internship report by usama

INTERNSHIP REPORT OF KANDHKOT GAS FIELD
PAKISTAN PETROLEUM LIMITED
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SUBMITTED BY
Muhammad Usama
Chemical engineering department
Final year (13CH41)
Mehran University of engineering and technology

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Contents: page
1. Acknowledgement 3
2. Health, safety and environment 3
3. Introduction to Kandhkot gas field 4
4. Compression plant 4
5. Equipment use in KFGCS 6
6. Utility area 8
7. Dehydration plant 8
8. Equipment use in dehydration plant 10

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1. ACKNOWLEDGMENTS
“In the name of Almighty ALLAH the most gracious and the most merciful”
First of all I would like to thanks Allah Almighty for the bestowal ofhis blessings and kindness. Secondly I
would like to express my gratitude to Pakistan Petroleum Limited (PPL) for trusting me and giving me a
chance to enhance my technical expertise and provide me opportunity to have an internship in extremely
professional environmentatthe KANDHKOT GAS FIELD. I would particularly like to thanks
1. Mr. Javed Iqbal (Manager of Kandhkot field)
2. Mr. Tashfeen Ahmed (Senior Engineer ofKFGCS)
3. Muhammad Anwar (Senior Engineer ofKFGCS)
4. Mr. Abdul Hafeez Babar (Operation Engineer)
5. Mr. Naseer Khan (Operation Engineer)
6. Mr. Khalid Aziz
7. Mr. Haleem
8. Mr. Arab Muhammad Bhayo (Chief Engineer Production)
9. Mr. Pir Muhammad Ali Shah. ( Senior Engineer Production)
10. Mr. Muzammil Hussain (shift Incharge of DHP)
Their support, valuable suggestions and critical analysis throughout the internship programme and project
work have encouraged me to study hard and have really enhanced my learning capabilities. Working with
the compression plant and Dehydration Plant Team is really an amazing experience.
2. HEALTH SAFETY & ENVIRONMENT
I was given briefinduction for HSE training from (HSEO) Mr. Shahid. It is a general rule that all accidents
can be avoided ifcare is taken while doing any job ata plant and on filed. It is said higher the valve for HSE
higher will be the profit for a company, therefore a lotof focus is given to this departmentin all the
companies. Same is the case here in Pakistan petroleum Limited.
General rules laid down by the administration here include:
1. Use of personal protective equipment(PPEs) like safety boots, helmets ear plugs, mask etc. is a
compulsive when in operation area.
2. Smoking is notallowed at plant and on field exceptatfew designated places.
3. Anything that can be ignite a fire or explosion like cigarette, lighter, matchbox mobile, cordless
phone, cameras are notallowed in operation areas. However, cameras can be used take pictures for
official use after taking a hot permit.
4. Anyone visiting the operation area must know the process taking places there in detail.

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3. INTRODUCTION OF KANDHKOT GAS FIELD:
OVERVIEW
KandhkotGas Field is situated on the right bank of Indus River in Upper Sindh, while the field’s reserves
are located in the Habib Rahi Limestone, Sui Upper Limestone and Sui Main Limestone reservoirs. The
field was discovered in 1959 and has 386 producing wells to date. Among them well number 4 has
abandoned and two for injection& 2 are exploratory wells. The average production ofthe field is
approximately 195 MMSCF/day. The leading sale gas consumers include WAPDA, SNGPL and SSGC,
whereas condensate is sold to PRL (Pakistan Refinery Limited).
Geologically KandhkotGas field consists ofthree domes:
(1) North-East Dome Discovered in 1958
The potential zone here for hydrocarbon lies in the reservoir of
Sui Main Limestone (SML) ii) Sui Upper Limestone (SUL)
(2) WestDome Discovered in 1971
The reservoir here lies in the formation of Sui Main Limestone (SML)
(3) South East Dome Discovered in 1986
Its hydrocarbon formation lies in
i) SML (Sui Main Limestone) ii) SUI (Sui Upper Limestone)
Iii) HRL (Habib Rahi Limestone)
4. COMPRESSION PLANT:
Introduction ofKFGCS:
KFGCS is stands for KandhkotField Gas Compressor Station. KFGCS was commissioned and isin
operation since 2nd Dec 2010.
KFGCS is usually designed to deliver pressure 4824 kpa to costumer through downstream of the DHP
(Dehydration Plant) at 210 MMCDF flow rate.
KFGCS came into operation in the year of2011, for compressing the natural gas from three gas reservoir
in Habib Rahi Limestone (HRL), Sui Upper Limestone (SUL) and Sui Main Limestone (SML) through three
Turbo-compressor (SIEMENS SGT400 Gas turbine driven).
KFGCS has 2 air compressor for instrument and plant air at 700 kpag. 02 insert gas packages installed for
nitrogen generation for compressor sealing and inertgas for purging.

