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Thru tubing fishing
20 March 2006
Advice required on: Thru tubing fishing with 2-7/8" drillpipe.

1. Racking back of 2-7/8" drillpipe in stands, seems to have been
typically best achieved by building a "nest" or "carousel" of larger
drillpipe to support and also to protect from wind loading. Has
anyone used any other methods to successfuly rack back stands of 2-
7/8" or smaller drillpipe/tubing?

2. Typical stackup (i.e. BOPs, riser, tie-in to rig circulating
system) used for this type of operation when the Xmas Tree is still
on the well?


5 answer(s)
Myspread Users
Total Posts: 1
Join Date: 20/03/06
If you are going to rack the pipe then an intermediate board is
almost essential. Some method of retention at the intermediate level
is required, and unless it is just a few stands that you can lash to
the coral,a racking board is the safest way.
Consider the time/cost of tripping singles versus time/costs of
modifying the rig.
Modifications can be expensive and time consuming, and a "Lot of
Tripping" can be done for the cost of rig mods.
Consider tapered string if your upper completion will take 3.5" pipe
which does rack readily.
Consider damage to DHSV (if it is not wireline retrievable)and you
plan to rotate your string during the fishing operation.

BOP, traditionally 7 1/16" BOP is used for this size of pipe.
Consider HP riser from the top of the tree up to the level you want
the 7 1/16" BOP to sit. Insert BOP and on top of that a bell nipple
or xover spool to the main rig bell nipple.
Consider using the same ram configuration as the conventional stack,
(just down sized) for ease of hook up of controls and C/K lines, as
long as it complies with minimum requirement as posted by Augusto.
This helps since no change required to remote panels, or policies or
procedures regards shut in, hang off, well kill line up.

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Consultant [retired Shell staff]
Total Posts: 249
Join Date: 02/09/05
1. Apart from the popular layer of 5" drillpipe as suggested, I've
seen rigs with an intermediate stabbing board - also called tubing
stabbing board.

2. You need a BOP with the bore equivalent to the tree bore with a
minimum of 2 7/8" positive rams, Blind-shear rams, Tool-Joint
positive rams or Variable Bore rams and a Bag Preventer with
Complete shut-off capability.

The BOP should be laterally suported - and partially lifted? - to
avoid 'rocking' over the tree top which would fret the ring joint
gasket and corresponding ring grooves; in this case, using 'Pikotek'
flat seals around the API ring gasket may prove wise.Load-monitored
fasteners would also help this critical connection.

Consultant [retired Shell staff]
Total Posts: 249
Join Date: 02/09/05
See below

I wonder what kind of Drillpipe/tubing protector are you using? The
smoothness of tubing ID is critical for ease of production.

I recall once using 13%Cr tubing plastic coated [ yes, plastic
coated] to get a production improvement of 12%...
Documents uploaded by user:
Total Posts: 1
Join Date: 01/03/06
The attached information may be of interest, sorry can not help
twith the second part of the question:

1. LEA Intro to TTRD touches on various aspects of TTRD for
platforms / land rigs.
2. Article from Offshore Magazine on changes made to SCOTT platform
Drilling Derrick to enable TTRD. Work carried out by Varco on their
Top Drive and PHM
Piperacking System. Link to web article is shown below:

Steve H
Documents uploaded by user:
Myspread Users
Total Posts: 3
Join Date: 20/07/05

It isn't recommended to set back 2 7/8" pipe in the derrick without
tying it back at mid point of the stand. Even when a protective row
of stands is in place, you need to have it restrained to prevent it
bending and possibly breaking at a connection. This is more likely
with drill collars so the recommendation there is not to set back
drill collars at all. For extended use of 2 7/8" DP a bellyboard
would be recomended.


John A.
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