OrMen Lange Decommisioning
OrMen Lange Decommisioning
OrMen Lange Decommisioning
1
Rev
Code
02.12.2005
Report
BSA
Prepared
by
EK
Checked
by
MP
Approved
by
Ormen Lange
Author(s):
Bernt S. Aadny
Issue Date:
02.12.2005
Document Number:
WE 00105
Approval:
Approved by:
_____________________
Mike Pollard,
Project Manager, Well Experts
Location / Hardcopy
Last Update Time Check:
02 December 2005
Contents:
Page:
1. Summary
2. Description of audit
4.8 Contingencies
4.9 Training and personnel involvement
5. Outstanding issues
15
Summary
15
Nomenclature
16
References
16
1. Summary
This report presents a short review of the Ormen Lange wells.
The well design is evaluated, and the test reports for some critical downhole components are
evaluated.
The design and the planning are well carried out to a considerable detail level, a work of high
quality. Critical components have undergone extensive testing, which qualifies them. Some
testing is in its final phase.
Although alternative solutions are possible, no major problems were discovered in the review.
2. Description of audit.
This audit is one of several audits regarding well design towards operators on the Norwegian
shelf.
The objective is to review Shell/Norsk Hydro practices for well barriers, surveillance and
testing, and, qualification and application of new technology.
Petroleumstilsynet has performed similar audits towards several operating companies, with
different focus. Usually it has been performed after incidents like well failures. This
particular audit is different as it is performed before the Ormen Lange field is developed.
The Ormen Lange wells are the first gas wells on the Norwegian continental shelf producing
through 9-5/8 in. production tubing, called "big-bore" wells. The large production rates from
these wells require application and qualification of new technology. This audit is limited to
the well.
This audit will not review all of the documentation developed for the project, only selected
reports directly related to the audit.
The participants are from the Petroleum Safety Authority:
Sissel stb, team leader
Hilde H. Lken
Arne M. Enoksen
Bernt S. Aadny, advisor
Figure 3.1: Base case design for Ormen Lange pre-drilled wells.
The design shown is a result of many analyses. Some design factors are:
-A long 9-5/8 in. liner from top reservoir to intermediate casing to eliminate borehole
stability problems in the Rogaland shales.
-Two production/completion packers where both the 7 in. and the 9-5/8 in liners is part
of the production strings.
-9-5/8 in. production tubing, called a "big-bore" producer.
-Double downhole safety valves, deep set to avoid hydrate problems.
The completion is a simple design. The wells are designed for 20 years of operation without
workover. In addition to a robust design, all equipment is quality checked.
In this report we will not present further description of the wells, but refer to the
comprehensive main drilling programme, ref.1, which contains the following chapters:
1. Non-conformances and HSEQ
2. General Information
3. Well objectives
4. Delivering scope contingency and flexibility
5. Operating schedules
6. Location data
7. Geophysics and geology
8. Reservoir technology
9. Formation evaluation and data acquisition
10. Drilling and completions fluids
11. Cementing fluids philosophy
12. Directional drilling
13. Casing design
14. Subsea
15. Completion
16. Well clean up
17. Operations
18. Activity summary
19. Appendix A: Template locations, safe handling zones and seabed layout maps
20. Appendix B: Formation evaluation and data acquisition
21. Appendix C: Drilling and completion fluids
22. Appendix D: Hole cleaning
23. Appendix E: Cement programme
24. Appendix F: Directional drilling
25. Appendix G: Casing design
26. Appendix H: Subsea equipment
27. Appendix I: Completion design
28. Appendix J: Operation schedules
29. Appendix K: Blow Out Preventer (BOP) Diagram
30. Appendix L: Drilling hazards of offset wells
31. Appendix M: Barrier diagrams
32. Appendix N: Well suspension and abandonment
33. Appendix O: Wellhead and conductor interface diagram
6
The issue of pressure testing has been a subject of discussion. A reduced test frequency might
be preferable from an operational point of view; however, this is not acceptable according to
regulations. Shell has developed a plan to analyze and approach this issue as follows. The
following is a quote from a Status note (ref. 4).
"Background
In a presentation given to Ptil on March 2nd 2005 regarding the status of the TR-SSSV qualification
testing, the Ormen Lange team indicated that a reduction of the regulatory inflow test frequency was
being considered. Main considerations for reducing the test frequency are:
-Ormen Lange TR-SSSV is not "off the shelf", but has undergone very extensive qualification
testing tailored to worst-case Ormen Lange Operating conditions.