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Two centrifugal pump (diesel engine driven) ofcapacity 454.2 m3 /hour feeding the 11 hydrant and having
two centrifugal jockey pump to maintain fire water header pressure on 950 to 1050 kpag.
KFGCS also has 02 water treatment packages with capacity of 10 m3 /day to provide
potable water.
KFGCS is comprised ofthree department.
1. Operation Central control room (OCCR)
2. Mechanical department
3. E&I department
Over all operation in KFGCS (i.e. gas compression operations and utility) arecontrolled in central control
room by shift Inchargeengineer and area operator offield. Laboratory section for testing (lubricating oil
testing, corrosion testing, condensate testing) come under OCCR.
Other department like mechanical and E&Iare supervised by their respective Incharge, but required permit
form control room for any kind of operational job.
Process description:
In kFGCS, the gas from gathering network enter into the slug catcher (v-4000A & v-4000B) .It consistof
eight parallel finger. During gathering, gas become cool and gives condensate.
The heavy hydrocarbon in from of liquid are separated from the gas, liquid from all eightfinger collected
and under level control sentinto the condensate recovery vessel (v-5701) through pump. And the process
gas is collected into common header and sentto the filter for further separation.
Liquid free Gas from slug catcher is sent the gas inletfilter (consistofthree gas inletfilter v-3000A/B/C),
which remove the entrained solids particles as well as liquid from the gas carried out through the
Slug catcher.
Each filter usually having two section, one section usually having filter and providing the filter facility for gas
that coming from the slug catcher and next section ofinletgas filter is vane type liquid mistextractor, which
remove remaining water (droplet) content.
From gas inlet filter (A, B AND C), the liquid free gas is collected into the compressor manifold, itis a 30”
header, from where it’s departed to suction scrubber (v-1000 A, B and C). Scrubber is basically the two
phase separator, where liquid is separated from the gas before entering to the Ist stage compressor and
collected into the condensate recovery vessel (V-5702).
Liquid free gas from top ofthe scrubber enter into the HP ist stage compressor (C-1000 A-C) , from where
the highly pressurize gas is passed to the 6 fin fan cooler (X-1001 & X-2001 A-C), where highly pressurize
and heated gas is cooled to 40C and collected into the header from various outlet ofcooling fin fan. During
this, gas is further depressurized and gives condensate, which sentto the intermediate scrubber (v-1001
A,B and C), where the liquid is sentto the condense recovery plant( V-5702 A), and the liquid free gas

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from the vessel is passes to the HP 2nd stage compressor. From where the highly pressurize and heated
gas is passed over the fin fan cooler (x-1002 & x-2002 A,B & C), Form where gas is cooled to 40 C. during
this gas gives condensate and sentto the scrubber (V-1002 A,B&C). Condensate from the bottom ofvessel
sentto the condensate recovery tank (V-5702) and gas from all 2nd stage scrubber is collected into
common header and deliver to the dehydration plant.
5. MAIN EQUIPMENT USE IN KFGCS:
SLUG CATCHER
Pipelines thattransport both gas and liquids together, known as two-phase flow, can operate in a flow
regime known as slugging flow. Under the influence of gravity liquids will tend to settle on the bottom of the
pipeline, while the gases occupy the top section ofthe pipeline.Under certain operating conditions gas and
liquid are not evenly distributed throughoutthe pipeline, buttravel as large plugs with mostly liquids or
mostly gases through the pipeline. These large plugs are called slugs. Terrain slugging is caused by the
elevations in the pipeline, which follows the ground elevation or the sea bed. Liquid can accumulate at a
low pointof the pipeline until sufficient pressure builds up behind it.
Filter:
Filter is use for removing the particles and liquid droplets. filter usually having two section, one section
usually having filter and providing the filter facility for gas that coming from the slug catcher and next
section ofinlet gas filter is vane type liquid mistextractor, which remove remaining water (droplet) content.
Scrubber:
Scrubber is usually two phase separator, water containing gas is enter into the scrubber and hit on the
baffle plate from where liquid move downward and allow water free gas to move upward.
Dualstage turbo compressor:
Three centrifugal gas turbine driven compressors namely TUCO A, B &C are used out of which 2 are
operational and one is standby. The compressor is divided into 2 stages; 4 enclosed impellers are in the
first stage and 3 enclosed impellers in the second stage. The centrifugal force forces the liquid into
impellers which discharges the liquid at a higher velocity. The discharge of one impeller becomes the
suction of the other hence converting the net kinetic energy into pressure energy by means of a volute or a
set of stationary diffusion vanes surrounding the impeller periphery. The compressor has a labyrinth seal
throughout, dry gas seal at inlet and discharge and barrier seal between dry gas seal and oil bearings. In
dual stage compressor, firstly gas come in 1ststage piston compressor the air is drawn into a cylinder and
compressed in a single piston stoke to a pressure ofapproximately 2880 kpag and heated to 98 0C, the air
is sent via an inter cooler tube to a second, smaller high pressure piston and compressed a second time
and compressed to a pressure of 4700 kpa Then it is sent through the after cooler to the storage tank.

