Download - 5 Pressure Basics Problems, PROBLEMS 1-6
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PAGE 5
2a. What is the hydrostatic pressure exerted by a
column of 16.8 ppg fluid at 13,780 ft.
!" # $% x .0&2 x '(%
!" # 16.8 x .0&2 x 13780
!" # 12038.208 or
!" # 12038 ")*
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2b. What is the hydrostatic pressure at the casing shoe
in a +ell 10,00 ft. -% 10,000 ft. '(%. 'he mud
+eight is 12.3 ppg and casing is set at &,&/0 ft.-%. &,03 ft. '(%.
!ydrostatic "ressure # $% x .0&2 x '(%
!" # 12.3 x .0&2 x &03
!" # 3222./// or!" # 3223 ")*
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/. +ell drilled to the depth of 11,200 ft. has casing set at 6,220 ft.
'(%. fter drilling out the shoe, the leaoff pressure +as 110
psi using a fluid +eighing .2 ppg. 'he present mud +eight is
10.3 ppg.. What is the estimated integrity fluid density maximum mud
+eight4
5. What is the estimated integrity pressure -)"4a. --W # ' "ress. .0&2 'est %epth4 9 ' -ud Weight
--W # 110 .0&2 62204 9 .2
--W # 3.6718& 9 .2
--W # 12.8718 or 12.8 ppg.
b. -)" # :*$% ; "resent -ud Wt.4 < .0&2 < 'est %epth
-)" # 12.8 ; 10.34 < .0&2 < 6220
-)" # 2.& < .0&2 < 6220
-)" # 808.6 or 808 ")*
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&. !o+ much applied pressure is re=uired to test a formation to the
e=ui>alent of 13.0 ppg 'he +ell is 7,000 ft deep, the casing is set at
3,&00 ft. and the test mud is 8.6 ppg.
pplied "ressure # : - Wt ; "res. - Wt4 x .0&2 x '(%
" # 13.0 ; 8.64 < .0&2 < 3&00" # /./ < .0&2 < 3&00
" # 800.8 ?
" # 801 ")*
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6. What mud +eight is e=ui>alent to a hydrostatic pressure of 11,00 psi
at 13,700 ft
@/
$luid %ensity # !" .0&2 '(%
$% # 1100 .0&2 13700$% # 16.70/08 or
$% # 16.7 ppg.
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"A: 11
1. What is the >olume of 6000 ft. of 13 3B8C casing 'he casing *% is
12.71& in.
(olume # Dapacity x ength
( # *%E 102./4 < 6000
( # 12.71&E 102./4 < 6000( # F12.71& < 12.71&4 102./G < 6000
( # F161.67122 102./G < 6000
( # .1&70&38 < 6000
( # /2.3228 or
( # /2.3 bbls
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/. %ataH 3 IC drillpipe, capacity .007/1 bblBft, displacement .00&1&
bblBft., 7C casing, capacity .0337 bblBft, -ud Weight 11./ ppg.
. !o+ many feet of drillpipe may be pulled JdryC before the !"decreases by 7&psi
-ax. ength "ulled J%ryC # F"ress. %rop .0&2 -ud Wt.4 < Dsg. Dapacity ; "ipe %isplacement4G "ipe %isplacement
-ax. ength "ulled J%ryC # F7& .0&2 11./4 < .0337 .00&1&4G .00&1&
-ax. ength "ulled J%ryC # F126.&1821 < .03/22G .00&1&
-ax. ength "ulled J%ryC # /.32/&31 .00&1&
-ax. ength "ulled J%ryC # 8/0.67 ft. r
-ax. ength "ulled J%ryC # 8/1 ft.
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/. %ataH 3 IC drillpipe,
capacity # .007/1 bblBft displacement .00&1& bblBft.
7C casing # capacity .0337 bblBft
-ud Weight 11./ ppg.