-The Ormen Lange configuration, with dual hot-stacked TR-SSSVs with independent control
lines and subsea wells at 850 m water depth, will have a considerably lower overall risk than
other fields in the Norwegian sector.
-The operational risks associated with frequent inflow testing, for example due to hydrates or
formation damage caused by MEG injection into the wells, can become significant for Ormen
Lange.
In a meeting with Ptil on October 20th 2005, the options for valve integrity testing were presented. As
part of the way forward, it was indicated how the project intends to further pursue the issue of testing
frequency. As requested at this meeting, this note presents a short view of the ongoing and planned
work regarding testing frequencies.
Workplan TR-SSSV Testing Frequencies
1. Decision on self-equalizing TR-SSSV
A non-equalizing TR-SSSV has been qualified for Ormen Lange. Qualification testing of the selfequalizing version of that valve is currently undergoing. In case of a successful test, the decision will
be taken to use self-equalizing TR-SSSVs for Ormen Lange wells. In case the test is not successful, the
Ormen Lange wells will be equipped with the qualified non-equalizing TR-SSSVs.
2. Risk study with Exprosoft
A study will be carried out by Exprosoft to investigate the following aspects:
-Overall safety availability of primary and secondary well barriers as a function of alternative
test philosophies and testing frequencies.
-Comparison between Ormen Lange risk levels and comparable fields.
The study will be carried out in Q1 and Q2 of 2006, with a final report expected by July 2006.
3. Evaluation of Exprosoft study and potential application for exemption
The Exprosoft study and consequences for Ormen Lange will be evaluated. Based on the overall risk
levels for Ormen Lange compared to other fields in the Norwegian sector, the preferred testing
philosophy and optimum testing frequency will be determined.
The results of the study and the consequences for Ormen Lange will be discussed with Ptil. In case the
optimum testing frequencies are not in accordance with the applicable regulations, a formal exemption
will then be applied for."
Reference 6 defines the procedures for the tests, whereas Ref.7, summarize results from
further testing. Below we will quote the conclusions from this study:
"The Baker Oil Tools TRSCSSV, model TSM-5 SS prototype, as redesigned 2004, was found to be the
best alternative among the 3 for the Ormen Lange application. This is mainly because it sustained the
demanding conditions during closing in a flowing gas well than the other valves.
It did not, however, seal well at low differential pressure across the flapper, for which the Halliburton
valve sealed best.
Therefore the recommendation for the Baker valve is subject to one condition: The differential
pressure to be applied during the field valve leak tests (inflow tests) will be above 30 bar. The time for
field leak tests increases significantly for the Ormen Lange gas well TRSCSSV with increased
differential pressure between the flowline and the well.
There are also subjects identified that should be followed up prior to and during manufacturing of the
production valves. Most of these apply to all valves requiring high reliability and thereby also the
Baker valve:
One should verify by adequate in-house tests the lower limit of the differential pressure when:
- The valve has been exposed/contaminated by fines
- The gas pressure is released slowly at the same time as the valve is in 45 deg. position with the flapper
pin pointing slanted upwards, as the leak test combined conditions from test 5 and 6.
The detailed test procedure should be evaluated when the field test procedure has been established.
This could be conducted at the manufacturers test facilities by simple means, provided sufficient gas
can be made available.
Specific items for quality assurance follow up are:
1. To specify tighter acceptance criteria for leak rates during the manufacturers QC test in the
workshop.
2. Improve the QC on the component dimensions and actual materials in general.
3. Improve the QC on the dimensional tolerances stack-up that affects the flapper hinge
clearances/performance.
4. Improve the QC on the filing system for manufacturers documentation.
All valves' flapper hinge components have been deformed. It is therefore assumed that this is
impractical to avoid as long as a valve type with a flapper design is used.
10
The second valve alternative is the Halliburton valve. This valve should be redesigned with respect to
its internal components' ability to absorb the forces caused by closure in a flowing well. The
components of most concern would be the flow tube and the flow tube upward end stop arrangement.
The latter should also assure that the hydraulic piston is not subject to the violent impact forces from
the flow-tube after the piston has reached its end stop.
The third valve alternative is the Schlumberger valve. This should be redesigned with respect to its
secondary seal, flow tube and reduced opening pressure.
The Lock Open Tools.
