53042620 Horizontal Oil Well Drilling Technology

8/20/2019 53042620 Horizontal Oil Well Drilling Technology

1/117

Suer,Canal

Universitlt

Faculty

of Petroletm Mining Eng.

P

etro

eum

Engineering

D ept.

HonrzoNTAL

nWprr

DTIuNG

TBcmxoLoGY

Dr. Mohamed

ShehataFarahat

(2000)


2/117

Suen

Canal

University

Faculty

of

Petroleum

Mining

Eng.

Petroleurn

Engineering

Dept.

HOruZONTTAL

n WpLL

DTLLII{G TpcHNoLoGY

Dr. Mohamed

ShehataFarahat

(2000)


3/117

CoNrsNrs

SELECTIoNAND

REAsoNs FoRDRILLING

HORIZONTAL WELLST

AND DRATNHOLES

l.l

Seleclion of horizontal wells

and drainholes

1.2 Reasons

or

Drilling

Horizontal Well and Drainholes

1.3 Main Aoolications of Hoizontal

llells and Drainholes

1,3.1 Thin Formatious

1.3.2. Verticsl Natumlly

Fractured Fornrations

1,3.3Lotv Perm abilityFormations

1.3.4Heterogeneous eservob

r Formstions

1.3.5

Applicttion

in Resemoits riflt Botton

Water or

with o

Gas Cap

1,3.6 Advantages of Horizontal lVells in Offshore

Applications

1.3.7HeavyOil Applications

1.3.8SandProduction

Typns oF

HoRTzoNTAL

WELLS AND

Dr

proRnnt

Dnrr,r,rNc ncnNrquns

Usno

2.1

Utru-shott Turnins Radius

2.1.1

SystemProcesses ,td Equipment

or

Multiplc

Radisk

2.2

Short Tarnins Radius

2.3 Medium-TurningRadias

Page

#

I

3

3

5

5

o

o

8

9

9

l l

t2

22

27


4/117

t-

2.i.1 Dil fins

rttt

Mulinn-Rutlius

Dtilling

2.3.2 Metliunt-Rsdius

Dri iug

MoJors

an{ SlsteuLs-

2.3,3 HigbMedium

and

Lott-Soeed

Drilling

2.3.4Medium-Radius-Hoizo rtttl lltell Sections

2.3,4.

Vertical

Section

2.3.4.2

Curved

Sectiau

2.3.4,2

Horizoutsl

Section

2.4 Lottg-Radius

Horizontgl

lyell

2.4,1

Vertical

Section

2.4.2 Cumed

(Turning)

Section

2.4.3

H

orizoutal

Section

Pt,nNNtNc

r

lloRrzoNTAL

WnLl,s

AND DRAINHOI,ES

G

NOUNTRY

j.

Geontetrv

of

Horizontsl

WelI

or Drainhole

3.1

lf ell

Diameter

3'2

VplLltpllle

3.2.1

Fktt

wells

3.

2.2 I)

n lulatiug

wells

3.2,j

Llpt'ard

nclined

uells

3.2.4

Dou,nward

ttclined

wells

3.2.5

Multilet

el t'ells

3.2.6

Multi brtuch

3.2.7

Grsvit

drsinage

wells

3.2.8

Complex

well

shryes

3.

3 D esistlEqip

ntal-lysll

f&i949

Prye#

2A

30

34

34

35

36

39

4l

43

43

43

I

1

I

i

6

46

47

47

47

48

48

48

48

48

48

48


5/117

Page #

Dmrlrxcl PRosr-svs ssocnrso wttH

HoRtzoNteL

WBU-

DzuLLINGaNo THBTRREMEDY

4.1 DeliNery Weisht to the Bit

4.2Reducing

TorqueandDrsg Forces

a3

Epls_ekutus

ale

ftliag;4e

4.4 Protectian of lyater SensiliveShales

4.5 Direclional Control

4,5.I C assifrcation

f

hotto,n-

4.5.2Measurfug t'.slrune ls

4,5,2,1Steering

ool

4.5,2,2 M essurcntent-whileuillittg (Mll/D)

4.5.2.3

Geosteering,

Equipnrcnt and Irrstrume tfltiort

DRILLSTRING

DESIGN

72

HonrzoNrat, WELLConrplnrroN

TncnNreuns

6.1 Comoletion

Technolosict

:fu-U X4:[ 41-LglL s

H o

izontal Radial B ore

rc e

6.2

Conpletion Oltion

for

Short-Rtttlius,

Mediam-Radius,

ond -ong-Radius

f Horizotrtsl y'elk

Draiflholg;-

6.2,1Open

hole cotn elion

54

57

58

s9

60

6l

6l

62

62

68

89

94

I

I

j

i

I

I

l l

95


6/117

Poge

#

6.2.2 Tail

completion

and

slotted

iner completiott

95

AppucarIoNoF

COILED

ueINc

TN

HoRIZoNTALDRILLING

AND

MULTI-LATERAT,

CASB

STUOII]S

AND

HlsroRms

7.1

Coiled

Tubins

Drilli,tg

7.2

M&LUels

I

Ci?,ts]J:t

ldtet

7,2.1Case

7.2.2

Case

7.2.3

Case

7.2,4

Csse

4

7.3Multilatersl

Case

Histot

Case1

RunnnpNcns

t00

t02

103

t05

t07

109

l l l

l l t

I l - l

lv


7/117

Cn.

I llotizort\t lre s

Dtiuhry |

Cu,rprnn

SELECTION

AND

REASONS

OR

DRILLING

TIORIZONTAL

WELLS.

AND DRAINHOLES

:

1.1 Selection

o-f

horizofial u,ellsarul drainltoles:

l lorizontal wells are ofgrcat ntelest o thcpetrolcutnndttstryodaybecattsc

they

proviclc

an attractivc

nrcans or improving

both

plodtrction

atc and

rccovery

efficiency.

'l'hese

are due to

that horizontal

wellsprovide a latger

area of contact

wit l l t lrc cscrvoif

hando vctt ical;

wclls ancl,r l addit ion,

hcy

provide a means or

the latetal lansPodation

f f lt l id.Thus,

he horizorrtal

wells

can be dril led

asnew u,ells r ho

zontal idctracks,

ri l led o revitalrze

ttrc

pcrformance f

exit ing vert ical

wclls hatarecallcddrainholes

llc

past

fcw

years

havcseen

reat

mprovement

n dril l ing

echnology. cvelopments

suclr

as t lre use of bent,downhole

ril l ing

notors,op

drive igs, andMWD

(measurcment hilc dLil l ing) r

advanccd 4WD

allcd

gcoslecring

cchnique,

togcther

with stccrable

drill systcms

have

grcatly rcduced costs. Recent

horizontal

wclls

havc costno mora

pcr nctctofrvcll

t lt i l lcd hltn

conlpatablc

conventional

wells. Thus,

great

advances

ave also bcen

in nlcthods or

drilJing hort-radiusrainholes

tom crisling

vel1ical

cl1s.

The construction

and

placing

ofhorizontal

wells hasbecome

autine Usually

it is

no longer speculative

as to whether

horizontal

rvellscan be drilled-

Tn

most cases

no|, the choicc

s not whethcr

one can

dlil l horizontally,

ut

whethclon should.

l),-.M.S.Farrhat


8/117

CIl- I

IIo

urtutl

lrt

s

D'lllinA

Grcat

advancosn the technology

f dril l ing

and

locating orizontal ells

continue to be made. Today

much attention s being

paid

to thc

problems

of

re-entering existing vertical wells

using smaller diameter,mcdium-radiusand

short-radius equipment. These improvements will allow

a much larger

proportion of existing conventional wells to have heir live extended y re-

completion

with

long,hofizontal r ianholcs. hc

provision

f M WD too ls hat

will opemte in smaller diameterholes

s a

particularly

active area.Thorc arc

developmcnt, too, in logging tools.

Tools arc now available hat can be

opcrated while dril l ing to

providc

ir lfornratiotr

bout hc rcscrvoir

being

encountored.ocating he logging sensors loser o the dril l bit to

allowa

nore t imely evaluationof thebit

posit ion

ndo the rockbcing

penctrated

s

anotherareaof active dcvclopment.

Thus,

drilling a horizortal well

to exploit a reservoir

usually nvolvesseveral

important

uestions.

hcse

uestions

reas

ollows:

1.

Whcrc houldhewell

be

ocated?

2.

lr whatdirectionhouldhcwell

bc

drillcd?

3. Whcrc houldhckick-offpointKOI') ohorizontll c?

4. IIow ongshouldhehorizontal

ection e?

5, ls it neccssaryo stirnulatchcwcll?

The answerof these

questions

equire

athering

nformation bout he

reservoit

nd heconditions

xisting

n

thcarca.[o[izontal

ell

should otbe

drilled in

all cases, ateful

studyof tcchnicnleasibility nd economical

potcntial

of holizontal ril l ing s needed

eforc

ts application.

or these

lcasors, ccuratcesewoir rd adjustvclldata

hould c

collected.

Therefore,

he

horizontal

wells

are corsidered

easible

primarily

in the

following

reas:

l. Thinpermeableormation.

2. Verticalnaturally-fracturedormation.

3. Low

permeability

omation.

4. Formation

ithsand

roduction.

5. Fomation

withwater oning.

6.FoImation

ith

gas

oning.

D,: Nl.S.Frrahrt


9/117

AL I ottzo,tk lllrtts

Drtltl

t

3

7.Offshore pplications.

8.

cavy

oi l appl icat ions.

9.Fonnation ccess lowouts.

1.2

Reasons

or

Drillitts

Horizontal

Well

and Drsinlrcles

' l

hclc arc scvcml cnsorrso l l i l l

a

rol izorr lul

cl lnr l l rcr

l r iur

vct l ical

c l l .

'l'hcsc

rcasonsre:

l. Increasing

il

productivity.

2.

Connecting

eltical aturally

ractures.

3.

Producingrom ow-pemeability

eser.roits.

4.

Staying

way i-om il-gas nd

oil-water ontacts.

