4.drilling equipment
DESCRIPTION
capitulo 8TRANSCRIPT
Instituto Superior TécnicoUniversidade de Lisboa
Masters in Petroleum Engineering 2014-2015
Drilling Engineering Course
José Pedro Santos Baptista
Mining and Geological Engineering Msc.Petroleum Engineering Msc.
Drilling Engineering Course
2
4. Drilling Equipment
Casing
Tubulars, Mud, and Cement
Drill Bit
Characteristics and Types
Drill String
Components, BHA Design
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
4. Drilling Equipment
3
Mechanics (Steel)
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Stress and Strength
Stress = Load divided by the cross-sectional area where the load is applied
Strain and Stretch
Strain = Stretch divided by original Length
Young Modulus
E = Stress divided by Strain
4. Drilling Equipment
4
Mechanics (Steel)
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Elastic limit
Limit beyond which, when stress is removed, the steel will have acquired a permanent stretchMinimum Yield Stress
The stress which gives a strain of 0.5%. When stress is removed, the steel will have acquired 0.2%of permanent deformationUltimate Tensile Stress
The maximum stress on the curve, very close to the stress which will cause steel failure
4. Drilling Equipment
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Steel Properties
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Yield Strength
The level at which the material changes from predominantly elastic to predominantly plasticstrain behaviour (psi)
Tensile Strength
The highest stress level a material achieves before it fails (breaks) (Lbs)
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Functions of Casing
Provide structural integrity to the well
Control troublesome zones (over-pressured, weak and fractured formations,unconsolidated, etc…)Prevent cave-ins
Isolate porous formations (different fluid pressure regimes) allowing drilling and production
Allow selective communication between the formations and the well
Cover up problems in existing casing
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Functions of Casing (Cont.)
Serve as a high-strength flow conduit from reservoir to surface both for drilling and productionfluids
Prevent near surface fresh water zones from contamination (reservoir fluids and drilling fluids)
Provide connection and support of the wellhead equipment and blow out preventers
Provide exact dimensions for running testing, completions and production subsurface equipment
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Functions of Casing (Cont.)
All Casing shall be designed to withstand all loads that can be imposed on them during installation and the lifetime of the well
No well construction program should be put forward without an approved casing design
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Types
Cassion Pipe
(not mandatory)
(Offshore) Driven into the sea bed
Tied Back to the conductor or surface casing and does not carryany load
Prevents washouts of near surface unconsolidated formations
Ensures the stability of the ground upon which the rig is seated
Serves as a flow conduit for the drilling mud to the surface
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Types
Conductor Pipe
Conductors can be driven, jetted in or drilled and cemented in place
Outermost casing string
Between 40-500ft in length onshore and up to 1000ftoffshore
Isolates weak formations
Prevents erosion of the ground below the rig
Provides a mud return path
Supports the weight of the subsequent casing stringsand the wellhead equipment
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Types
Surface Casing
Depths vary from 300 to 5000ft
Setting depth is often determined by regulators orcompany policy rather than technical reasoning
Provides a base (means to nipple up) for the BOP
Provides a casing seat strong enough to safely shut-inthe well
Provides protection for shallow aquifers
Provides wellbore stabilisation
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Types
Intermediate Casing
This casing type should be set within more competent formations than thesurface casing, thus allowing higher blow out protection for drilling deeper
Purely technical casing (a.k.a. protective casing)
Length varies from 7000 to 15000ft
Provides isolation of potentially troublesome zones
(abnormal pressures, unstable shales, lost circulationzones, salt sections, etc.)
