UNIVERSIT]

FINAL EXAMINATIONSEPTEMBER 2012 SEMESTER

couRSE : PAB1033 / PcB1033 RESERVO|R RocK AND FLU|DPROPERTIES

DATE : 2"d JANUARY 2013 (WEDNESDAY)TIME : 9.00 AM

- 12.00 NOON (3 HOURS)

INSTRUCTIONS TO CANDIDATES

1. Answer ALL questions from the Questions Booklet.2. Begin EACH answer on a new page in the Answer booklet given.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.6. Engineering Data and Formulae Booklet is provided.

Note : There are FIFTEEN (15) pages in this Question Booklet including the coverpage and Appendices.

Universiti Teknologi PETRONAS

1.

PCB 1033

Porosity is a measure of the space available for the accumulation and storageof fluid in the rock.

a. Differentiate between the absolute porosity and effective porosity.Decide which porosity to be used when characterizing a core sample

[4 marks]

b. lf reservoir rocks have significant variation in porosity in differentsection in the reservoir as shown in FIGURE e1b, state TWo (2)suitable methods that can be used to calculate the average porosity.

[4 marks]

FIGURE Q1b

A core sample coated with paraffin was immersed in a tube. A clean,dry core sample weighed 25 g. The dry core sampre coated withparaffin weighed 27 g.The paraffin coated sample displaced 14 cm3 ofliquid. Assume the density of paraffin is 0.g g/ cm3. The grain vorumeof the core sample was found to be 8.5 cm3.

i. Calculate the bulk volume of the sample.

c

2

[5 marks]

PCB 1033

ii. Calculate the porosity of the sample.[3 marks]

iii. State the type of porosity calculated in part e1c (ii)[2 marks]

d. Discuss the main differences between primary porosity and secondaryporosity.

[2 marks]

a.2. Define effective and relative permeabilities.

[4 marks]

b, What is the Klinkenberg effect? Draw a sketch of the relationshipbetween measured permeability and absolute permeability to showKlinkenberg ef[ect.

[6 marks]

c. TABLE Q2c shows permeability data of a reservoir. A hydrocarbonreservoir is characterized by five distinct formation segments that areconnected in series. Each segment has the same formation thickness.

TABLE Q2c : Permeability DataPermeability (mD)

150200 50

3020

200 10

State the averaging method that willaverage permeability of the reservoir.

[2 marks]

State TWO (2) the assumptions that you use for yourcalculations.

ilt Calculate average permeability of the reservoir.

use to calculate the

il

3.

PCB 1033

a' Using appropriate sketches, illustrate how contact angle is related tothe wettability characterstic of a rock. Assume that you have oil andwater in the system.

[4 marks]

b' With the aid of a sketch of oil-water relative permeability curves,describe the difference between oil wet reservoir and water wetreservoir indicating the two phase flowing regions, s*", and so.. Labelyour sketch clearly.

[6 marks]

c. Describe step by step how drainage process is performed on the coresample in the laboratory.

[6 marks]

d. Sketch a capillary pressure curve and indicate in your sketch, freewater level (FWL), water-oil contact (woc), transition zone andthreshold capillary pressure.

[4 marks]

4PCB 1033

You are a surveillance engineer working in Ariana field. You have collected agas mixture in a 1.5 ft3 container from the stock tank. Composition of the gasmixture is shown in TABLE Q4. The reservoir condition for the Ariana field is at180"F and 3000 psia. (Note : ,R =1 0.72 psia ft3 / oR-lb-mole)

TABLE Q4 : Composition of gas mixtureComponent Mole

FractionMolecular

Weiqht?"c ('R) Pc (psia)

COz 0.02 44.01 547.91 107 1Nz 0.01 28.01 227.49 493.1Cr 0.85 16.04 343 33 666.4CC 0.04 30.1 549.92 706.5C: 0.03 44.1 666.06 616.4-Cq 0.03 58.1 734.46 527.9

n-C 0.02 58.1 765.62 550.6

a. Define the Law of Corresponding States. What is it used for?[4 marks]

b. Calculate gas compressibility factor.[7 marks]

the reservoir,

[3 marks]

the reservoir,

[3 marks]

Discuss about the results of gas density calculated inpart Qa(d).

part Q4(c) and

[3 marks]

c. Assuming that the gas mixture behaves as an ideal gas indetermine the gas density at the reservoir condition.

d. Assuming that the gas mixture behaves as real gas indetermine the gas density at the reservoir condition.

e.

a.5. TABLE Q5 shows the initial reservoir fluid datadifferent reservoirs.