5. !o+ many feet of drillpipe may be pulled J+etC before the
!" decreases by 7&psi
-ax. ength "ulled JWetC # F"ress. %rop .0&2 -ud Wt.4 < Dsg. Dap ; "ipe %ispl. ; "ipe Dap.4G "ipe %ispl. 9 "ipe Dap.4
-ax. ength "ulled JWetC # F7& .0&2 11./4 < .0337 .00&1& .007/14G .00&1& 9 .007/14
-ax. ength "ulled JWetC # F126.&1821 < .02681G .012&6
-ax. ength "ulled JWetC #3.31&32 .012&6
-ax. ength "ulled JWetC # 270.0&6 ft
-ax. ength "ulled JWetC # 270 ft.
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&. %'H
%rillpipe # & in. Dasing # 13 3B8 in.
Dapacity # .01776 bbl B ft Dapacity # .1&/& bbl B ft
%isplacement # .0070 bbl B ft -ud Weight # 1/.2 ppg. !o+ much +ill the !" decrease if +e pull /6& ft. of pipe JdryC"ressure %rop B $t # -ud Aradient x "ipe %isplacement
%ry4 Dasing Dapacity ; "ipe %isplacement
# 1/.2 x .0&24 x .0070
.1&/& .0070# .738/ x .0070
.1/7&
# .00&23&2
.1/7&
# .03&/28 psiBft # .03&/28 x /6&
# 16.&0/1&2 psi or
# 17 psi.
'he boo says 16.3 psi. 'he boo is W?KA.
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&. %'H
%rillpipe # & in. Dasing # 13 3B8 in.
Dapacity # .01776 bbl B ft Dapacity # .1&/& bbl B ft
%isplacement # .0070 bbl B ft -ud Weight # 1/.2 ppg
5. !o+ much +ill the !" decrease if +e pull /6& ft of pipe J+etC
"ressure %rop B $t # -ud Aradient x "ipe %isplacement 9 "ipe Dapacity4
Wet4 nnular Dapacity
# 1/.2 x .0&24 x .0070 9 .017764
.1&/& .0070 .01776
# .738/ x .02/8&
.127/
# .0183/2
.127/
# .1/1/30& psiBft
# .1/1/30& x /6&
# 6&.8 psi or 66 psi.
"A: 7
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"A: 7
@1 'he +ell depth is 11,800 ft. and the mud +eight is 12.2
ppg. Dasing is set at 3770 ft. 'he +ell is shut in on a gas
ic. )*%"" # 220 psi, )*D" # 37& psi. What is the
e=ui>alent mud +eight at the casing shoe
:-W # 'otal pplied "ressure .0&2 '(%4 9 "resent -ud Weight
:-W # 37& .0&2 '(%4 9 "resent -ud Weight
:-W # 37& .0&2 37704 9 "resent -ud Weight
:-W # 37& .0&2 37704 9 12.2
:-W # 1.1287/ 9 12.2
:-W # 1/.11287/ ppg or
:-W # 1/.1 ppg
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PAGE 99
#3 What is the capacity bblsBft4 of 17 IC open hole
*nternal Dapacity # *%E 102./
*nternal Dapacity # 17.&E 102./
*nternal Dapacity # 17.& x 17.& 102./
*nternal Dapacity # 306.2& 102./
*nternal Dapacity # .27&03/ or
*nternal Dapacity # .27&0 bblsBft
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PAGE 100
#11 'he 13 3B8C casing to be run is in Jrandom /0Ls 9 /0 ft
per Moint4. *f the *% is 12.61&C, +hat is the >olume in one
Moint
*nternal Dapacity # *%E 102./
*nternal Dapacity # 12.61&E 102./
*nternal Dapacity # 12.61& x 12.61& 102./
*nternal Dapacity # 1&.13822 102./
(olume # .1&/&31 x /0
(olume # 6.18372/ bbls
(olume # 6.2 bbls
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STOP
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1. Dasing is set at 6000 ft. '(%. n 8 bbl. gain +as
noticed. %epth of the +ell is 12,000 ft. '(% )*%"" is /&0
psi and )*D" is 800 psi. 'he mud +eight is .8 ppg. Whatis the estimated formation pressure
$ormation "ressure # !"dp9 )*%""$" # $% < .0&2 < '(%4 9 /&0
$" # .8 < .0&2 < 60004 9 /&0
$" # 30&7.6 9 /&0
$" # 3&07.6
$" # 3&08 ")*
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2. !o+ much +ould the !" be reduced if 0 ft. of 6 IC drill
collars +ith an *% of 1 NC +ere pulled dryfrom 8 1B8C casing
+ithout filling the annulus. Dasing capacity is .0&1&6 bblBft.
