handoutroles of drilling fluid
TRANSCRIPT
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8/22/2019 HandoutRoles of Drilling Fluid
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Global Research & Technology Centre/ GRTC
Training Department
Roles of Drilling Fluids:Roles of Drilling Fluids:Functions andFunctions andMeasurementMeasurement
Roles of Drilling Fluids:Roles of Drilling Fluids:Functions andFunctions andMeasurementMeasurement
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THE DRILLING TEAM
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Drilling a Hole
Drilling out formationwith bit
The MUD bring thecuttings up to surface
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Logging in Production Hole
Pulling Out Of Hole (POOH)the Drilling Assembly
Running-In Logging Tools
Logging-up the formation
Circulation condition hole prepare MUD in the hole forstatic condition before loggingoperation
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Casing & Cementing
SURFACE CASING
Pulling Out Of Hole (POOH) theDrilling Assembly
INTERMEDIATE CASING
Running - In Hole (RIH)the Intermediate Casing
Pumping Cement
Displacing Cement with MUD
Waiting On Cement (WOC) to dry
Circulation condition hole prepareMUD in the hole for static conditionbefore running-in casing
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Why Do We Need Mud ?
TO CLEAN THE HOLE
How?How?
By bring the drillcuttings up to surface
How can the mud bringHow can the mud bring
the cutting?the cutting?Mud Viscosity
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What if it failed?
Drill cuttings slipped downto bottom
Drill string get STUCK !!
Drill cuttings filled up theannulus and bottom of thehole
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Why Do We Need Mud ?
TO CONTROL FORMATIONPRESSURE
How?How?
By provides HydrostaticPressure of the fluids column
How can the mud giveHow can the mud giveHydrostatic Pressure?Hydrostatic Pressure?
Mud Density
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What if it failed ?
FORMATION FLUIDS (WATER/OIL/GAS) FLOWS INTO THE WELLBOREUNCONTROLLABLE
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K+
K+
What does the mud do inside the hole?
Chemical ion toinhibit the clayfrom swelling ordispersion
Polymer toencapsulate drillcutting andpreventing it toabsorb water
Form mud cakeas a thin wall toprotect formationfrom mud filtrateinvasion
formation wellbore
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Function of Drilling Fluids
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MudCirculating
System
MudCirculating
System
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Mud Pump
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SHALE SHAKER
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Density
When we drill the wellbore wereplace a cylinder of rock with acylinder of mud.
The first critical step towardsdesigning a drilling fluid is to
establish the mud weight requiredto provide the correct level of borehole pressure support.
Pm - mud pressure
Pf - formation pressure
Bore hole pressure support
Pm > Pf
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Rheology/Viscosity
PLASTIC VISCOSITY As low as possible elevated plastic viscosity
levels are detrimental to everyaspect of thedrilling process. Every endeavor must bemade to control and minimise the plasticviscosity value.
6 RPM value
Low shear rate rheology, i.e. representative ofthe flow regime in the annulus.
Control 6 rpm value on the basis of hole size,well profile, anticipated pump rates andallowable drill string rotation (RPM).
YIELD POINT Yield point is driven by the appropriate low shear rheology, ie
the 6 rpm viscometer dial reading, for optimum hole cleaningefficiency.
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Filtration / Fluids Loss Control
API Filter Press HTHP Filter Press
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Filtration
The passage of filtrate into the formation due to thedifferential pressure
If the solids cannot block the pores and/or fractures thenmud will flow into the formation (lost circulation)
The solids in the mud usually forms as a filter cake whichprevents excessive fluid loss, the filter cake should :
Be thin
Have a low permeability - correct solids distribution
Have a low friction coefficient
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Filtration
Dynamic Filtration
cake builds until rate of erosion equals rate of deposition
when filter cake reaches equilibrium thickness fluidloss is constant
Static Filtration
cake growth with time
rate of filtration continues to decrease
static cake is thicker than dynamic cake
static rate of filtration is less
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Mud Composition (Retort Kit)
H2O
salt
100%
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Sand Content
Sand is abrasive, could createproblem in drilling equipment
Field practice : < 2% by volume
H2O
4.5 %
5.0 %
5.3%
Barite
Sand
Chemicals
Sand Content = 0.5%
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What is mud
LIQUID MUDSOLIDS
WATER
OIL
SALT
CHEMICALS
BARITE
BENTONITE/GEL
DRILL SOLIDS
WATER-BASE MUD
OIL-BASE MUD
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What is mud
LIQUID MUDSOLIDS
WATER
OIL
SALTCHEMICALS
BARITE
BENTONITE/GEL
DRILL SOLIDS
WATER-BASE MUD
OIL-BASE MUD
PRODUCTS PRODUCTS MUD SYSTEM
WATER
OIL
SALTCHEMICALS
BARITE
BENTONITE/GEL WATER-BASE MUD
OIL-BASE MUD
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Mud Component
1. Base fluids
2. pH Control
3. Viscosifier
4. Filtration Control
5. Weighting agent
6. Additional product :
Shale Control AdditiveCorrosion Inhibitor
Lubricants
Dispersants
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How to mix mud
Base Fluids
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How to mix mud (on the rig site)
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What should it do with drill cutting
To be separated out from themud
How?How?
Using Solid ControlEquipments
What equipment?What equipment?
Screen
Hydroclones
Centrifuge
Solids to
discard
Clean
mud to be
recycle
Mud + Drill
cutting from
hole
screen
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Solid Control Equipments
SHALE SHAKER
CENTRIFUGE
DESANDER
DESILTER
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Relation of Particle Size to Solids RemovalEquipments
SHALE SHAKERDESANDERDESILTERCENTRIFUGE