L

PCB 1033

for two wells from

ldentify the possible fluid classifications of theJustify your answer.

c.

ii. sketch the corresponding phase diagrams for the fruids inboth reservoirs.

[4 marksJ

Describe the difference between alkenes and alkynes. Give oNE (1)example for each.

[3 marks]

The producing gas-oil ratio of a well is 1000 scf/srB and the specificgravity of the gas is 0.756 and the Apl gravity of stock tank oil is40.3oAPl. The liquid in the reservoir is at its bubble point at reservoirconditions at 3385 psia and 205oF. Determine the pseudo liquiddensity at standard conditions.

-END OF PAPER -

7

TABLE Q5 : data for initial reservoir fluid

Well -1 Well -2

SurfaceAppearance

Black ViscousLiquid Light color

Gas-Oil Ratio 300 scf/STB 2906 scf/STBOAPI 26 50

[7 marks]

PAB 1033

APPENDIX I

,goo-

do-a

oL

=6ooLCL

o,Loo!=olrtfL

700

600

550

500.6

550

500

450

400

350

1_0 1.1 1.2 1.3Gas speciflc gravlty

1,0 1.1 1-2 1"3Gas speciflc gravity

8

1-71-61.51.4

E.o

-F

@

too-fD

o

=(JoE(D

o-

.6 1_6 1.7

m8xrocoz0- fL

Corlprr:ssittilitv Factclrs llr lrlatLtral (iases ar: aFunction af Fseudtlreduc:ecl Fressute anrl TemperatLlre

Pserrclo R+rJricerl Prelisure, P121.15ii7

-l/--jPseudoRpducrl Terrrpeiaturu _----:H-5-

11

1

(i ,i

').:;11

10

''-\ L'') (-l

//

\L\r -

-f rrIII /|i--,----tffi ,// ;,'

1itr15

1tt

t i-i

1-ll.i

N_

tl i(_,

GLL,- I I l.'r.:'=VJ rlJ lL_

o{j tt4

1

1ti

0g

0

(r r-J

1J5lii

4l:,

1.1

l/

/,/// /

,/ ,/ ,/ 1./ _/ 'i.. i ',t

,/ -\, "/ -/.,,

',/,+{;\t!./ //

rf ,\

.(_.

[.':r1li '5 5i li il i qr fll.rtLlt.il {-:resr,lri. 1. l9Jli

,l 1(j l1 1! 1:jPseurjo RerJrri:rd PrcssLrre. P

t.IJ4

0 016

0.15

0 14

0 013

0.012

0 tl'11

0 01

09

0 008

0 00/

0.006

0 00s

0.004

10

J-Jttttcor

05Gas Gravity iAr = 1)

-*rr.

HrSlJLiJ'i-

tl5 10 15

lrllle per nt HS

r il tr tt tl tt ii tt tl tl tt30 4D 50 60 70 B,t

6

50

40

'5

D

ia!0o;+D3jt>oO

r JU

=

I ';rt. lJ

a,

PAB 1033

APPENDIX III

t. - .\/ !t0st,/ t ptrtrti]:,inperitrrrlSrld frt.rssutt, ttl l)ilti3

!.q - ',rrsrl,r l 1 / p (1flTjtrdrfif ;i rq lctlrtf lilfr'js, lni,rics

32 34

J

Id::

0!

(,'.

