T
T
h
h
is
is
is
is
t
t
h
h
e
e
m
m
o
o
s
s
t
t
im
im
p
p
o
o
r
r
t
t
a
a
n
n
t
t
s
s
u
u
b
b
j
j
e
e
c
c
t
t
o
o
f
f
t
t
h
h
is
is
s
s
c
c
h
h
o
o
o
o
l
l
–
– The practices use
The practices used by most groups are
d by most groups are completely i
completely inappropriate
nappropriate
–
– The serious problem
The serious problems experienced a
s experienced are self-inflict
re self-inflicted, and
ed, and
unnecessary
unnecessary
This section will cover:
This section will cover:
¾
¾
What is required for safe tripping
What is required for safe tripping
¾
¾
Practices
Practices
¾
¾
BHA requirements
BHA requirements
¾
¾
Backreaming
Backreaming
¾
¾
Is it good or bad ?
Is it good or bad ?
Tripping & Backreaming Practices
Tripping & Backreaming Practices
Tripping & Backreaming Practices
Tripping & Backreaming Practices
•
•
Ba
Ba
ck
ck
-r
-r
ea
ea
mi
mi
ng o
ng o
r p
r p
um
um
pi
pi
ng
ng
ou
ou
t s
t s
ho
ho
ul
ul
d b
d b
e a
e a
vo
vo
id
id
ed
ed
whenever possible in high-angle wells
whenever possible in high-angle wells
–
–
The ability to trip
The ability to trip
out
out
without
without
pumping or backre
pumping or backre
aming is a
aming is a
critical objective
critical objective
–
–
Choosing any practice or equipment that forces you to
Choosing any practice or equipment that forces you to
backream to trip out makes a mockery of risk-management
backream to trip out makes a mockery of risk-management
•• Beca
Because b
use back-r
ack-reami
eaming a
ng and/or
nd/or pumpi
pumping o
ng out
ut are
are the
the singl
single-mo
e-most
st
dangerous operation in any ER well
dangerous operation in any ER well
–
– Maximum risk of stuck
Maximum risk of stuck pipe, and of destabi
pipe, and of destabilizing the wellbore
lizing the wellbore
–
– It is also time consumin
It is also time consuming, and destructive on B
g, and destructive on BHA equipment
HA equipment
–
– Engineers :
Engineers :
Classic train-wreck story
Classic train-wreck story
•
•
K&
K&
M s
M s
ee
ee
/ r
/ r
ev
ev
ie
ie
w a l
w a l
ot
ot
of
of
hi
hi
gh
gh
-a
-a
ng
ng
le
le
tr
tr
ai
ai
n w
n w
re
re
ck
ck
s
s
–
– Most have al
Most have almost identica
most identical chain-of-eve
l chain-of-events
nts
–
– 2 common theme
2 common themes :
s :
•• Those
Those that
that had b
had bad hol
ad hole cle
e cleaning
aning while
while drill
drilling (
ing (but t
but they t
hey thoug
hought it
ht it
was good).
was good). These also
These also tend to
tend to have poor
have poor tripping p
tripping practices.
ractices.
–
– More common with mo
More common with motor BHAs
tor BHAs
–
– Note –
Note – Can have good h
Can have good hole cleaning with moto
ole cleaning with motors !!
rs !!
•• Tho
Those t
se that
hat had
had goo
good ho
d hole c
le clea
leanin
ning wh
g while
ile dri
drilli
lling,
ng, but
but sti
still h
ll have
ave poo
poor
r
tripping practices.
tripping practices.
–
– This has become the mo
This has become the most common of the two,
st common of the two, ever since RSS became
ever since RSS became
popular
popular
–
Say operator is drilling high or medium angle hole
Say operator is drilling high or medium angle hole
1
1..
