A REPORT ON TRAINING IN OIL AND NATURAL GAS CORPORATION LIMITED
SURFACE TEAM AHMEDABAD ASSET
SUBMMITTED BY: -
ACKNOWLEDMENT
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Firstly, we would like thanks Mr. N. Khanduri for his great efforts in arranging our training at Ahmedabad asset under surface team. We would would like like to expr expres esss our our sinc sincer eree than thanks ks to inst instal alla lati tion on mana manage gers rs of GGS GGS mote motera ra KALOL,C.T.F KALOL,C.T.F,, G.C.S,G.C. G.C.S,G.C.P, P, KALOL G.G.S VII , E.T.P, C.W.I.P, Nawagam Nawagam C.T.F, Desalter plant, Artificial lift & security dept. O.N.G.C O.N .G.C AHMEDABAD. We express our deepest thanks to Mr. M.G Desai (Head of Chemical Engg Dept.) for providing us the moral support and encouragement, without which it would have been difficult to complete this training.
Preface
Theory of any subject is important but without its practical knowledge it becomes useless, particularly for technical students. A technical student cannot become a perfect engineer or
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technologist without practical understanding of their branch, hence training provides a golden opportunity for all technical students to interact with the working environment. The principal necessity of in-plant training is to get details about unit operation and unit process which are carried out in chemical industries and to know more about the equipments used in these industries. The in-plant training training program is very advantageous advantageous for the technical students students who have a vivid idea about the industries. This training helps to understand the basic concept of the industry. During this period the students becomes aware of the problems faced in the plant and are also aware of the industrial atmosphere and also with the industrial people.
CONTENT
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TOPIC
PAGE NO.
1. GGS Motera
1
2. KALOL GCS (GAS COLLECTION STATION)
6
3. GAS COMPRESSION PLANT (GCP)-KALOL
11
4. CENTRAL FARM TANK (CTF)-KALOL
15
5. GGS VII-KALOL
20
6. EFFLUENT TREATMENT PLANT (ETP)-II (KALOL)
26
7. CENTRAL WATER INJECTION PLANT (CWIP)
30
8. CENTAL TANK FARM (CTF) – NAWAGAM
33
9. DESALTER PLANT: NAWAGAM
35
10. WWTP-WASTE WATER TREATMENT PLANT
39
11. ARTIFICIAL LIFT (Ahmedabad)
43
GGS-MOTERA
INSTALLATION MANAGER - Mrs. Mrs. Purvi Purvi Dutta choudhary
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DATE OF COMMISION: 29.03.1992 AREA OF INSTALLATION: WELL PRODUCTION STATUS :
TOTAL WELLS CONNECTED-33 TOTAL FLOWING WELLS-28 TOTAL LIQUID PRODUCTION-40 m3/day WATER INJECTION WELLS- nil GAS INJECTED-20000 m3/day VESSELS:
LOW PRESSURE SEPARATOR- (vol- 6 m3) GROUP SEPARATOR- (vol-6 m3) TEST SEPARATOR- (vol- 6m3) VERTICAL SCRUBBER-(capacity-1.7 lacks m3/day) HORIZONTAL SCRUBBER-(capacity- 50000 m3/day) BATH HEATER- 1 NO.S TANKS
OIL STORAGE TANKS- 3 NO.S (45 m3) FUNCTION:
At group gathering system (GGS) fluid from various wells is collected in header from various wells through pipeline network. Then the low pressure fluid (1- 2 kg/cm2) goes to the low pressure separator, and then in the output we get separated oil and gas. Oil goes directly to storage tanks and gas goes to common sucker separator. On the other hand fluid of 4-5 kg/cm2 pressure goes to group separator. Then from the outlet of this separator gas goes to common suction separator and oil goes directly to storage tanks. Then in common suction separator all the gases from the outlet of group separator and low pressure separator is further separated, thus if any amount of oil is still present in gas can be separated. So after after separation gas is directly directly sent to to GAIL and oil oil goes to storage tank.
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The gas which was present in above withdrawn oil is low pressure gas, but some high pressure gas also comes out of reservoir. So that gas is sent to gas scrubber where whatever amount of gas is present in gas is separated and the gas what we get after separation is not suitable for consumers so it is sent back to reservoir for artificial lifting. GGS FACILITIES 1.
PIPELINES
For oil- 4inches in diameter Highly resistant against corrosive action of fluid For gas- 2inches in diameter
2. SCRUBBERS Horizontal scrubber Function- extract oil from gas • Pressure- 40 Kg/cm2 •
• •
3.
SEPARATOR:
Vertical scrubber Function- same as above Pressure- 70 Kg/cm2
To flash the well fluid to separate into liquids and gas at a controlled pressure. Flow lines from various wells open into the pipelines of GGS.
Various provisions for various supplies to 3 types of separator: •
TEST SEPARATOR
Fluid enters tangentially and due to the sudden pressure drop to the set level , the fluid gets separated into separated into liquid and gases. Baffles are fitted inside the separator to help in better separation. It is used for testing the fluid obtained from a source. It can withstand pressure of 9 kg/cm2.
•
GROUP SEPARATOR
It is also a two phase vertical cylindrical vessel just the same as the previous one but here fluid from all the well comes whose pressure is upto 4-5 kg/cm2. Separated gas is sent to flare lines.
