Well serving structures support pipes, equipment, and mechanisms used in drilling and well operations. These structures include crown blocks, derricks, masts, travelling blocks, racking boards, and sub-structures. When an oil field is located on land or offshore, drilling equipment is transported on mobile offshore drilling units and erected to begin drilling operations. Key components of well serving structures are described, such as crown blocks, derricks, masts, reeving, and connections.
2. What are Well Serving Structures?
These processes are done by travelling
blocks, rotary table, racking boards, dead
lines anchors, drums, etc.
Well Serving Structures are structures
that support these pipes, equipment and
mechanisms.
Oil
Rig
W.L
Seabed
D
r
i
l
l
P
i
p
e
Crown Block
Derrick
(Upper Sec)
Derrick
(Lower Sec)
Sub-
Structure
When oil field is found on land or under
the sea, drilling equipment (DEs) are
brought to the site on mobile offshore
drilling units (MODU)
When oil field is found on land or under
the sea, drilling equipment (DEs) are
brought to the site on mobile offshore
drilling units (MODU)
At the site, Drill pipes are erected, joined
and brought down into the sea.
3. Crown Block
First Line Sheaves
API SPEC 8C
Cluster Line
Sheaves
API SPEC 8C
Crown Block
Main members
API SPEC 4F/ AISC 335-89
Shafts &
Shaft Houses
API SPEC 4F
Handrail & Kick
Plate
(Prevention of
drop objects)
API SPEC 8C
First Line
(Wire Rope)
API RP 9B
Cluster Line
(Wire Rope)
API RP 9B
Design - AISC 335-89 (CH D, E, F, H, J)
Fabrication - AISC 335-89 (CH M)
Welding – AWS D1.1/D1.1M:2010
4. Crown Block (Cont.)
Gin-pole
A hosting arm mounted on main members
Used for lifting during maintenance of crown block equipment
Substitute in the place of frame structures of early kind of crown block
Frame Structures used for lifting of
crown block equipment
5. Padeye attached to Crown Block Structure
Padeye for Tugging Padeye for Lifting of Crown Block Structure
7. Wire Rope
Selection of wire rope, clips and thimble eyes are done in accordance with API RP 9B 4th
Edition
Wire rope Clip
Thimble Eye
Turn Back Length
8. Derrick vs Mast
Derrick
Bolts & Nut connected Structure
Disassemble member by member during
transportation when necessary
Mast
Welded Structure
Lay down during transportation when
necessary
Design - AISC 335-89 (CH D, E, F, H, J)
Fabrication - AISC 335-89 (CH M)
Welding – AWS D1.1/D1.1M:2010
9. Travelling Block & Guide Track
Travelling Block runs up and down on guide
tracks to raise and lower drill pipes
Travelling Block
10. Racking Board (Finger Board)
In derrick, racking boards are inside the structural frame, but they are outside of the frame in mast
Racking boards are used as a support to rack drill pipes
11. Bolt & Nut Connections in Derrick
Main Vertical Members Connections
Diagonal Members Connections
Anchor Bolt Connection
Derrick members are joined by bolts & nuts which are selected by using
‘Specification for Structural Joints using ASTM A325 or A490 Bolts’
Derrick Structure is fixed at four locations at sub-structure using
anchor bolts connection
12. Mast Support – A Frame
Operating Condition Lay Down Condition
