-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 1/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
RUBRIQUES: CASING REPAIR
TECHNIQUES: INTERNAL CASING PATCH
CASING BACK-OFF & RECONNECTION
KEYWORDS: CORROSION LOG, CASING DAMAGE, CASING REPAIRINTERNAL
CASING PATCH,HYDRAULIC CASING BACK OFF TOOLCASING RECONNECTION,
CASING ALIGNEMENT TOOL
SUMMARY: The 9 5/8 casing in well AK-13-1 was damaged @ 300
m,MDfollowing an heavy fishing operation. A USIT Corrosion
logindicated 1) oval casing and strain hardening (jarring effect),
2)deep marks resulting in reduced thickness of the casing
(millingeffect).The casing was first successfully repaired in June
1998 with anexpandable internal casing patch, in order to complete
andproduce the well as quick as possible.In January 1999, the well
was to be side tracked. Uncertainty onactual ID of the patch led to
the decision to recover the topsection of the 9 5/8 casing,
including the patch and toreconnect new 9 5/8 casing.The 9 5/8 top
casing was successfully cut, then backed-off. Anew top 9 5/8 casing
was successfully reconnected.The damaged top section of the 9 5/8
casing was then studiedin detail.
TYPE OF FICHE: OPERATIONAL REPORT
CONTACT: J. CAUREL, X. CHASSERIAUD, B. GRIMBERT, L. LEGURUN,Y.
MOINEL, A. RAZIMBAUD, DO/D, TOTAL ABK.
REF. DOCUMENTS: AK-13-1, WELL REPORT, TOTAL ABKAK-13-2, WELL
PROGRAMME, TOTAL ABKAK-13-2, WELL REPORT, TOTAL ABK
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 2/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
TABLE OF CONTENT
1. WELL AK-13-1 SITUATION (June 1998)
2. USIT CORROSION LOG and RESULTS
3. INTERNAL CASING PATCH
4. OPTIONS TO SIDE TRACK AK-13-1 (January 1999)
5. CASING RECOVERY, CASING RECONNECTION
5.1. OPERATION PREPARATION5.2. CUTTING AND PULLING THE
CASING5.3. BACK-OFF5.4. RECONNECTION OF THE NEW CASING5.5. LANDING
CASING ON EMERGENCY HANGER (CAMERON MC2)
6. COSTS & CONCLUSIONS
7. DETAILED ANALYSIS OF THE CASING AND PATCH AFTER RECOVERY
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 3/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
1. WELL AK-13-1 SITUATION (June 1998):
A whipstock accidentally set at 303 m (vertical section of the
well) in the 9 5/8 casing in well AK-13-1. It was jarred (up to 200
klbf overpull) and milled (washed over) until it was recovered.The
resulting damage to the 9 5/8 casing was evaluated with a USIT
corrosion log (cf. 2).Analysis of the results indicated that the
casing had to be repaired.Well AK-13-1 was expected to be a good
producer (Horizontal drain in Thamama 1 reservoir) andwas to be
drilled to TD and completed as quickly as possible. It was decided
to repair the damagecasing with an expandable casing patch (cf.
3).
2. USIT CORROSION LOG and RESULTS
After the fishing job, the casing was positively tested to 3000
psi. A USIT corrosion log was runfrom 350 m to 150 m. Two types of
damage to the casing were detected:
- Oval casing, from 281.5 to 282.25 m, reduction of the casing
thickness to 7 mm (strain hardeningof the casing due to jarring
effect). The resulting burst capacity for the damaged casing is
3842psi.
- Milling damage (deep marks), 279 to 281.5 m, reduction of the
casing thickness to 6.3 mm. Theresulting burst capacity for the
damaged casing is 3393 psi.
Figure 1: USIT corrosion log showing jarring and milling
damage.
The milling damage to the casing was not taken as a matter of
concern because the corrosionrate could be reduced to less than
0.01 mm/ year with corrosion inhibitor.
The cold work of the casing resulted in a plastic deformation
largely exceeding the yield strength of thematerial. The deformed
section would be a zone of stress concentration under internal
pressure and would
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 4/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
render it sensitive to Sulphide Stress Corrosion Cracking
(highly likely in sour wet gas environment). Thissituation was not
acceptable.Although the safest recommendation was to remove the top
damaged 9 5/8 casing, it was urgent to completeand produce the
well. It was decided to repair the damaged 9 5/8 casing using an
internal casing patch thatwould cover the stress concentration zone
in the damaged casing with an excess of 2 meters on each side.
