Offshore Oil & Gas Future Development

Conductor Driving On ANDP-B Platform
(Petronas Angsi Development Project)

The above picture taken during installation of ANDP-B platform offshore Terengganu, Malaysia. ANDP-B was my first platform I’ve installed during the early stage stage of my career as a Field Engineer. The installation was performed utilizing Mc Dermot DB30. Enough of the flash back! Here i would like to share my experience/tips in conductor installation on Fixed Offshore Platform.

Conductor Plan view.
(Captured from Autocad Drawing)

Before i start on the conductor installation, lets assume some of the conductors properties & operational constraint. With reference to the above picture, we assume;

• 18 Nos. of conductors slots
• Slots 6, 12 & 18 are 30″ Conductors.
• Slots 1,2,3,4,5,7,8,9,10,11,13,14,15,16 & 17 are 24″ Conductors.
• Slots 8,9,10 & 11 are Straight Conductors (SC).
• Slots 1,2,3,4,5,6,7,12,13,14,15,16,17 & 18 are Curve Conductors (CC).
• Slots 1,2,3,4,5,6,7,12,13,14,15,16,17 & 18 PRE-INSTALLED in Fabrication yard with zip-up closure installed.
• 5 section for each conductor.
• BATCH A : Slot 1,2,3,4,5
• BATCH B : Slot 7,8,9,10
• BATCH C : Slot 14,15,16,17
• BATCH D : Slot 6,12,18
• Barge Set up for conductor installation is at Row A.
• Installation of conductor at barge stern.
• COnductor transportation barge alongside DLB Starboardside
• Conductor Driving by hammer MHU 270 or IHC 90.

With the above assume condition, I’ve come out with various option of conductor batch driving. Here is one of them which is the most optimum sequence.

1. All curve conductors are hangoff (Pre-installed)
2. Stab and Weld CC2 (Curve Conductor Section 2) Batch D
3. Lower Down for self penetration of CC2/CC1 Batch D
4. Stab and Weld CC2 Batch A
5. Lower down for self penetration of CC2/CC1 Batch A
6. Stab and Weld CC2 Batch C
7. Lower down for self penetration of CC2/CC1 Batch C
8. Hang Off SC1 (Straight Conductor Section 1) Batch B
9. Stab and Weld SC2 & CC2 Batch B
10. Lower down for self penetration of SC2/SC1 & CC2/CC1 Batch B
11. Drive All Batch B
12. Drive All Batch A
13. Drive All Batch C
14. Stab and Weld CC3 Batch A
15. Stab and weld SC3 & CC3 Batch B
16. Stab and weld CC3 Batch C
17. Drive SC3/SC2 & CC3/CC2 Batch B with hammer MHU 270 or IHC 90
18. Stab and weld SC4 & CC4 Batch B
19. Drive to target penetration of SC4/SC3 & CC4/CC3 Batch B with hammer MHU 270 or IHC 90
20. Drive CC3/CC2 Batch C with hammer MHU 270 or IHC 90
21. Stab and weld CC4 Batch C
22. Drive to target penetration of CC4/CC3 Batch C with hammer MHU 270 or IHC 90
23. Drive CC2/CC1 Batch D
24. Stab and Weld CC3 Batch D
25. Drive CC3/CC2 Batch D with hammer MHU 270 or IHC 90
26. Stab and weld CC4 Batch D
27. Drive to target penetration of CC4/CC3 Batch D with hammer MHU 270 or IHC 90
28. Conductor Final Cut-off

If you have better ideas/comments on the above sequence, please share it in the comment section. Now lets go into details the reason behind the above sequence.

• I start with the 30″ conductors first up to self penetration to minimize time required to change or reset the ILT (Internal Lifting Clamps) back to 24″. And also to ensure the 30″ is no longer hang-off during piling of all the 24″ Conductors.
• Self-pen all pre-installed conductor to minimize conductor frame loading (Refer to Conductor Hangoff Study).
• Hang off all remaining straight conductor.
• After all self pen all the 24” conductor, and one time drive all the 24” conductors. Before you decide on this, please refer to Conductor Drivability study to ensure it is not in 24 hours SetUp range. (Driven Pile/Conductor Refusal API RP2A)
• The best practice in conductor driving is, drive the inner slots first, which is in this case is Batch B. Why? Because if you drive the outer slots first, it will compress the soil in the middle creating more resistance during driving the inner slots.
• With this reason, I drive all Batch B until it target penetration achieved.
• Next I’m concentrate on Batch A. This is because, the conductor transportation barge was alongside at DLB starboard side. So, to lift and swing conductor for batch A require traveling over Batch C. If I install Batch C first, it will create an obstruction during installation of Batch A.
• After complete Batch A, then followed by Batch C.
• Upon complete driving Batch C, the hammer sleeve need to be changed, therefore meanwhile this activities, Fitter can concentrate on performing the 24” conductor final cut off. One important tips, Changing from smaller sleeve (24”) to bigger hammer sleeve (30”) is always easier then vice versa (Because cutting is easier than welding).
• Then, complete all the 30” conductors.

Ok, I think that is it the reason behind the conductor batching & sequence.

Haiyya! 2PM already! … To close out this articles here is the list of main equipment required for conductor installation.

• Hammer MHU 270 or IHC 90
• ILT set to 24”
• ILT set to 30”
• 24” Bear Clamps
• 30” Bear Clamps