N
No
o p
prro
ob
blleem
ms
s d
drriilllliin
ng
g tto
o T
TD
D
••
G
Go
oo
od h
d hol
ole c
e cle
lean
anin
ing w
g wh
hil
ile d
e dri
rill
llin
ing
g, a
, an
nd n
d no c
o cav
avin
ing
gs r
s reepo
port
rted
ed
••
H
Ho
ow
w d
do
o tth
heey
y k
kn
no
ow
w iit w
t waas g
s go
oo
od
d h
ho
olle
e cclleeaan
niin
ng
g ??
••
N
No
o ttiig
gh
ht
t h
ho
olle
e aat
t cco
on
nn
neeccttiio
on
nss
••
G
Go
oo
od
d ccu
uttttiin
ng
gs
s ffllo
ow
w
2.
2. At TD
At TD, hol
, hole is cl
e is clean
eaned up
ed up
•• Mu
Multi
ltipl
ple b
e bot
otto
toms
ms up
up ci
circ
rcul
ulat
ated
ed at
at TD
TD
•• Sh
Shak
aker
ers c
s cle
lean
an up
up qu
quit
ite s
e soo
oon …
n …
team thi
team
thinks hol
nks hole
e m
must be
ust be cl
cle
ean
an
••
IIn r
n re
eal
aliity
ty,
, hol
hole
e cl
cle
eani
aning s
ng sys
yste
tem
m has
has sh
shut d
ut dow
own w
n whe
hen l
n low
ow--RP
RPM
M
used for clean-up cycle
used for clean-up cycle
3.
3. Tri
Trip com
p comme
menc
nces
es
•• S
So
oo
on
n p
pu
ulllls t
s tiig
gh
htt..
•• At
Atte
temp
mpt to
t to ba
back
ck-r
-rea
eam t
m thr
hru t
u tig
ight
ht sp
spot
ot
•• Ho
Hole p
le pack
acks of
s off (i
f (init
nitiati
iating
ng cir
circul
culati
ation o
on or so
r soon
on afte
after)
r)
•• 1
1
st
st
cavings reported at this point
cavings reported at this point
4
4..
B
Baacck
k--rreeaam
miin
ng
g cco
on
nttiin
nu
uees
s …
…
••
P
Paacck
kiin
ng
g o
offf
f aalll
l tth
he
e w
waay
y tto
o tth
he
e ssh
ho
oee
••
Re
Rela
lati
tiv
vel
ely
y li
litt
ttle
le cu
cutt
ttin
ings
gs w
wh
hil
ile
e b
bac
ack-
k-re
ream
amin
ing,
g, u
unt
ntil
il
≈≈30
30
o
o
, then
, then
shakers blind with lot’s of cuttings…
shakers blind with lot’s of cuttings…
a
an
nd
d cavings
cavings
..
••
P
Paacck
ks
s o
offf
f aallsso
o iin
nssiid
de
e ccaassiin
ng
g
5. Trip Back In
5. Trip Back In
••
F
Fo
or s
r so
om
me r
e reeaasso
on
n, t
, th
he t
e trrip
ip b
baacck
k--iin i
n is w
s wh
his
istl
tlee--ccle
leaan
n…
…
despite the nightmarish trip out…
Tripping & Backreaming Practices
Tripping & Backreaming Practices
What we will cover in this section:
What we will cover in this section:
•
•
P
P
a
a
r
r
t
t
1
1
–
–
W
W
h
h
a
a
t
t
i
i
s
s
h
h
a
a
p
p
p
p
e
e
n
n
i
i
n
n
g
g
d
d
o
o
w
w
n
n
h
h
o
o
l
l
e
e
•
•
P
P
a
a
r
r
t 2
t 2
–
–
H
H
o
o
w t
w t
o e
o e
na
na
b
b
l
l
e t
e t
r
r
ip
ip
p
p
i
i
ng
ng
o
o
n e
n e
l
l
e
e
va
va
t
t
o
o
r
r
s
s
•
•
P
P
a
a
r
r
t
t
3
3
–
–
T
T
r
r
i
i
p
p
p
p
i
i
n
n
g
g
p
p
r
r
o
o
c
c
e
e
d
d
u
u
r
r
e
e
s
s
•
•
P
P
a
a
r
r
t 4
t 4
–
–
B
B
a
a
c
c
k
k
r
r
e
e
a
a
m
m
i
i
n
n
g p
g p
r
r
o
o
c
c
e
e
d
d
u
u
r
r
e
e
s
s
Tripping & Backreaming Practices
Tripping & Backreaming Practices
•
•
P
P
a
a
r
r
t
t
1
1
–
–
W
W
h
h
a
a
t
t
i
i
s
s
h
h
a
a
p
p
p
p
e
e
n
n
i
i
n
n
g
g
d
d
o
o
w
w
n
n
h
h
o
o
l
l
e
e
–
– How does the c
How does the cuttings bed & BHA
uttings bed & BHA interact when tripp
interact when tripping ?
