1 FUNCTION
2 TYPES AND CHARACTERISTICS
3 MAIN SYSTEMS
- Main Drum
- Catheads
- Stationary Brake (Main brake)
- Auxiliary brake
4 POWER CALCULATION
5 INSPECTIONS
- Manufacture specifications
The Drawworks is built in according to specifications in API 7K or related ISO (International
Organization for Standardization) 14693.
2 TYPES AND CHARACTERISTICS
Depending on the engines on the rig, the drawworks can be either:
- MECHANICAL
- ELECTRICAL
- MECHANICAL
Diesel engines are directly connected (compounded) to the drawwork by chain.
This system is still in use for small Drilling Rigs (under 1500 HP), but is no longer used on medium-Hi powered rigs( 1500 & 3000 HP).
- ELECTRICAL
Electrical system are normally used today on land rigs and is the only system in use on offshore rigs. The drawworks are generally connected to 1000 HP D.C. engines, although A.C. engines are
now being used as well
- Connection Drawworks-Engines
The connection between the drawworks and the engines can be either:
- CHAIN DRIVEN
- GEAR DRIVEN
3 MAIN SYSTEMS
a- Main Drum b- Catheads
c - Stationary Brake (Main brake)
d - Auxiliary brake
a - Main Drum
- Main Drum Diameter
The diameter of the main drum is a function of the diameter of the drilling line being used.
It is preferable to have the drum as large as possible to reduce the number of wraps and the bending of the cable.
- Drum Length
The length of the drum is a function of the distance D between Crown block and Drawworks.
- Fleet Angle
To reduce the wear on the drilling line, it is good practice to keep the angle alpha under 2 degrees.
b - Catheads
- Spinning line and Breakout Cathead
Catheads are winches with pneumatic clutch and are mounted on the extremity of the secondary drum of
the drawworks.
The make up cathead is located beside the driller's console and the break-out cathead is located on the opposite side of the driller's console.
The catheads apply the pulling force on the hand tongs connections.
- Model 16 Spinning line Cathead
- Model 16 Breakout Cathead
- Employment scheme
For safety reasons and convenience their employment comes supplanted from the dedicated equipments.
c - Stationary Brake
- Band Brake
- Disk Brake
- Regenerative Brake System
- Band Brake
- Description (parts)
- BRAKE HANDLE
- LEFT BAND
- RIGHT BAND
- BALANCE BAR
- Braking action
Braking action is activated by pushing the D Brake handle down towards the floor.
Through a strength multiplier system, the braking force is transmitted on the D balance bar, then to the brake bands, and finally to the two drums on either side of main drum.
Heat produced by the braking action is dissipated through the circulating water cooling system.
- Disk Brake
Depending of the size the drawworks, there are 2 to 4 hydraulically-actuated calipers.
In addition to these main calipers, each disc brake system has 2 dedicated calipers (normally closed) that are used as the emergency and parking brake.
These calipers are actuated by an independent hydraulic system.
Disk brakes can be mounted on Drawworks that was originally equipped with band brake.
- Advantages
The advantages are:
- Greater braking capability
- Emergency braking system
- Possibility of Remote control
- Significant noise reduction during drilling
- Use
Disk Brake is a development of the band brake, due to the necessity to handle heavier loads
- Regenerative Brake System
- New generation of drawworks
The newest generation of drawworks (4000-5000 HP), mounted on ultradeep offshore rigs, have a direct drive transmission system, permanently connecting the drawworks to the motors.
When the travelling block descends in the derrick, the motors turns in the opposite direction, producing an opposite current and hence a braking action.
- NOTE: This braking system, is not able to hold, when the motors are rest, hence the need for emergency and parking the disk brake system.
d - Auxiliary brake / dynamic brake
The function of the auxiliary brake is to assist the main braking system during rapid descent of the blocks with heavy string weights. The auxiliary brake prevents the overheating and premature wear of main brakes.
Types:
- Hydrodynamic Brake
- Elettromagnetic Brake
- Hydrodynamic Brake
That system is still in use on small drawworks. However, on medium-Hi powered drawworks, this system has been replaced by the Electromagnetic brake.
- Description
The Hydrodynamic brake consisting of two box with a rotor pressed onto the main drive shaft and two stators.
When the main shaft rotates the rotor drags water against the two stators, producing a braking action.
Braking capability can be regulated by increasing or decreasing the water levels in the "Hydraulic Brake box".
- Hydrodynamic Brake
The electromagnetic brake consists of a stator with coil, two magnetic poles and a rotor pressed onto the main drive shaft.