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Turbine:
In KFGCS, turbine is the prime driver for the compressor. A twin shaft gas turbine comprises of eleven
stage compressor and four stage itselfturbine is used to drive centrifugal compressors. These gas turbines
works on Brayton cycle principle and can be called as generators. Gear box in the turbine increase the rpm
to 3000 at which combustion chamber fires. A shim pack coupling, which is used to couple these
generators with centrifugal compressors, makes the compressor operate at 9500 rpm. Operating
temperature can be controlled by ventilation ducts.
They basically involve three main sections:
1. The compressor, which draws air into the engine, pressurizes it, and feeds itto the
combustion chamber atspeeds ofhundreds ofmiles per hour. Initially it rum by swift pump’s
2. The combustion system injecta steady stream of fuel into combustion chambers where it
mixes with the air.The combustion produces a high temperature, high pressure gas stream that
enters and expands through the turbine section.
3. The turbine As hot combustion gas expands through the turbine, it spins the rotating blades.
The rotating blades perform a dual function: they drive the compressor to draw more
pressurized air into the combustion section, and they spin the dual compressor by acting prime
driver.
Fin/Fan Coolers
Coolers are used to control temperature of gas that is compressed by centrifugal compressors.
Corrosion Inhibitors
Corrosion inhibitors are using PD pumps to inject chemicals in pipes so that inner walls may not be
corroded.
Flare Knock Out Vessel

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Gas from various equipments is vented to atmosphere through flare K.O vessel and is burnt out through
flare stack. This also helps in flaring the gas in case of any equipment shutdown or if any safety gets
operated.
6. UTILITY AREA
This area comprises of
Power Generation
It includes three gas generators (GENSET A, B and C) and one dieselgenerator use for emergency.One
of these GENSETS is isolated so that can be used for maintenance purpose.
Reverse Osmosis (RO)
It includes sedimentation ofwater to reduce its TDS and to make it portable for personal usage.
InertGas System
Nitrogen is an inert gas so is being collected from air for two purposes.One is used as sealing elementfor
compressor’s shaftso that lube oil and raw gas cannot be reacteach other and other is to purge gas from
pipes to preventwear. Inert gas compressors are used to compress it.
Fire Water system
In case offire or any other emergency jockey and dieselpumps are planted, collectwater from storage
tanks so that situation can be controlled with in no time.
Air Compression Package
Air is being filtered to remove its moisture contentand being compressed to instrumentation vessel for
instrument purposes such as pneumatic valves and plantvesselfor plantpurposes such as gas turbine.
Storage Tanks
Storage tanks are used to store water. Two storage tanks are located, one is fire water tank and the other
is portable water tank.
Cooling Towers
Two cooling towers are linked with GENSETS to cool generators by using LTand HT heat exchangers.
Positive displacementdiaphragm pumps are used to injectchemicals in water so that scaling would notbe
occurred on heatexchanger plates.
7. DEHYDRATION PLANT
Introduction ofDHP