3. INTERNAL CASING PATCH
The Homco internal expandable casing patch (weatherford) was
available inAbu Dhabi. Its technology had been looked in the past
and was felt reliable.
The patch is a corrugated shape liner (star shaped cross
section), withfiberglass cloth on the outside (epoxy applied to the
fiberglass when runningin hole) that is forced to expand and
anchored against the casing wall by anexpanding cylinder. The
expanding cylinder is driven inside the patch (forcingit to expand)
by a dual hydraulic cylinder assembly (slide valve, bumper
jar,hydraulic hold down, dual cylinder).
1 - Setting assy.
2 - Tubing is raised to close the circulating valve.
3 - Hydraulic pressure is applied to force out buttons on the
hydraulic holddown. This anchors the cylinder firmly and isolates
the work string from alltensile loads caused by the setting
operations.
4 - Pressure on underside the pistons pulls expander assy into
the bottomof the patch. As pressure increases, the expander
assembly is forced furtherinto the patch, expanding it against the
inside of the casing (5 of patchexpanded per stroke). The
circulating valve is opened by lowering tubing andtelescoping the
slide valve. Tubing is raised again to pull up the cylinders
inrelation to pistons held down by the expander assembly. Expanded
sectionof patch is anchored to the casing wall by friction caused
by compressivehoop stress. Hydraulic pressure is again applied to
tubing after closing thecirculating valve. Hydraulic hold down
buttons expand to anchor the cylinderin a new, higher position.
5 - The expander assembly is again forced through the corrugated
patch,expanding it against the inside of casing. This procedure is
continued untilthe entire patch is set. The epoxy resin coating is
extruded into any leaks orcavities in the casing wall and acts as a
gasket and additional sealing agent.Setting time normally requires
less than 30 mn for a 20 patch. The tool isthen removed from the
hole and the patch is pressure tested as required.
Figure 2: Patch design and summarised setting procedure(from
Weatherford document)
14
5
3
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 5/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
The patch was successfully set from 285.75 m to 273.75 m (40) in
June 1998 to cover thedamaged section of 9 5/8 casing. The first 5
were set with 3200 psi, the rest with 3000 psi(theoretical
capacity: 9850 psi internal, 894 psi external pressure).
The theoretical ID of the patch, once set, is 8.381, based on a
circular 9 5/8, not taking intoaccount the 9 5/8 casing
deformation, the thickness of epoxy and the surface defects of
bothcasing and patch. The actual ID of the patch, once set, has not
been measured.
The well was completed as a gas lift horizontal producer
immediately after the patch operation.
4. OPTIONS TO SIDE TRACK AK-13-1 (January 1999)
In January 1999, AK-13-1 was to be abandoned and side-tracked to
a new location. The new welldesign involved pulling out completion,
abandoning the drain in AK-13-1, opening a window in the 95/8
casing (permanent whipstock), 8 drilling and 7 liner.
The results of the USIT corrosion log were further investigated.
The deformation of the casing(strain hardening, marks, thickness
reduction) was confirmed but the definitive ID of the patch
could not be deducted. The patch ID would be in the interval
[8.25 8.38].Figure 3: Uncertainty on the ID of the patch, from USIT
corrosion log (data can be used as
qualitative indications but not strictly quantitative).IR:
internal radius (MX, MN, AV: minimum, maximum, average)ER: external
radius (MX, MN, AV: minimum, maximum, average)
This uncertainty led to several options for the side-track of
the well:
1. leave the patch in the well, drift it, down-size the drilling
tools and liner equipment:- The drift would be known just before
running the whipstock, which would lead to ultra short notice
before under-sizing the equipment.- The mills for the window
milling in the 9 5/8 casing could easily be down-sized to the
required ID
(the body of the whipstock is 8).- 8 3/8 drilling instead of 8
would be conventional (if compatible with the drift of the
patch),
smaller size would lead in difficulties to find bits and
problems of compatibility with the liner size.The use of bi-centre
bits would be a back-up option.
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 6/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
- The smallest dimension of the liner hanger (Nodeco) can be
reduced to 8.29. This minimum linerID would be acceptable or not
depending on the actual drift of the patch.This option led to very
heavy contingencies with several batches of equipment dimensions
requiredfor the operation. It would even not be acceptable if the
patch is drifted to an ID < 8.29.
2. Mill the patch: Milling operation was studied with Smith and
Baker. It was felt risky and notsatisfactory as an additional patch
would be required after the side track operation, until thenext
re-entry.