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•
LOW PRESSURE SEPARATOR
When the fluids coming out of the wells have pressure of about 1-2 kg/cm2 then fluid goes to this separator. All these separators have same capacity.
4.
VALVES
Gate valves: used to minimize the pressure drop in the open position and stop the flow rather than controlling it Check valves: it is one-way valve which normally allow fluid to flow through it in only one direction. This prevents the back flow of fluid into wells.
5.
STORAGE SYSTEM
Purpose:
To store oil before transporting
To measure oil produced
Process:
Oil from bath heater and separator is taken into overhead cylindrical tanks for measurement.
6.
OIL DISPATCH SYSTEM
Purpose:
To dispatch oil from GGS to CTF.
Process: Oil stored in the storage tanks is sent to CTF by road tanker as there is no pumping system available in the installation.
7.
BATH HEATER
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Used to reduce the viscosity of oil coming from reservoir by heating that oil in bath
heater.
8.
FIRE FIGHTING SYSTEM
Large water tank- (capacity- 350 m3)
Small water tank- (capacity- 100m3)
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KALOL GCS (GAS COLLECTION STATION) INSTALLATION MANAGER : Mr.B.B.Patel ESTABLISHED IN : 1973 RECEIVING STATUS :
Total Wells Connected-32 Total Working Wells- 13 Receiving pressure-4kg/cm2 OBJECTIVES:
To collect natural gas from wells
To collect associated gas from GGS
To send gas to GCP.
To send compressed gas (CG) to GGS for artificial lifting
To send CG to IFFCO,RIL, etc.
FUNCTIONS:
Its main function is gas collection and distribution. GCS receives associated gas from GGS and natural gas directly from the wells. They both are mixed in scrubber, treated and they are transferred to GCP for further compression. Now the compressed gas is again received back by GCS and then the compressed gas is sent to various destinations. GCS FACILITIES 1.
MANIFOLDS
Gas grid manifold (to provide high pressure compressed gas through 4’’ & 6’’ pipeline to north and south Kalol gas system) 2.
BEAN HOUSING
to control the flow of gas from the reservoir
3.
SCRUBBER
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Purpose
It is a purifier that removes impurities from gas. Scrubber systems are a diverse group of air pollution control devices that can be used to remove particulates and/or gases from industrial exhaust streams. Traditionally, the term “scrubber” has referred to pollution control devices that use liquid to “scrub” unwanted pollutants from a gas stream. Recently, the term is also used to describe systems that inject a dry reagent or slurry into a dirty exhaust stream to “scrub out” acid gases. Scrubbers are one of the primary devices that control gaseous emissions, especially acid gases.
Process It involves the addition of an alkaline material (usually hydrated lime and soda ash) into the gas stream to react with the acid gases. The acid gases react with the alkaline sorbents to form solid salts which are removed in the particulate control devices. These systems can achieve acid gas (SO2 and HCl) removal efficiencies.
4.
SEPARATOR
Functions at 4kg/cm2
In this only natural gas is separated to remove any condensed liquids if present. The gas firstly goes to separator then to scrubber.
5.
STORAGE TANK
3 storage tanks of 45m3 are present but they are not under usage.
6.
VALVES
Shut down valve-used in case of leakage or in any other emergency
Control valves- when pressure in the pipelines increases beyond the limit then these valves get open itself to prevent danger.
7.
FLARE
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Used for burning off unwanted gas or flammable gas released by pressure relief valves during unplanned over-pressuring of plant equipment.
GAS ANALYSIS
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COMPOUND
MOL%
Methane(CH4)
87.150
Nitrogen(N2)
0.160
Carbon di oxide(CO2)
1.36
Ethane(C2H6)
5.22
Propane(C3H8)
2.5
Water(H2O)
0
Hydrogen bi sulfate(H2S)
0
Carbon monoxide(CO)
0
Oxygen(O2)
0
I-butane
1.35
N-butane
0.82
I-pentane
0.36
N-pentane
0.39
Hexane
0.68
Heptane
0
Octane
0
Nonane
0
Decane plus
0
Helium(He)
0
Argon
0
SUPPLY FROM GCS
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GAS SUPPLIED TO
QUANTITY
IIFCO (Associated. Gas)
30000m3/day
SAHAND-II (Natural Gas)
50000m3/day
Bharat Vijay Mill(Sintex)(Associated Gas)
15000-20000m3/day
RIL (Compressed Gas)
1 lacks m3/day
Compressed gas to Grid
4.30 lacks m3/day
Gurukul (Kalol)
300 m3/day
Central Farm Tank (CTF) (Associated Gas)
1700m3/day
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GCS ( GAS COLLECTION STATION)
- 15 -
GAS COMPRESSION PLANT (GCP)-KALOL
INSTALLATION MANAGER : Mr. Rajesh Kumar DATE OF COMMISION:
GCP-I: 26.02.1990 GCP-II: 15.03.1994 TOTAL CAPACITY : 5 lacks m3/day TOTAL COMPRESSORS: 10
6 in old plant and 4 in new plant Capacity (old) =3 lacks m3 /day Capacity (new) = 2 lacks m3 /day REVERSE-OSMOSIS PLANT (R-O): two DISCHARGE PRESSURE : 40 kg/cm 2 PROCESS DESCRIPTION:
In this plant, gas from GCS (gas collecting system) at 4kg/cm2 pressure comes through pipelines to GCP. Firstly it goes to common inlet separator, where the primary separation is done, usually the content of oil in gas is negligible but if it’s there it gets separated. Now the gas goes to 1 st stage suction separator, there further separation is done. Till now the pressure is 4kg/cm 2, now this gas goes for first stage compression goes into compressor. After compression the gas we get is of 12-14 kg/cm2 and because of compression temperature rises to 1250 C so to low down the temperature to 40-450C, compressed gas is sent to inter gas cooler. Now the cooled gas of 12-14 kg/cm2 pressure goes to 2nd stage suction separator where further separation occurs. Then it goes to 2nd stage gas compressor there compression is done and in the output we get gas of 40 kg/cm2 pressure but temperature has again gone up to 1450C because of compression so it again goes to cooler which is also known as after cooler . Now as cooling has occur so condensation will be done so again whatever amount of oil will be there will be drained out from discharge separator. Then finally gas from the discharge separator at 40 kg/cm2 pressure is sent back to GCS. GCP FACILITIES
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1.
