report on field visit to dakhni oil field

REPORT

ON

FIELD TO DAKHNI OIL FIELD

SUBMITTED BY:

SABA SAIF

SUBMITTED TO:

MAM SAIMA AKBAR

SUBMISSION DATE:

13-DEC-2012


ACKNOWLEGMENT

All praise to Allah Almighty who blessed us with the courage and ability to work on this report

and to compile it.

We would like to thank Mam Saima Akbar whose guidance and vast knowledge and interest

helped us a lot in understanding different oil and gas exploration techniques and also helped us in

the field and to get a practical knowledge about the field.

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TABLE OF CONTENTS

Chapter #1: Introduction

1.1 General statement………………………………………………………………………..…05

1.2 Location of the Field …………………………………………………………………….…05

1.3 Accessibility………………………………………………………………….………….….05

1.4 Purpose of the visit………………..…………………………………………….…………..05

Chapter # 2: Production and Precautions at the Field

2.1 Health Safety Precautions …………………...……………………………………….……07

2.2 Working……………………………………………………………….……………….…...08

2.3 Control and Improvements…………………………………………………………………09

3.0 Conclusion ………………………………………………………………………………....09

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CHAPTER # 1

INTRODUCTION

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1.1 GENERAL STATEMENT

This report has been compiled in response to the field trip that was arranged by the Department

of Earth and Environmental Sciences (E& ES) on 1st December,2012 for BS Geophysics V,

under the supervision of Madam Saima Akbar .This was a field trip to Dhakni oil field by

OGDCL to observe the drilling and extraction of oil, gas and other various products at the field.

1.2 LOCATION

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Dakhni oil field is located 33°24'30"N 71°56'28"E. The Dakni oil field is located at a distance

of about 135 Kms in the south-west of Islamabad. The field was discovered in Feb. 1983 and

came on regular production in December 1989. Gas contains 6-8% H2S in the well stream.

1.3 ACCESSIBILITY

Dakhni oil field is located at Kohat road near Jhand. We approached Dakhni oil field from our

university by following the route to Tarnol first and then we moved on Kohat road to Tehsil

Jhand and from there we followed the route towards the field.

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1.4 PURPOSE OF VISIT

The purpose of our visit to Dakhni oil field was to understand the various exploration techniques

observed for oil and gas. To observe the drilling methods and the processes by which oil, gas and

other products that are being extracted at the dakhni oil field and also to get a practical

knowledge of the field.

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CHAPTER# 2

PRODUCTION IN THE OIL FIELD

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2.1 DHAKNI (GAS/CONDENSATE FIELD)

OGDCL is the national oil & gas company of Pakistan and the flagship of the country's E&P

sector. Dakhni Gas Condensate Field is located at a distance of about 135Kms in the south-west

of Islamabad. The field was discovered in Feb. 1983 and came on regular production in

December 1989. Gas contains 6-8% H2S in the well stream.

Conditioning, treating and processing of raw natural gas/oil to obtain marketable products i.e.

fuel gas, stabilized oil, motor spirit, kerosene, diesel, LPG & sulphur through processing plants

via optimum safe & environment friendly process plants operation and maintenance.

2.2 PROCESSING OF HYDROCARBONS AT DHAKNI’S PROCESSING

PLANT:

A) SEPARATOR:

Basal plants are present in separator, in which water and H2S is entered in it. Domestic pads are

also there. When pressure drops due to specific gravity, as a result of which water and

hydrocarbons are

separated. Hydrocarbons

are present in the middle

of chamber, while water

is in the bottom of a

chamber and top of the

chamber possesses gas

in it.

There are three types of

separators:

1) horizontal

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2) vertical

3) Spherical

In DHAKNI plant horizontal separators are installed.

When pressure abruptly goes down, than they are separated. H2S and hydrocarbon gas is

forwarded. All the precautions are taken which are recommended by environmental agengy.

If there is high pressure , and any breakage happens than there main feeding vent is directed

towards the flares and all of the gas is burnt down , in order to remain protect from any disaster.

If pressure exceeds 1265 psi than the values are opened here and the oil is burnt Acid

flares/pipelines are there for oil transfer.