3. Recover the top casing section (patch included) and reconnect
new casing, retrieving fullcasing integrity and drift. This option
was studied with Baker, Smith and Enterra. The top sectionof the 9
5/8 casing is not cemented, recovering the casing should therefore
be possible. Using anhydraulic back-off machine provides great
confidence in backing-off exactly where required. Smithalso
proposes a casing alignment tool in order to re-connect the new
casing without damaging theconnection left in hole after back-off.
This option was chosen because confidence was gained inthe tools
proposed for the operation and because it was the most comfortable
for the future of thewell.
Remark: an external casing patch option (Bowen, rubber, 5K) had
been looked as an alternative tothe new casing reconnection. When
comparing the two options, reconnection of new casing looksfar more
practical.
The operation could be planned in 2.5 days (first conservative
estimate), which makes iteconomically attractive.
Option 3 was the best: recovering the top 9 5/8 casing (300 m),
replacing with new casing.
5. CASING RECOVERY, CASING RECONNECTION
The operation was successfully carried out in January 1999. None
of the anticipated problems occurso that it was a particularly
smooth operation. The complete 9 5/8 integrity and full drift
wererecovered.
5.1. PREPARATION
- (AK-13-1 is killed, the completion is removed, the well is
abandoned with a cement plug acrossthe top 7" liner)
- Cut the casing below the patch with casing cutters,
conventional operation,
- Check the depth of the casing left in hole with same cutters.
The casing left in hole should not betagged between back-off and
reconnection of new casing in order not to damage the
connectionleft in hole (pin or box) after back-off.
- Pull the cut top casing with Casing Hanger Running Tool. The 9
5/8 is not cemented above 1050m. However, cement bridge could
prevent from pulling the top 9 5/8 casing. In this case, the top
95/8 casing would be cut and pulled in slices.
- Back-off the cut joint with the hydraulic back-off machine.
The machine is a torque tool, anchoredon two packer across the
coupling to back-off. The machine has been chosen because it allows
toback-off exactly at a given coupling. It can provide up to 48
klbf.ft torque per cycle [1/2 turn percycle]). The indication of
back-off is based on torque for each cycle.
- Complete back-off and pull the backed-off joint with the
casing spears.
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 7/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
- Check whether the connection left in hole is a pin or a
coupling (note that statistically, most of theleft in hole
connections after back-off are pins).
- Adapt the casing alignment tool to the situation. The casing
alignment tool is based on the use ofa bushing to guide the new
casing and re-connect without damaging the connection left in hole.
2bushings are available depending on the situation: Pin or Box left
in hole.
- Reconnect and Torque up new casing from surface with the
casing tongs,
- Land casing on emergency hanger.
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 8/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
Coupling
289.4 m
Coupling
301.7 m
Casing Patch
273 - 286 m
Casing cut
@ 291.5 m
BOX UP
left in holePIN UP
left inhole
Casing back-off @ 301.7 m
Casing Connection
with Casing Alignment tool
Casing
Alignment
Tool
Top Sub
Vam Pro Boxx
New Vam Pin
New Vam Boxx
New Vam Box
X-Over
New Vam Pinx
Vam Pro Box
X-Over
fitted inside tool
Vam Pro Coupling(if Pin Up left in hole)
Guide, according to Pin or Box left in hole
Figure 4: Recovering top 9 5/8, casing, connecting new 9 5/8
casing.
Smith was chosen for the operation for their Hydraulic Casing
Back-off Tool, their casingalignment tool and the quick
availability of their equipment. They actually provided a
completepackage for the entire operation and were involved at the
earliest stage of the decision process.
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 9/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
The preparation of the casing alignment tools (with 2 bushings
to be able to cope with thesituation: Pin or Box left in hole) was
slightly more complex due to the use of Vam Pro connection(Vam Pro
connection cannot be cut locally, gauges are not available). The
top Casing alignmenttool was cut in New Vam, a New Vam x Vam Pro
X-over was made up on top. A Pin x Pin, NewVam x Vam Pro X-over was
fitted inside the tool. Would a coupling be left in hole, the Vam
ProPin down would be run (inside the proper bushing); would a Pin
be left in hole, a Vam Pro couplingwould be made up to this X-over,
the Vam Pro Box down would run (inside the proper bushing).
1:1 scaled schematics of the various possible situations before
reconnection clearly indicated thatit would be impossible for the
casing alignment tool to miss the left in hole connection. The
re-connection should therefore be straight forward. Would a
coupling be backed-off and fall in thehole while being pulled out,
it would still be easy to re-connect new casing.