GAS COMPRESSION SYSTEM
PURPOSE
•
to compress gas at high pressure
PROCESS
It has two stage gas compression systems. First stage compressors takes gas from first suction separator and other stage takes gas from second suction separator as shown in the flow diagram. •
•
RPM= 990
•
Capacity-2100m3/hr
•
Model- 14 X 8 X 5 2 RDH-2
•
Make-Ingersoll sand
•
Type- double-acting reciprocating horizontal
•
Number of stages- Two
2.
RAW WATER TREATMENT SYSTEM (R-O Plant)
Purpose:
•
to remove true deposit solids from water
Process
Firstly the raw water from the storage tank flows into pipelines and come into desired location. To this raw water we add sodium hypo chloride which destroys the bacteria present in water. Then the water is treated with sodium bi sulfate to reduce the chlorine content which would have increased because of sodium hypo chloride addition. Then this treated water with sodium hexa meta phosphate so that scaling can be minimized which will occur in tubing having membranes. Then this water goes to multi grade filter where various types of gravel, sand are filtered. Then the filtered water is treated with 98% H 2SO4 so that pH of water is maintained. Then again this water goes to cartridge filter, so that if any filtration is left can be •
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completed. Now this filtered water is pumped into tubing system having membranes with the help of high pressure pump. Then there high- quality demineralised water is produced which is then sent to storage tanks.
3.
AIR COMPRESSION SYSTEM:
Make- Ingersoll Rand
Model- 8 X 5 E&1-NL2
Discharge Pressure- 110 PSI
Capacity- 200 CFM(each)
4.
COOLING SYSTEM:
Purpose:
There are two types of gas coolers inter gas coolers and after gas coolers. It’s a type of heat exchanger. Running water through it helps in cooling of gas and they are sent finally to discharge separator. Inter gas cooler takes the gas of first stage compression and gas cooler takes second stage compression. •
Process:
It’s a type of heat exchanger, it contains baffles and one shell and two tubes pass exchanger system. Cooled treated water enters from one side and gas enters from the other side. There occurs a counter current flow. This results in exchange of heat between two liquids and hence the fluid is cooled. •
5.
GAS DETECTION &MONITORING SYSTEM
Used to detect the leakage of gas in the plant
6.
FIRE FIGHTING SYSTEM
6 fire fighting pump
4 diesel pump and 2 motor driven pump
7.
ELECTRICAL SYSTEM
- 18 -
Two 11 KV sub-station
8 step down transformers
- 19 -
- 20 -
CENTRAL FARM TANK (CTF)-KALOL INSTALLATION MANAGER : Mr. T. C. Tiwari COMMISSIONED IN : August, 1971 OBJECTIVES:
Collection of oil from Kalol, Sanand, Jhalore, South Kadi ,Viraj , Paliyad, Limbodra
Treatment of crude oil
Chemical analysis
Pumping oil to desalter Nawagam plant
Pumping effluent to ETP (effluent treatment plant)
RECEIVING SYSTEM
Crude oil received at CTF Kalol through.
8’’ diameter line from Sanand and Jhalore field at 1000m3/day.
12’’ and 8’’ lines from Kalol field at 170m3/day.
12’’ lines from south Kadi and Viraj field at 43m3/day.
COLLECTION
6000 m3/day
FUNCTIONS
Crude oil is received from various GGS. The oil which is having higher water cut is sent to heater treater while oil having low water is directly dispatched to desalter. TESTS PERFORMED •
•
Test for specific gravityA hydrometer is an instrument used to measure the specific gravity (or relative density) of liquids; that is, the ratio of the density of the liquid to the density of water. A hydrometer is usually made of glass and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright. The liquid to be tested is poured into a tall jar, and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer is
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noted. Hydrometers usually contain a paper scale inside the stem, so that the specific gravity can be read directly.
Test for water content (DEAN STARK METHOD)
This method is used for determining water-in-oil. The method involves the direct codistillation of the oil sample. As the oil is heated, any water present vaporizes. The water vapors are then condensed and collected in a graduated collection tube, such that the volume of water produced by distillation can be measured as a function of the total volume of oil used. CTF FACILITIES 1.
