[p.t] well comp let ions and production [jul-2009]

8/8/2019 [p.T] Well Comp Let Ions and Production [Jul-2009]

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UNIVERSTTITEKNOLOGIP ETRONAS

GOURSE : PAB2O94 WELL COMPLETIONS AND PRODUCTION

DATE : 18 NOVEMBER 2009 (WEDNESDAY)

TIME = 2.30 PM - 5.30 PM (3 HOURS)

INSTRUGTIONS TO GANDIDATES

1. Answer ALL questions from the Question Booklet.

2. Begin EACH answer on a new page in the Answer Booklet.

3. lndicate clearly answers that are cancelled, if any'

4. Where applicable, show clearly steps taken in arriving at the solutions and

indicate ALL assumptions.

5. Do not open this Question Booklet until instructed.

Note : i. There are NINETEEN (19) pages in this Question Booklet

including the cover page and Appendices.

ii. Graph and Semi Log papers are provided.

iii. Engineering Formula Booklet are given.

Unlversiti TeknologiPETRONAS



a..

PAB 2094

A reservoir is producing at stable conditions with following data:

average reservoir pressure' P'= 1800 psi

bottom hole flowing pressure'P*f= 1000 psi

bubble Point Pressure' P6 = 2000 Psi

oil flow rale, qo=210 bbl/daY

By using Vogel's equation,

calculate the maximum oil production' \

{".r .. [2 marks]

\*\plottheinflowperformancerelationshipassumingbottomhole

flowingpressuresofl350psi,g00psi,450psi,and0psi(graphg

paper is provided)'[6 marks]

(vDetermine the specific productivity index for a well producing ttpj{'""

bbl/daywithaflowingbottomholepressureof2350psi.Thereservotrl'

thickness is 40 ft and average reseryoir pressure is 3390 psi.\'...4.

[4 marks] \t"'

,1'-il.

b.

c. lf a second well in the same oil

reservoir at a location where the

the flowing bottom hole Pressure

(b).

field as in Part (b) j=tftes the

reservoir thickness i. 99ii calculate

at the same rate as the well in Part".\.,*

[4 marks]

2



2.

PAB 2094

An oil well has been drilled by Myanmar oil and Gas Enterprise. when it was

found that therewere three_P19duqtive zones in this well, it is required to

accomplish bottom-hole completions to produce well fluid from this well. well

completions should include apprgry|a! :91pl_"li:: ::1incomponelts' rhe

information on these three productive zones is listed"lii-.fhe tottowing table.

TABLE Q2

Productive

Zone

Depth Bottom-hole

Pressure

TYPe

of Fluid andconstituents

Specific

Gravity ofFAd

Tone I 10000 ft 3550 psi oil aJjT

Zone 2 10050 ft 3600 psi Oil, with sand

particles \

0.78

Ir*'\ /

Zone 3 10150 ft 3700 psi oil \ \?Ii

t. To produce oil from zone 1 and

segregated whilst zone 2 shut-in.

zone 3 commingled or

[3 marks]

: '/ii. To produce oil from .9n*g"gregated with no sand p-articles 0

whilst zone l and zone 3 shut-in.

[3 marks]

iii. To produce oil from zone 1 and zone 2 segregated, and

simultaneously whilst zone 3 shut-in

[3 marks]

Draw

fnecpmpletion configuration for each of the following cases.

,t\r

I,t:

\r

{1.'

i1L

. btr'

J:'''r

a.

.

,J\'

It\-



tv.

PAB 2094

To produce oil from zone 1, zone 2 and zone 3 segregated' and

simultaneouslY.

[3 marksJ

List THREE (3) completion string components consisted in your

suggestedwellcompletiontype,andgiveanexplanationfor-eacft

component.

,'

Svd11* ,-fr

.\d{

rfl.

/-lI"Y(iis'z-Jr

,\\u o r"{f; r!, r-'' \\'' ,r'

1f"'- rr-{rr

l-

4



PAB 2094

operating principle of ESP system with the aid of a neat

[4 marks]

ListFoUR(4)componentsofanEsPsystemandexplainthefunctions

of these comPonents'

[4 marks]

Make a proper drawirlg of surface equipment layout for gravel pT[]g

o p e ratio n a n d ex p I a i n s-u rra ce iiEia-ti*o n-p

roce.gure f o r g rave I

?":::;r,

Discuss the suitability of ESP and GL artificial lift systems for both

onshore and offshore application'

[4marks]

tthe

,1"t"

\:

,\,

d.

t,

r'\\'



PAB 2094

ln Field X, three wells were completed in similar formations at depths

ranging from 5,000 ft to 10,000 ft. The individuat well information is

given in TABLE Qaa(i).