5.

Injecting tream

thcrrral

il rccovery).

6. Controllingand roduction.

7. I'r'oducinghin

hydrocarbons

eservoirs.

8. lncreasingnjccl

v

ty.

9.

l'roducing

as

iorncoal

scanls nd

proving

cttcr

wccp

fficicncy.

l0.lncreasinghe etumon he nvestment

ROl).

Sornctimes,

he cost

of a drilling a horizontalwell is more

than hat

ofa

vcr t ica lwcl l and

complet ior rostsarc usual lyh ighcr ' .lowcvcr ,

nto lc o i l

would be ultiuratcly ccovered

y thc horizontal cll.

[hus,

horizontalwcll

is

justified

n view ol'quicker

eturnon well investment.

Horizontal

wells and drainhole

can be mainly applied or the

following

circumstancer

pay

zollcs

reservoir-s)

halactcristics,amcly:

l. Thin

permeable

ornrations.

2. Verlicalnaturally racturedonnations.

3. Low

pelmeability

'ornrations.

4. Formzrtion ith sandproduction ndconingproblems.

1,3 Mgitr

A

licntionsof Hori ntal ,Y'ellsa,td Drainltoles


10/117

Iha izintal

llitlk

Dj iIIi

1.3.1

Thin

Formstions

When

consideriirg

hjn

onnation

or homogeneous

crnration,

t shoulcl

void

dtil l ing a horizontal el l into his onration hickcr han200 t. however,lr is

maximum pay

zone thjcloress

does

not hold

tnrc for

formatiolls

with

helerogeteous

fonnation

or

fotmaljon

with verlical

naturally

fractures,

as

shown

n Figure

1.1and

ig.

1.2.

Thlrrproducli lgzonos

Wale rcon lngprob lems

cas

con lng .p rob lems

Other

pp l l ca( ions :

leavy

rude,

on l

scams,

fo rmal ion

ccess ,

lowouts .

Fig.

1.1 A4oin

pplicotiotts

ofhorizottttl

trll,r.

INTERSECTION

F VERTICAL

FRACTUR€S

BY

I.JORIZONTAL

ELL

Fig. 1.2.

, / . M .S .F r r

xh r i


11/117

C

.

I llorizofttdl

lYc4s

Dtiqi ry

5

' lhus,

the

productivity

ndex

(PI)

for a roriT-ontalveilreflectshe ncreases

arca ofcontact ofthc

well

with the reservoir.

l'ypically,

the Pl for a horizontal

well maybe increased

y

a factor

of4

compared

o

a verticalwell

pcnctrating

the same reseloir, although enhancementby a factor of l0 or more may be

aclrievablen certain ircunrstance,sshown n Figure1.2.

1.3.2. Vet'tic Natt,trallv Fr'flct.rred Forut ions

A horizontal

well

provide

a means of communicatingwith natural vertical

fractures,

.

g.,

a high fractured

imestone.fthe

well

is orientedo intcrcst

thcsc ractureshe

productivity

ndexcanbe substantiallyncreascdvcn vhcn

thc

lrac(ure density is

low. Unfottrnatcly, his can also accclcratc hc

movement fgas or water o

reach

he wellbore.

l. 3. 3 Low Pernrcabilitv Fornntio tts

One

qucstion

is often asked by the opcratol tlrat is how low should thc

pcrnrcabil i ly

be

in a horrrogcnousornration

cforc

consi


12/117

CII. I

lln,ito

d lITtts

Dti i"p

PEBMEN

ILITY

EFFECT

75

lronizoNl

t wErt

vlntl :At.

wn.t

Irig. I -.1

Penrcdbili0

effcc|.

Heterose

Rese

ir

or Fo,'ntsti

A

l r . l i zo r r l , I

vc l l

r r r r ry

r . . v i r l c

r r r r r r r r l x r

r ' r r r r ' r r r r ( r r11es

' r rc r r

r .sc r r ' i r .

hclcrogencity

exisls

n thc

horizonlalplanc.

A

horizonlal

vcllborc

rr

lhc

lescrvoir provides

potential

for

far more

information

about he

reservoir

halr

would

nornrally

bc availnblc.

s logging

nd

conrplclion

cchrrirlucs

ccorno

more sophisticated,his aspect of horizontalwells is l ikely to be usecl

advantage.

Frotn a

prodrrction

iewpoint,

a

horizontal

ell in

an rregular

cservoir

ray

provide

a

mcans

faccessing

solated roductive

oncswhich

nright

other.wisc

be

missed.

Furthermore,

n

beterogeneous

eservoirs,

he

influence

of the

hctclogcneous

long hcwcllbolc s r.ctluccclry thccornpositc or,v con]clry,

so

thrt

production

ltcs

arcgclrcrl l ly

cnhlnccd

n

lhcsc it.crrnrs{anccs.

L3.5

Application

n Reselyl|I

tl'ith

BottQn

yqlqor

with n

Gns Cor2

In nrany

cascs,

rosclvoil

is thc

lhc nos l n tpor l ln l

i rc lo rin r i t ing

hc

p loc l r rc t ion

fo i l

f ionr

tcndcncy

bl

rvtrtcl

ionr

atrurrclcrlyi lg

cluitlr.,

r-

as

iorl

n

1]r.

M.S. , :rr , 'hxt


13/117

Ctl- I lloti. ti l lYdts

Dti ing 7

gas

cilp, to

bc dlawn vcr(ici i l ly

to

thcprod(rction

cll. l lor.izontal cl lscan

have substantial

advantages n

such lcsctvoirs. The conventional rvay

of

reducing thc

effect of coning

is to complete he vertical

well over a linritcd

vcrl icnl distaDce

o tnaxinlizc hc

stand ff front hc watcr

or

gas

cap,as hc

cascmaybc.

Because f i ts extended

ontact with the eservoir,

lrorizontal cl l

usually

has

lcss

pressure

rawdown

or a

givcnproduction

atc han

docsa

vcrtici l l

wcll.

This reduced

drawdown essenshe

endencyot thc coning

ofwater

or

gas

with the

produced

oil.

Thus, for example,horizontal

wells

may be

operatedat ths

santc atesas

aonventionalwells

but

rvith

less-sometimes

uch

less-coning,.e., witlr

bctterwater-oil

atios r

gas-oil

atiosor both,

n some

case,

productiol

without

coniDg

nray be economic

using horizontal cl ls,

whcrc it would

be

plohibitively

slow

with

conventionalwells.

In

situations

where the

jlitial

rate

for

production

without

fiee

gas

coning would

be

impractical \a,ith vcrtical

wells,

it may be

possible

with

horizontal

wells to

aclrieveeconomic

roduction

y

gravity

drainagc i lh

onJya small

atcofgas

injcction o maintain ascapplessure.

Even if oporation below

thc critical rate

or coning s impractical

bccausc

of

economics,

thero can stil l

be a large advantage or

horizontal welis.

This

situation s conlmonwhen

viscous,

onveutioualeavy

oils ale

produced

ronr

abovc a watcr layer.

When the

high oil viscosity nd helow

diffcr.encc

n

tlcnsity between the

oil and waler makcs

coning, or more

concctly fingcrrng,

occLucven

at

vcty

low

productiolr

atcs. n thcse

ascs,hcvolume

ofoi] thnl

is

produccd

is approximatcly proportional

to

thc

volurne

swept

by thc

watef

finger. As

is shown in Figure

1.4, horizontalvells

havcanadvantage

vcr

vcrl ical wells

herebecausehe igure

really

a crest

hapediked he oofofa

housealong

the length

ol-thehorizontal el l) has

a much ar.gerolume

and

this algercrcstdisplaces

nruch arger olurue

foil.

Dr. M.S. I : rrahrt


14/117

LI1. I Ilotito

rl ll'clls

Dtilti g

@

CohparLon_or.a

dcr

.rre

Leto* ,

v.r

catUdt ent,

-

(,

e. t

treror,

s.ciion

ora

fizontat

iveu

VEBTICAL

ELL

WITII

RISING

ONE

HORIZONTAL

ELL

WI'rH

RISING

REST

Fis. 1.4.

1.3.

6 Atlttantages

o.fHorizontnl

rySAtjlt

O:fit ,4tU,lk l j

Many horizontal

welis

have

beendrilled from

offshore

platforms.

Suchwells

oflct savings

n

Plalfolrl

rursls l

nrkii l ion

o l lt( ' i t{ l i l l l i t[,r.ti

tr lrrrl rrslrrtr,,

Fot

example,

one operator

tatcs hat

thecost

ofhis North

Sea

platforrns

s

approx imatc ly

6 mi l l i on per . rvc l l

l o t .

Js ing o r i zon la l

vc l l s ,

hcsanrc

nunrbcr

of well

slots on a platfonrr

an

proclucc

incc

cachhorizonlal

wcll

is

note

productive

han

each convcntional

wcll.

I\rr.thcrntorc,

ince

ollbhore

wells

are nolmally

highly dcviatcd

n any

casc hccxlla

cost br

horizontal

dli l l ing can

be relatively

rralJ.

7,'\

/ )r ' . \ { .S.Farrh^t


15/117

a:lL

t Ilotitotthtt tl' rDti it|')

Commcrcial

ofl 'shore orizontal vell

projects

n

various alea ncludingthe

ArI i i l l ic,

lrc Nor h Scn l||( l

lrc

lirvn cas

rc losclihc(ll l l l l c l i lclr(lrrc.