B) ABSORBER:

Chemical “AMINE” is present in the absorber. This chemical amine absorbs H2S in it.

Showering of amine is

taken place in the

absorber and all the H2S

is separated.

Hydrocarbons are

obtained in the range

of :

C1-C4

C1 : Natural gas

(SNGPL – supply to

homes)

C2-C4 : LPG (filled in

cylinders and domestically used)

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Chemical amine absorbs H2S and here pressure is dropped and temperature is increased

and absorption level is less and H2S goes up and the amine is separated in the bottom and

again the cycle continues . So, high temperature and pressure is kept in the pressure of

AL2O3 catalyst.

C) SULPHUR RECOVERY UNIT:

Products: natural gas , LPG and sulphur.

CCL3 and CCL4 present in liquid form in the cylinders i.e LPG. Liquid hydrocarbons

come in the fractional H2S is present in liquid form. High temperature is given to liquid

hydrocarbons so that its boiling point became low and it becomes a gas. In the bottom

inlet is present.

The solubility decreases when temp. increases.

1600 Barrels/year hydrocarbons is obtained.

Tanks are also present there that stores SNGL hydrocarbons. Then it is send to refinery.

In a DUE POINT REDUCTION UNIT (DPRUP) high pressure and temperature is

decreased , as a result of which due point is decreased according to the range. C3 and C4

are heavier hydrocarbons , their due point are less and are easily converted into liquid .

C1 can easily be separated as a gas.

D) REFRIGERATION UNIT:

Refrigeration unit is there to cool the gas so that to convert it into the liquid.

2.3 WASTE WATER TREATMENT

PLANT: DHAKNI

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Dakhni Oil Field Water Treatment Plant is located at a distance of 120 Km from Islamabad on

Islamabad – Kohat Road. The plant will supply treated water and process water to the Sulfur

Recovery Plant in the Oil /Field. Raw water for the plant is abstracted from river Indus through

an intake structure and is pumped the treatment plant through a M.S Main which terminates at

the inlet of the Clarifier at the treatment plant where it is treated to meet the WHO Drinking

Water Standards. The treatment process includes coagulation, flocculation, sedimentation,

filtration, Ph-correction and disinfection. The main components of the plant include Clarifier,

Medium Gravity Filters, Control Weirs, Treated Water Collection Tank, Chemical Dosing and

Chlorination Equipment, instrumentation and Central Control Console. The works also included

complete power distribution, electric control panels, and area lighting of the plant premises. The

plant at present is operating to its full capacity and is supplying the requisite flow of treated

water to the Sulfur Recovery Plant.

2.4 PROCESS DESCRIPTION:

The demineralizer plant is designed to produce high purity water with low sodium leakage by

Packed-bed counter-current flow technique. The resin in the vessel is packed with very limited

volume of free space available with operating vessels. The flow of water being treated and

regenerate flow are in opposite directions (counter-flow), the treated water leaving the bed

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during the exhaustion cycle will be contacting the most highly regenerated section of the resin

bed, and thus extremely low concentrations of sodium will be obtained in the treated water.

2.5 DESIGN BASIS:

The demineralizer system capable of producing 8,000 l/hr of de-ionized water.

In Coming Feed water Limit

Conductivity: <500 micro Siemens

Free chlorine: <0.01 mg/l

Temperature: < 400C.

2.6 TREATED WATER QUALITY:

The water quality after the Demineraliser system will be 10 micro Siemens and below

2.7 PROBLEM FACING IN EXISTING PLANT:

Previously installed PLC malfunctioning and client was running water treatment plant on manual

basis. The Features of Full Auto modes were not applicable due to problems in PLC. They

require a PLC system that was fully reliable and capable enough to handle the harsh acidic

environment along with an HMI to operate the Plant in Fully Auto, Semi Auto and Manual

Mode.

2.8 PRODUCTION ESTIMATES:

GAS PRODUCTION: 45-50 million cubic feet/day.

CRUDE OIL: 1600 Barrel / year.

SULPHUR PRODUCTION: 65-75 tons per day.