An external casing Patch (Bowen rubber type, 5000 psi) had been
mobilized in the very unlikelypossibility of failure to reconnect
the 9 5/8 new casing. However, would the first reconnection
beimpossible, a second back-off (1 joint deeper) and a second
reconnection would be attempted,then a third, .The probability to
run the external casing patch was close to zero.
5.2. CUTTING AND PULLING CASING
The casing was cut @ 291.5 m,MD, 7 below coupling to leave a 30
cut joint in hole, as per Smithrecommendation (3.25 hours for the
entire operation). The left in hole casing moved 20 cm down.The
casing hanger + casing were straight pulled out (5.5 hr for the
entire operation).
The recovered 9 5/8 casing and couplings were in excellent
condition, looking new. It has beencut and analyzed in details.
5.3. BACK-OFF
The Hydraulic Casing Back-off Machine was run across the joint
to be backed-off. 10 cycles (5000psi pressure up/ bleed-off),
equivalent to 5 turns were applied to back-off the coupling.
6 h for the entire operation (M/U: 2 h, RIH: 2 h, M/U
circulating head + test line + back-off: 1.5 h,Drop ball to restore
circulation: 0.5, POOH: 1 h).
Casing spears were run in hole. 3 turns were applied to complete
the back-off. The joint waspulled to surface.
A coupling was backed-off and pulled out (as per statistics).
The connection was looking so new(with original grease) that it was
decided not to attempt to clean it before re-connection.
5.4. RECONNECTION OF THE NEW CASING
New 9 5/8 casing was run with the Casing Alignment Tool fitted
with a bushing designed to coverthe Pin left in hole and a Vam Pro
coupling down a short X-over inside.
The casing was run in hole slowly, with rotation (casing tong:
coordination between casingelevator and the air winch). No sign
showed on surface when the guide covered the casing left inhole.
400 lbf slack-off indicated casing contact. The connection was made
up to 12200 ft.lbf, inone go, working the string with +/- 50 klbf.
It was then made up to 12700 ft.lbf with an additional turn,
working the string with +/- 30 to 70 klbf. The casing would not
turn more and the torquewould not increase from this final torque
value.
12650 ft.lbf is the optimum make-up torque for 9 5/8, 47#, Vam
Pro connection, it is assumedthat the torque @ 300 m vertical is
similar to the surface torque.
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 10/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
The casing was positively tested to 3000 psi for a few minutes.
4.75 h for the entire operation.
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 11/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
5.5. LANDING CASING ON EMERGENCY HANGER (CAMERON MC2)
BOP were lifted, emergency slips set (with 125 klbf tension on
casing) and casing cut. The top 95/8 was machined. Although this
operation was straight forward, it is reported here as the firstuse
of the 9 5/8 Cameron C22 emergency hanger
6. COSTS
There is a significant difference between the two types of
operation. Nevertheless, the results areof course not the same. In
one case, it is a temporary repair allowing to put the well on
productionas quick as possible and giving a casing integrity which
cannot be guaranteed at 100%,especially with H2s and C02 contents.
In the second case, the well is fully repaired and comesback to its
original status.
Internal Casing Patch:
Total cost for the Patch: Patch: 38600 US$Associated rig time:
11000 US$TOTAL: 49600 US$
Casing Back-off and reconnection:
Lump Sum for the Smith operation: 92000 US$Associated rig time:
11000 US$New 9 5/8: 19400 US$Associated rig time: 50416 US$TOTAL:
172816 US$
7. DETAILED ANALYSIS OF THE CASING AND PATCH AFTER RECOVERY
A. CONCLUSION
Five main points:-The Homco patch was necessary the 1st time
(sulfide stress corrosion cracking) andconfirmed by the results of
analysis identifying heavy metallurgical changes on the steel.-The
Homco patch was not properly deployed and the life of the casing
would have been mustprobably shorter than expected.-The change of
the casing top part is the best solution if the equipment is
available, despite ofa cost which is not negligible. It also allows
the re-entry with the standard bit.-USIT in caliper mode is an
accurate tool.-Damages on casing are due to the heavy jarring at
shallow depth, causing pipe deformationsand the thickness reduction
due to the milling (and washing over).
B. CASING PART RECOVERED
The casing was cut in the hole @ 291.5 m MD, 1.99 m below the
(last) coupling. Oncearriving in surface, due to the internal Homco
patch the N-1 connection was not able to beunscrewed. The casing
was torched-cut above this connection. The last piece recovered
wascomposed of a full casing joint 12.97m long (collar 0.21m) and a
casing butt of 2.20m long(collar 0.21m).