Dollar capacity is .0030 bblBft and displacement is .0381
bblBft. -ud +eight is 13.& ppg.
psiBft # -ud Aradient < "ipe %isplacement
Dasing Dapacity ; "ipe %isplacement
psiBft # 13.& < .0&24 < .0381
0.0&1&6 0.0381
psiBft # 0 .702 < .0381
0.013/6
psiBft # 0.0267/62
0.013/6
psiBft # 1.870876
psiBft # 1.870876 < 0
psiBft # 178.83788
psiBft # 17 psi
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3. !o+ many barrels of fluid +ould it tae to fill
/3& ft. of /C drill pipe +ith an *% of 3.3/0C
*nternal Dap. # *%E 102./4 < ength
*nternal Dap. # 3.3/0E 102./4 < /3&
*nternal Dap. # 11.1&&6 102./4 < /3&
*nternal Dap. # .010836 < /3&
*nternal Dap. # /.71/0&1&
*nternal Dap. # /.7 55
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/. Dasing +as set at &&3/ ft. '(%. fter drilling 2& ft of
ne+ hole +ith 11.2 ppg mud, the +ell +as circulated
clean. 'he drilling program called for the formation atthe casing shoe to be tested to an e=ui>alent mud +eight
of 1/.& ppg. What surface pressure +ill be re=uired
" # :-W ; D-W4 < .0&2 < '(%
" # 1/.& ; 11.24 < .0&2 < &&3/
" # 3.3 < .0&2 < &&3/ " # /.63//
" # &0 psi
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&. 5efore a trip out of the hole, the pits held 62& barrels of
12.6 ppg mud. What should the pit >olume be after
tripping out JdryC
%ataH
7&0 feet of 7C drill collars 12,300 feet of & IC drillpipe
Dapacity # .0073 bblBft Dapacity # .02162 bblBft%isplacement # .0/03bbBft %isplacement # .002& bblBft
8 &B8C pen hole ne stand of drillpipe is 3ft. long.
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&.
'otal %" # %isplacement < ength'otal %" # .002& < 12300
'otal %" # 113.77&
'otal %" # 11/ bbl
'otal Dollar %ispl. # %isplacement < ength
'otal Dollar %ispl. # .0/03 < 7&0
'otal Dollar %ispl. # 30.22&
'otal Dollar %ispl. # 30 bbl"it (ol. # riginal (ol. ; %" %ispl. ; Dollar %ispl.
"it (ol. # 62& ; 11/ 30
"it (ol. # /81 bbl
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O6. %rilling fluid used in a +ell has a density of 16.8 ppg.
!o+ many JdryC stands 3feet per stand4 may be pulled
before the !" is reduced by 7& psi Dasing capacity is .060&
bblBft and drillpipe displacement is .00818 bbl.
-"% # F"ress. %rop .0&2 -W4 < D)A Dap ; "ipe %ispl. 4G "ipe %ispl.
-"% # F7& .0&2 16.84 < .060& .008184G .00818
-"% # F8&.8&16/2 < .0&277G .00818
-"% # /.&3031 .00818
-"% # &&3.837&/
-"% # &&/ ft.
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O7. With casing set at /000 ft '(%, a leaoff test
+as conducted. 'he '" is &0 psi using .7ppg fluid. %rilling resumed and at 10&00 ft, the
+ell iced +ith 10.& ppg mud in the hole. 'he
+ell +as shut in and pressures stabiliPed +ith a)*%"" of 2&0 psi and )*D" of /7&. !o+ much
pressure the formation liely +ithstand before
breaing do+n
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7. --W # '" .0&2 '(%4 9 'est - Wt.