DISPATCH SYSTEM
Dispatch is done through 12’’diameter line, 51Km long pipeline to desalter Nawagam through to pumps at 130 m3/hr rate.
6 effluent dispatch pump each of 50 m3/hr capacity.
Oil dispatch pump
•
(A-700) BPCL 3 in number each of 120 m3/hr capacity.
•
(C-558)BPCL 4 in number each of 135 m3/hr.
2.
MASS FLOW METER
Coriolis meter
3.
STORAGE TANKS
10 tanks of capacity 2000 m3 out of which 2 are used for effluent storage and rest for storage of oil.
8 tanks of capacity 10000 m3 for storage of oil.
4.
SCRAPPER SYSTEM
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There are two scrappers receiving platforms from 12’’ pipeline for S.Kadi and 8’’ pipeline for Sanand- Jhalore field also there is one scrapper launching platforms for 12’’ pipeline desalter plant NGM.
5.
HEATER TREATER
In all 6 heater treater are there in this plant.
4 of which are of capacity 300m3/day.
2 jumbo heater treater are also there, one of which is of capacity 800m3/day and second one is of 1000m3/day
One jumbo heater treater is under construction.
5 heater treater feed pump are available which are centrifugal and there capacity is 45
m3/hr.
It has three chambers namely
•
Heating chamber
•
Middle chamber
•
Electrical Chamber
HEATING CHAMBER: The fire tube which extends up to this section is in submerged condition in emulsion oil. The heating of oil emulsion decreases the viscosity of oil and water and reduces the resistance of water movement. The heat further reduces the surface tension of individual droplets by which when they collide form bigger droplets. This progressive action results in separation of oil and free water. MIDDLE CHAMBER: The fluids from heating enter into this chamber through fixed water .It doesn’t allow gas to pass into electrical chamber. The gas which enters heating chamber leaves from top through mist extractor. The oil in this chamber is controlled by oil level controller. ELECTRICAL CHAMBER: In this section constant level of water is maintained so that oil is washed and free water droplets of water are eliminated before fluid proceeds towards electrode plates (electric grid). These plates are connected with high voltage supply of 10000 to 25000 volts. When fluid passes through these electrodes the droplets polarizes and attracts each other. This attraction causes the droplets to combine; they become large enough to settle into oil and water layers by the action of gravity 6.
FIRE FIGHTING SYSTEM - 23 -
4 Motor driven pump of 410 m3/hr capacity work at 10kg/cm2 pressure.
2 diesel engine driven pump of 410 m3/hr capacity work at 10 kg/cm2 pressure.
Jockey pumps are 2 in number which are motor driven and there capacity is 80 m3/hr.
Various potable fire extinguisher are present such as dry carbon, carbon dioxide.
HEATER TREATER
- 24 -
CTF (Central Tank Farm)
- 25 -
GGS VII-KALOL
INSTALLATION MANAGER - Mr. Ajay Ratan DATE OF COMMISION: July- 1976 WELL PRODUCTION STATUS :
TOTAL WELLS CONNECTED-57 TOTAL FLOWING WELLS-52 TOTAL LIQUID PRODUCTION-380 m3/day WATER INJECTION WELLS- 20 GAS INJECTED-40000-50000 m3/day VESSELS:
TEST SEPARATOR- (working pressure-6 kg/cm2 and hydraulic test pressure- 9 kg/cm2) EMULSION SEPARATOR-(working pressure-6 kg/cm2 and hydraulic test pressure- 9 kg/cm2) EMULSION SEPARATOR-(working pressure-6 kg/cm2 and hydraulic test pressure- 9 kg/cm2) EMULSION SEPARATOR-II: (working pressure-6 kg/cm2 and hydraulic test pressure- 9 kg/cm2) EMULSION SEPARATOR-III: (working pressure-6 kg/cm2 and hydraulic test pressure- 9 kg/cm2) HIGH PRESSURE SEPARATOR-(working pressure is 15 kg/cm 2 and hydraulic test pressure-24 kg/cm2) HEATER TREATER: 2 in number, first one is of 800 tons/day capacity and second one is under construction BATH HEATER- 1 NO.S TANKS
Tank- I: 90000 Liters Tank-II: 90000 Liters Tank-III: 400000 Liters
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TCS I &II: 32000 Liters and 3 Kg/cm2 pressure. FUNCTION:
At GGS well fluid is connected in header from various wells through pipeline network. There gas is separated from liquid in group separator and send to GCP through GGS to return back compressed gas for gas lift wells. Then water is separated from oil in heater treater. Oil is stored in tanks and sends to CTF (central tank farm). The effluent remained after separating from oil is send to ETP (effluent treatment plant). GGS- VII 1.
HEATER TREATER
NAME- crude oil emulsion treater
TYPE- vertical flow horizontal CE treater
SIZE- 8’ X 20’
CAPACITY- 800 tons/day
DUTY- Continuous
WORKING PRESSURE- 50 PSI
WORKING TEMPERATURE- 900 C maximum
TEST PRESSURE- 75 PSI (hydraulic)
CURRENT- 25 Amp
VOLT-250 volt
Reciprocating pump is used to transfer the fluid from separator to heater treater
•
Power- 375 KW
•
Volt- 415 V
•
RPM- 1410
2.