ing ?
•• Tr
Trou
oubl
ble-
e-fr
free t
ee tri
ripp
ppin
ing, v
g, vs ti
s tigh
ght ho
t hole
le
•• Nor
Normal
mal tri
trippi
pping vs
ng vs. Ba
. Back-
ck-rea
reami
ming vs
ng vs. Pum
. Pumpin
ping Out
g Out
–
– Separating my
Separating myth from reality
th from reality
–
What happens downhole when POOH ?
What happens downhole when POOH ?
Most people visualize that tripping looks something like this …
Most people visualize that tripping looks something like this …
And
What really happens
What really happens
downhole when POOH ?
downhole when POOH ?
What happens downhole when tripping in a deviated well ?
What happens downhole when tripping in a deviated well ?
–
– Firstly, assume
Firstly, assume that
that
the
the
ho
ho
l
l
e
e
i
i
s
s
N
N
O
O
T
T
1
1
0
0
0
0
%
%
c
c
l
l
e
e
a
a
n
n
–
–
Even with a thorough c
Even with a thorough clean-up
lean-up
–
–
Even with Rotary Steering Tools !
Even with Rotary Stee
ring Tools !
–
– The BHA does
The BHA does NOT pull cuttings u
NOT pull cuttings up the hole
p the hole
–
–
Cuttings
Cuttings
f
f
l
l
o
o
w
w
a
a
rou
rou
nd
nd
the BHA, until they become too compressed
the BHA, until they
become too compressed
–
–
BHA design is critical to “flow a
BHA design is criti
cal to “flow around”
round” ability
ability
–
What happens downhole
What happens downhole
when POOH ?
when POOH ?
•• When
When pulli
pulling o
ng out, t
ut, the B
he BHA p
HA pulls
ulls up t
up throu
hrough th
gh the di
e dirt …
rt …
•• For a
For a trou
trouble-f
ble-free
ree trip,
trip, the
the dirt
dirt must
must flow
flow aroun
around the
d the BHA as
BHA as the
the
BHA moves through the bed
What really happens
What really happens
downhole when POOH ?
downhole when POOH ?
The dirt must be able to flow through the bit & BHA
The dirt must be able to flow through the bit & BHA
••
Just like mud, we have a serious problem when the dirt
Just like mud, we have a serious problem when the dirt
can’t get past the BHA
can’t get past the BHA
When driller sees tight hole …
When driller sees tight hole …
what is happening downhole ?
what is happening downhole ?
Video Clip
Video Clip
If this component blocks the flow of dirt,
If this component blocks the flow of dirt,
then tight hole looks like this …
What is tight hole ?
What is tight hole ?
Note that thi
Note that this volume of dirt
s volume of dirt is small …
is small …
•• Only re
Only require
quires kilogr
s kilograms (no
ams (not tons) to be stu
t tons) to be stuck)
ck)
Unfortunately
Unfortunately, this is
, this is the most common situation
the most common situation
•• Beca
Because of
use of typi
typical b
cal bit & B
it & BHA des
HA designs
igns
•If you pull too far, you can’t go
•If you pull too far, you can’t go back down
back down
•Turning pumps on is
Backreaming Practices
Backreaming Practices
What is backreaming?