When the driller activates the brake control, a magnetic field is produced by 4 electromagnetic coils mounted concentrically inside the drum.
By varying the amount of current to these stationery coils, the driller can control the amount of braking torque applied to the rotating drum.
- "Baylor" brakes
The use of electromagnetic brake began with diesel-electric rigs. Almost all drawworks today are equipped with "Baylor" brakes.
Baylor Brakes are manufactured in 5 standard sizes for nominal drilling depths up to 30.000feet.
- Braking force
The diagram shows the values of braking force as a function of rpm of the drawworks shaft.
Notice how the electromagnetic brake is also effective at low speeds.
4 POWER CALCULATION
WORK = Force x Step
POWER= Force x Pooh velocity
- Hook Power Ph = P xVe / 75
Where Ph = Hook Power (HP) Ve = Pooh velocity (m/s)
P = Weight on Hook (kg)
- Drawwork Power = pa = F x Vf/75 x E
where F = Pull to Fast line equal to:
P = (Weigh on Hook) / N (Number of lines)
Vf = fast line velocity equal to:
Ve * = 2 R n (rpm drawwork shaft)
E= Efficiency of sheaves. This value (empiric)
provided by API in function of number of lines.
6.5 INSPECTIONS
- Periodic inspections
The API applicable references are:
API RP 7L and API RP 54 (chapt. 9.4 and 9.5). and the Manufacturer's recommendations.
inspection (as per API RP 7L) every 5 years.
Monday, 23 July 2012
Derrick
1 CONCEPTUAL DESIGN
2 TYPES AND CHARACTERISTICS
- DERRICK
- MAST
- RAM RIG
3 RIGGING UP
4 DRILLING LOADS
- Calculation of Drilling Loads at Crown Block
- Definition of Gross Nominal Capacity
5 INSPECTION
1 CONCEPTUAL DESIGN
- Derricks
Derricks and Masts consist of a steel framework with a square or rectangular cross-section.
Their purpose is to support the hoisting equipment and rack the tubulars while tripping.
The number of joints in a stand (single-double-triple) that the rig can pull is dependent on the height of the derrick.
- Manufacturer Specifications
Derricks are manufactured in accordance with API 4F or related ISO (International Organization for Standardization) 13626 draft.
This specifications covers the design, manufacture, and use of derricks, portable masts, crown block assemblies and substructures.
- Nameplate Information
Derricks built within API/ISO specs must have a specification nameplate attached in a visible place containing the following information:
a. MANUFACTURER’S NAME.
b. PLACE OF CONSTRUCTION.
c. STANDARD ADOPTED (ex. API 4F). d. SERIAL NUMBER.
e. HEIGHT ( ft ).
f. MAXIMUM STATIC HOOK LOAD ( lbs) FOR STATED NUMBER OF LINES TO TRAVELLING BLOCKS. g. MAX. RATED WIND VELOCITY (Knots) WITH RATED CAPACITY OF PIPE RACKED.
h. EDITION OF THE API SPEC. USED
I. GUYING DIAGRAM (when applicable)
j. The following note: “CAUTION: ACCELERATION OR IMPACT, ALSO SETBACK AND WIND LOADS WILL REDUCE THE MAXIMUM RATED STATIC HOOK LOAD CAPACITY.”k. LOAD DISTRIBUTION DIAGRAM.
l. GRAPH PLOTTING MAX. ALLOWABLE STATIC HOOK LOAD VERSUS WIND VELOCITY. m. MAST SETUP DISTANCE FOR MAST WITH GUY LINES.
2 TYPES AND CHARACTERISTICS
There are 3 different types of derricks:
- DERRICK
- MAST
- RAM RIG
- DERRICK
Pyramidal steel framework with square or rectangular cross section assembled as fixed structure.
- API Definition
A semipermanent structure of square or rectangular cross-section having members that are latticed or trussed on all four sides.
This unit must be assembled in the vertical or operation position, as it includes no erection mechanism. It may or may not be guyed.
Derrick Types
Derrick are normally used on Offshore rigs and can be divided into categories:
- Stationary Derrick
Derrick used on offshore fixed structures
- Dynamic Derrick
Heavyweight derrick used on floating rigs subjected to marine stress.
- MAST
Installation on offshore floating unit
A Mast is a steel framework with square or rectangular cross-section comprised of multiple sections assembled together.
Mast are normally used on land rigs; they are rarely used on offshore rigs.
Most masts have one side open (window side), while others have both the front and rear side open
(full view).
Generally masts are assembled on the ground in horizontal position and are raised using the drawworks. Some masts use telescopic sections and are assembled in vertical (boot strap).