DEMULSIFIER
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CHEMICAL DESCRIPTION: mixture of ethoxylated, propoxylated surfactants and organic aromatic solvent as inert diluents.
PHYSICAL & CHEMICAL PROPERTIES
•
Ionic Nature- non-toxic
•
Viscosity at 300C- less than 100 poise
•
pH of 5% solution- 5.5 to 8.0
•
Solubility in H20- dispersible
•
Solubility in xylene & tolune- soluble
•
Flammability- inflammable
LABELLING, STORAGE & HANDLING
•
Storage conditions- store in cool, well- ventilated area
•
Disposal- incinerate in a furnace as per local state or national legislation
EMERGENCY MEASURES
•
Spillages- adsorb onto sand, earth or similar adsorbent material .Wash the spillage area.
FIRST AID
•
Skin contact- wash with water followed by soap & water
Eye contact- irrigate with clean water or an eye wash solution, obtain medical attention as precaution. •
•
Inhalation- The affected person should be moved to fresh air & made to rest.
•
Ingestion- Give water or milk to drink.
3.
TRIPLEX RECIPROCATING PUMP
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Used for pumping oil from storage tank to discharge line to NAWAGAM
Maximum pressure- 64 Kg/cm2
Input- 86 KW
Pump RPM-260
Oil used for lubrication- 80L
Servo gear HP- 140
It is motor driven pump
•
KW- 110
•
HP-150
•
RPM-1480
4.
BOOSTER COMPRESSOR
Used to compress the gas which comes out from the separator vent at pressure 1.5 kg/cm2 to 4 – 5 kg/cm2 which is then send to GCS for further compression.
Make- Ingersoll rand
Model- 8.5” X 7” single stage
Capacity- 10000m3/day
Suction pressure- 1.5 kg/cm2
Discharge pressure- 5 kg/cm2
5.
POWER SUPPLY
Normal power is supplied from 11KV grid of the electric board The overall normal requirement envisaged has been of the order of 100KVA
Emergency power plant is maintained by 320KVA diesel generator whose power factor is 0.8 and power of engine is 396 HP.
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6.
FIRE WATER SYSTEM
2 reservoir of water having capacity 120 m3 and 350 m3 respectively are available.
2 pumps are also present one is motor driven and second one diesel engine driven. Second one is used as stand by.
Specifications of motor driven pump:
•
Capacity- 170 m3/hr
•
Discharge pressure- 6 Kg/cm2
Specifications of engine driven pump
•
Head- 100 m
•
Discharge rate- 171 m3/hr
•
Size- 100X 125 mm
•
Speed- 1800 RPM
•
Pump input- 64.9 KW.
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EFFLUENT TREATMENT PLANT (ETP)-II (KALOL) - 31 -
INSTALLATION MANAGER- Mr. Ajay Ratan
DATE OF COMMISION - 05.07.1993
RECEIVING STATUS :
Effluent from
GGS- I (Kalol),
GGS-VII (Kalol),
GGS-II (Kalol),
CTF-(Kalol) and to CTF effluent of GGS- IV also comes. PRODUCTION- 1000 m3/day and 50 m3/day (max.) of oil. POWER CONSUMPTION - 19378 KW/day OBJECTIVES
The main objective of this plant is to collect effluent from various GGS and CTF and treat that water.
Finally the treated water is sent to water injection plant for final treatment.
PROCESS DESCRIPTION
Firstly effluent from various GGS (as mentioned above) comes into header of ETP and from those headers it goes to hold up tank .Then it goes to equalization tank where effluent is allowed to stand for some time. Thus because of this settling time water settles down and oil at the top. Then on weekly basis oil from the top is sent to sludge separating tank as the content of oil in it is very less. But water goes to receiving sump through centrifugal pump. Then from receiving sump it goes to flash mixer where alum and polyelectrolyte are added in 200 ppm and 10 ppm concentrations respectively. Alum acts as coagulant & polyelectrolyte is added to separate further. Then from there water goes to clariflocculator which has agitator inside the vessel. After agitation sludge settles down and after some time it is sent to sludge sump and then it is pumped to sludge
- 32 -
lagoons there sludge from sludge separating tank also comes and from there it is sent for bioremediation. Now water which comes out of clariflocculator goes to clarified water tank and from there it is pumped into sand filters where the final filtration is done and then this water goes to conditioning tanks where again some settling time is given so that even if some amount of impurities is there can settle down and finally the treated water goes to storing tank and from there it is pumped into Cental Water Injection Plant (CWIP) through pipelines. ETP FACILITIES 1.
FLASH MIXER Capacity- 1.2 m3
Alum and poly electrolyte are added
Alum as coagulant
Poly electrolyte for separating oil from water
2.
CLARIFLOCCULATOR Capacity-224 m3
Purpose- it helps in separation of water from oil.
It consists of huge cylindrical tank with a hollow cylinder inside. The solution of oil and water enters through this hollow cylinder with oil on top. Oil separates at the top through V-notch provided at the sides(its periphery). Sludge settles down in a feet bottom and sludge is pumped through pump to lagoon. Whereas water is transferred to storage tank-2 (SR-2) and from there water is sent to filter for further purifications •
3.
PRESSURE FILTER CAPACITY- 2.5 m3 Number- 2 Nos., but one filter is used at a time other is used as a standby.