What is backreaming?
St
Sta
and
nda
arrd tr
d triip
p
–
– no rotation or
no rotation or circulation,
circulation, harmless cutti
harmless cuttings bed by-passed
ngs bed by-passed
Backreaming
Backreaming
–
– rotate and cir
rotate and circulate while POOH, cut
culate while POOH, cuttings bed fully rem
tings bed fully removed
oved
from the bottom of the hole. Cuttings drop out to form a dune above the BHA
from the bottom of the hole. Cuttings drop out to form a dune above the BHA
Backreaming Practices
Backreaming Practices
Backreaming Practices
Backreaming Practices
Pumping Out is Even Worse!
Pumping Out is Even Worse!
Pumping Out
Pumping Out
–
– dirt still pile
dirt still piles up behind the
s up behind the BHA due to high ve
BHA due to high velocity around
locity around
the bit, stabilizers, and drill collars, but the
the bit, stabilizers, and drill collars, but the
conveyor belt is off!
conveyor belt is off!
Video Clip
Video Clip
Backreaming Basics
Backreaming Basics
•• Wha
What are t
t are the dow
he downsi
nsides/
des/ris
risks as
ks associ
sociate
ated wit
d with
h
Backreaming?
Backreaming?
–
– Stuck pipe
Stuck pipe
–
– BHA equipme
BHA equipment failures due to vi
nt failures due to vibration
bration
–
– Key seating
Key seating
–
– Lost returns (if pac
Lost returns (if packoffs exceed fra
koffs exceed fracture gradient)
cture gradient)
–
Backreaming Basics
Backreaming Basics
•• Bac
Backre
kreami
aming its
ng itself do
elf doesn
esn’t dam
’t damage th
age the wel
e wellbo
lbore…
re…
–
– Rather, it is the
Rather, it is the
Hydraulic Hammer
Hydraulic Hammer
effect that causes all the
effect that causes all the
problems…
problems…
–
– Sudden large ECD
Sudden large ECD pressure shock
pressure shock below pack-off
below pack-off
•• Same
Same princ
principle
iple will
will destr
destroy p
oy pipel
ipelines,
ines, powe
power sta
r stations
tions, et
, etc ..
c ...Why
.Why
expect it to be less severe in a wellbore?
expect it to be less severe in a wellbore?
Hydraulic Hammer
Hydraulic Hammer
•• Wha
What PW
t PWD se
D sees wh
es when hy
en hydrau
draulic h
lic hamm
ammer oc
er occur
curs …
s …
•• Pre
Press
ssure s
ure spik
pikes a
es are of
re often “
ten “off t
off the s
he scal
cale”
e”
•• Reme
Remember,
mber, when
when you s
you see a p
ee a pack-
ack-off at
off at surfa
surface, yo
ce, you only
u only see
see
what’s left are dampening thru the bit, BHA & drillstring
what’s left are dampening thru the bit, BHA & drillstring
3
3
p
p
p
p
g
g
s
s
c
c
a
a
l
l
e
e
Normal drilling ECD …
Backreaming Basics
Backreaming Basics
•• In
Inter
terpr
pret
etati
ation of “
on of “we
well
llbo
bore st
re stab
abil
ility
ity”” pr
probl
oblem
ems cha
s chang
nges
es
entirely if the wellbore has been “
entirely if the wellbore has been “
H
Ham
amm