--W # &0 .0&2 /0004 9 .7
--W # /.&67307& 9 .7--W # 1/.2 ppg
-)" # :*$% ; "res. - Wt.4 < .0&2 < '(%
-)" # 1/.2 ; 10.&4 < .0&2 < /000
-)" # 3.7 < .0&2 < /000
-)" # 76.6
-)" # 76 psi
dded "ress. # -)" )*D"dded "ress. # 76 /7&
dded "ress. # 2/ ")*
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O8. When drilling ahead +ith a 10.& ppg mud, a 1& barrel
ic +as taen and the +ell +as shut in. )hutin pressures
stabiliPed at )*%"" of 301 psi and )*D" of &2& psi. 'heformation fracture at shoe depth of 3&00 ft '(% +as estimated
to be e=ui>alent of a fluid density of 1&.0 ppg. What is the
e=ui>alent mud +eight at the casing shoe no+
:-W # )*D" .0&2 '(%4 9 "res. - Wt.
Q :-W # &2& .0&2 3&004 9 10.&
Q :-W # 2.88/61&1 9 10.&
Q :-W # 13.38/61&
Q :-W # 13./ ppg
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O. *f 5!" exceeded formation pressure by 200 psi
using 11.7 ppg mud, ho+ far +ould the fluid ha>e to fall
before losing the o>erbalance
'(% # !" $% .0&2
'(% # 200 11.7 .0&2
'(% # 328.7310
'(% # 32 ft.
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10. ssume a JdryC trip out of the hole using &C drillpipe
capacity # .0171 bbls. ft and .00827 bblsBft displacement4.
'he casing *% is 8.83&C and the mud +eight is 16.7 ppg. !o+
much !" is lost if 260 feet of pipe is pulled +ithout filling thehole
")*B$' # $A x "ipe %isplacement
Dsg. Dap. ; "ipe %ispl.
")*B$' # 16.7 x .0&24 x .008274
*%E 102./4 .00827")*B$' # 16.7 x .0&24 x .008274
8.83&E 102./4 ; .00827
")*B$' # .868/ x .00827
.07&8278 .00827")*B$' # .0071816
.067&&78
")*B$' # .16303 ")*B$' x 260
")*B$' # 27.63878 ")*
")*B$' # 28 ")*
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What is the !" at the casing seat in a +ell 128/0 ft. -%
6& ft. '(% 'he casing is set at &280 ft. -% and 372
ft. '(%. 'he mud +eight is 11.& ppg.
!" # $% x .0&2 x '(%
!" # 11.& x .0&2 x 6&
!" # &776.082 psi
!" # &776 psi
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Q-1 (S)The well took partial losses as it is drilled to
9600 ft TVD. Driller quickl li!ed up a!d "lledthe hole with sea water de!sit of #.$ pp%u!til the &uid le'el stailied at surface. The*+ at the ti,e of losses was 1.$ pp%. Thefor,atio! stre!%th at the loss o!e isesti,ated to e 0.$1$ psift.
/alculate the hei%ht of sea water colu,!whe! the well stailied.
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O2'he 12 R Jhole +as drilled to 600C -% and .&B8 casing +as
run and cemented at &&60 ft '(% +ithout any problem. fter
drilling out the shoetrac and 1& ft of ne+ formation a leaoff
test +as performed. 'he leaoff pressure is estimated to be 380psi +ith 12.8 ppg mud in hole. %rilling continued and the +ell
too a gas ic at 880 ft '(% +ith 13.& ppg drilling mud. 'he
+ell +as shut in successfully and pressures +ere allo+ed to
stabiliPedH ?eadings are as follo+sH)*D" # 180 psi )*%"" # 110 psi "it Aain # / bbls
What is the safety margin
a. 18 psi
b. /7 psi
c. &6 psi
d. Ko -argin
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$racture "ressure # 380 9 12.8 x 0.0&2 x &&60
$racture "ressure # 380 9 3700.736
$racture "ressure # /081 psi
)o the maximum limit is /081 psi SS
pplied pressure no+ # 180 9 13.& T 0.0&2 T &&604pplied pressure no+ # 180 9 303.12
pplied pressure no+ # /083 psi
)o the current applied pressure at the shoe is more than
the fracture pressure.
Ko safety margin left.
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THE
END