The filter consists of membrane made of sand and gravel (sizes ranges from 9mm600mm).Water is circulated here and all particles are filtered by them.
Back Wash Water arrangement is also made in order to clean the filter when its cleaning is required. This is done daily as two pressure filters are available, one is used at a time and other is used as stand by. 4. PUMPING SYSTEM •
7 centrifugal pump Capacity- 40 m3/hr
•
Head- 50 m
•
Speed- 1470 RPM
•
Input- 13KW
•
Efficiency- 41% - 33 -
3 screw pump
•
Head- 30 m
•
RPM- 1200
•
HP- 1.5
SAND FILTER
- 34 -
- 35 -
ETP (EFFLUENT TREATMENT PLANT) CENTRAL WATER INJECTION PLANT (CWIP) INSTALLATION MANAGER -Mr. Ajay Ratan DATE OF COMMISION -04.04.1990 UNIT PRODUCTION - 1680 m3/day POWER CONSUMPTION - 20000 KW/month DISCHARGE RATE- 35 m3/hr CHEMICALS USED Sodium sulfide- 40 ppm Scale inhibitor- 20 ppm Corrosion inhibitor- 20ppm PROCESS DESCRIPTION Water from ETP through pipelines comes to CWIP for further chemical treatment before it is sent to GGS for water injection. Water at 35-37 m3/hr of flow rate and at pressure of 4 kg/cm2 is pumped into CWIP through pipelines from ETP. Effluent enters the treated water tank (600 m3) where tube well water is also added in fixed proportion. This tube well water (raw water) is passed to three micro filters of 25 micron,10 micron and 3 micron one by one and then finally it is sent to raw water hold tank. At the outlet of the tank three chemicals are added, sodium sulphite (40 ppm) which acts as oxygen scavenger, corrosion inhibitor (20 ppm) is added to prevent corrosion and scale inhibitor (20 ppm) is also added to decrease precipitation formation. Now this effluent is sent to treated water tank where water from ETP is mixed with it by mean of agitator. This effluent is then pumped with the help of water injection pump to headers. Now from headers the water is injected at high pressure and at low pressure through four inch pipe line. Water is injected at high pressure of 60-62 kg/cm2 to 13 wells used for artificial lifting which are connected to GGS VII. Low pressure water is injected at 40-42 kg/cm2 connected to 28 wells used for artificial lifting. Here 4 wells are connected to GGS I, 4 wells to GGS XI, 10 wells to GGS II and 10 wells are connected to GGS VII. So total wells connected to CWIP is 52 wells. CWIP FACILITIES 1.
PUMPING SYSTEM
4 reciprocating pumps are available and out of which 2 are working and 2 are stand by. - 36 -
•
Specifications of pump are: Capacity-35 m3/hr
•
RPM-314 Maximum working pressure- 170 kg/cm2
•
BKW- 190.78
MOTOR
•
RPM-1455
•
HP/KW-322/240
•
Efficiency-95.5%
•
Volt-415
2.
STORAGE SYSTEM Balancing tank- 200 m3 Storage tank -600 m3 Treated water tank- 600 m3
•
- 37 -
CWIP (CENTRAL WATER INJECTION PLANT)
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CENTAL TANK FARM (CTF) – NAWAGAM
INSTALLATION MANAGER - Mr.B.K.Shit AREA OF INSTALLATION - 100 Acres RECEIVING STATUS
GGS- I, II, III – 500 m3/day
Ramol, Nandej, Wasna fields- 800-900 m3/day
CTF Kalol- 8000 m3/day
Mehsana fields- 8000 m3/day
STORAGE TANKS
8 tanks- 2000 m3 MAIN OBJECTIVE
As such in this installation no processing is done, they just pump desired crude desalter plant which has come from various CTF.
oil to
Every hour water content is checked in the samples of treated crude oil of desalter plant after fulfilling the desired conditions of refineries dispatching is done from desalter to refineries .
They target to have have water content of 0.5-1 % in oil before discharging.