Provides integrity to withstand the high mud weightsto reach TD or the next casing string
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Types
Production Casing
This type of casing is often not cemented to surface
Set through the productive zone(s)
Designed to hold the maximum shut-in pressure
Designed to withstand the stimulating pressuresduring completions and workover operations
Provides zonal isolation (prevents fluid migration)
Confines production to wellbore
Provides the possibility to install subsurfacecompletion equipment
Provides protection in case of tubing failure
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Types – Liners
Casing strings that don’t run all the way to the surface, beinghung in the previous casing shoe or even overlapping theprevious casing
Drilling Liner
Production Liner
Scab Liner
Scab Tie-Back Liner
Mainly run for economic reasons but also mechanical,technical and safety (avoid having an annulus up to surface)
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Classification
API Standardisation is the most commonly used method of classifying casing
Outside Diameter (OD)
Inside Diameter (ID)
Length (range)
Weight
Type of Connection
Grade
API: 5C3, 5CT, 5L, 5B
Size
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Size
(OD-ID)/2 = Wall Thickness
Manufacturers often produce casing slightlylarger than specified, nonetheless, there isan approved OD tolerance: -0.5% to +1%
ID is specified in terms of wall thickness anddrift diameter (size of a drift mandrel)
Minimum wall thickness is 87.5% of thenominal wall thickness
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Length – Range
API 5CT
Casing Weight
Determined by nominal pipe body wall thickness expressed as weight per unit length
Nominal Weight, Plain-end Weight or Threaded and Coupled Weight (Average)
Tolerance: -12.5% to 0%
Range Length (ft) Average Length (ft)
1 16-25 22
2 25-34 31
3 Over 34 42
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Type of Connection
Mechanical device used to join pipe together (>90% of string failures occur in the connection)
Should be as strong as the pipe it connects and have similar geometry
Structural elements (properties)
Threads
Shoulders
Seal
Body
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Grade
The steel grade of the casing relates to the tensile strength of the steel
The steel grade is expressed as a code number which consist of a letter and a number
Letter Arbitrarily selected to provide a unique designation for each grade of casing
Number Designates the minimal yield strength of the steel (in thousand psi)
Example: K-55 Yield Strength of 55000psi
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Mechanical Properties
Casing is subjected to different loads during running, landing, cementing, drilling andproduction operations
Tensile LoadsBurstCollapseWear (erosion)
Combination of several loads combined (Von Misses equivalent, VME)
VibrationShock (pounding)Gun perforatingCorrosion
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Mechanical Properties
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
How do we select it?
It usually depends on four considerations
1) Physical Strength (tension, burst, collapse, torsion, compression or combined tri-axial loads
2) Chemical Properties (resistance to H2S, CO2, water, etc…)
3) Availability
4) Cost
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
How do we select it? – Physical Strength
Pressure – Burst
Pressure – Collapse
Axial – Tension
Triaxial (VME) Combination of pressures and tensions/stresses
Maximum Load Case Condition for Burst
Calculate resulting loads (Load Line)
Multiply Load Line by Design factor (Design
Line)
Select Casing String with load capacity
equal or bigger than Design Line
Maximum Load Case Condition for Collapse
Calculate resulting loads (Load Line)
Multiply Load Line by Design factor (Design
Line)
For casing selected in burst design, check that load capacity
equal or bigger then Design line
Maximum Load Case Condition for Tension
Calculate resulting loads (Load Line)
Multiply Load Line by Design factor (Design
Line)
For casing selected in Collapse design, check
that load capacity equal or bigger then
Design line
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Grade is selected! How long is each string and how many strings?
Casing Shoe/Seat Placement
Initial selection of casing setting depth is based on the pore and fracture pressure gradients forthe well
Lithological Column (problem zones, salt zones, fractured formations, etc…)
Minimum Hole Size in the reservoir
Temperature Profile
Fluids encountered (Water,oil, gas, H2S and CO2)
Well objectives (exploration – cost is secondary; or development – minimise cost)
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Grade is selected! How long is each string and how many strings?
Casing Shoe/Seat Placement
Should Be designed from bottom upwards
After the preliminary shoe depth selection, hole sizes and mud weights has been done a study of kick tolerance should be carried out at each shoe
The hole section shouldn’t be drilled deeper than is possible to safely circulate out a kick!