me
erre
ed
d
””
–
– Often, the presen
Often, the presence of cavings afte
ce of cavings after packoffs is perc
r packoffs is perceived as
eived as
the very cause of the packoffs
the very cause of the packoffs
•• K&M c
K&M conte
ontend th
nd that i
at it is
t is more
more like
likely th
ly the pa
e packoff
ckoff crea
created t
ted the ca
he cavings
vings
due to the hammer effect
due to the hammer effect
•• Evi
Eviden
dence
ce of t
of this
his is “
is “wel
wellbo
lbore
re stab
stabili
ility”
ty” pro
proble
blems o
ms ofte
ften go
n go awa
away wh
y when
en
tripping practices are modified (due to
Tripping & Backreaming Practices
Tripping & Backreaming Practices
•
•
P
P
a
a
r
r
t 2
t 2
–
–
H
H
o
o
w
w
to
to
e
e
na
na
bl
bl
e
e
tr
tr
i
i
pp
pp
i
i
ng
ng
o
o
n e
n e
l
l
e
e
v
v
a
a
to
to
r
r
s
s
M
Many
any op
ope
errato
atorrs s
s say
ay “
“d
don’
on’t b
t back-
ack-rre
eam
am un
unlle
es
ss y
s you h
ou hav
ave
e to …
to …”
”
B
But e
ut exp
xpe
erriie
ence
nced
d E
ER
R p
pe
eop
oplle
e “
“kn
know
ow”
” that
that no-
no-m
mat
atte
ter
r w
what t
hat the
he
pr
proce
ocedur
dure
es s
s say
ay,
, that’
that’s t
s th
he
e on
onlly
y w
way
ay the
they
y can
can g
ge
et out of
t out of the
the
hole
hole
T
T
h
h
e
e
a
a
b
b
ilit
ilit
y
y
t
t
o
o
t
t
r
r
ip
ip
r
r
e
e
g
g
u
u
la
la
r
r
ly
ly
o
o
n
n
e
e
le
le
v
v
a
a
t
t
o
o
r
r
s
s
is
is
p
p
o
o
s
s
s
s
ib
ib
le
le
–
How clean must the hole be for tripping ?
How clean must the hole be for tripping ?
−
−
It depends on the bit & BHA ...
It depends on the bit & BHA ...
BHA components are critical
BHA components are critical
to ability to trip
to ability to trip
BHA components are critical
BHA components are critical
to ability to trip
to ability to trip
••
Un
Unle
less
ss th
the
e BH
BHA
A co
comp
mpon
onen
ents
ts ar
are
e ad
addr
dres
esse
sed
d as
as a
a hi
high
gh pr
prio
iori
rity
ty ….
….
–
–
Conventional tr
Conventional tripping may be
ipping may be impossible desp
impossible despite best prac
ite best practices
tices
–
–
IIt onl
t only t
y take
akes on
s one
e com
compon
pone
ent to m
nt to make
ake a B
a BH
HA
A un
un--tr
triipp
ppabl
able
e
••
No matter how much circulation is done
No matter how much circulation is done
–
–
Th
Th
is
is
m
m
a
a
k
k
e
e
s
s
a
a
m
m
o
o
c
c
k
k
e
e
ry
ry
o
o
f
f
e
e
v
v
e
e
ry
ry
ris
ris
k
k
m
m
a
a
n
n
a
a
g
g
e
e
m
m
e
e
n
n
t
t
p
p
re
re
c
c
a
a
u
u
t
t
io
io
n
n
w
w
e
e
m
m
a
a
k
k
e
e
,
,
if
if
this isn’t addressed as the highest priority
this isn’t addressed as the highest priority
THI
THI
S
S
I
I
S
S
THE S
THE S
I
I
NG
NG
L
L
E B
E B
I
I
G
G
G
G
E
E
S
S
T
T
THI
THI
NG
NG
YO
YO
U
U
CA
CA
N
N
D
D
O
O
TO
TO
RED
RED
UC
UC
E
E
(
BHA design for tripping
BHA design for tripping
What needs to be done to bit & BHA ?
What needs to be done to bit & BHA ?
