LEC 4 OCT III The Drilling Fluid.pptx

7/17/2019 LEC 4 OCT III The Drilling Fluid.pptx

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The Drilling FluidLecture 4

PETQ 1 2015-2016

Abu Dhabi Polytechnic



Drilling fuid technology has become increasinglysophisticated and deserves treatment as a separate eo the drilling system



Drilling Fluid

•The rst drilling fuids consisted owater, later "mud”

•Use o salt water, various types onatural and synthetic oils, air, nitrogen,natural gas, mist and oam

•Selection o drilling fuid to use or aparticular well, and the selection o

materials to add is determined bywell ob!ectives,

epected ormation types,

subsurace temperatures and pressures,

anticipated drilling problems, and

material cost and availability

The variabilityparameters negives rise to a o mud types,broadly classi

three categori



Drilling Fluid Types

•Water-base systems, resh or salt water, commercialadditives designed to optimi#e mud properties

•Oil-base systems, diesel oil or a synthetic oil$ These havtendency to alter formation properties and cause damathan water%base muds, and are more suitable or high-temperature environments$

•Pneumatic systems, air, gas, or oams, which are or ushard roc& or severely depleted ormations



Drilling Fluid Types

' properly designed and well%maintained mud sysinstrumental in

• (ontrolling subsurace pressure

• )emoving and transporting drilled cuttings, andcuttings in suspension when circulation is halte

• Sealing o* permeable ormations and stabili#inwellbore

Drilling Fluid



Drilling Fluid Functions

• +reventing ormation damage

• (ooling and lubricating the bit and drillstring

• Transmitting hydraulic horsepower to the

bit

• acilitating the collection o ormation data



't any point in a wellbore, a column o drillingfuid eerts a hydrostatic pressure -+. that ise/ual to the density o the fuid - . times theϱheight o the fuid column -h.

Control of Subsurface Pressures



Control ofSubsurfacePressures

controlling the pressureo the fuid column byad!usting the drilling fuiddensity, or mud weight,such that the resulting

wellbore pressurecounteracts the ormationpressure% T0D -h. beingcontrolled by drilling



Control ofSubsurfacePressures

The goal is to &eep themud weight high enoughso that ormation fuidscannot enter the wellbore,while at the same time

&eeping it low enough tooptimi#e drillingperormance and avoidracturing the subsuraceormation



CuttingsRemoval,Transport andSuspension

• The drilling fuidmust have su1cientviscosity to lit roc&cuttings rom

underneath the bitas they are drilled,and carry them upthe annulus to thesurace



CuttingsRemoval,Transport andSuspension

• a drilling fuid msu1cient gel stcuttings in suspcirculation stop

•

the fuid velocitimportant to prcleaning

• 'nnular velociti100 and 200 ft/m6s7 are usual

• 'nnular velocitito calculate the a given sample removed rom tthe hole, which correlated to de



Sealing oPermeable

Formations,Stabilizing theellbore andPreventingFormationDamage

• Drilling fuids shodesigned to depopermeability "ltsolid mud particlborehole wall op

permeable orma This imro!es "elan# re!ents a nu#rillin% an# ro#ucsuch as 'ti%ht' holoor lo% (uality& intor(ue an# #ra% o

strin%& stuc) ie& an# $ormation #am

*ar# roc) $ormatioha!e a ten#ency tbe #rille# "ith air&"ater as a #rillin%



Sealing oPermeable

Formations,Stabilizing theellbore andPreventingFormationDamage

,ellbore stability is controllethe hy#rostatic ressure o$ than# artly by chemical interamay occur bet"een the mu#

minerals "ithin a %i!en $ormhemical a##iti!es may rommu#.s ability to re!entin% $oinstability& but e!en more imthe lacement o$ a (uality /l

the "alls to )ee +ui# in!asiominimum



Cooling and!ubricatingthe "it andDrill String

This $unction is rimarily er$the bottom o$ the #rill strin%&bit is $orce# a%ainst the bottohole an# rotate#

orce alie# to the bit may 10&000 to #$$,$$$ lb 45 to an# rotatin% see# may ran%to %$$ rpm



Cooling and!ubricatingthe "it andDrill String

This combination o$ "ei%ht a%enerates tremen#ous fricti"ithin the bit that must be re

the circulatin% +ui# to re!en"ear Lubricants a##e# to thesystem can hel re#uce $rictibit an# bet"een the #rillstrin



Transmitting&ydraulic&orsepo'erto the "it

Durin% circulation& the rate o(o' shoul# be re%ulate# so mu# ums #eli!er the otimo$ hydraulic energy to clea

ahea# o$ the bit*y#raulic ener%y also ro!i#$or mu# motors to rotate the easurement ,hile Drillin% Lo%%in% ,hile Drillin% L,D7



Transmitting&ydraulic&orsepo'erto the "it

*y#raulics ro%rams are bassizing the bit nozzles to mthe hy#raulic horseo"er or

$orce imarte# to the bottom



FacilitatingtheCollection ofFormation

Data

The mu# system is critical tosuccess$ul $ormation e!aluatro%ram Durin% #rillin%& $or mu# lo%%ers monitor mu# re#rille# cuttin%s $or mineral coan# in#ications o$ hy#rocarbo



FacilitatingtheCollection ofFormation

Data

They recor# this in$ormation lo% that sho"s litholo%y& enrate& %as #etection an# oil-stcuttin%s

easurement-,hile-Drillin% Lo%%in%-,hile-Drillin% L,D7 are li)e"ise in+uence# by thero%ram& as is the lannin% ae8ecution o$ corin% ro%rams"ireline lo%%in% ro%rams



Drilling FluidFormulation

A "i#e !ariety o$ mu# comonents an# chemica!ailable to hel control #rillin% +ui# roertiessystem er$ormance :ome common e8amles

• )iscosi*ers& such as bentonite& "hich im

+ui#<s ability to remo!e cuttin%s $rom the "esusen# cuttin%s an# "ei%ht materials #urinnoncirculation

• eighting materials& such as barite bar"hich are use# to increase #rillin% +ui# #ens

• Rheology control additives& such as lignopolymers& "hich are use# as thinners to im

roerties• !ost circulation materials; any o$ a !ariet

act to lu% orous& ermeable 9ones& inclu#ishredded cellophane, mica (a+es, and v

• any other a##iti!es are #esi%ne# $or $unctip& control to shale stabilization to corr

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LEC 4 OCT III The Drilling Fluid.pptx