The Baker LOT successfully passed the in-house tests and the DTL 3rd party test. The LOT supplied
by Halliburton and Schlumberger were not subject to tests at DTL because of their deformed flow
tubes. A subsequent in-house test with the Halliburton LOT after the gas slam tests at the Halliburton
facility was attempted without success.
Further, the LOT for both Halliburton and Schlumberger were assessed to have more uncertain design
and operational features that the Baker LOT."
As seen above, Bakers valve were found to be the best. This non-equalising valve is accepted
with the concerns identified above.
4.3.2 Equalizing safety valve
Both equalising and non-equalising safety valves are considered for Ormen Lange. These
two concepts have some differences in application, especially related to pressure tests.
A qualification test was conducted on an equalising Baker TRSCSSV. The report of these
tests is given in Ref. 8. This valve did not qualify. Below is a summary from ref. 8:
Our understanding is that the equalising valve did not pass the tests, and that further
development and testing will be carried out.
4.4 Tubing hanger
During selection of the tubing hanger one chose different strength and steel qualities in tubing
and hanger. It was decided to carry out a test program to qualify the tubing hanger. The test
report is expected at the end of 2005.
11
12
13
14
5. Outstanding issues
At the date of this report, the following reports are not finished.
Final test report for the equalising TRSCSSV.
The second report on the equalizing safety valve is expected at the end of 2005. After that, a
decision will be made of which of the two valve types will be installed on Ormen Lange.
Lower completion (gravel pack - screens).
This report is expected in week 47, 2005
Connection testing of 9-5/8" and 13-3/8" connections.
Report expected mid-December 2005.
Testing of tubing hanger and liner hanger
Report expected week 47 2005.
Strategy for pressure testing of downhole safety valves.
Expected established July 2006.
Summary
This report presents a short review of the design of the Ormen Lange wells.
The well design is evaluated, and the test reports for some critical downhole components are
evaluated.
The design and the planning are well carried out to a considerable detail level, a work of high
quality. Critical components have undergone extensive testing, which qualifies them. Some
testing is in its final phase.
Although alternative solutions are possible, no major problems were discovered in the review.
15
Nomenclature
HSEQ
TRSCSSV
QC
LOT
MEG
FIV
KM
SIMOPS
HAZID/HAZOP
PSA
DNV
References
1. Ormen Lange Main Drilling and Completion Programme. Doc. No. 37-1B-NS-K15-007, Final,
01.12.2004A/S Norske Shell E and P Ormen Lange.
2. Regulations Relating to Design and Outfitting of Facilities etc. in the Petroleum Activities (The Facilities
Regulations). Petroleum Safety Authority Norway (PSA) 3 Sept. 2001.
3. Guidelines to Regulations Relating to Conduct of Activities in the Petroleum Activities (The Activities
Regulations). Petroleum Safety Authority Norway (PSA), 1 January 2002 (Updated 1 January 2005).
4. Status Note: Ormen Lange - Ongoing and planned work regarding inflow testing frequencies of sub-surface
safety and tree valves. A/S Norske Shell E&P Ormen Lange, from Roel Aretz, date 15.11.2005.
5. TRSCSSV test data overview and basis for conclusions. ExproSoft DNV, Doc. no.: 2004-DNVEx-3-041.
6. Qualification procedures for new technology. Recommended Practice DNV-RP-A203, Sept. 2001, Det
Norske Veritas.
7. TRSCSSVs - Ormen Lange application - Comparison. Report No. 2-20, Det Norske Veritas, date: 2004-1112.
8. Baker Equalising TRSCSSV Tests 2005. Report No.C20,Det Norske Veritas. date: 2005-06-21
9. Test Results Summary of 7" 32.0 # SM13CrM110 VAM TOP HC for Norsk Hydro Ormen Lange Project.
R&D Job No. IR140. VAM PTS Company, date 6-20-05.
10. Qualification Test Results of 7" x 32.0# SM13CRM-110 x F6NM75 VAM TOP HC Tubing Hanger.
Report G3130, Sumitomo Metal Industries, October 2005.
11. Qualification Test Results of 7" x 32.0# SM13CRM-110 x AISI420 VAM TOP HC Tubing Hanger. Report
G3131, Sumitomo Metal Industries, October 2005.
12. Ormen Lange Contingency Well Configurations. A/S Norske Shell E&P Ormen Lange. Doc. date:
05.12.2004
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