1,3.7 Ieu_y

Oil Annlicttions

Probably

hc most

prospective

rca or

usinghorizontal

wells

ies n the

ield

of

heavy oil recovery,

articularly

hcmral ecovery

singstrcarn. or

exanrplc,

lre bitunren

epositss Canada,

hich arc intpossiblco rccover

economically

y

corlvcntional ethods, ave

a volttnre f oil in

placc

approximatelyqual o that of all the known couvcntionalrudc il tn hc

world. One approaclr

scd o rccovcl hcsc

csourccss operr

pit

nrining.

l l o rvcvcr ' ,

h is s i r r r i l c r l

r lhcsnr i r l li ac l io r t f l l l cA t l r i r l ) r sc i t

- csc tvo i r

ha t

s

close to

the surfacc

and thc approacl rnvolveshandling

vastqurntii ics f

natclial. In

situ hclmal ccovcty

s trolc

gcnclally

p;tl icablc,

ltcrtpcr


16/117

CI. I llo,izont.tl llcls Drillirrs l0

crodes and

plugs

the equipmcnt and rcstrictiog thc flow rates.Scrccnsand

gravel placing

limit

sand entry into thc

rvcllborc

and n somc cases cduces

productions

rates, less

pressure

rawdowneliminates he necd or screenand

gravcl placing

ndallorvs iglrcr

roduction

atcs rorlrdrainholc r horizontal

wcll.

ti

. ,

D/ Nl .S.Fxr.hxl


17/117

CII. II

Dti

i'tg Tcchttiques

l l

c[AP'ftrR

lt

TypESOF HoRIZoNTALWELLs Ar'ln DlnrnnsNr

DRrr,r,rNG

pcuntQu

sUssu

The

choice of

drilling me0thod

depends

pon

drilling cost,

well spacing

and

the

mcchanical

ondition

fa

verlicalwellbore

s existing

Also, he csctvoir

consideratiols are also important n sclecting he drilling method.During thc

last decade,

he incrcmental

cost ofdrilling

horizontal

wells and drainholes,

over

a vcrlical

well cost,has

come down considerably.

But

today oil industry

grains

nore

experienccand

tses ewcrdri l l ing

echnologics,

n tum thecost

of dril l ing

horizontal

clls

nraybe

furthcr educed.

ccorclingly,hc

practical

holizontal

drilling

methods can be classified

into four broad

categories s

shown

n

Figure

2.1,depending

pon hc urning adius

cquircd o turn ionr

a

vertical o a horizontal direction. lso, heuseofa top-clrivc t. i l l ing ysfenr

(TDS)

is essential o the successful

mplementation fa horizontal ri l l ing

program

fol: deeper

wells; larger wellborcs; ouler-rorv

wells

(olfshore

platforrns);

Gumbo

or bentonitichole sectious hcndril led

with water

base

mud; whcre simultaneous igh torque and tension

s requiled o be applicd

dril lstring.A discussion fvariousdlil l ing

methods re

given

below or caclr

typesofhorizontalwell anddrainhole.

2.1

Ultra-short

Turning Ra irls

Ultra-shor1

urn-radius horizontal lroles, sometinres

called drainhole. nthis

mothod, t uti l ized

waterjef o

dril l

100-200t longdrainholcs ith a tulrrirrg

radius of 1 to

2 ft. thesearc dril led in

ptcviously

cascd

often mrrll iplc

horizontal laterals are drilled lrom the samewcllbore, as shown n Iiigure 2.2.

It is repofied hat, sidetmcking

ay be donewith a

whipslock

eviating

ool

with a curwed

uide.

Also, a ongslender tcel

ubc

its

nside he dril lpipe nto

the top of the whipstock

uide,

sshown n Figurc2.2.Tbe upperendofthe

tube has a

pressurc

seal to contain

pressule

and

divert drilling flrrid through

the tube. Thejet

nozzle its on

the

owererd ofthc tubc.' l 'hus, t i l l ing

rate

s

controlled

with a letaining able onncctedo tlre

op ofthe tubcasshown n

D,: M.S. Fnrahat


18/117

CH.ll D

lli

E

T..huiques

t2

Figure 2.2. The

hole is

prepared

first

by

plugging

the lowcr required

and

removing a

scctionof casing

by nril l ing

the

section s undcr-reamed

o

increase

he

hole

diamctet,

.e. he

proccss

nvolt,es

rdcr-reaming

hc vertical

wcllbore and

then dril i ing

severai

adials

ionr the under-rearned

one.

Howevcr,

lte length

of the s€ction

and diameter

oftl ieunder

camedhole

basccl pon thc

specification

f deviating

ool.A

spccial

acker

s

placed

n

thc casingwith

a curved guide

bclow thc

milled

section. he

whipstock

tlcvittirg

tool is

conncctcd o

thc

cl.i l lpipc

ntl usscrlbly

urr rr lu

lrc rolo

positioned

t the

kicl(-off

point.

l 'he

whipstock

s oriented

and

setontne

packer.

Then, tlre

slender

ubc is

owered

with the

ctaining

ablc..l.he

nud

purnp

s stattccl

nd circulatiotr

cgins

downs

thcdril lpipc lrrough lcnclcr

tube and ort thejet

nozzlcs.

lydtaulic

nrud

pressure

gainst

he

ptcssure

cal

on lhc ol)

oflhc tubc

orccs

t downward.

ltc

tl l l)c

)asscs

hrouglj hc

cur.vcd

guidcs

ol lhc r,vhipstock.

l

hcsc urn

hc

ul)c hrough

90

anglc irrrrr

cltrcal

to horizolttal.

A strcam

ofhigll

prcssurc

rruclionr

hcjcl

rrozzlcs

torlcs

he

lor.nralionnd

dril ls hc

rolc

horizontally

hcn

hc

horizonlal

ccliorr

s


19/117

CIL II

Dti

i,l4 lcchltiqrcs

I J

A

/ i i ,.

1l

"r'

i

o"

\ ' r -

l

100

-

300

ll

-:-

|

A

{ili"

fi'

T-

Fig.

2.2 URRS.

r.soo

_

3.ooo

t

+

|

2,OOO

S,OOO

r

---

:' I

Molion

Controuer

O.ill

String

Working

Str ing

HighPr€ssur€,

R€movabl€

€al

=-:- -

und€rream€d

zon€

Dri l l

Sk i i lq

"t')'*

,1+

Fig.2.1.

D/. M.S.

Fnrahat

Fadia l

Bor€

Hole


20/117

Cll,

Dt lhtU l'dt,tltlurN

t4

R.dlal

Compl.tlon

yit.n

PERSPECTIVE

Fig.2.1 URRS.

16 Ftrr=ll11'11

lr''"'"'''1,,,'

l Orl

1[:

rr" .rL,r l

-a

l : l

i l l ,

"" ' ' ' '

l l l l

l l - l l t - -

. -- , r l l l

r t

1|=l l l

| - '

Sectlon A

PaY

.utto

Fig, 2.4.Multiple-rodiol otnpletion.

,l),rM.S.Frrnh:ra


21/117

A

lry


22/117

I

t l

a

I

I

I

I

I

CIL II

Drillirtg

T,

owrate de er rn ines

Dri l l

Str ing peed

ControlOr i fce

Mot ionControl ler

Direc t io r t f Mot io r r

Dri l l

Str ing

Vert ical ubir tg

tr ing

Trapped

Water

Seals

Flow

to Conica l e t

Penelal orr corr 'ol v,lt Ied i I ng.'ig.

t

;l

ril

2.:

b::li,;tl

nrir r,rqsrr",r";

Er,-

t l o, , r r , r , , r

r ,P5, jc5

lsr. i r i i

ct l Drrt

i r , , r ;

; r , ' , : : r . :

, r r , '

' ' l r w

l l r r ,

r ' r \ l r l x , , , l

. r { r c . , j

l , f e l ' J s l k

h , 1 , 1

, r ,

l \ . 1 , , wi , .

. 1 , ' i l i , r

i ' l

DrillStrins

[:"_..1t;

d

Hig l rProssu f€Soa l

W h i p s t o c k

w , l r , r i l , ' r ' , r

. n r , r

nnl sh4. :s a br, , {r d, id

.onrr ' .

l l ,c D,, l l S l , r ,q

- . -

Dr i l l

S l r inq

l io '

l ' , ' ,

t l

I

Dr i l l t r ing

l1 'e,

r ' r r r


23/117

The second

component

s the motion

controller

Figure2.5) on the

tail of

the

dl i l lstr ing,

vhich

acts as a hydraul ic

estraint.

n csscncc,

t is

a pistonwit lr

external

seals

hat slide

within a

special snrooth

borehole

portion

of

the

vcrt ical

wolkstring.

fhc

high-plcsstrrc

ettcr

ushcs n

thc op of tho

not ion

controller,

and water

is trappcd bctrveen

t

and he

high-prcssureeal

at the

bottonr

of the

workstring. Water

can escape

only

througha centralorificc

wit lr in thc

corrlrol lcr

Fig.

2.5). t lrc

cstt l tss a hy


24/117

CII. II Drillirtg'I.echniqtcs

t8

l t ig. 2. ' l t t shows lsclrcnlatic

f t lro orr ical jct. t t lrr: op

ol t lrc i igrrrc . ' / t is

a standard rrllirnated

et

nozzle.The addition

of

fixed vaneswithin

the nozzle

causesa conical shell of high-velocity water

particles

o

fonl a conical

iet

(I; ig. 2.7b). l 'hc sizc of t l tchoriz.orrtalolcholc s cstablishctly lhc wistof

thc vattcs,'uvlr ichrr ttrncotrtrols,

lrc utglcoIr l ivclgcncc f

t lr t: orrc f wir{cr '

patticlcs. ig.2.7c

andFig.2.7dshowvancs 'or

1wodiffclcnt

onical

nglcs.

Fig. 2.7

Cotticul

et

nozzle.

Fig. 2.8a slrows water

jets

resultirrg

ronr variorrs

eglees

1'vanc u,ist

n l-

microsccolld

lash

photoglaphs

I a col l i l tratod

ct

and wo cl i l lcl .cnt

orr ical

iets.

Theconical ngle

s not affected

y dri l l ing-flrr id

ressure.

hese

onical

jets function

at both

ambientand

clcvatcd

back-pressurcs.

t highcr

back-

pressules,

avitationdoes

not appear

o be an mportant

utting trechanisrn.

Fig. 2.2 sltows hc

basic rvhipstock

olt[ igul i t l iorr,

r lorrbly rr lvotlrrvcl lctl

qLrcstion

rark.

nsidc hc

IJRRSwhipstocl


25/117

CII.