PUMPING SYSTEM
Make- BPCL
Type- Quintuplex plunger pump
Maximum discharge- 120 m3/hr
Maximum operating pressure- 40 kg/cm2
Rate BHP- 430 HP
MOTOR
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HP- 545
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KW-400
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RPM-1450
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Voltage-415
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Frequency- 50 Hz
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Current- 676 Amp
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DESALTER PLANT: NAWAGAM
INSTALLATION MANAGER : Mr. B.K. Shit DATE OF COMMISION : 01.01.1995 PLANT CAPACITY : 6.7 million metric tons per year NUMBER OF TRAINS (UNIT) - 3 trains of 2.23 million metric tons per year (2 trains are operating and 1 is stand by) RECEIVING STATUS
Crude oil from
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Mehsana
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Ahmedabad Assest
FEED STOCK CHARACTERSTICS Chloride in oil feed water: 45oo ppm Chlorides as Cl salt- 81 ptb Specific gravity of oil-0.8948 Total sulphur, %wt- 0.007 Wax content,%wt-6.8 Total acidity, mg KOH/gm- 4.65 DESALTED CRUDE OIL CHARACTERSTICS Salt content-10-15 ptb PROCESS DESCRIPTION Crude oil is received from the existing tank farm to new tanks through a 30” suction header. 4 Nos. feed pumps are installed for pumping feed to desalter to three trains whereas the fourth pump is common stand by for all the three trains. Demulsifier chemical is mixed with the feed crude oil in the suction line in the feed pump. Crude oil from the feed pump is further mixed with wash water at a rate of approximately 0.5 % of the crude before the crude is sent through heat exchanger. In this heat exchanger the feed is heated to about 630C by exchanging heat with the outgoing treated crude oil from the desalter. Treated crude passes through the tube side of the heat exchangers. The crude from the exchangers will pass through the feed heater where in the temperature is raised to 1000C before entering the desalter vessel. In the desalter vessel feed crude is fed at lower portion of vessel where in it travels and separates through electrostatic grid. The electrostatic grid aids the breaking of emulsion and settlement of water at the bottom. The crude
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after losing water/salts will be let out through the crude outlet line from the top of vessel. Desalter has bottom outlet connections at intervals for removal of water and sediments settled at bottom of desalter. Part of the produced water is circulated back into desalter vessel through desludging pump (rated at 50 m3/hr and 25 m head) to maintain the water phase in the desalter in a fluidized conditions so that the sediments settle down at the bottom of the vessel and form the thick mud. The desalter vessel is provided with sampling valves at various elevations to collect and analyse the samples at various elevations on the desalter vessel. So by analyzing these samples discharging is done. NAWAGAM PLANT FACILITIES 1.
Storage system
Crude oil
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No. of tanks: 4
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Type: floating roof Capacity:30,000 m3
Water
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Raw water tank:2
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Type: cone roof Capacity: 700 m3 each
2.
POWER SUPPLY SYSTEM
Distribution voltage:415 volts
Normal power: 240 volts, AC
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Shut down: 110 volts, DC
Fire alarm system: 240 volts AC
3.
FIRE FIGHTING SYSTEM
2 JOCKEY pump: Working pressure: 8 kg/ cm2 Feed rate: 10 m3/hr
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4.
2 diesel engine driven pump Feed rate: 410 m3/hr 1 electrical driven pump Feed rate: 410 m3/hr 2 water storing pond are there of capacity 3200 m3 each PUMPING SYSTEM
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Rotating pump
Quantity
Type
Capacity (m3/hr)
Head (m)
Desalter feed pump
4
Centrifugal
330
146
Service water pump
2
Centrifugal
40
50
Process water pump
2
Centrifugal
40
135
Desludging pump
2
Centrifugal
50
25
water 2
Centrifugal
5
25
Centrifugal
700 lpm
29.7
Drinking pump
Injection pumps (reciprocating)
4
5.
COMPRESSORS
Air compressor
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Quantity: 2 Capacity:350 Nm3/hr Discharge pressure: 9kg/cm2
6.
BURNERS
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No. of burners: four reactor
Type of burner: forced draft
Type of fuel: natural gas
Heat liberation(max) (mm BTU/hr): 8
7.
MISCILLANEOUS
Instrumental Air Dryer:
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Quantity: 2 Capacity: 150 m3/hr
Demulisifier mixer
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Quantity: 2
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WWTP-WASTE WATER TREATMENT PLANT
This plant is the part of DESALTER PLANT as the treated crude oil is sent to refineries but effluent is sent to WWTP for chemical treatment. WWTP FACILITIES 1.
WASH TANK
Number of units- 2 Capacity- 1000 m3 Storage temperature- 600C Water from desalter plant is stored in these wash tanks, after filling of one wash tank to the desired level, valve of 2nd wash tank is opened and 1st tank is taken into consideration. 2. TPI (TILTED PLATE INTERCEPTOR) SEPARATOR The effluent from wash tank is routed to TPI. The TPI consists of 3 bays each having one plates pack. It has one inclined plate at 450, depth of third bay is largest, the oily sludge is collected at the hopper is discharged into wet sump by gravity. So here the primary separation takes place. 3.
FLASH MIXER
Number of unit- 1 Capacity-4.25 m3
Alum- 50 ppm
Waste water after removal of free oil in TPI flows by gravity into flash mixer where alum is added as coagulant. A suitable agitator is provided to mix alum solution with the waste water. Suitable MS ladder and MS rungs epoxy painted are provided in the system for approach and maintenance.
4.
FLOCULATOR
Type- paddle type
Chemical added – polyelectrolyte Volume of unit- 7 m3
DISSOLVED AIR FLOATATION UNIT (DAF) The DAF unit is carbon steel epoxy painted construction fitted with flocculator. The effluent water after getting dosed with alum in the flash mixer flows by gravity into the DAF unit. The already coagulated effluent is added with deoiling type polyelectrolyte in the flocculation unit before DAF chamber. Floatation of solids is accomplished by introduction of millions of
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microscopic air bubble. As these bubbles rise they attach themselves to the particles in the suspension and carry them to the surface for removal. An important principle of DAF system is the introduction of air in the recirculation effluent and blending the raw flow where the millions of microscopic bubbles are found to which the suspended particles get attached and lift to the surface removal. A skimming arrangement is provided at the top to remove the floatation sludge blanket and this scum is routed to oily sludge sump and from the bottom water goes to receiving sump and from there it is discharged. 5.