–
– Junk-slot-area & junk-slot-tortuosit
Junk-slot-area & junk-slot-tortuosity are key BHA
y are key BHA
design priorities
design priorities
•• Rem
Remove s
ove slee
leeve st
ve stabi
abiliz
lizers o
ers on big
n big-OD c
-OD coll
ollars
ars
–
– 6¾”
6¾” tools for 8½”
tools for 8½” hole, 5”
hole, 5” tools for 6 ½”
tools for 6 ½” hole
hole
–
– Especially on RSS, motor
Especially on RSS, motors and MWD-LWD tools
s and MWD-LWD tools
–
– Shoot for a mini
Shoot for a minimum of 30% open
mum of 30% open area
area
•• Or d
Or dow
owns
nsiz
ize to s
e to sma
mall
ller c
er col
olla
lars
rs
–
– Eg. 6 ¼”
Eg. 6 ¼” tools instead of 6 ¾
tools instead of 6 ¾”” for 8 ½”
for 8 ½” hole (or drill 8 ¾
hole (or drill 8 ¾”)
”)
Sleeve vs. Integral Blade
Sleeve vs. Integral Blade
How a
How a Sleeve Stabilizer
Sleeve Stabilizer
sees
sees
How an
Component Trip-ability Example
Component Trip-ability Example
Consider this New Zealand ER Well…
Consider this New Zealand ER Well…
•• 9
9
1
1
//
2
2
”” tang
tangent to
ent to ±610
±6100m (20
0m (20,000
,000’) MD
’) MD
•• Exc
Excell
ellent HC p
ent HC param
aramete
eters
rs
o
o 700
700 gpm
gpm / 15
/ 150 rp
0 rpm
m
o
o 3xBU clean
3xBU cleanup cycles
up cycles, shakers clea
, shakers clean after 2xBU
n after 2xBU
•• Previ
Previous wells ha
ous wells have never ha
ve never had proble
d problems tripp
ms tripping
ing
o
…However, the bits have changes “a bit”…
…However, the bits have changes “a bit”…
Trip
Trip
#1 (
#1 (
5 Bl
5 Bl
ade, 14
ade, 14
.5in
.5in
22JSA)
JSA)
No problems, very similar to behavior on first well (similar bit)
No problems, very similar to behavior on first well (similar bit)
Minor 20-30k “
Minor 20-30k “
peak”
peak”
over pu
over pu
ll in places
ll in places
(fairly sli
(fairly sli
ck on average)
ck on average)
Aver
Aver
age
age
F
F
F
F
=
=
0.1
0.1
6 –
6 –
0.18
0.18
Trip
Trip
#2 (
#2 (
9 Bl
9 Bl
ade, 12
ade, 12
.5in
.5in
22JSA)
JSA)
Long and troublesome trip with several intermediate circulation
Long and troublesome trip with several intermediate circulation
points required due to 50-60 k overpull in several locations
points required due to 50-60 k overpull in several locations
Average FF = 0.19-0.20
Average FF = 0.19-0.20
Trip
Trip
#3 (
#3 (
8 Bl
8 Bl
ade, 20
ade, 20
.9in
.9in
22JSA)
JSA)
Very smooth trip with the fewest number of tight spots of all the
Very smooth trip with the fewest number of tight spots of all the
tr
tr
ips
ips
out
out
.
.
“
“
P
P
eak”
eak”
overpu
overpu
ll
ll
of <
of <
15k.
15k.
