fluid influx when circulation stops. It is a common problem where difference between pore pressure and formation fracture pressure is small, orYou want to use a heavier mud to improve wellborestability but you can’t due to increased risk of mud loss, such as in ERD wells (small difference between collapse pressure and formation fracture pressure).
Where it is run?• High in the drillstring, in the vertical section of the well close
to surface.
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Major benefits of ECD reduction
Improved wellbore stability by tolerating higher static mud weights
Extended hole intervals and reduced number of casing strings
Reduced impact of uncertainty on casing setting depth by widening the usable PP/FG margin
Reduced lost circulation and differential sticking
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Description – 8.20” ECD RT
Modular design - 3 primary components
• Hydraulic turbine drive
• Annular pump
• Sealing element
Total Length ~ 30 feet.
Tool diameter 8.20 inch.
Applicable in 9-5/8” (47# or lighter) and 10-3/4” casing pipes.
Normal circulation rate 500-550 gpm; 600 gpm max.
TURBINE PUMP SEALS
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Operational Advantages
Portable tool; Requires no rig modification
Drill string component; Quick rig-up / rig down. Only a short trip of 7 stands is required to add the tool in drill string.
For use on land and offshore applications
Use for planned and or unanticipated problematic intervals of the well
Does not impede mud pulse telemetry
Does not affect normal drilling operations
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Flow loop tests
Performance characterization
The effect of LCM in the drilling fluid
The effect of reverse flow (bull heading)
The effect of gas in the return fluid
P1P3
P2
Flow
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Circulation rate, gpm
Ann
ulus
Pre
ssur
e R
educ
tion,
psi
Annulus pressure reduction as a function of circulation rate and mud weight
14.5 ppg
16.5 ppg
17.8 ppg
19.2 ppg
10.4 ppg
Water
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0
5,000
10,000
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25,000
0.0 1.0 2.0 3.0 4.0 5.0 6.0ECD Reduction, lb/gal
Verti
cal d
epth
, ft
Projected ECD reduction versus depth
14.5 ppg
16.5 ppg
12.5 ppg
10.4 ppg
PECD Reduction =
.052*Depth
Circulation rate: 525-550 gpm
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Extra standpipe pressure (SPP) requirement
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Circulation rate, gpm
Extr
a St
andp
ipe
Pres
sure
, psi
19.2 ppg 17.8 ppg 16.5 ppg 14.5 ppg 10.4 ppg Water
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Full scale technology tests
Primary Objectives
1.Quantify pressure reduction
2.Measure transient pressure spike at the start of rig pumps
3.Quantify Surge and Swab effects
4.Demonstrate compatibility with mud-pulse telemetry
5.Assess longevity of the tool at normal circulation rate
Rig floor
Flow line
Ground
ECDRT
Bit
Cement in lower two joints
P1
P2
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ECD Reduction demonstrated in technology trial
Circulation rate
ECD
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Field trials conductedRig floor
ECDRT
Annular pressure sub
Objectives Achievements
Quantify ECD reduction
Demonstrated expected ECD reduction
Evaluate operational procedures
Did not impede normal drilling operation
Cuttings flowed through the pump easily
Mud pulse telemetry worked normally
Assess reliability Reliability proved to be a weakness. Maximum drilling achieved was 500-ft of 8.75” hole. Focus of recent development was to improve longevity and reliability.
Drilling operation was monitored by standpipe pressure, hook load, real-time ECD and fluid return.
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ECD reduction in Arkoma field trial
Circulation rate
ECD
Mud Weight
Normal ECD
Circulation rate
ECD
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6.75" 6.75" 8.20"
44" 355.6" (29' 7.6")
UPPER GAGE CARRIER ECDRT
5.0"
LOWER GAGE CARRIER
44"
6.75"
Forward Plan - Next Field Trial Plan going forward is to run a successful field trial and we are actively looking for an opportunity.
Casing size 9-5/8” (47 lb/ft or lighter) or 10-3/4”
Circulation rate between 475-550 gpm; mud type and weight do not matter.
Ability to drill ahead 1500 to 2000 ft with the ECD RT located in the vertical hole. ECD RT starting location is 650-700 ft from surface.
Instrumentation for real time display of downhole pressure, ECD and circulation rate.
© 2007 Weatherford. All rights reserved.
SummaryECD RT potentially offers significant benefits to drilling operations
The concept of ECD RT has been proven in field trials
The present design will function in 9-5/8” (47# or lighter) and 10-3/4” casing pipes and handle up to 600 gpm circulation rate
Looking for additional field trial opportunity to prove reliability and longevity of the tool.
Likely to develop other sizes subsequently.