Drilling

T chniqucs

l 9

The

whipstock

is

held in

place

by

downhole

anchor

rws

engaging

hc

rvcll

casing.

The

anchoring

aw

aresetby

rotating

he

4.25 n.

vcrtical

workstting'

To

erect

the

whipstock,

the

workstring

s raised

about

ft by theblocks,

he

resulting

verlical

motion

erects

he whipstock,

e workstring

and

whipstock

arc

lrelcl

ercct

by a set

of hydraulic

cylinders

t hc

wcllhcad

hatmaintain

cotrstant

onsion.

Aftcr

each

adial

placcnrcnt,he stcps

or","u"r."d.

Thc

rvhipstock

an hcn

bc

cle-erccted,

otated,

and re-erected

ownhole

without

osing

ts

calibration.

gyroscope s

used o set

he

whipstockazimuth]

or

each adial.

Thus,nrultiple

radialscanbe placedat differcntazimuths ownholewithout having o trip the

whipskrck

ack

o thcsttt ' lacc

ctwccn

ach

ttcccssivc

arl ial.

After

each

radial borehole

s drilled,

a 3D

positional urvey

can be applied

(Fig.

2.8b).

The 1.25

n. drillstring

canbe surveyed

o determine

ts trajectory

with special

flexible

radius-of-curvature

ROC) survey

oolsdesigned

o

pass

through 12

in

(or

smaller)

end

adiusof

the drillstring.

The

ROC survcy

ool

was developed

o

provide

both

plan

(azimuth)

and

profile

(up/down

rajcctory)

data.'It

is

pumped

down

the

workstring

and enters

and

passes

hrough

he

drillstring

as

a wireline

tool. The tool

(Fig.

2.8b) resernbles

n animal

backbone

and has

long slide

wires

placedat each

quadrant

hat

rnovewithin

veftebrae

attached

o a flexible, torque-resistant,

ire-cable ackbone.

he

slicle

wires actuate

very

prccise

sensors

hat measut'e

hc nrovetlret of

eaclr

slide wire separately, ranslating directly nto the curvaturc f the ROC tool.

And,

in

turn,of thc

dri l lstr ing.Within

heROC

oolarcan

nclinometcrnd a

roll

sensor.All

these data are

transmitted

o the surlace

by

wireline"l'he

curvature

s

converted nto

convctrtional

azintuth and

nclinationby

rrpholc

software,

rovidinga 3D

printout

of both

he

azimuthand

he bore nclination'

However,

he drilling

methodused or

ultar-short

adius

poses he following:

l. turning

adiusof

I to 2 ft.

2.

lengthofdrainhole

of 100 o 200 ft.

3.

the

first

drilling system

requiresa

48 in. dianreter

under-reamed

one

while

the mproved

second ystem

equires

4 in.

diarneter one.

4. the

under-reamed

one length

varies lrom 6

to l0 ftdepending

on

the

systcm

ti l ized.

/)r. M,S.

Faraltat


26/117

UI.

DrilllngI'r:chuiqres

5.

thedrainholc

iamcter

aries .5 o 2.5 n. lttts

wo

or

trtol 'ctuilrltolcst'o

d il lccl.

6, fol

sarrd ontrol, hc hl irrholcs

tc crorrrplclct lsirrg i l lrcr

slol lcrl irrcrs s

gravel

packing.

7. after

completing

he drainhole, he

pipe

s several,hen fdesired,

a slotted

lincr

is l incr is inscrtcd

n thc uutlcr-rcarncdonc, he dircctiotral

t trvcy

tools att

rcuscd.

8.

t lr is

nrcthoclasbccn

succcssful

rr lrc

rrnbonsolidatcd

arrrls,t t tr l ccctt l ly

it hasbcen

used o drill hard ock such

asgrarrite.

9.

a large

under-reamedone

may

pose

difficulties n reservoirs

with

strong

bottonr atcrdrive.

At last hc

short-radiusri l l ingmcthod

oscs

lrc bl lowing:

l.

l 'he

process

nvolves utt ing | 5 b 2{) l lorrgwindow n t lrc

casing

f

an

existing

erticalwell andkicking-off thedlainhole hrough be

window.

2. A

whipstock ndcurved ri l l ingerrtry

uide

assistlexible hell

pipes

30

60 ft) or wiggly dri l lcol lars

n making

a 20 to

40

lt turring aclius. lso,

dilcct ional urvcymay

rc

usod o

locatc r 'ainlrolc

ath.

3.

'f ' l rc

ltot

zontit lpor(ion

wi{lr t

, l l /2

kt

(r

- l l4 in t l irtrrc: l t :r,s

rrotrrrrr l ly

completcd ithelopenhole

r by

insert ing

slottedincr n

thc holc.

n

thc

case of unconsolidated

and reservoirs,

a wire mesh

seven s

wrapped

around

he

iner for sand

control. t

is

possible

o drill

several lainholes t

dif crcntclcvations

lrrough singlc

crt icalwr: l l .

4.

' l 'he

short urning adius

ri l l ingntcthod

asbccnvcry

succcssfullr nrarry

field applications. ut the imitationol thismethod, s that t doesnot offer

0 sclcctivc otl l l) lct ion

ption. rr

ot lrcl

wotls, i t is rrot

possilr lc

o

isolrr lc

ccrtain

protlucing

orrcs

clcctivoly.

l

his

coulcl ausc

diff icult ics

n lhc

cilscs whclc

frirclrucs intcrsccting

lhc

drainlrolc

f lrc in dircct

conrnrun

catiorr i th

eithcr opgas

or bo{toltr atcr.

5, Moreover,

milling a widow

in thc

casing

can be

very

expensive nd

time

consuming.f possible, prefcncdoplion s to dri l l a drainholchrough

new verticalwell

with arr

openhole

section.

6, A

90

ft

turning radius

drainholc

s

a succcssful

echnology.

This

technology

employs a downhole

nrud

motors

and articulatcd

drillstring.

Also, t hasbeen

ucccssful

crncntccl

hocasing

rra curvcd

cotion

l '90

ft

turning

adius

hole

and harrging,

he olntation

valuation

ools

canbe

uscd.

l

h is l r i l l i ng

oc l r r ro logy

ou l t l

l r rob lb ly

c

uscr l o

rh i l l 2 ( ) o 2( )0 l

t r r t r r ingar l ius c l l s

by rnor lc l i r rg

l rc

< l l i l l s t r . i r rg

r l i cu l l r l ion .

Dr.

M.S, Falalrat


27/117

CH. II Drilling

I'echniques

Fig. 2.8a. Waterets.

c )

3 O " C o n l c a l

J e l

n o z r l e a t

o . 4

M P 8

Separ

lor

Tool Cross-Sect ion

Slide

Wke

L----

Convgr lo r

Computer

To

FOC

Tool

lExcitation-----'/

I

Sourye

Electr ical chemat ic

Pr nter

1)r.M.S. Farnhat

Fig.2.8bROC tool.


28/117

Cn l l

L, r i i ' t ( 7 i lhr iqur \

22

2.2Short

Turnine

Radius

Short-lul lr toIizorrtal

(ctns

Ituvc

a tu|1t

mdius

ol about

0_00 l,

lbr.dri l l i Ig

fiom cascdholcs.

Thc

proccss

bcgins

by sicletrucking,

uilt l irrg

ngrc, rru

dti l l ing thc

curved

ectionwith

a

special nglc

building

sscnrLrly.

.lrrrs,

ol

a

re-entry

dri l l ing

system

o be

tcchnically

succcssftrl,

t mustbccapablcof

dri l l ing a

consistort aclitrs

f ourvaturc

rrcl

ol dr.i l l irrg

ut.vc

rr hc

lcsitccl

dircction,

hcsc cqrrircnrcnt

l isc

rorrr

lrc cc


29/117

CII. II Dritti"g

luhniqucs

23

Rotating-guidcdsystems

are a third category of short-radiuscuwe-drilling

tools.

Fig. 2.9 slrows hc downlrole onrponcnts f

onc such systcm.

l'hcy

include

he curve asscmbly,lexibledril i

collars,and oricntation quipment.

Thc

lclativclyshortcurvc

sscmbly ncorpotatcs

flcxiblc.jointhat s

pushcd

to onc sidc of

thc holc lo ti lt {hc bit. ' lhc oricntation

qttipnrcnt onrprisc

standard

muleshoc sub for

gyro

orienting or

a nonmagnctic collar and

rnulcslroc trb or

magnclic

licnting-

his basic ool corccpthasbcenarotrnd

for decades, ut

problems vith angle builds and directional ontrol have

limitcd

its conrmercial ucccss.lolvcvcr, hc

apPcal

of

dril l ing horizontal

wc l ls l rc lp lywi thsuch qu ip rncr tc r r ra i r rs .

Fig. 2.10

highiights the evolution of rotary-guided

cuwe drilling tools before

1988.Early described

tool in 1934 hatuseda flcxiblejoint

to allow the

bit

to be tilted o sidetrack

well. In 1944,Miller

patented

similarcurve-dtil l ing

assembly

Fig.

2.10a) n

which

hc bit t i lt direction

ould

bc

oricntcclo dcflcct

the borehole

in a

particular

dircction. lt

was assumed that, aftcf initial

orieniation,

he assembly ould continue o dril l in a consistent irection.n

1952, Sanders sed a curve-dril l ingasscmbly

Fig.

z.l0b) whose

near-bit

reamer

caused he bit to the inclined.

This

systemalso incorpolateda flexible

joirrt

to allow su{Iicicnt tilt to drill short-radiuscurvcs. The curvc direction

was detcrmincdby the orientationof a whipstock, again it was assunred hat

thc asscnrbly

ouldcontinuc

o dril l in a consistentircction.

In 1964,

(Fig.