It is a sour plant because of the presence of H2S.

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Before going to the field we have to take the health safety precautions so as to avoid any kind of

mishaps. For this there is a health safety department .

3.1 HAZARDS:

H2S is a colourless gas , possessing a rotton egg smell. It is a killer gas , that may cause

death. Its specific gravity is 1.89, that can travel on the surface of earth. Sweet plant is

that in which H2S is not produced along hydrocarbons. Rotten egg smell,its presence is

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7% in the plant i.e ; 70,000 ppm. If 10 ppm is present in the environment than one can

work about 8 hours. If the concentration is 20 ppm than one can work for only 15 min.

If 100 ppm concentration of H2S exists, than sense of smell is lost.

Any area in the field possessing H2S gas more than 20 ppm , than that area is considered

as prohibited area.

In the plant 70,000 ppm is present only in the closed system where as in the environment

there is only due to the leakage in the piping system.

This gas is heavier than air.

One have to evacuate from that area of field if any one feel the presence of this gas

(H2S).

3.2 IN CASE OF EMERGENCY:

I. PROCESS CONTROL:

It can be controlled through various processes. H2S is separated from the hydrocarbons, Digital

meters can also be used for this purpose with alarm, if the concentration increases it

automatically starts alarming.

II. ERP-EMERGENCY RESPONSE PLAN:

If leakage exceed the ERP comes in action and sound in the plant begins. If the concentration of

H2S increases than everyone should have to evacuate the area and one should have to reach the

mustard point. There are two mustard points in this “DHAKNI PLANT”. We have to see the

wind direction possessing H2S gas in it. We have to go to that mustard point , which is opposite

to wind direction at that particular time. So that the worker remains safe.

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III. FIRE CONTROL MEASURES:

To control fire , fire extinguisher of DCP is present there on the field at “DHAKNI”.

At dhakni , we mostly deal with liquid hydrocarbons that comes under class-B .

For fire, fuel and oxygen are the essential components , so we have to remove one of

them to control the fire. If fuel is removed , temperature is decreased.

Foam type fire extinguishers are also used. Water is also commonly used.

Hydrocarbons specific gravity is very low so foam is used which makes a layer over it

and hence it cuts oxygen supply which is important for the burning process.

IV. PERSONAL PROTECTIVE SAFETY MEASURES:

PPE (personal protective equipments) like shoes, helmets etc are used for person’s safety.

Three general things are extracted:

i) Water ii) H2S iii) Hydrocarbon

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3.3 CONTROL AND IMPROVEMENTS

Control room is used to control the temperature and pressure also measured through it.

Previously there was an old plant that had a capacity of 60 tonnes but now a new plant

has been installed that has a capacity of producing about 80 tonnes and it has the latest

DCS system installed in it.

Now a new plant (chamber) is also being built to store all the sulphur and to convert the

blocks of sulphur into grains form and to improve its quality and make it more useful.

The fire blazing at the tower is to burn the extra hydrocarbons produced so that

environment is not contaminated and also to avoid any harmful conditions in case of

emergency.

4.0 LAST WORDS:

After we visited dhakni oil field, which was very educative and a marvelous academic

experience. We went to their rest house 5 minutes away. It was built very nicely and reflected

status of company very well.

Our instructor (Sir Naveed Ahmed) was very experienceed working for about 15 years in this

field. He was very clear and provided deep practical knowledge about industry. We were also

shown manufacturing of sulphur.

We rested their and offered prayers. Then we got fresh and were served lucnch. They had a very

well kept garden which was very refreshing with a number of beautiful flowers.

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Then we went back to our university in islamabad. The trip was a great addition to our practical

real world field knowledge and created deep intrest in us.

5.0 CONCLUSION:

The trip was very knowledgeable and widened our scope in our field. We came to know how oil

is being produced, how different separators are used to extract different products from crude oil,

how OGDCL works, and how different environmental precautions are taken at the field.

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report on field visit to dakhni oil field

Education

dhakni oil field

location dakhni oil

accessibility dakhni

field trip

dakhni gas condensate

daknioil field

dakhni oil field1

dakhni oil fieldchapter