The

well

ideal producing rate, q of an undamaged

in a steady state flow can be estimated

Using your answer in part (ii), indicate

from an acid treatment and estimate

increase after the treatment'

(skin S = 0) oil Producing

from the reservoir data

[4 marks]

[4 marks]

which well would benefit

the potential Production

tabulated in TABLE Qaa(ii)'

TABLE Qaa(ii)

OilviscositY

ffi@

6cp

1.2

800 ft

Wellbore radius 0.25 ft

Calculatetheidealwellproducingratesforallwells'

ii. Compute the skin factor for each well'

6

TABLE Q4a(i)

Flowrate (bbl/d)

Reservoir thickness (ft)

Drawdown (Psia)

0il PermeabilitY (mD)

iii.

12 marks)



b.

PAB 2094

A well was completed over a 500 mD formation with a well spacing of

40 acres (r, = 745 ft). The wellborediameter is 7

ftinch. lf it is decided

to case the hole, the pay zone will be perforated with a through ,Y!]nn

gun where the perforation charges have a depth of penetration of

1 4 inch rh" dtrhg'S-"9{r.9g$'m?1iy fllf i".:trnJ o"pttl 9f dfllle"d-Jgsi"11lgry the wellbore' rABLE Q4b

tabulate the available mud tYPe.\il-

TABLE Q4b

Mud A B C D

Permeability in damaged zone (mD) 100 20 300 200

Depth of invasion (ft) 16 0.8 2.0 2.3

From a well productivity point of view, which mud system would you

recommend for the following completions? Justify your answer'

Open hole.[5 marks]

ii. Cased hole.

[5 marks]

7



a..

PAB 2094

Data for a completed well in Field Y are tabulated in TABLE QSa'

TABLE QSA

Tubing length 8500 ft

Flowrate 4000 barrel liquid Per daY

Tubing diameter 4 inch

Well head Pressure 120 psi

Average reservoir Pressure 2500 psi

ProductivitY lndex 4.0 (linear)

Gas Oil Ratio 400 scf/bbl

Water cut 50%

b lr!

\\q

i.

y(. --\i !.,"

l ,,1

,:l:

t"t

t.-l

. /ri\ '\-'

' [3 marks]

ui,l

/"

// * ,'j'

v'

Determine the following:

i. The gas liquid ratio to flow the well'

,lt' '^, I Vi,'t''

TABLE Qsb

Depth of tubing 7000 fr

Average reservoir Pressure 2700 psi

Pl (linear) 3.5 b/d/psi

Wellhead pressure 1 20 psi

Gas Liquid Ratio 300 scf/bbl

Tubing diameter 4 inch

, )r

\\t\

ii. Amount of injection gas per day required if gas is injected at the

bottop of the tubing.

i; t [6 marks]

b. A well and reservoir have the following completion and reservoir data,

tabulated in TABLE QSb. The flow is 100% oil',).1



Using the Gilbert Chart attached in the APPENDIX l,

the inflow performance relationship curve andintake

curve. Use the graph paper provided.\\:

PAB 2094

construct

pressure

[5 marks]

ii. From answer in part (bxi), determine the operating point.

[2 marks]

iii. Discuss the effect of tubing size and water cut towards the

operating rate.

[4 marks]

(Note: Show all your workings in Gilbert Charts in APPENDIX I and submit all

the working together with the answer script).

o



PAB 2094

6000

5600

5200

g 4800oO

Ec 44@o4o)Ei 4000

:sE

$*mo

3200

2800

., t'.\O.Vt Gas lift performance curve for Well 1, Well 2 and Well 3 are shown in FIGURE

\l-\ 6a, 6b and 6c respectively.

34 345rale (MM sc'l/d)Gas iniectlon rate {M[,] sct/d]

FIGURE 6b

Gas Llft Perbrmance - Well 3

G* iniesden r{b ruM ec{/d}

FIGURE 6c

10

3200

2800

24W

P ?ooo

5osc 1600oujtod 1?m

3'F

$u*(5

400

I

FIGURE 6A

Ot00

2EOO

2&O

I 20005{!Es 1600

IgE6E troo

E'3F

B aoo

u

{o0

0

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[p.t] well comp let ions and production [jul-2009]

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