2.10c), Frisby

proposed

an assembly that used an

eccentric

stabilizing sleeve o control the bit tilt to orient the tilt in a

parlicular

direction

and to function as a stabilizer to minimize bit

wobbling

and oscillation. The

eccentricsleevecould be

positioncd

eithcr aboveor below thc flexiblejoint. It

was attashed otationally to the ddllstrimg

with

a

pin

that

was

releasedby fluid

pressurewhen drilling mud was cilculated through the tool. This sleeve rs

similar o one

proposed

y Gilcs in 1955 or long-radius li l l ing, cxccpt hat

Gilcs

slcevewas oricntcd hc dril lstring ounter-clockwisco cngage lock to

position

the sleeve n the desireddirection.

Development

was renewed in the 1980's. Holber

(Fig.2.10d)

and

Schuh

workcdon

dril l ingan unpredictablcadius fcurvatutc auscd y instability t

the

dril l bit, cspccially

when

hebit dril led

an oversize oleor became

Dr: lU.S.Farahat


30/117

\-

' ,

\ - -

,r\,,rt.rnlIolt"

Nonmagnetic

Drl l l

Col lar

Dri II rt

1;

7'c


31/117

CII. II Drillitg

Tcchniqucs

25

unstable

as it crossedbedding

panes.

Burton

addressed

lre

problem

ofpoor

oricl l tat iorl

ontrol by

introducing tron-rotat ing

ccentricleevc

Fig.2.10c)

with splingJoaded

blades

o

glip

the wellboreand

o

lnaintain

orientation s

the drilling

assembly s

wellbore and to maintainorientation

s he drilling

assembly s advanced.Burton advocated eriodic epositioning f the sleeve

so hat

a

Dlanet

urvccould

bc

dri l lcd.

Fig. 2.10 Historical

evolution of tlrc

rotaryt-guided lrcrt-radius

atrve-drillin.g

tool.

Fig.

2.11 shows hat

he

flexible

a short-radius

urve.Thus,

o tilt

sulficiently

to drill

a short-radius

llows the bit it hasbeen

useda

non-rotatinglexible

tubular steel shell

madeofshoft lengths

fpipe. The

engths onnect

ogether

with articulated

connectiorrs

or

flexibility.

This flexible

shell

carries he

vertical

thrust to the bit and

acts asa sprirrg

o facilitated uilding

angle.A

flexible

liner nside he shell

contains

ressure

or circulating

drilling fluid.

An

internal drive

shaft supportedby

bearing

packs,

carries

torque from

the

drillstring

to

the bit. The horizontal

ection s

drilledwith

a similar echnique

but

longer flexible

shell

without spting

action and stabilizer

o control

direction

as shown

in Fig. 2.11.The ole

s

preparedirst by milling

a section

of casing

and under-reamed.

he

whipstock

is run ot'iented

o the con'ect

directionand

set, he anglebuilding

assembly

s run into

the hole.

Sidetracking

begins by rotating the angle-building sserr.rblys t guidesoffthe faceof the

1987

e

1}. l\ '1.S,

Falahnt


32/117

( ' l l .

1 l

l \ l l l t tH

I 'nhu\ t t rs

Ltl

whiPs lock '

i dc t r i l ck i r rg

nc l

l l i l l i ng

or r l i r r t ro

r r hc

curvc t l

ro lo

cc t i . .

r ta r r

i 'creasiug

upward

ngle

n the

di 'cction

f the

whipstock

acc

nt i r

t

is

bcing

hodzontal.

Then

the

angle

building

asserrbly

s

pulled

out

of the

hole.

The

stabilized

rilling

assembry

s

run,

and

he

str-aight

orizontal

ection

s

dri

ed.

Also, there is another ersionof thcsystcm.otates

he

bit

with

an

articulatccl

nrotor,

which

improve

lrole guida'ce.'fhe

welr

s compretetr

s

an

open

rore

or a

special

lexible

ype

slotted

incr

s r.un.

Fig.

2'I |

,4scltetnntic

f

o

'shorr-t'aditr,s

rriling

racrtttiqrrc

r,sittry

inirtra

drillin g

ioirtt.

/)r'.

M.S.

Fa

a hat


33/117

CIL DTiIi'tgTcchniqnes

2.3 Mc tl r nt

-

Tu n n

g-Bg1 4;

Although the long-radius

approach to drilling horizontal wclls is

highly

developed nd very successfirl,

hc radius cquircd estrictshe applications

possible.

Medium-radius ril l ing

extends

hc

ecbniqueso thatbuild

sections

with a radius

down

to

about 300 ft

(90nr)

can

bedril lecl. olcsdril lcd ry

m€dium-radiusechniqucsrave

scveral advantagcsonrparcdo long-radius

wells

and almost no disadvantages.

lrey

can be

dril lcd

with

conventional

dril l ing rigs, although hey require

some special,but now wcll-developed,

equrpnrent.

Mcrliunr-radius cchniqucs sc rroir-irrl icrrlalcd

til l slrings

nnd

hcntt

nrrrl

nrotors.' l cscarc hrcc

principal

-ccluircnrcnts:

The bottom-hole

assenrbly ust

be able

o

dril l alonga trajectory ith

the

rcquircd

adius.

)

Thc dril lstringmust be sufficiently

lexible to follow the dril l without

mechanicalailurc.

Tools used n thc hole must

be able o be moved around he curved

parts

of

thehole.

It is important o note

that he hird equirement

istedabove imits he

ools

that cau bc used ir the horizontal art

ofthe holeevcn hrough

hc curvature

thcrc is ncgligiblc.

fhese

requirctrrctrtslacc

linritations n whal

can bc

achicvcd by mediurn-radius

ril l ing.Thc rcquircmentor dril lstring

lexibility

mcans dril lstringsmust be

snraller n dianreteror highcrcurvatures.

tthc

lirnit, it is necessary,

.g., articulated trings,coiled

tubing type strings

strcsscd eyond hc clastic

inrit, andstrings r.dc

o

cxot c highcr-strength

thc nralcrials uchas itanium, arbon

iberor steel-reinforcedroscs.

hargcs

of thissortmove he cchnique

cyond hcboundary fnornralmcdiunr-radius

dr i l l ing .

The

trend to

using smaller diameterdrillpipe

goes

along with the

drilling of

smaller

diameter

roles. notherdriving orcemoving

he

eclrnology

owards

strlall

dianreterss the nccntivc

odlil l horizontal rnihs

tarting

with

cxisting

veltical wells.To do this,mctliunt-radius

quiptnenthdtcarl

bc

inscftcd

own

thc cxisting erticalwell casing s nccdcd.

Dr. M.S. Ferahat


34/117

CH.II DtilingTechniqnls

2a

Drii l ing

motors of

both he

angle-build

nd

angle-hold

ections

fa medium_

radius

horizontal

wcli must

bc shorl

cnorrgh

o

fass

il.ound hc

cut.vilut.c.

Doublo-ti l t

l tolors

arc

ooll l l lon,particular'ly

br

unglc-hold.

.hc i lt

in angrc_

build motors

s relatively

Iarge

and thc

motors

are not

rotatable

steerable).

Medium-radius

hole

can

be drilled

fronr the

side

ofan existing

casedvertical

well

or from

a newly

dril led

open

bole. Ifan

existing

erticalwell

istobe

used,

a

rvindow

s

milled

in thc

cxisting

casing

at ihc

dcsirctl cvcl

and

a

whipstock

locked

to the casing

n the designed

rientation

below

the window.

'lhis

lvhipstock

dirccts

hc nrcdiunr-r'adius

tr(l

nrolor

rlr i l l in thc

rlcsircd

azimuth irection.

2.3.1Drillnhrcfor

Mediun-R

litts Driltins

' I lrc

firstmcdiurn-radius

ti l l ing systcnr

vas

cscribcd

y Dcch,

flnd lcnhart

n 1986. t

allorvcd

holcs

l6 in. in

diarrrctq.

o

horizontal istance f 1000 t with

a

build atc

ofabout20

30nr

l lcarn,

Sclrulr

bc

r l r i l l c r l

o

( r00

0.

'l'hc

systcrnused

a narrow,diarnetcr,

pccial

comprcssive

orvicc

drillpipc

(CSDP)

arrying arger-diameter

ear

knots.

I.' igurc .12a

shows

hc wo

conrmoncst

izc

ol'compre

sivc

ew ccdr.il lpipc.

'lhc

pipc is ficqucnllynxrrlcirrrrrr(xt-lltfl lcli0,llsl(lrril iclccl irl rrsc rrru

magneticsurvey

nstruments

nd

n holes vhere

hebuild

ratcare

greater

han

l5 i tOm

(100

t . ) .

In holcs vilh

a lowcr

build atc han

5230

nr,hcavy-wall

lril lPipoc.g.

ovi-

watc) s

uscd.

fhis

pipc

has rvall

lrickncss

hich

lakcs t

itt)orrtwo

alld l

half timesas

lreavyas

standard

rillpipc c. g.

62.5

Kg/rn or.4.5in.pipc

comparedo

25.3Kg/nr

or standardipc).

n adtlition,

cvi-rvllc iqrc

us,

n

each30 ft length,

centml pset

ection hich

behavcs

irnilarlyo

thewcaf

knots r

CSDP. hcwear

nots

Fig.2.l2b)

ccp hc

drillpipc way

rour

hc

wall

of the hole

in thc curved

ectiol.

This rcduccs

oth

rotating

nd

longitudinalriction,

esulting

n less

trikirrg.t

is also hrough

hewear

nots

hclpkecp

hccuttings

n suspcnsion

n thc

drill ing luid.

1fr I I .S.

Faribat


35/117

CII. II Dtillittg

T

cch

iqxes

Compressive

Strength

Drillpipe

COMPBESSIVE

EBVICE

RILLPIPE(CSDP)

2-7tA

3.1 t8

2

3 .1 1 2

2 1 3 1 1 6

10120t3a

Fig. 2.12a

5"

Wear-Knots

2-7

IB"

s-1t2"

Fig- 2.12b Contpressive trengthdrillpipe 5 in -wectr-lutots.