- API Definition
3.16 mast: A structural tower comprised of one or more sections assembled in a horizontal position near the ground and then raised to the operating position.
If the unit contains two or more sections, it may be telescoped or unfolded during the erection procedure.
Mast Types
There are 2 different types of masts for land drilling and service rigs:
- STATIONARY BASE
- WITH GUY LINES
- RAM RIG
The RAM RIG is a new concept used to hoist the drill string.
The Drawwork and the drilling line are replaced with a system of hydraulic pistons and rams. Ram rigs can be used with singles or stands, depending on the height of the derrick.
They have only recently been developed and are not yet classified within API/ISO Specs
3 RIGGING UP
- Conventional Mast (Land rig)
Erection sequence
- Vertical Mast (offshore Rig)
- Trailer Mounted Rig
Rigging Up Sequence of a Trailer Mounted Rig
- a) Deploying of substructure base
- b) Anchoring of trailer to substructure base
- c) Extension of the telescopic sections
- d) Installation of the hydraulic rams
- e) Anchoring the mast to the substructure
- f) Raising the mast in vertical position
- Final Position
4 DRILLING LOADS
- Forces on the Derrick
Derricks are subjected :
- Weight of the derrick itself
- Wind load
- Stress induced by Floating hull motion
(for floating vessels)
- Horizontal component load of the drill string when racked back
- Hoisting load
5 INSPECTION
- Periodic inspections
The API applicable references are:
API RP 4G and API RP 54 (chapt. 9.2 and 9.3). and the Manufacturer's recommendations.
ENI policy is more strict and requires the API Category IV inspection (as per API RP 4G) every 5 years instead of 10.
Mast/derricks and substructures on mobile offshore drilling units or fixed platforms are exempted from the requirements of a Category IV inspection.
2 TYPES AND CHARACTERISTICS
- DERRICK
- MAST
- RAM RIG
3 RIGGING UP
4 DRILLING LOADS
- Calculation of Drilling Loads at Crown Block
- Definition of Gross Nominal Capacity
5 INSPECTION
1 CONCEPTUAL DESIGN
- Derricks
Derricks and Masts consist of a steel framework with a square or rectangular cross-section.
Their purpose is to support the hoisting equipment and rack the tubulars while tripping.
The number of joints in a stand (single-double-triple) that the rig can pull is dependent on the height of the derrick.
- Manufacturer Specifications
Derricks are manufactured in accordance with API 4F or related ISO (International Organization for Standardization) 13626 draft.
This specifications covers the design, manufacture, and use of derricks, portable masts, crown block assemblies and substructures.
- Nameplate Information
Derricks built within API/ISO specs must have a specification nameplate attached in a visible place containing the following information:
a. MANUFACTURER’S NAME.
b. PLACE OF CONSTRUCTION.
c. STANDARD ADOPTED (ex. API 4F). d. SERIAL NUMBER.
e. HEIGHT ( ft ).
f. MAXIMUM STATIC HOOK LOAD ( lbs) FOR STATED NUMBER OF LINES TO TRAVELLING BLOCKS. g. MAX. RATED WIND VELOCITY (Knots) WITH RATED CAPACITY OF PIPE RACKED.
h. EDITION OF THE API SPEC. USED
I. GUYING DIAGRAM (when applicable)
j. The following note: “CAUTION: ACCELERATION OR IMPACT, ALSO SETBACK AND WIND LOADS WILL REDUCE THE MAXIMUM RATED STATIC HOOK LOAD CAPACITY.”k. LOAD DISTRIBUTION DIAGRAM.
l. GRAPH PLOTTING MAX. ALLOWABLE STATIC HOOK LOAD VERSUS WIND VELOCITY. m. MAST SETUP DISTANCE FOR MAST WITH GUY LINES.
2 TYPES AND CHARACTERISTICS
There are 3 different types of derricks:
- DERRICK
- MAST
- RAM RIG
- DERRICK
Pyramidal steel framework with square or rectangular cross section assembled as fixed structure.
- API Definition
A semipermanent structure of square or rectangular cross-section having members that are latticed or trussed on all four sides.
This unit must be assembled in the vertical or operation position, as it includes no erection mechanism. It may or may not be guyed.
Derrick Types
Derrick are normally used on Offshore rigs and can be divided into categories:
- Stationary Derrick
Derrick used on offshore fixed structures
- Dynamic Derrick
Heavyweight derrick used on floating rigs subjected to marine stress.
- MAST
Installation on offshore floating unit
A Mast is a steel framework with square or rectangular cross-section comprised of multiple sections assembled together.