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Dehydration plant at Kandhkot was installed in 1987 as two units (unit 1 and unit 2) each with a capacity of
30 million standard cubic feet of gas per day. Later on with increase in demand the plant was extended to
unit 3 and unit 4 with 100 and 130 MMSCFD capacities respectively. Currently only unit 3 and unit 4 are in
service producing 165 MMSCFD of gas at an average heating value of 838 BTU per cubic feet with 4-5
lb/MMSCF moisture contents. This gas is supplied to SSGCL (Sui Southern Gas Company Limited),
WAPDA and SNGPL (Sui Northern Gas Pipe Line) as per agreement. A part ofit is consumed in the power
house at field for producing electricity. The higher hydrocarbons in the range of gasoline are recovered
from the gas as condensate and dispatched to PRL (Pakistan Refinery Limited) for sale.
Unit consists of:
 Scrubber
 Pre Gas Filter
 ContactorTower (Absorber)
 Glycol Regeneration Skid
 Pump Skid
 Filter Skid
 Post Gas Filter
PROCESS DESCRIPTION
Natural gas saturated with water arrives at the inlet of the Dehydration Unit at 100-130 0F,
Wet compressed gas nearly at680 psig enter into gas inlet scrubber (v-0102, v-0103), where liquid come
down by gravity and gas move above from the top ofthe scrubber.
After scrubbing, gas pass through the upstream PECO filter ( s-04-01, v-110) where particles and water
dropletare settle down and filter gas sent to the contact tower or absorber ( C-2201, C-3201, C-401).
The gas rises through a chimney tray to the upper section where itpasses through the bubble cap trays,
the rising gas is in intimate contact with the descending tri-ethylene glycol.
Lean glycol is fed to the top of an absorber , the glycol removes water from the natural gas by physical
absorption and is carried outthe bottom of the column. Upon exiting the absorber the glycol stream is often
referred to as rich glycol. The dry natural gas leaves the top of the absorption column and passes through
the downstream filter (s-04-02, V-1103) where glycol particles are drained, after this dried gas sent to the
customer (WAPDA, SSGC, SNGL) through metering station.
The rich glycol having enough pressure to drive the kimray double piston pump, rich glycol is fed to a flash
vessel separator (V-2001, V-3001,V-4001) through pump, from where hydrocarbon vapors are removed
and any liquid hydrocarbons are skimmed from the glycol, separated gas hydrocarbon are use as fuel for
the reboiler and instrument gas.
This step is necessary as the absorber is typically operated at high pressure and the pressure must be
reduced before the regeneration step. Due to the composition of the rich glycol, a vapor phase having a
high hydrocarbon content will form when the pressure is lowered.

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The separated glycol from the separator passes through coil in the top ofthe still column to provide reflux to
the rising water and glycol vapors inside the still column.
The glycol pass through the coil in the storage tank where it preheated and cooled the regenerated glycol.
Preheated glycol is sent to the fire type reboiler (H-2001.H-3001, H4001) after passing through filter, where
it heated to 370 0F where glycol is thermally regenerated to remove excess water and regain the high glycol
purity. and stored in to the downward tank (T-2001, T-3001, T-4001).
The hot, lean glycol is cooled by cross-exchange with rich glycol entering the stripper. It is then fed to a
lean pump where its pressure is elevated to that of the glycol absorber. The lean solvent is cooled again
with a trim cooler before being fed back into the absorber. This trim cooler can either be a cross-exchanger
with the dry gas leaving the absorber or an air-cooled exchanger.
8.MAJOR EQUIPMENTS AT DHP
PECO FILTER
Filter separators are used to remove fine liquid mists and dispersions of solid particles that remain after
primary separation. Filter separators are normally used upstream of process equipment.
INLET SCRUBBERS
Gas Scrubber usually having the deflected plate, removes traces of liquid droplets from gas streams to
protect downstream equipment from damage and failure.
ABSORBER/CONTACT TOWER
It offers a wide range of absorbers (contactors) that are used to contact natural gas with TEG to
remove water vapor from the gas. In absorber glycol and gas move crossly.
REGENERATION TOWER
Regeneration tower is used to regenerate the rich glycol. It have a fire tube reboiler which operates at a
temperature of 375 F, the steam or water vapors are remove from the smoke pipe while the flue gases of
fire tube exits from the stack. Still tower have coils inside it where rich glycol physically contacts with the
lean glycol to pre heat the glycol.
INCINERATION TOWER
This tower is responsible for removing the toxic compounds from the steam which is going to flare. It is
installed for the environmental safety purpose.
GAS CONDITIONING VESSEL
The gases flare from the flash separator is used to ignite the fire tube inside re boiler. These gases have
Sulphur and other inflammable compounds which decreases the life of fire tube of the re boile r. For
removing these compounds the gas from flash tank is first passes into the gas conditioning vessel and then
transfer into the re boiler.

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