/lr. l l.S. I.arahat


36/117

CII. II Dti ing lethuiqn.s

30

2.3.2 lf nlinnrllntli us Ilrilli rt

g

ll I

ot o,'s .tnrl,l_t'st,'r,,s

Medium-radirrs,

ngle-buildmotol's

ypically have wo

bcnds

n

their ength.

Motors of lhcse ypes

are showr in Fig. 2.13.

Arotlrer nrotor ritable

or

building angle n rnediun-radius

oles s

shown

n

Irig.2.14. n thisasscnrbly,

a motorwith a bend s

ointed

o thedlil lstr ing

ia a bendsub.

t

he

otal i ltof

the motor s equal

o

the

sumofthc two individual

ilt angles.

l 'ablc

2.I

shows

thc holc chanrctctistic

hat can bc oblailcrl

Lrsing rcdiunr-r 'rrr l irrs

ril l ing

systcms.or fivc differentmotor

sizcs. lrc

two

argcst

motor.sizc

lc linrilcrl

kr

dli lf

ng holc

wi(h au arrglc-builciatcof

lcss l] l| i |, 4730

nr(I00 ll) rr|


37/117

CII. II Drilling

TcchtiquL's

3 l

EA,STMAN

HRISTENSEN

HORIZONTAL

OTOHS

Fig. 2.1-t.

DYNA-DRILL

OUBLE

BEND

MEDIUM

RADIUS

MOTOR

.,.,ii'tm:i,1{;#tr3,y3;ry1;,;1;,i

Itig. 2.14.

1)r. N{.S. iarahat


38/117

C . Dti

ittg'Icch

iqkcs

32

I

49'

I

6.75"MWDDlrocllonal

€nsor

5"

Non-Msgn€llcrlll

Plpe

(He8vy

Welght)

5" Non-Msgn6tlcrl l l

Plpe

(Heavy

Welght)

11.75" tsbllhor

(Non-Mognollc)

8"

Bcnl

HouslnoMotor

(Slnolo

end)

12.125"

tablllzor

12.25" lt

Fig.2.l6

Stu{at'ehole

BII4.

Itig.

2. |

5

('rttlrr

tot. tolt,

n l/l.

5"

Non-Maono

Drl

ptpe

(Hsqvy

W6lght)

0.76"

MWU

Dhoctlonsl

onsor

Gemma ay/Reststtvlty€nsors

fn"'xil-$3p;iy"

n

o,o.

11.75"

tsblll:sr

(No|FMagnotlc)

8" B.ntHourhrcMotor

(Slngle

ond)

12.'125"

tsbtttz.r

I

B'

70'

I

I

I

Dr. I\,1.S. llrrhrf

12.2 "

tl


39/117

CII.

Driuilg'Icchniqu.s

E

+6'

r

I

I

7'

5" Non-Magnellc

rlll

Plpe

(Heavy Welght)

6.75"MWD

Olrecllonal

€nsor

Gamma

RaySensor

FsslstlvltySonsor

7.75"Stablllzer

(Non-Magnetlc)

6.75"

Ooubl6B6nl

Houslng

otor

8.375"

tnbi l izer

Fig. 2.18

Invertetl drillstring

desi.gn

or

horizontal

ole

section.

lrig. 2.17

Hot zo tal hole

BIll


40/117

CII. II Dri hry'lttl'|iquts

34

2.3.3 Hieh Medium a d Lov Saeed Drillins

l'he medium-radius

echniquecan

be usedwith both high-speed,medium-and

low speed nolors: ]'hc types of motor uscddcpcndsupon tlrc contlitions. loth

rolling cone and fixed cutter(usually polycrystallinediamond compact PDC)

bits can be used. Rolling-cone its are nearly always

used

with

low and

medium-speedmotors, .e. for rotary speedsess

han

about

200 rpm. PDC bits

can be used

with

either ow-speedor high-speedmotors.

Both

categories

fbit

hlvc advantagcs

n


41/117

CII.

II Drilling Tcchtiqucs

35

NATURAL

DIAMONDS

ON TOP OF BEVEL

FOR PROTECTION

URINGBACKHEAMING

Fig.

2.19

Fig.

2.20.

2.3.4. Vertical Sectiorr

It

is the

{irst

section rilled

rom

surface ntil the kick-offpoint

(KOP)

for a

horizontalwell or newerwell (Fig.2.15)or section rom surface ntil milling

windon'

for recomoletedmatureor old

well

for drainhole.

SIIOHTEFI

FLAT'I

ER

PDC

BITS

FOR IMPFIOVED

STEEBABILITY

N I-IORIZONTAL

.IOLES

Iton

lones 1990

Fig.2.2I.

T[€ POCb lor

t lE r ight earu,es

a shotl\ucil.;lnnk,

lhl(dki

pro

l i l c

i rd s lu l , r ro , l

0a ( ( ro

o|( l lh .

Theso leahrcs

atu d{rsn.blo

ld

Dr'.M.S. Farah:rt


42/117

ctl.II lrtiuitru t.thniqn.s

36

D

-lt

vd t la lhd .

i l , l l l . . l

,nJ . " .d

ro . r . t i co

o,

t , , r , , rd i r ro

c . j t , )u

Dot , , r

V. r ' l c r l

d . r thn

rrnotro

ro,nnr lon

c.D, i t^ j , ,o .

i , , , t

u . i to r r t , , , , i t l

v . r r l c . l

ho lo p lusood.bJct

o k lck ot t

p . i j r r

Cur .d

ho lo ucr lon d , l t tod

tvo 0h

90-

l rn r r . l i . .

l lo rhonr . l

I ' o lo 66cr lon

dr i l lod

curv . i l

ddd

ho. i lon t . t ho toE.cr ton ,

asod

,nd

cuUFv(uu

Ititrg.2.224ttl iuut

unt hori;ottIrtIu'tlL

2.3.4.2CurvedSectiatt

' l lrc

crrlvcrl

cclion fhorizontal olcs

rrms hlouglr

90'

cu vc lrcrnvc rcnl

lo horizontal

wilh

an avclage urn laclius

l-

3(X)-tt(X)i. Ihis cun

bc ckrnc

thfough

he ollowing:

C t r)i dotv

or

|ertictl well: At kick

offpoint, hc scclionnril l

( lr ig.

2.23) s

t t t t t t r r l l t ccns i t rg ,s t r i l l c r ltg i r rg i r r r r t j

l o . \2

11

s in , l i V is

gr ' l

r r r r r lv i t l r

lhrccstcps.

' lhlce

diffcrent rolton-holeassclllblics fc uscd to sidc thc

wcfll

alicr sct

whipslockas shown in Frg.

2.24

shows typical

conllguration

l notor

dcviation

cction 'orkick-off,brildirrg nrl horizontal lo(or rsscniblics-uscd

for drainhole

n

Egyptian-westem

eseit.

/ lr ' . l .S. I:rurh:r l


43/117

CIl.

II

Dri

i,tg

Tcchniqrcs 31

H

I

Hydru l i c Jar

61 /4

61 /2

5 3 /8

4

3 / B

T,

oa

I

r

I

t_

Bit Sub

Boot

Basket

Sect ionMi l l

Taper

l ,4 i l l

5 1 t2

a

1 /4

1 /8

1 /2

5 1 t2

a

1 t4

Fig. 2.23 tuIil rt

g

ass

nfu

y.

Dr'.M,S. Farahat


44/117

CH. II

Dtilti g

Techniqnes

38

J

A

J

A

B

Limber

=

Molor , B=

Bear ing

i l

,

D= Bent housing

Bent-Housing

Pad

and

Bent Hous ing

Bent

Sub

Benl

Sud

-

and

Benl-Housing

assembly

,

C :

E: Pad,

and

Ouipu t

sha f t

anc l

F : Bent

sub

Fig. 2-24

Motor deviati)

sectian.

/ f / . NI.S,

:rrahnt


45/117

CIt-

II Dri hlg Tc.hrirlt.s

39

Anglc-buikling

ontinuous ilh

thc sidclrack

motorasscmbly.

t i l l ing insidc

cascd

holcs

(usually 7 in. diattrctctor

Iilrgcr casirtg)

s

donc

with strtall

diameter,

slim-hole

ools. A sectionof

casing s

removedby nill ing,

a

sidctrllcking

plug is

sot

and drcsscdoff. Somc

opcrators

prcfcr

to sidclrack

o t

olcascd

hole

with lowcr build

ratc, trcrcasing

hc build

latc allcl dli l l ing.r

part of curved section.

Drilling and

angle building

operations

continue,

rneasuring

drift angle

and dircction

pcriodically.

Inclined

or first build

arc

(curvc),

straight

tangcnt)s clril lctl o lhc

rcqLtit.ctlcplh.

'hctt, a dircctional

motor

assembly

s run, and anglc-building

ontittucs

n a slnooth urvc

unli l

the

hole becomes

horizontal. The curved

scction of

the hole may be

cased

before drilling the horizontal section,or both holc may be cased togetller.

Running

of the

casingdcpends

upon the turn

radius, engtlrof

horizontal

section,

ormation

conditions, orquc and

drag.

2.3.4.

2 Horizonto S ectiott

Hotizontal

section

of medium-radius

has angle of

about 90o. The

horizontal

section

s drilled

using low angle build stecrable

nrotor

assctnblyas shown itt

Fig.2.25.

A commonsteerable

ssembly asa bend

rousing

with a low angle

bend

of 0.25'- 0.5",

possibly with

a

very tlrin deflcction

pad

to

prevcnt

motor

housing

(as

shown in Ftg.

2.26) wear reaming

nonnally is unnccessary

because

he assemblies

re rcflectively limber.

Reaming car be

done with a

nonaggressivc

camingassenlbly,

frcquircd.Thcn,drill ing

contirucs ntil

thc

torizontal

scction

s conrpleted.

Lastly,

the

features

of this drilling method

used or medium-radius

horizontal

well, are

given

as follows:

tn this method,

he turning radius from a

vertical to horizontal

direction is

about300 to 800 ft.