4. Drilling Equipment
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Casing
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Casing Shoe/Seat Placement – Pore & Frac
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Functions of Mud
Remove cuttings from the well
Control formation pressure
Suspend and release cuttings
Seal permeable formations (mud cake)
Maintain wellbore stability
Minimise reservoir damage
Cool, lubricate and support the bit and drilling assembly
Transmit hydraulic energy to the tools and bit
Ensure adequate formation evaluation
Control corrosion
Facilitate cementing and completion
Minimize impact on environment
Prevent gas hydrate formation
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Functions of Mud – Remove cuttings from the well
Function of
Mud Loggers determine the depth where the cuttings originated and analyse at their properties at the well site
Mud properties are critical are the primary cause of non productive time in drilling
operations
Strongly influence bit performance
Cutting size, shape and density
ROP
RPM
Flow rate and profile (annular velocity)
Wellbore orientation (inclination)
Mud Properties (density and viscosity)
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Functions of Mud – Control Formation Pressure
Avoid losses, kicks and formation instability
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Functions of Mud – Formation Damage (Skin)
The drilling muds selected in the drilling program need to minimise the formation damage,especially in the reservoir
Formation damage
Specially designed fluids are used for workover and completions
Reduction of the natural
porosity/permeability/
Wettability
Mud or drilling solids invade the formation matrix
Swelling of formation clays within the reservoir
Solids precipitation with the fluid mix (insoluble salts)
Mud filtrate and formation fluid form an emulsion
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Types of Mud
Water Based Mud
Water base with clays (bentonite) and other chemicalsLowest Cost but can react with some formations
Oil Based Mud
Base petroleum product (e.g. diesel); ToxicVery good drilling/formation propertiesMid Cost; use might be restricted
Synthetic Based Mud
Base synthetic oil (less toxic)Very good drilling/formation propertiesHighest cost
Thin and free flowing while pumped
Thick when pumping stops (gelling)
Non damaging to the reservoir (low reactivity)
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Mud Additives
Alkalinity and PH Control
Bactericides
Calcium Reducers
Corrosion inhibitors
Defoamers
Emulsifiers
Filtrate reducers
Flocculants
Lime, caustic soda and bicarbonate of soda
Paraformaldehyde caustic soda, lime and starch preservatives
Caustic soda, soda ash, bicarbonate of soda, some polyphosphates. Prevent contamination effects
Hydrated lime and amine salts. Prevent effects of oxygen and hydrogen sulphide (OBMs excellent anti-corrosion)
Reduce surface tension. Reduce foaming action in salt/saltwater mud based systems
Create an homogeneous mixture of two liquids. Fatty acids, amine derivatives and modified lignosulfonates
Reduce the amount of water lost to the formations. Bentonite clays, CMC and pre-gelatinized starch
Salt, hydrated lime, gypsum and sodium tetraphosphates
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Mud Additives
Foaming Agents
Lost Circulation Materials
Lubricants
Pipe-Freeing Agents
Shale-Control Inhibitors
Surfactants
Weighting agents
Used in air drilling. Create foam in the presence of water
Plug large openings preventing loss of whole drilling fluid. Nut shells (nut plug) and mica flakes
Used to reduce torque at the bit by reducing friction. Soaps, and some oils
Spotting fluids in areas of stuck pipe, reduce friction increase lubricity and inhibit formation hydration. Soaps, detergents, oils, surfactants
Control hydration, caving and disintegration of shale/clay formations. Gypsum, sodium silicate and calcium lignosulfonates
Reduce the interfacial tension between fluids (oil/water, water/solids, water/air, etc..)
Provide weight to the mud beyond its specific gravity. Barite, hematite, calcium carbonate and galena
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Drilling Fluid System
Delivers hydraulic horse power (HHP) to the bit
Cleans the bottom of the hole enabling the bit to reach new formation
Cools the downhole tools
Carries cuttings to surface
Design is a compromise between:
Bit Power
Hole Cleaning
Losses
Hole washouts
Equipment pressure (flow rate limits)
Pump Reliability
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Drilling Fluid System
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Drilling Fluid System
Tanks (pit) and mixers
Shale Shakers
De-gasser
Cyclone De-sander
De-silter
Mud Cleaner
Centrifuge
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Drilling Fluid System
Tanks (pit) and mixers
Shale Shakers
De-gasser
Cyclone De-sander
De-silter
Mud Cleaner
Centrifuge
4. Drilling Equipment
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Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Drilling Fluid System
Tanks (pit) and mixers
Shale Shakers
De-gasser
Cyclone De-sander
De-silter
Mud Cleaner
Centrifuge
4. Drilling Equipment
39
Drilling Fluids – Mud
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Drilling Fluid System
Tanks (pit) and mixers
Shale Shakers
De-gasser
Cyclone De-sander
De-silter
Mud Cleaner
Centrifuge
4. Drilling Equipment
40
Drilling Fluids – Cement
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Purpose of Cement
The introduction of cementacious material into the annulus between casing and the open holeprovides:
Zonal Isolation
Support for the axial load of subsequent casing strings (shear bond)
Casing support and protection
Support the borehole
Oilfield cement is manufactured according to the API specification 10A (classes: A to H)
4. Drilling Equipment
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Drilling Fluids – Cement
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Purpose of Cement
Cements may be modified with “additives” to deliver required properties according to thecement job:
Accelerators
Retarders
Slurry density reducers/enhancers
Temperature Resistance
Compressive Strength
Flow properties
Elasticity
4. Drilling Equipment
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Drilling Fluids – Cement
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Purpose of Cement
Cementation is the final, and crucial, operation in securing a well section!
