1. Overview of Drilling Fluids

Advanced Drilling Fluids PE 7123 Fall/2005

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Overview

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Schematic of Example Rig Circulating System for Liquid Drilling Fluids

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Drilling Fluids 

API defines a drilling fluid as:  –  A circulating fluid used in rtar! drilling t

 "erfr# an! r all f t$e varius functins re%uired in a drilling "eratin 

&$is i#"lies t$at rtar! drilling is i#"ssi'le (it$ut a circulating fluid

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Fails t cnsider t$e five #a)r #ud functins

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Drilling Fluids 

A 'etter definitin  –  An "ti#u# drilling fluid is ne in ($ic$ t$e

fl( rate necessar! t clean t$e $le results in t$e "r"er $!draulic $rse"(er t clean t$e 'it fr t$e (eig$t and rtar! s"eed i#"sed t give t$e l(est cst* "rvided t$is c#'inatin f varia'les results in a sta'le 're$le t$at #eets fr#atin evaluatin criteria and "enetrates t$e desired target+ Advanced

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Drilling Fluid Functions 

-ling and lu'ricating t$e 'it

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-leaning t$e 'tt# f t$e 're$le f drilled cutting

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&rans"rting cuttings t t$e surface

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.ta'iliing t$e (ell're

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All(ing ade%uate fr#atin evaluatin

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 And more… Eert sufficient $!drstatic "ressure against  "rductive fr#atin t "revent t$e# fr# fl(ing int t$e (ell're  ee" t$e (ell're "en until steel casing can 'e run  .eal ff t$e "er#ea'le fr#atins (it$ a t$in filter cae  Assist in t$e cllectin f infr#atin fr# t$e (ell in t$e fr# f cuttings* cres* and (ell lgs  .u""rt "art f t$e drillstring t$rug$ 'u!anc!  -ntrl drilling rates 

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Drilling Fluids Should O! 

e $ar#ful t "ersnnel nr t$e envirn#ent

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Interfere (it$ fr#atin evaluatin

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Da#age t$e "rductin rate fr# t$e fr#atins

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-ause crrsin f t$e drilling e%ui"#ent and su'surface tu'ulars

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"hy Are "e Concerned over Drilling Fluids 

All drilling "r'le#s are related t drilling fluids

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6an! (ells are a'andned 'ecause f "r drilling fluids

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Drilling fluid csts can 'e ecessive ver 81*000*000 n s#e (ells9

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Drilling Fluids Are Selected on the #asis of  

&$e t!"es f fr#atins s$ale!ness9 t 'e drilled

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&$e range f te#"erature and "ressure encuntered

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&$e t!"e f fr#atin evaluatin needed

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&$e (ater %ualit! availa'le

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Eclgical and envirn#ental cnsideratins

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And* 888888

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!ypes of Drilling Fluids 

Air;as  –  Dr! air r gas  –  Fa# #uds  –  Aerated #uds

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=aterase 6uds  –  entnite  –  P$s"$ates  –  A gelc$e#ical #ud  –  -alciu# #uds  –  >( slids/nndis"ersed

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