Two systems

are available

o drill thesedrainholes.

l

hesesystems

used n

general

are: downhole

mud motors

and flexible

drillpipe. One system

utilize

build-motors

for angle building

al a rate of

about 2dl100

ft. thc

horizontal

potlion

is

ddlled by using angle

hole-motors

which drill at

a rate

of about30'/100 t. Suchsystem asbccnusedsucccssfulo dril l 1000 o

1500

t long wells in

fracturcd ormalions.

/)r.

N{.S.F:rrxhnt


46/117

(:IL

II l)tilling

I-u.hniques

40

Flcqucnt ly lrcsc

wclls al 'c r lso

conrplcto( l

sirrg

lot lct l i r rcr.s. ' l l r r :

cl ls

c i ln l ) c

loggct l r rs i t rg

ornr r roro ia l ly

rv i r i l i rb l r :

o i lo t l

r r l r i r rguor r r r le t l

f ir ' rnnl iorr

vnlunl

on ools.

S

abl l lzed

ent

l lous ng |nolor

Survcy

too l

Pos l l i v r - .

l i sp

r rccr r r

t r

r lowt r l to lc

r to o

SlecraLrlo

rac l i l ts

f

c r r rva luro

Top

s lab l l l re r

n = lln(lhtsot curvnll| lo

Degrco

ol l)cn(l

R

Ben l -hous lng

s lab l l l zo r

T14tca s ee alt e

s),s

e

n.

/)r. M.S. Iarahal

Fig. 2.25


47/117

CH. II Drilling

I'echniqrrcs

4 l

o

rrlrri:ur r-ir;:trl.iEir

ffiffiHm"TF-lH. llw i

-lN

iiffi'1

tffillffil

lilrlH-

ig.

2.26.

Long-turn

adius orizontal el l classificationsredri l lednrainly y deviation

in openho1es.Wells

n

this classification

re

charactcrized y

larger

holesizes

zurd

alc vcry

susccptiblc

o lr igh

drag

and orquc rccauscl longopcnholc

section. Flole ize

ange p

12.25

n cl iameterlthough rrral lct iarrcter oles

are lltote conln'loll.

We ls

with a radius of crirvatureof about 300

m

(

I 000 ft) in the deviated

sectiorrs

re commonly dr-i l led sing he cclrniques

as

shown n Fig.2.27)

a

stcerable cnt

nrr.rd rotorand MWD to

locate hehole

as

dri l l ing

proceeds.

Also,

therc are significant dvantages

n using op-drivcralhcr lran

otary

table drilling rigs,

and top-clrive rigs ate

commonly used in offshore

applications.

Fer.vand rigs havehad

op-drivebecause f

tl-re ost nstallation,

howevcr, erv op-drive esigncclpccifical lyor landopcrationsr-e vailable.

Dr. M.S. Farahat


48/117

CII. II Drillitrg I'ecluriques

[?or ong-radius or izontal

wells

dr i l l ing,

the Navigat ionDli l l ing

Systenr

(NDS)

empty a NorTrak streeable

motor

with

doubletilted

U-joint housing

(DT[J)

as shown

n

Fig.2,2B.The systenr an dr i l l direct ional

rof i les

and

nrakc

coutsccorrections ithout costlyasscnr[rly

hanges.

42

Inlo$r.r l

blado

slabli lzor

0ouble-bend

0t0r

conli[uration

Drilex

f ' o5 i l l vo

l i r , ) lnoo

l

r l

w i l l l

bon l

l lous ing

Fig.

2.21.

$teeraDle

tBtqi'

xc0nf

Uurati0n

Pos i l i ve l i s l ) lacon on l

o lo r

w i l l t

p l ( l

an ( l

l ) r r | t l

l r ) l [ ] i n ( l

( '

'

I : ir:. .29.

Y

...

1 \ ' l

f cf '^'- '-" '

I I

L J J

Also, hc D 'U lrousing as wo sl iglrtbcnds-[r 'strronc cl i lccl iorr,l rorrn thc

opposite-to

lightly tilt the

bit's

axis

fronr thc hole axis.

tcsultingol-['sct nglc

can

bc

configulccl i'om 25" o 78'Loplovitlc

doglcg capabilityup to 6'1100 t

rvhile

drilling

in the oriented

mode. Mren hc

rotary

ablc

s

engaged hile

the

NorTrackmotor

continues

o run, bit offset s negated nd the

NDS assembly

drills

straight

a

head.To keep he well

on course, tientedand rotaly

sections

can bc t l t c r r r i r lod i thout r ipp i r rg

u {

o l '

l l t c l ro lo .

l

l r c

t lo t rb lc - t i l tl cs ig l r

brings he motor

axis

back into alignment vith the

boreholeaxis,

providing

/ )r ' .Nl.S.

l : t r ' : rh:r t


49/117

CE.II

Dti i'tg

lechniqnes

directional

control

and consistent

well

path

curvature

with low bit offset

and

nrirrinral

ousing, caring,

nd

dr-ivc sscmbly

trcsses.

2,4.1 Venical

Section

It is

drilled ftom

surface

or sea bed until

KOP

(Kick-off

point)

using

convenlional

ools.

The

cuwed

section of

horizontal tum

holes through

a 90"

angle from

horizontal

to

vertical with an

average um

radius of

1000-3000 t.

The first

stcp

s to deviated

and bcgin

dril l irrg

hc curvedscction.

fhe

same

gcneral

proceduresare used for

drilling the high-angle

directional and

mcdium-turn

pattcrns. {cducedanglcsof brri ld and longcr opcn holc scctionsmust be

ollowed.

tt is necessary

o establislr

curualute

and thcn

drillcd witlr one

of

several

assembly

options,

as shown irr Fig.2.29

pattemswith longer

turn ladii

arc dti l lccl

usingditectional

ri l l ing cchniqucs

n thc

carlicr

part

ofthe

cuwcd

section.

I

his is mote

common

where bit

walk and angle

s about 20o.

l'hen

arr

angle

s

about 6d. Drilling

continues

o higher

angles

with rotary assenrblics

in

a few

cases, such

as a hole

with

vety long tums-

Normally,

rotary

assemblies

are less

efficient for building

angle

and controlling

direction

at

lo

horizontal

with motor

assemblies,

rilling

with steerable

motor assemblies

as often

as

possible.

Tangent

sectionsslrould

be

drilled as needed.

Tangents

are often

placed at an inclination

of 60'.

Tangents

are omittcd

in some

holes

that havc

longer

turn radii because

drilling

longer sections

plavidcs

tin'le

for

morc rvcll path adjustments.

2.4.3

Horizontal

Section

Horizontal

sections

f long-turn

holes

have angles

of

about90o depending

upon onnationconditions ndwell pattems. he horizontal ections drilled

with

either a

hold or low-angle-build

feeable

motor

assembly.

rocedures

2.4.2CurvedTurnin

Dr. trt.S.

Farih,rt


50/117

CIl. II lttiUh,E Tt?huiqu.s

similar

to dr:i l l ing he

horizorltal

eclion f tlrc ncdium-lunr

attcrn

lc uscd.

Ro(arynsscnrtr l ics rcscldonr scd.Drag

anrl orquc ncrcirscvillr

rrr:rcasing

depth. Torque nay approacb

he ma;rimurr linliting

torquc-strongth

ofthe

dlil lstring

n very

deep holes.

ThishasoccuLredven

n

a complctcly

ased

hole. Moto[ assemblies

hould e used

ere, ince l]edo

not

require

otating

the dril lstring.Drag and orquemaybe nrinitl izedwith tlrecorrect ypehigh

qua l i ty

mudsys lem nd

o thcr c t ions .

44

Fig. 2-29Long hutt horizontal well.

Ilowever, this dril l ing met hod

long-lurning

mdius) has a turning adius f

1000 to 3000 ft in most casesalrd uscsmostly convcntional

ools. A

combinationofdril l bits with bcnl subs ncl ownhole rucl notors lc usco

o

dril l 2000 o 5000 t longhorizontal ells,

sometimes

educeso 4000

t

long.

The advantages nd disadvantagcs

r

iinrjtations

fthis dril l ingmethod sed

lo r o r )g id iushor izon ta le l l . n r r

c

sr r r r r r r r r i zcd

.

fo l lnws:

1 These

wells can

be

cored,

oggedand treated.

2. Problems in cetnenting the lrighly

deviated

wellbores are

furtllel

aggravatcdn horizontalwellbotes,especially n regald o displacement

frour heholeandunifoml comcnt

lacemcnt

round lrcwcllbolcs.

TI;

II

\

iJ

br

Drl l l lns

l l 'o

0 i l l l i r i l l ' o

CJ-r Fd

q9e

l-srr

,/

/ ,'1n"rl^i'r

/ /

|

soct ion

\+4rf

D/. M.S. i,r.rh.rf


51/117

(:8.

lI

DtillinE

li.hriqrcs

45

Rccontadvlrrccs,

owovcr,

ndicatc hc

possibil i ty fccnlcntirrg

otizorrtt l l

wclls and

pcrforating

hemsclcctivcly.

A selective

ompletion

ption, major

advantageflong

radius orizontal

wells,

would facilitate

producing

only

from the oil

bearing zones

and

shutting-offhigh

alcl or gasproducirtgones.

A typical

tuming of

1000 o 1500

ft roquires

hat hc well

perletrates

rescrvoir

2000 o 5000 t a

way l iom thc spudding

oint. 'his lrrgc Iatcrr l l

space

equitcment

imits tho trse

of this

techniquen many

shorc iclds

where the

typical vertical

well spacing

is l0 to 80

acres.However,

his

types oftechnique

is

very useful n offshore

drilling

D,-. Nl.S.

F'Ar:rhat


52/117

CIL III Har

tt:

ofllotiznalal

tt'c|lr

46

CunprulrII

PLANNING

OF

HORIZONTAL WELLS AND

DRAINIIOLES

GnonlrTnv

I

l-Qeagg11y

of Horizontal ll/eu or Drainholc

Wcll dianrctcr',cll tnrjcclory ntlshapc vithirrhc rcsclvoirhavca sigrrificarrt

impact

on costsand overall

rvcll

success. .

g. productivity

and recovery.