This operation must achieve:
High quality uncontaminated cement that bonds the casing with the formationHigh compressive strength
Well control during the operationFloat equipment (prevent flow inside casing, AKA U-tubbing)
Prevent channelling (flow outside casing)Isolation of water/hydrocarbon zones
Protection from corrosive fluids
4. Drilling Equipment
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Drilling Fluids – Cement
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Downhole Cementing Equipment
Float Equipment
Prevent back-flow when cement is pumped in place
Provide landing shoulder for wiper plugs (collar)
Provide guide for casing (shoe)
Enable pressure test of casing after displacement cement (collar)
4. Drilling Equipment
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Drilling Fluids – Cement
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Downhole Cementing Equipment
Wiper Plugs
Remove drilling fluid residue from casing (bottom plug)
Separate drilling fluid/spacers from cement
Wipe Cement residue from casing
Enable pressure test of casing after displacement;
landing on float collar (top plug)
4. Drilling Equipment
45
Drilling Fluids – Cement
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Surface Cementing Equipment
Cement Head
Enable sequential release of cement plugs
Provide circulation path for drilling fluid,spacers and cement
4. Drilling Equipment
46
Drilling Fluids – Cement
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Accessories: Cementing Equipment
Centralisers
Provide casing centralisation (stand-off from the bore hole)
Minimising cement channelling, enable cement uniform distribution
Scratchers and Wipers
Scrape the “wall cake” from the borehole enabling cement bonding
More on Cementing operations in the next lecture
4. Drilling Equipment
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Casing & Cementing Example
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
4. Drilling Equipment
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Drill String
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
“The combination of the drillpipe, the bottom hole assemblyand any other tools used to make the drill bit turn at thebottom of the wellbore.”
- Schlumberger
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Steel-toothed piece of equipment attached to the end of thedrill string designed to crush, scrape and grind rock
Roller CuttersSteel ToothTungsten Carbide Inserts
Fixed Cutters (Drag Bits)DiamondPolycrystalline Diamond Compact (PDC)
Hybrid
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
During the planning stage, the drilling engineer mustreview all the offset well data (bit performance record)and correctly select the drilling bits required to drill thewell
Expected lithological column w/description of each formation
Drilling fluids details
Well Profile
4. Drilling Equipment
51
Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters
Two or more cones containing the cutting elements
The cones rotate around the their axis, they rotatedue to string rotation and not due to any internaldriving force
Structural Materials
Bearing-seal-lubricating design
Cutting Structure and hydraulic arrangements
4. Drilling Equipment
52
Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters
Tungsten carbide insert (TCI)
Inserts pressed into the cone
Milled Tooth (MT)
Steel Tooth pre-milled and covered withhardfacing
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters – External Anatomy
1 API Pin (American Petroleum Institute)
2 Leg
3 Shirttail
4 Nozzle Boss
5 Nozzle
6 Cone
1
2
3
4
5
6
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters – Internal Anatomy
1 Secondary (inner) Bearing
2 Primary (outer) Bearing
3 Primary Seal
4 Secondary Seal
1
2
34
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters – Internal Anatomy
1 Grease Reservoir
2 Grease Long Tube Hole
3 Ball Hole
4 Seals
5 Ball Bearings (cone retention)
1
2
345
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters
TCI Cone
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters
Milled Tooth Cone
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters – Structural Materials
Appropriate yield strength
Impact resistant
High machinability
Subjected to heat treatment
Cones are usually heat treatedNiMo-Steel alloy
Teeth are heat treatedNiCrMo-Steel alloy
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters – Bearing-Seal-lubricating Design
Function as a unit
Must Withstand
Types of Bearings
Large Impact LoadsHarsh Chemicals of the drilling fluidsHigh temperatures
Standard Open BearingsSealed Bearings (Grease Lubricant)
Journal Bearings (Solid Lubricant)
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters – Cuttings Structure Arrangements
1 Indentation and Fracture Weight On Bit (WOB)2 Tooth Displacement Rotations Per Minute (RPM)
Soft Formations – Gouging and Scraping
Most Aggressive Cutting actionHigh Rate of Penetration (ROP) Applications
Hard Formations – Chipping and Crushing
Most Durable Cutting ActionLow ROP Applications
1
2
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters – Cuttings Structure Arrangements
Offset is the horizontal distance between the axis ofthe bit and a vertical plane of the journal
4. Drilling Equipment
62
Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters – Cuttings Structure Arrangements
Journal angle is the angle formed by the axis of thejournal and a plane perpendicular to the bit axis
Soft-Medium formations
Low Journal Angle (30°- 33°)
Medium-Hard formations
High Journal Angle (34° - 39°)
4. Drilling Equipment
63
Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters – Cuttings Structure Arrangements
The Cone may have different tooth shapes
Long Designed to drill soft formations, with lowcompressive strength (easily penetrated,more yielding)
Short Designed to drill hard formations, with high compressive strength (by fracturing)
4. Drilling Equipment
64
Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Fixed Cutters (Drag Bits)
Fixed cutter blades that are integral with the body of the bit, rotating as a unit with the drill string