Average FF = 0.16-0.18
Bit Design for Tripping
Bit Design for Tripping
–
– Straighten up highly tortuous component
Straighten up highly tortuous componentss
Prioritize Bit Junkslot Area
Prioritize Bit Junkslot Area
–
– Steel body bit
Steel body bits have much larg
s have much larger JSA than Matrix
er JSA than Matrix
–
– Better impa
Better impact resistance
ct resistance with Steel too
with Steel too
12 ¼”, 6-Blade
12 ¼”, 6-Blade
Steel
Steel
Body Bit
Body Bit
12 ¼”, 6-Blade
12 ¼”, 6-Blade
Matrix
Matrix
Body Bit
Body Bit
Bit Design for Tripping
Bit Design for Tripping
BHA Design for Tripping
BHA Design for Tripping
–
– A very effective
A very effective option to enable n
option to enable normal tripping with
ormal tripping with
“tigh
“tight”
t” comp
componen
onents is t
ts is to enl
o enlarge
arge the h
the hole
ole
•• Usi
Using Re
ng Ream
am-Wh
-While
ile-Dr
-Drill
illing (
ing (RWD
RWD) und
) under-
er-rea
reamer
merss
•• Ve
Very
ry po
popu
pula
lar i
r in t
n the
he No
Nort
rth Se
h Seaa
Under-Reamer Considerations
Under-Reamer Considerations
How the
How theBHA
BHA
sees a “Dirty”
sees a “Dirty”
under-reamed hole….
under-reamed hole….
Ho
How
w Casing
Casing
sees a “Dirty”
sees a “Dirty”
unde
underr--rre
eam
ame
ed
d hol
hole
e…
…
••
K&
K&M r
M rec
ecom
omme
mend
nd th
this
is as
as a s
a sho
hort
rt-t
-ter
erm “
m “ba
band
nd-a
-aid
id”,
”, un
unti
til t
l the
he
root cause is fixed, due to side effects of using RWD
root cause is fixed, due to side effects of using RWD
–
–
The danger of th
The danger of this technique is th
is technique is the “false sense
e “false sense of security”
of security”
gained from a trouble-free trip out prior to running casing…
gained from a trouble-free trip out prior to running casing…
Video Clip
Video Clip
Hole Cleanup Practices
Hole Cleanup Practices
T
T
h
h
e
e
h
h
o
o
le
le
m
m
u
u
s
s
t
t
b
b
e
e
c
c
le
le
a
a
n
n
e
e
d
d
u
u
p
p
p
p
r
r
io
io
r
r
t
t
o
o
t
t
r
r
ip
ip
p
p
in
in
g
g
•• To
To be s
be suc
ucce
cess
ssfu
ful, t
l, the f
he fol
ollo
lowi
wing i
ng is ne
s nece
cess
ssar
ary :
y :
–
– Conveyor belt must be turned on (> 120 rpm)
Conveyor belt must be turned on (> 120 rpm)
–
– Sufficient circulation is required
Sufficient circulation is required
•• Mu
Mult
ltip
iple B
le BU re
U requ
quir
ired a
ed at > 1
t > 120 r
20 rpm
pm
•• Lo
Look
okin
ing f
g for
or at
at le
leas
ast 2
t 2 wa
wave
vess
Cleaning up for a trip
Cleaning up for a trip
•• Th
The C
e Con
onve
veyo
yor b
r bel
elt r
t req
equi
uire
res >
s > 12
120 r
0 rpm
pm
•• Co
Comm
mmon
on di
dire
rect
ctio
iona
nal-
l-dr
dril
illi
ling
ng pr
prac
acti
tice
ce ….
….
•RPM is often slowed whenever off-bottom
•RPM is often slowed whenever off-bottom
(see next slide)
(see next slide)
•Hence, hole cleaning system is shut-down, convincing the team that
•Hence, hole cleaning system is shut-down, convincing the team that
the hole is clean
the hole is clean
•
•
Cuttings don’t know if the bit is on or off bottom !!
Cuttings don’t know if the bit is on or off bottom !!
•• Conve
Conveyor be
yor belt mu
lt must be on
st be on when bi
when bit is off
t is off-bott
-bottom too
om too..