Mast are normally used on land rigs; they are rarely used on offshore rigs.
Most masts have one side open (window side), while others have both the front and rear side open
(full view).
Generally masts are assembled on the ground in horizontal position and are raised using the drawworks. Some masts use telescopic sections and are assembled in vertical (boot strap).
- API Definition
3.16 mast: A structural tower comprised of one or more sections assembled in a horizontal position near the ground and then raised to the operating position.
If the unit contains two or more sections, it may be telescoped or unfolded during the erection procedure.
Mast Types
There are 2 different types of masts for land drilling and service rigs:
- STATIONARY BASE
- WITH GUY LINES
- RAM RIG
The RAM RIG is a new concept used to hoist the drill string.
The Drawwork and the drilling line are replaced with a system of hydraulic pistons and rams. Ram rigs can be used with singles or stands, depending on the height of the derrick.
They have only recently been developed and are not yet classified within API/ISO Specs
3 RIGGING UP
- Conventional Mast (Land rig)
Erection sequence
- Vertical Mast (offshore Rig)
- Trailer Mounted Rig
Rigging Up Sequence of a Trailer Mounted Rig
- a) Deploying of substructure base
- b) Anchoring of trailer to substructure base
- c) Extension of the telescopic sections
- d) Installation of the hydraulic rams
- e) Anchoring the mast to the substructure
- f) Raising the mast in vertical position
- Final Position
4 DRILLING LOADS
- Forces on the Derrick
Derricks are subjected :
- Weight of the derrick itself
- Wind load
- Stress induced by Floating hull motion
(for floating vessels)
- Horizontal component load of the drill string when racked back
- Hoisting load
5 INSPECTION
- Periodic inspections
The API applicable references are:
API RP 4G and API RP 54 (chapt. 9.2 and 9.3). and the Manufacturer's recommendations.
ENI policy is more strict and requires the API Category IV inspection (as per API RP 4G) every 5 years instead of 10.
Mast/derricks and substructures on mobile offshore drilling units or fixed platforms are exempted from the requirements of a Category IV inspection.
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.
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.
Drilling Rig Main System
There are 4 main system on a drilling rig :
1. Hoisting and Rotation system
2. Power Generation System
3. Mud Circulation System
4. Well Control System
Main system :
1. Hositing and Rotation System that is including
1. MAST & SUBSTRUCTURE
2. CROWN BLOCK
3. TRAVELLING BLOCK
4. TOP DRIVE
5. ROTARY TABLE
6. DRAWWORKS
7. DRILLING LINE
8. DEADLINE ANCHOR
2. Power Generation System
AC-DC POWER GENERATION STATION EXAMPLE
1. GENERATORS
2. CONTROL PANELS
3. TRANSFORMER
4. DC MOTOR
5. DIGITAL DRILLER CONSOLE
6. MOTOR CONTROL CENTER
3. Mud Circulation System
1. MUD PITS
2. MUD MIXING HOPPER
3. MUD PUMPS (HI AND LOW PRESSURE)
4. SHAKERS
4. Well Control System
1. RIG FLOOR MUD MANIFOLD
2. INSIDE BOP
3. BOP STACK
4. CHOKE & KILL LINES
5. CHOKE & KILL MANIFOLD
6. BOP ACCUMULATOR
7. BOP CONTROL MANIFOLD
1. Hoisting and Rotation system
2. Power Generation System
3. Mud Circulation System
4. Well Control System
Main system :
1. Hositing and Rotation System that is including
1. MAST & SUBSTRUCTURE
2. CROWN BLOCK
3. TRAVELLING BLOCK
4. TOP DRIVE
5. ROTARY TABLE
6. DRAWWORKS
7. DRILLING LINE
8. DEADLINE ANCHOR
2. Power Generation System
AC-DC POWER GENERATION STATION EXAMPLE
1. GENERATORS
2. CONTROL PANELS
3. TRANSFORMER
4. DC MOTOR
5. DIGITAL DRILLER CONSOLE
6. MOTOR CONTROL CENTER
3. Mud Circulation System
1. MUD PITS
2. MUD MIXING HOPPER
3. MUD PUMPS (HI AND LOW PRESSURE)
4. SHAKERS
4. Well Control System
1. RIG FLOOR MUD MANIFOLD
2. INSIDE BOP
3. BOP STACK
4. CHOKE & KILL LINES
5. CHOKE & KILL MANIFOLD
6. BOP ACCUMULATOR
7. BOP CONTROL MANIFOLD
Subscribe to:
Posts (Atom)