Cutting elements
Design Parameters
Steel CuttersDiamond CuttersPolycrystalline Diamond Compact (PDC)
Bit ProfileBlade ConfigurationCutter LayoutCutter OrientationNozzle PlacementGauge Pad Considerations
4. Drilling Equipment
65
Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Fixed Cutters (Drag Bits) – Bit Profile
Apex Geometrical centre of the bit
ConeShallow Cone (~150°)Medium Cone (~115°)Deep Cone (~90°)
SteerabilityBit CleaningAggressiveness (ROP)
StabilityDiamond Volume in the centre
Bit StabilityDiamond Volume in the centre
SteerabilityCleaning EfficiencyBit aggressiveness (ROP)
4. Drilling Equipment
66
Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Fixed Cutters (Drag Bits) – Bit Profile
Nose
Large RadiusHard transitional formationHigher surface area (better load distribution)
Small/Sharp RadiusSoft homogeneous formationLower surface area (higher point loading/Increase penetration)
4. Drilling Equipment
67
Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Fixed Cutters (Drag Bits) – Blade Configuration
Number of blades From 3-20 blades
Blade Symmetry
Blade Geometry
Cutter Size >Larger Diameter > more aggressive (in mm)
Cutter Structure
SymmetricAsymmetric
Straight Spiral
Single SetMulti Set
RandomForwardReverse
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Roller Cutters Vs Fixed Cutters (Drag Bits)
Less Torque
More Vibration
Non Homogeneous formations
Moving Parts
Older > Optimised Design
Cheaper
More Torque
Less Vibration
Homogeneous Formations
Solid and Stronger
Newer
More Expensive
4. Drilling Equipment
69
Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Bit Classification – Drag Bits
International Association of Drilling ContractorsIdentify similar Bit types made by different manufacturers
Each type of bit has a four digit code
1st Digit Defines the type of cutter and body material (letter: D;M;S;T;O)2nd Digit Defines bit profile (number, 1-9 and G= gauge height or C= cone height)3rd Digit Defines the hydraulic design (number, 1-9)4th Digit Defines the cutter size and density (number, 0-9)
4. Drilling Equipment
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Drill String - Bits
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Bit Classification – Roller Bit
International Association of Drilling ContractorsIdentify similar Bit types made by different manufacturers
Each type of bit has a four digit code
1st Digit Defines if MT or TCI and formation hardness (number, 1-8)2nd Digit Defines sub classification of formation hardness (number, 1-4)3rd Digit Defines type of bearing and presence of gage protection (number, 1-7)4th Digit Defines general bit information (letter, A-Z)
135MSoft Formation milled tooth bitRoller bearings w/ gauge protectionMotor Application
4. Drilling Equipment
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Drill String – Hole Openers/Gauge maintenance
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
4. Drilling Equipment
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Drill String – Hole Openers/Gauge maintenance
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
4. Drilling Equipment
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Drill String – Drill Pipe
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Serves as a conduit/conductor for drilling fluid and transmits rotation from surface tothe bit
A pierced, seamless tube of forged steel or extruded aluminium tool joints attached toeach end of a seamless tube
The tool joints provide drill string connectivity and are separate pieces of metal weldedto the tube, thick enough to have a pin or box cut into them
Classified with: Size, Length (range), Grade, Weight and class
Example: 5’’, Range 2, G-105, 19.5 ppf, New
4. Drilling Equipment
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Drill String – Drill Pipe
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
4. Drilling Equipment
75
Drill String – Drill Collar
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Heavy walled metal tubes with threaded ends (box and pin)
Provide weight on bit and keep the string from buckling
Spiral collars are used where there is a change of getting stuck in the hole
Square collars are used in crooked holes
4. Drilling Equipment
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Drill String – Drill Collar
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Protect the drill string from bendingControl direction and inclination of wells
Drill straighter holes or vertical holesProvide Pendulum effect
Reduce dolegs, key seats and ledgesImprove the probabilities of running casing in the hole
Increase bit performanceReduce bouncing and sticking of the string
4. Drilling Equipment
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Drill String – Heavy Weight Drill Pipe
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
HWDP has higher weight and longer tool joins than normal DP
Used in transition zones between the DCs and DPs avoiding the DP from buckling(theoretically may be used in compression) and to provide a smooth transitionbetween different sections of the drill string components
Shouldn’t be used to obtain WOB in vertical wells (may also buckle)
Same OD as DP but with much smaller ID
4. Drilling Equipment
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Drill String – Pipe
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
All drill string components, especially pipe (DP, HWDP and DC) should have amechanical thorough study regarding (mechanical) loads
Tension
Torsional Strength
Burst
Collapse
Biaxial (Tension & Torsion and Tension and Collapse)
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Drill String – Stabilisers
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Stabilizer tools are an important part of the BHA that allow the DD to control
Control Hole DeviationDogleg Severity
Prevent Differential stickingConcentrate the weight of the DC on the bit
Stiffness of the DS (reducing torque and bending stresses)
Centralise the DS without digging into the borehole wall!
