# Pune University Exam Papers

## (2008 Pattern) (Sem. – II)

Time :3 Hours]                                                                                              [Max. Marks :100

Instructions to the candidates:-

1)            Answer Q.No. 1 or Q.No. 2, Q.No. 3 or Q.No.4, Q.No. 5 or Q.No. 6, from Section -1 and Q.No. 7 or Q.No.8, Q.No. 9 or Q.No. 10, Q.No. 11 or Q.No. 12 from Section – II.

2)            Answers to the two sections should be written in separate books.

3)            Neat diagrams must be drawn wherever necessary.

4)            Pigures to the right indicate full marks.

5)            Use of logarithmic tables, Slide rule, Mollier charts, electronic pocket calculator and steam tables is allowed.

6)            Assume suitable data, if necessary.

SECTION – I

QI) a) Which type of separator you will recommend in following conditions?

Explain the necessary features useful for this.

i)  Offshore processing facility, large amount of solids expected.

ii) Cost effective for given gas capacity.

iii) For better liquid-liquid separation and to handle foaming crudes.

b) Write and explain the four principal mechanisms governing the separation process inside a two or three phase separator.

OR

Design a two phase horizontal separator using the following data: [9]

Gas flow rate (Qg) = 10 MMscf/day

Oil flow rate (Qo) = 2100 bbls/day for 42° API

Operating Pressure = 960 psia

Operating Temperature = 60°F

Specific Gravity of Gas a 0.6

Gas Compressibility = Z = 0.83

From graph, value of k = 0.284 (Constant based on liquid gas properties)

Liquid drop to be separated = dm = 100 micron

Assume slenderness ratio of 3 8 4. Retention time 2, 2.5, 8 3 minutes.

b) To obtain a desired oil pad height inside a three phase separator, water weir should be set a distance below the oil weir. Derive an equation to calculate this. Also draw the neat schematic sketch of a bucket and weir arrangement inside a three phase separator.

Q3) What is a Group Gathering Station? Discuss various operations and stages of separation that takes place in it. Draw the schematic of layout of this separation facility (block diagram) and show the various features.                                  OR

Q4) a) Write the necessary elements required for an emulsion to exist. What is the role of an emulsifying agent in it? Explain.

b)           Draw the neat schematic sketch of a vertical treater or horizontal heater treater indicate various components and explain the working of it in brief.

Q5) a) Explain the corrosion process in brief.

b) Write the various forms and causes of oil field corrosion in brief.

c) How will you identify potential sources of corrosion? Write the role of following factors that contribute to corrosion process.

i)  presence of air.

ii) dissimilar metal in physical contact.

iii) fluid velocity and turbulence.

iv) different types of water.

v) presence of acidic gases.

OR

Q6) a) Describe in brief various methods / steps to prevent and reduce or control the corrosion of oil field equipments in a production facility.

b) Discuss in brief Cathodic protection.

SECTION – II

Q7) a) Write any three flow assurance related problems and give their solution in brief.

b) Assume typical grain size distribution / pattern of produced sand on a graph of Cumulative weight percentage Vs Grain diameter. Given that Mean grain size is 0.0116 inch. Cumulative weight fraction of 40% sand has a diameter of 0.036 inch. Use Saucier and Shwartz’s correlations and describe the method of optimum gravel and screen sizing for a sand control job to this distribution. Draw and show the schematic of relevant finding using these correlations on a graph paper. Refer the given table 1 of standard sieve sizes.

OR

Q8) a) What do you mean by problem well analysis? What are the various ways and methods to know decline in well productivity? Draw typical sketches, production logs, DST chart, IPR or nodal analysis curves and show or explain in brief how you will you identify, evaluate and handle any two well production problems.

b)            Calculate pressure drop in the skin damaged zones for a vertical well and a 2000 ft long horizontal well and give your comments on it. Following reservoir properties are known.

Skin factor = +2 for both the wells, Pay thickness = 40 ft, Horizontal well production rate = 3000 bbls/day, Vertical well production rate = 1100 bbls/day, Permeability, Kv = Kh = 40 md, Bo = 1.07 rbbl/STB, Oil viscosity = 0.9 cp.

Q9) a) Write the advantages of side tracking from old vertical wells and horizontal well technology with reference to,

i) reservoir aspect.

ii)  decline in field production.

iii) low permeability and formation damage problem.

b)  A 400 acre lease is to be developed using 10 vertical wells. It was proposed to consider horizontal well application for this field development. If a vertical well effectively drains 40 acres, what will be the drainage area for a 1000 ft and 2000 ft long horizontal well in the same field? How many horizontal wells will be required to drain this sand effectively?OR

Q10)\f the production of ‘ABC’ field is on its declining stage, discuss in detail your step by step approach and general strategy for the following field conditions to improve the overall productivity of 60 wells from two different productive formations. Other field properties are as given below.

a) Offshore deviated wells, low to medium API gravity.

b) Anticline structure having solution gas drive.

c) Consolidated thick sand.

d) Depth around 10,000 ft, HPHT wells.

e) High pressure, low permeability.

f) High GOR, pressure less than bubble point.

g) High water cut along with some sand production.

h)  Target of primary recovery component achieved.

i) Scale and wax problem experienced.

QII) a) What is completion? Draw a neat schematic sketch and describe any one completion techniques for a Multilateral well trajectory.

b) What are the components of an intelligent well completion technique. Draw the schematic sketch and explain the function of each for the overall optimization of field roduction.

OR

Q12)Describe the objectives and challenges or field data in brief and discuss any one case study or field methodology of, (attempt any three)

a) Down hole separation and processing of produced fluid.

b) Heavy oil recovery.

c) Offshore production.

d) Intelligent completion.