Consequcntly

cometry

s a criticalaspcct f horizontal

vcll

dcsign.

i.I

lTell Diameter

The diameter of horizontal section is the easiest

well geometry

element to

identify.

t shouldbc thesnrallest ianrctcr',

\,hich ' i l l

al low hc following:

l. Use of

controllablc ncldtil l ing asscnblics nd hydraulic

programs

o

achicvc

laccrrrcnt

bjcclivcs nrlholcstlbility.

2. Sufficient

lcatancco run thc neccssalvvaluationools.

3, Sufficient

clearance o install the requircd complction,

production,

and

wolKover

qulpmenr.

4. Sufficicnt iarnctcr

or ccononricil roducfion.

llowcvcr,

lrc nit ialhotizontalwcll in a f icld

dcvclopmcnt

houlcl c dcsigncd

wilh largcr dialnctcr

o

allow

running an

cxtra string of

casing n case

of

unexpected

ole

problems,e.

g.

influx of rvate ror

gas.

lolc diamcter an

possibly c rcduced ncedrill ing/conrplctionlacticcs ndconcspondingtolc

,D,: U.S. ':rrrhat


53/117

CIL

III I'ttrti'tg ttl Ilorizotttt

tvctls

4',7

conditiorshave been

evaluated n the first

well. Also, the well

diameter

sclcclion s tcstrictcd

y thc cliamclcl f

cxis(ing crticalwcll

1()

c

rc-ctltctcd.

' l

he csll icted

diametermay

itnit well lcngth, valuatiorr.

Completionor produotion pclationoptions. l ' lrcscconsctptcuccstust bc

considered

arly during the wcll trajectoty

design.

lL lV_

,ProfiLe

' fhc

nlost increasingwoll goomctly aspect s tlre wcll plofi1e withirr l lrc

reservoir s shown

n Fig. 3.1 that l lustratcs

orizontal vell

profi les

used or'

d fcrcrrt

pp cations.

Fig. 3.1 llasic

well

profilcs.

1.., l, t

3.2.1 Flat wells:

are uscd inhornogeneouscscrvoirs

to solvc

watcr

or

gas

coning

problems.

Thjs is

the easiest and least expensive

design shape to

accomplish,

ut t

provide hc castoptions ver

hc well

l i fe.

j,2.2

[]nddotittg

'ells:

^re used in

reservoirs containing

impertneablc

barlicrs hatscpalatchc €scrvoit'sDto wo oI n]olc solatcdeservoirs.

Dr.

['1.S.

F:lrnhat


54/117

CH. III Ptautittg

ofnotizohtdt utetls

4a

i,2.3 Upword nclined welk:

arc

tsed in

dirty rcservoirs

wheregas

coning rs

a

problcrn.

s the

gas

ntcrlacc

nrovcs

downwarl

and clr(crs

hc lal crrci

f lhc

horizontal

cl l .

Ihe

endofthe

wcll

canbe

plugged

nd

production

ontimred.

' lhis

wcll

plofilc

has hc

advanlagc

hrt it loculcs

ll

of t lr c fluirl cvels

rrr rr

I l i vcs

l r ( i

) l l t i ( ) l

l

l r l r rgg i r rg

r r rc l il rc

c r r t i r r .

ro r izor r t r r lcc t io r r

r r r r l

r r rxhrc i r r l l

thc well

asa vcrtical vell.

3.2.4 Dotptut'ard

itclined *ells:

are

used

in dirty resewoirs

where water

coning s a

problcnt.

As thc watcr

nterlace

movesupward,

waiel

comes Dto

the far endof the well f irst.The inclinedwell can herefore c pluggcdback

and corrtinues

o bc

produced

after watel

breaktlrrough.

3.2.5 ll[ultilct'el

wells: are

usedwith

sand cnscs

and with

rcscn,oirs

sepnrated

by inrpcnncable

anicrs.

lhesc

v,clls

have

a higlrer

hallenge/risk

n tcrms

of

hajeclorycontrol

but

provides

or

dual

brcak hr.ough

n the rvcll

s life

by

iso l r r l i r rgr 'q r l r rg .g i r rg

l rc o rvcr

tcp r l ld

un( :c ( ) r r r r i c

, te r l rx l l l ( - t i (n rr j r rs_

3.2.6Mt l i

hrot,(:h:

Sllortradii

are widcly

uscd.

Multi branch

ncdium

antr

long adiiwells

arebeginniug

o be

usccl nd

should ind

widcspr.cacl

sc n thc

lcxt l-cw

cafs

duc

o thcir

nrprovcrl

cotronrios

nd ncr-cascd

|rlr irragc

rca.

j.2-7

Gmrit.1, rainocc

,cl ls:

ar.e cirrg

dri l lcri n

dcplctc(l

cscrvoir.s i l l l

lro

dlivc nechanisnr ther hangravity. t is

likcly that

gravity

drainage

clls

can

be tser ln rcavy

i l s t rcnrn

io , r , l ingro jcc ts .

3.2.8

Conple.r tell

sltopes:conbine

molc

than

one oftire abovc well

sfierpes

and are useri

n rcsovoirs

with

con4rlcx

gcology

hrt

varicswidcly

ovcr lhc

length

of

horizontal

vell.

1.3 D

esigttllOt'i.zot,

o lt ellI 4ie.'tot

In

accordance

ith

hehorizontal

cll

drilling,

her.crc hrce

cotionrarlcly:

L

yertical

sec(iol; t

is dril led

rom

scabed

rnud

irc)

unlil kick-offpoint

(KOP).

l)/'.

M.S. Iarahrt


55/117

CIL

III

Planning

of llorizontol

llclls

Ttutting or curvetl or

angle

build section:

it is drilled

from kick-off

point

(KOP)

o theend-of-curve

[OC).' l 'his

section

ncluclcshc first-build

rc,

t lrcstraiglrt

angcnt,hcsccontl- l l r i l t lu'c.

llorizontal section:

t is drill(xl lronr

hc

cnd of sccond-hrrild

rc

(llOC)

to

thc end ofproposeddistartceo be dr:illed orizontally n thc pay zone, ll

accordanccith t lrc

ypc

o[ 'hor

zorrtal cl l to bc dri l lcr l.

The

designof horizontal

well

rnentioned ere

s a

part

of Farahat's esearclr

published

y Cairo university.

{r '

nternational

onference,eb. |999. l 'his

.

design

s

basecl

n the conccptof tlre sirnple

angent

build

curvc. The three

majorscctionshat omr a horizontal ,el lor drainholc roshowlt n Fig. 3.2.

Thus,

rom this Figure, he thteesection

may

be

designed s

-ollows:

,1

Ha

-

V

3.

V €

G E O M E T N Y

A S I C

U t L

ol

I

D

C

U N

H-|

Fig. 3.2 Design of ltorizontol v,ell trajectotlt using he sinrple

vEnncAL

sEcr ioM

n

tangent build c:ut

e nrelhod.

Nl.S. rarah:rt


56/117

CH.III

Planni'ry of Hotizottol tlclk

50

l. Thc build-radius f the irst-build rc:

R: 5730B,

( l )

2. leightof the ir'st-buildrc:

D'

:

R(Sin r-Sin 1),

3. Heightofstraight

angent

D,

:

L,

Cos

r,

4. lleight

ofthe

second-buildrc;

D,: R(Sin

-Sin

lr),

5.

The engthofthe first section fhorizontalwell: KOP

KOP TVtLD,-Dr-Dr,

6. The displacementfthe first-buildarc:

(2)

(4)

II,

=

R(Cos icos I),

(6)

7.

l:hc

displaccrncntf thcstmightangcnt:

H,

:

L2 Sin Ir,

8. The displacement

f the second-build rc:

lIr

:

R(Cos Ir-Cos It,

9.

The length ofthe

first-build arc:

(3)

(5)

(7)

Dr M.S. I'arahat

.

(8)


57/117

CH.III

Platui

g

of lrorizon,tt

Welts 51

Lr : 100

l i l r ) /8 ,

10.The

cngth fthesecond-build

rc:

L3 100 I,- lr)/B

(e)

( 0)

||. Ihc rrcusulcd

cpth tlhccrxl

of

lho irct-l)uiltlfc:

MDr KOP

l-

Lr,

l 2 .

l

hc rnc l rs r r r

r ldcp l l )

a t t l r ccn ( l

' f

s t |1 r igh t| rogc :

MDr=MD,+Lr ,

13.Themcasured

epthat the

endofthe

second-build

rc:

MD3 MD'

-F

L3,

The engtb

ofsecond ection

L,

+

L2

+

L3or MD3-KOP.

( l

t )

( t2)

(13)

t4. The length

ofhorizontal

section

or third

section: H (14)

This length

is selected

according

o the tuming

radiusof horizontal

well

to be

ploposcd.

EX. l: During

dril l ing a horizontal

wcll

in Egyptian

dril l ing concession,

he

follorving

data wcre requircd

o design

his well trajcctorl,

namely:

Minimum expected

nglc

build ate:8?100

ft.

Minimum angent

cngth

=

120 t

r anScnrngte

=

)u.

Tarrgcnl ngle90'al S000 t TVD.

Design

well

trajectory.

EalJlti 2 f

l.

'Ihe

build-radius

fthe

first-build

rc:

R: 5730t8 5730/8: '1 t6t

Dr: iU.S.

hr:rhnt


58/117

cn.III

Phn

iry

ofrrotizontat

ttlerts

53

MD,

=

16P

't

t,

=

8206

625

8831

t.

12.The

measured

epth

at

theend

ofstraight

angent:

MD,

:

MDJ

J

Lr

:

8951

F

500

=

9451

t.

I-cngth

fsccond

scction:

Lt

J

[_,

+

Ll

:

625

+120

+

500

1245

t.

14. Length

of

horizontal

section

or third

section

=

H

proposcd

ength

naccordance

i th

R:

716 t ,

where

:800

53042620 Horizontal Oil Well Drilling Technology

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Transcript of 53042620 Horizontal Oil Well Drilling Technology