Substructure

1 FUNCTION
2 SUBSTRUCTURE LOAD and DIMENSIONS
3 TYPES AND CHARACTERISTICS
4 RIG UP SYSTEMS
"SWING UP" - PYRAMID "SWING LIFT" - BRANHAM "SLING SHOT" - DRECO
5 INSPECTIONS

1. Function.
The substructure has the function of supporting the drawworks, rotary table, stands of DP and derrick. The top side is generally called the rig floor.
Substructure are made following API STD 4E or 4F regulations. There is usually a plate mounted on the substructure identifying its main characteristics.

2. - Substructure Load
A Derrick or mast weight
B Rig Floor and equipment
C Maximum load of pipe that can be set back in the derrick
D Maximum hook load
- Dimensions
Substructure dimensions are proportional to the rig power.
3.- Substructure Types
Land rigs are made for frequent Rig Up, moving and Rig Down.
This is the main reason why different substructure types have been developed.
Two main types
- Type Box on Box
- Type: High Floor Substructure

- Type Box on Box
Different modules or boxes are positioned to raise the rig floor.
The numbers of boxes depends on the height required to install the wellhead and BOP stack
- Type: High Floor Substructure
These have been developed to accommodate higher BOP stacks and wellheads.
Although each builder has their own model, they all have the following characteristics:
Enables the drawworks and derrick to be rigged up at ground level, eliminating the need for big cranes; Uses the rig's drawworks to raise the floor and derrick (some models use hydraulic pistons).

4 RIG UP System
- "SWING UP" - PYRAMID
- "SWING LIFT" - BRANHAM
- "SLING SHOT" - DRECO

- SWING UP - PYRAMID
Drawwork lifts the mast, the substructure and the complete rig floor. Only 2 main lifts are required
- 1st lift to pick up mast and part of rig floor

- SWING LIFT - BRANHAM
- Position of lifting cables
- 1st PHASE: A-frame positioning
- 2nd PHASE : Lifting the Mast
- 3rd PHASE : Lifting the Drawworks

Dedicated hydraulic pistons to lift derrick, substructure and complete rig floor. Lifting sequence

5. Inspections
Periodical inspections
Substructure, derrick and lifting equipment must have periodical inspections, (every six months)
following the builder's instructions and the API regulations: API RP 4G ed API RP 54.
International Organization for Standardization (ISO) ISO 13534.
ENI rules ask also a complete re-certification of the derrick/mast every 5 years.