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 12/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
C. CASING INSPECTION
(i) Visual inspectionThe visual inspection of the last casing
part shows outside heavy damages,particularly in the middle of the
pipe where big humps are located caused by steeldeformation. The
torched-cut (picture1) end does not allow inspecting the
sealingbetween the patch and the casing at this level (like
welded), but it is possible todiscover that the patch was not fully
applied inside the casing (picture2). A significantwave aspect
proves that the setting tool did not deploy fully the patch (when
run thepatch is compressed with large undulations).
Picture1 Picture2
Heavy damages on the pipe
(ii) GaugingA special gauge was manufactured to drift the casing
in order to verify the expectedrestriction inside the patch due to
the heavy casing deformation and its ovality. The8.29 drift gauge
was stuck at 3.79m after the torch-cut end. The ovality was up to7%
of the diameter.
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 13/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
(iii) Outside measurementsThe outside measurement was made with
a caliper. Depending on deformations 4then 8 on reference
generating lines (refer to drawing). Each section measured wasalso
referenced to the top the casing.
OUTSIDE DIAMETERS
8.8
9
9.2
9.4
9.6
9.8
10
10.2
10.4
10.6
289.29
288.29
287.29
286.29
285.29
284.29
283.29
282.65
282.55
282.45
282.35
282.29
282.24
282.19
282.14
282.09
281.99
281.89
281.79
281.29
280.29
279.29
278.29
277.29
276.54
(iv) Thickness and inside diameterThe thickness of the pipe was
measured at the same referenced points as per theoutside records.
This led to calculate the internal diameter.
INTERNAL DIAMETER
8
8.5
9
9.5
10
10.5
11
289.
29
288.
29
287.
29
286.
29
285.
29
284.
29
283.
29
282.
65
282.
55
282.
45
282.
35
282.
29
282.
24
282.
19
282.
14
282.
09
281.
99
281.
89
281.
79
281.
29
280.
29
279.
29
278.
29
277.
29
276.
54
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 14/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
LENGTH 279.29M
200
250
1
2
3
4
5
6
7
8
LENGTH 280.29M
200
250
1
2
3
4
5
6
7
8
LENGTH 281.29M
200
250
1
2
3
4
5
6
7
8
LENGTH 281.79M
200
250
1
2
3
4
5
6
7
8
LENGTH 281.89M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LENGTH 281.99M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LENGTH 282.09M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LENGTH 282.14M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LENGTH 282.19M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LENGTH 282.24M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LENGTH 282.29M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LENGTH 282.35M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LENGTH 282.45M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LENGTH282.55M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LENGTH 282.65M
200
250
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Non-scaled schematic of pipe measurements (red= ID,
blue=thickness)
D. COMPARISON WITH USIT CORROSION LOG
The results we found on surface after having measured the casing
demonstrated that theanalysis and the interpretation of the USIT
(run as caliper) was correct. The USIT showed aminimum thickness of
less than 6.3 millimeters and we measured in reality 6.5
millimeters.All the deformations highlighted by the USIT were found
and located at the right place.
E. PATCH INSPECTION AFTER CASING CUTS
The pipe with the internal patch was cut in10 sections to allow
a visual internal inspection.It was noticed that the patch was
never deployed fully as waves were systematically foundwhat ever
the inspected section. A particular check was done at the beginning
and at the end
-
FICHE FEED BACK N Date: 02/99 Auteur: J.CAUREL B.GRIMBERT
9 5/8 CASING REPAIR: Filiale: TOTAL ABK
TEP/DO/FPL/MTH - INTERNAL CASING PATCH- CASING BACK OFF &
RECONNECTION Page: 15/ 15
File : H:\section-DO-D\Procedure\fiches de feedback\Casing
patch\958repair.doc
of the patch, to ensure that the gluing was efficient. The waves
phenomena was alsoidentified at those levels. We cannot ascertain
that the gas would not have been able tomigrate between the casing
patch and the pipe.
F. HARDNESS CONTROLS
The hardness tests were done in three different zones at the
bump level, at the place wherethe thickness was minimum and above
and below the damaged part.The standard Vickers hardness
measurement for L80 steel is Hv=230.
We found:Hv< 170 at bump level which means very soft
steelHv> 300 at thickness mini which means steel harder than
normal. It is due to the matting.Hv =+/- 210 on the pipe which
means a slight change (no given interpretation).