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Drill String – Stabilisers
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Directional Assemblies using Stabilizers – Pendulum Principle
Removing the stabilizer above the bit and adding additional DC making the BHA more flexible
The upper stabilizers, properly placed, hold the bottom DC away from the low side of the hole
Gravitational forces act on the bottom collar and bit causing the hole to drop (decrease inclination)
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Drill String – Stabilisers
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Directional Assemblies using Stabilizers – Fulcrum Principle
Installing a stabilizer just above the bit, when it is rotating, enough weight is applied bowing thebottom collars
The bow causes the bit to push against the top side of the hole, resulting in a build up (increaseinclination)
4. Drilling Equipment
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Drill String – Stabilisers
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Directional Assemblies using Stabilizers – Stabilization Principle
Installing stabilizers at specified points in the BHA to increase stiffness, preventing the string tobend or bow forcing the bit to drill a straight hole
Packed Assemblies are designed to maintain borehole angle
4. Drilling Equipment
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Drill String – Motors
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Turbine Multistage blade-type rotor and stator sections (vary from25-50), a thrustbearing section and a drive shaftRotor blades connected to the drive shaft and powered by the circulating mud
PDM (Positive Displacement Motor)
Rotor and Stator (power section), by-pass valve, universal jointand a bearing assembly
4. Drilling Equipment
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Drill String – Motors
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
PDM (Positive Displacement Motor)
Power Section
Helical Steel rotor fitted inside a spirally-shaped elastomer moulder stator
Mud fills the cavities between the rotor and stator displacing the rotor causingrotation (elliptical movement) which is then converted into circular rotation by theuniversal joint assembly
4. Drilling Equipment
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Drill String – Stabilisers + RSS/Motor
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Directional Assemblies using Stabilizers
4. Drilling Equipment
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Drill String – Float Valve
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Check valve that has a spring-loaded plate (or flapper valve)
May be pumped through, generally in the downhole direction, but closesif the fluid attempts to flow back through the drill string to the surface.
Reverse flow might be encountered due to
U-tube effect when the bulk density of the mud in the annulus is higherthan that inside the drillpipeWell control event
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Drill String – MWD
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Measurement While Drilling
Real time well site evaluation tool (data) basic trajectory parameters
Inclination DirectionTool-face
Consists of a sensor package (accelerometers and magnetometers), Electronics package and aTransmission system
Powered through lithium batteries or with a downhole turbine (generator)
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Drill String – MWD
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Measurement While Drilling
Sensor package
Accelerometers gravitational measurement
Magnetometers magnetic field measurement
Electronics package
Transmission Mud PulseEM signalsWired pipe
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Drill String – MWD
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
Measurement While Drilling
Transmission Mud Pulse
Signal used for directional data
Opens (positive surge) and closes(negative surge, drop) a valve
Range of 10-15 psi decoded by a transducer in the standpipe
No depth limitations but rely on proper drilling fluid
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Drill String – Other equipment
Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
LWDXover
Bent SubsWhipstocks
4. Drilling Equipment
91Drilling Engineering Course 2014-2015 Masters in Petroleum Engineering
End of Drilling Equipment
Next Chapter: 5. Drilling Operations
Questions?