7/27/2019 Past Year Exam

1/4

VENUE/S: DATE:

Office use only

C:\Documents and Settings\jishan\Desktop\RE2011\EXAM2010\Sem 1 2010 Exam Coversheet.doc

EXAMINATION COVER SHEET(Do not alter this form)

THIS FORM MUST ACCOMPANY EVERY EXAMINATION PAPER

School / Centre / Discipline: Mechanical Engineering ______________________________________________________________

Unit Code: Name of Unit : Reservoir Engineering ________________________

Paper No: (if more than one) _____________ Number of Candidates: 110 _________ No of pages in exam: 4 ____________

Duration of exam: 2 hrs (and 10 minutes) 3 hrs (and 10 minutes)

Other ____________________

Name of examiner: Jishan Liu/Jiang Guo Wang _________ Telephone No: 7205 ______ Mobile: _______________________

Name of Admin Officer / Assistant: _________________________________ Telephone No: _____________________________

IS THIS PAPER AVAILABLE FOR PUBLICATION (e.g. Library)? Yes No

STATIONERY AND AIDS(Please tick appropriate boxes)

Calculators (Permitted)(Please tick box) YES NO

PLEASE STATE ANY ADDITIONAL REQUIREMENTS (e.g. maths and stats tables, special instructions, formula, maps, musicmanuscript paper, text books, notes)

________________________________________________________________________________________________________

________________________________________________________________________________________________________

________________________________________________________________________________________________________

________________________________________________________________________________________________________

THIS EXAMINATION PAPER HAS BEEN CHECKED: ____________________________________________________________Signed by Examiner

__________________________________________________________________

DatePlease note that the cos t of re-printing any examination papers wil l be charged to the School/Discipline

Answer books(please use discretion)

6 Writing Pages ______ each

10 Writing Pages ______ each

18 Writing Pages ______ each

Multiple choice answer sheets.

125 questions

(Student Admin supplies 125 question only)

Graph Paper (Please attach sample)Student Admin supplies1mm and 2mm only

______ each Double sided printi ng

Single sided printin g

P E T R 3 5 1

X

X

X

X

1

X

7/27/2019 Past Year Exam

2/4

PETR3511/PETR8053 FINAL EXAM 2010

SECTION A (30 Marks): There are six questions in this section. Please provide your answers on the answer book, clearly stating the question number.

1) (5%) Define dissolved gas-oil ratio, s R , and volatilized oil-gas ratio, v R .

Assuming a single-phase oil reservoir, what is the relation between s R and v R ?

2) (5%) Define the compressibility for gas. Discuss how the reservoir pressure

affects the compressibility for the ideal gas.

3) (5%) For a single phase oil reservoir, use the initial free phase oil, foi N , and the

initial dissolved gas-oil ratio, si R , to define OOIP (original oil in place) and OGIP

(original gas in place).

4) (5%) Use two-phase oil formation volume factor to define the oil phase

expansivity. Discuss how the oil phase expansivity changes as the reservoir

pressure decreases.

5) (5%) Define the relative permeability and explain why neither of the two relativepermeabilities in a two-phase reservoir can ever be greater than 1.

6) (5%) Name three factors that affect the hydraulic diffusivity. Discuss how each of

them affects the magnitude of the hydraulic diffusivity.

7/27/2019 Past Year Exam

3/4

PETR3511/PETR8053 FINAL EXAM 2010

SECTION B (20 Marks): There is one question in this section. Please provide your

answers on the answer book, clearly stating the question number.

A small gas reservoir has an initial pressure of 3000 psia and temperature of 220F.The following table gives the pressure and production history.

Complete the following questions:

1. Calculate the gas expansivity, g E , at the end of each interval.

2. Calculate the accumulative production gas volume at the reservoir condition at

the end of each interval.3. Assuming no water influx and neglecting formation compressibility, calculate the

OGIP using production data at the end of each interval

4. Discuss your calculated OGIPs and explain why they indicate a waterdrive.

5. Assuming the real OGIP is equal to scf 6101000 , use the MBE,

W B BGF gig fgi += , to calculate the water influx, W , at the end of each

interval.

SECTION 2: Pressure and Production History

( ) psi p ( )scf G p610 ( )scf Bg / ftres

3

3000 0 0.0055

2500 100 0.006

2000 300 0.007

1500 500 0.008

SECTION 2: Pressure and Production History

( ) psi p ( )scf G p610 ( )scf Bg / ftres

3

3000 0 0.0055

2500 100 0.006

2000 300 0.007

1500 500 0.008

7/27/2019 Past Year Exam

4/4

PETR3511/PETR8053 FINAL EXAM 2010

SECTION C (10 Marks): There is one question with two parts in this section. Please

provide your answers on the answer book, clearly stating the question number.

PART I (5%): For a one-dimensional incompressible flow system as defined in thefollowing graph, the pressure distribution along the flow path, ( ) x p , is determined bythe permeability distribution only. Use the information given in the graph to

determine the pressure distribution along the flow path.

PART II (5%): Assuming the flowing liquid in Part I is an ideal gas and k k k == 21 ,

the relation between the gas density, , and the gas pressure, p , can be defined as

p = ( is a constant). Assuming the viscosity as , prove that the Darcy

velocity, xu , can be calculated as

pk

u x

50=

mDk 100001 = mDk 102 = psi p10

1= 0

2= p

00.5 1.0

X (ft)

No Flow No Flow

No Flow No Flow

Definition of a one- dimensional flow system

mDk 100001 = mDk 102 = psi p10

1= 0

2= p

00.5 1.0

X (ft)

No Flow No Flow

No Flow No Flow

mDk 100001 = mDk 102 = psi p10

1= 0

2= p

00.5 1.0

X (ft)

No Flow No Flow

No Flow No Flow

Definition of a one- dimensional flow system