:;Fr

\=)

L)UJi-

5 10lrlo e per cen N

!l0 51015

Mole per cent C02

20

+U

uoott:qr

ot,! o tl](]

15

llllttig0 1001n

LI 0.8 1t 12 14 16 18 20 22 24 26 28 30Pseudoreduced Iemperature.

* ,{t0 I 5!-o4!qt {r.trl0:'3,9rnnNt)o

ftrlolecular V/eighi

10

PAB 1033

APPENDIX IV

PHYSICAL PROPERTIES OF THE PARAFFIN HYDROCARBONS & MISCELLANEOUS COMPOUNDS

COMPOUND MOLECULARWEIGHT

BOILINGPOINT AT14.7 PStA

"F

CRITICAL CONSTANTSLIQUID DENSITY60"F, 14.7 PStA

GAS DENSITY80'F, 14.7 PStAIPERFECT GAS

CU FT GASPEH GALLON

LIQUID(ACTUAL

PRESSUREPSIA

TEMPEFATURE"R

GnPERcc

POUNDSPER

CU FT

POUNDSPEFMCF

CU FT GASPER

GALLONLIQUID

METHANE 16.04 -258.7 673 344 42 27ETHANE 30.07 127.s 709 550 79 23PROPANE 44.09 -43.7 618 666 0.5072 31.66 116.19 36.35 35.78ISO-BUTANE 58.1 2 '10.9 s30 733 0.5625 35.1 2 153..15 30.59 29.70N-BUTANE 58.12 31 1 551 766 0.5836 36.43 153.15 31 75 30.77ISO.PENTANE 72.15 a2 1 482 830 o.6241 38.96 1 90.1 1 27.3s 26.17N-PENTANE t.t5 96.9 485 847 0.6305 39.36 190.1 1 27.63 o.JoN-HEXANE 86.1 7 155 7 434 915 0.6637 41.43 227.07 24.34 22.83N-HEPTANE 100.2 209 2 397 973 0.6875 42.92 264.03 21.69 1 9.95N-OCTANE 114.2 258.2 370 .1025 o.7062 44.09 300.99 19.s5 17.77N-NONANE 128.3 303.4 335 1 073 0.7211 45.02 337.95 17.78 15.88N-DECANE 142.3 345.2 312 1115 0.7333 44.78 37 4.91 '16.30 14.30

AIR 28.97 -.t t t -t 547 239NITROGEN 28.02 -320.4 492 227OXYGEN 32.00 -297.4 732 278CARBON DIOXIDE 44.01 '109.3 1072 548HYDROGENSULPHIDE

34.08 -76.5 1 306 b/J

WATEB 18.02 212.O 3206 1 165 0.9991 62 37

11

Density of propane plus, lb/cu ft!d(o)aoa

C]

Ao

O(f

N

LDO

N)Density of system including nrelhane and ethane, lb/cu ft

TTt -Tl2orxP

PAB 1033

APPENDIX VI

10

a

e

5\

4\

3\

4

I

o23

f-()

.qrno-\-q-

l-Ldo(G'>-

'rl]Eq)Eanl.Eq)=ln

PAB 1033

APPENDIX VII

l0_o

LF-

a()

0.0 tG.2 1-O

Pseudsreduced pqessure, ppr

NN- \

ss N-\- \N N\\\ \N\N N

l\ N I

\ \

To''

\\-- \t\ I ,00.80.60.l+-

-{-\3-i6-

\ :t.

EQUATIONS

Effect of non-hydrocarbons on calculations of z-compressibility factorsTt

-'l- -

ca(,

: P,T,'" Tu, * ! r,r(l _ y, ,r)c

Coefficient of isothermal gas compressibilityC/- PrL- tP

PC

14

^S, = q-ltL

2ftkh(P" -

P.)

P - (h- r)

kor:

ql=

P,: 2 a *oCos 0

k_av

oilP -

(77s8 )v,( 1- s*" )ROrrP

-

(77s8 )V,3( 1- S," -

S,, )

srorrP -

(775B rvo l" l l'r ( I - s *" - s "' )

15