This is one of the most common mistakes
This is one of the most common mistakes
…
RP
RPM vs Time lo
M vs Time lo g - Clean up on
g - Clean up on 18 July
18 July
2 200 4 400 6 600 8 800 1 10000 1 12200 1 14400 1 16600 P P i i p p e e R R P P M M R
RPPM drops fM drops from 138rpm rom 138rpm to 80+ to 80+ rpm.rpm. Cleanup is therefore largely Cleanup is therefore largely non-existant, and tripping starts in dirty existant, and tripping starts in dirty hole hole d d D D r r i i l l l l i i n n g g . . S S t t a a r r t t c c l l e e a a
n n u u p p
Time-log showing RPM at end of
Time-log showing RPM at end of drilling, and then
drilling, and then
during clean-up cycle
during clean-up cycle
••
Drill
Drilling RPM = 13
ing RPM = 138, clean
8, clean-up RPM onl
-up RPM only 80 –
y 80 – 90
90
•• Shaker
Shakers clean
s cleaned up
ed up soon .
soon ... hole
.. hole was in
was interpre
terpreted as
ted as clean
clean
••
This was thei
This was theirr expect
expected result sinc
ed result since they were using a
e they were using a
rotary-steerable !
rotary-steerable !
Hole Cleanup Practices
Hole Cleanup Practices
How much clean-up is necessary ?
How much clean-up is necessary ?
Cleaning up takes time
Cleaning up takes time
–
– Bottoms up is irrelevant for high angle wells
Bottoms up is irrelevant for high angle wells
•• Ex
Expe
pect
ct 2 –
2 – 4+
4+ x B
x BU f
U for
or cl
clea
eanu
nup t
p tim
imee
–
– This is very sensiti
This is very sensitive to angle ab
ve to angle above 70
ove 70
o
o
(
(
see
see
nex
nex
t pa
t pa
ge)
ge)
–
– Patience is
Patience is critical
critical
•• AN
AND
D on
only
ly “c
“con
onve
veyo
yor b
r bel
elt O
t ON”
N” ti
time
me co
coun
unts
ts
–
Effective C
Effective Circu
ircu lation Volum
lation Volum e vs.
e vs. Angle
Angle
20,000' (6000m) tangent length, shallow KOP
20,000' (6000m) tangent length, shallow KOP
1 1 2 2 3 3 4 4 5 5 6 6 7 7 M M i i n n . . C C i i r r c c u u l l a a t t i i o o n n V V o o l l u u m m e e
This gives some feel for
This gives some feel for how much circulation is
how much circulation is
necessary for different angles
necessary for different angles
•• Note
Note –
– only
only conv
convey o
ey or be
r belt cir
lt circulatio
culation co
n counts
unts !!
This is a mi
This is a minimu
nimum volum
m volume requir
e requirement …
ement … the
the
“talk
“talking”
ing” at the s
at the shakers
hakers takes p
takes priori
riority in
ty in
decision-making.
decision-making.
Notice how “gut feel”
Notice how “gut feel” and “experience
and “experience
betray you, once ang
betray you, once angle gets > 70
le gets > 70
o
o
Hole Cleanup Practices
Hole Cleanup Practices
–
– You are looking for a
You are looking for at least 2 waves
t least 2 waves of cuttings
of cuttings
•• Sa
Salt
ltat
atio
ion
n fflo
low
w si
side
de eeff
ffeecctt
•• If yo
If you’ve
u’ve been
been drill
drilling s
ing start
tart-stop
-stop styl
style, th
e, then e
en expec
xpect mo
t more wa
re waves
ves
Hole Cleanup Practices
Hole Cleanup Practices
A 2
A 2
n
nd
d
wave of cuttings flow is very common, if
wave of cuttings flow is very common, if
cir
circulati
culation c
on conti
ontinue
nues (wit
s (with the c
h the con
onve
veyo
yor
r be
bellt on)
t on)
••
Si
Sim
miilla
ar
r to g
to grra
ave
vel
l pa
packi
cking
ng, i
, in r
n re
eve
verrs
se
e
V V o l o l u u m m e e c c u u t t t t i i n n g g s s
Norm
Norma
all
circulation
circulation
At
At >
>8
80
0
oo,
, 2
2
ndndwave
waveis ofte
is often
n
after
after 3
3
rdrdbottoms up
bottoms up
1
1 22 33 44