TREATED EFFLUENT SUMP
The treated effluent from DAF is routed by gravity to the treated effluent sump. Arrangements should be made to pump the treated water to depleted pump.
Number of unit- 1
Material of construction- RCC Effective capacity- 50 m3
Detention time- 0.25 hrs
6.
OIL SLUDGE SUMP AND PUMP HOUSE
The oil sludge generated during treatment in TPI and DAF units flows by gravity to oil sludge from there it is pumped to sludge thickener for thickening.
Number of unit- 1
Material of construction- RCC Effective capacity- 6.75 m3
Detention time- 1hr
Number of pumps provided- 2
Type- horizontal, centrifugal Capacity- 10 m3/hr
Installed HP of drive- 3
7. THICKNER Thickening is the unit process which is employed for thickening of the sludge to increase the sludge content in the sludge. The stream entering the thickener is sludge from oily sludge sump. Here agitation is done and after that settling time is given so that sludge can settle at bottom and oil is sent to wet slop from the top.
Number of unit- 1 Material of construction- RCC - 46 -
Effective capacity- 85 m3
Detention time- 1hr
PROCESS DESCRIPTION
Effluent from the desalter through pipelines is pumped into wash tanks and from there is sent to TPI and then it is sent to flash mixer where alum is added. Then the effluent by gravity flows to DAF and oil to oil sludge. In DAF polyelectrolyte is added
And finally the effluent is sent to receiving sump and oil is sent to oil sludge and from there it is sent to thickner and then sent back to desalter.
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ARTIFICIAL LIFT (Ahmedabad) Head of artificial lift- Mr. A. K. Pan
Guided by- Mr. M. K. Agarwal Mr. R. L. Patni Mr. P. Deka In many wells the natural energy associated with oil will not produce a sufficient pressure differential between the reservoir and the well bore to cause the well to flow into the production facilities at the surface .In other wells, natural energy will not drive oil to the surface in sufficient volume. The reservoirs natural energy must then be supplemented by some form of ARTIFICIAL LIFT. Types of Artificial Lift Systems
There are four basic ways of producing an oil well by artificial lift. There are. (1) Gas Lift. (2) Sucker Red Pumping. (3) Submersible Electrical Pumping. (4) Subsurface Hydraulic Pumping. (5) Screw pump (pc pump). Choosing an Artificial Lift System
The choice of an artificial lift system in a given well depends upon a number of factors. Primary among them, as far as gas lift is concerned is the availability of gas. Then gas lift is usually an ideal selection of artificial lift. The Process of Gas Lift
Gas Lift is the form of artificial lift that most closely resembles the natural flow process. It can be considered an extension of the natural flow process. In a natural flow well, as the fluid travels upward towards the surface, the fluid column pressure is reduced and gas comes out of solution. The free gas being lighter then the oil it displaces, reduce the weight of the fluid column above the formation. This reduction in the fluid column weight produces the pressure differential between the well bore and the reservoir that causes the well to flow. When a well makes water and the amount of free gas in the column is reduced the same pressure differential between the well bore and reservoir can be maintained by supplementing the formation gas with injected gas. Types of Gas Lift
There are two basic types of gas lift systems used in the oil industry. These are: (1) Continuous flow (2) Intermittent flow
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Continuous Flow Gas Lift:
In the continuous flow gas Lift process, relatively high pressure gas is injected down hole into the fluid column. This injected gas joins the formation gas to lift the fluid to the surface by one or more of the following processes. 1. Reduction of the fluid density and the column weight so that the pressure differential between the reservoir and the well bore will be increased. 2. Expansion of the injection gas so that it pushes ahead of it which further reduces the column weight thereby increasing the differential between the reservoir and the well bore. 3. Displacement of liquid slugs by large bubbles of gas acting as pistons. Intermittent Flow Gas Lift:
If a well has a low reservoir pressure or every low producing rater it can be produced by a form of gas lift called intermittent flow. As its name implies this system produces intermittently or irregularly and is designed to produce at the actual rate at which fluid enters the well bore from the formation. In the intermittent flow system, fluid is allowed to accumulate and build up in the tubing at the bottom of the well. Periodically, a large bubble of high pressure gas is injected into the tubing very quickly underneath the column of liquid and liquid column is pushed rapidly up the tubing to the surface. The action is similar to firing a bullet from a rifle by the expansion of gas behind the rifle slug. The frequently of gas injection in intermittent lift is determined by the amount of time required for a liquid slug to enter the tubing. The length the gas injection period will depend upon the time required push one slug of liquid to the surface. Advantages of Gas Lift
1) Initial cost of down hole equipment is usually low. 2) Gas lift installations can be designed to lift from one to many thousand of barrels. 3) The producing rate can be controlled at the surface. 4) Sand in the produced fluid does not affect gas lift equipment is most installation. 5) Gas lift is suitable for deviated well. 6) Long service lift compared to other forms of artificial lift. 7) Operating costs are relatively low. 8) Gas lift is ideally suited to supplement formation gas for the purpose of artificially lifting wells where moderate amount of gas are present in the produced fluid.
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9) The major items of equipment (the gas compressor) in a gas lift system are installed on the surface where it can be easily inspected, repaired and maintained. Limitations
1. Gas must be available. Natural gas is quite cheap as compared to air, exhaust gases and nitrogen. 2. Wide well spacing may limit the use of a centrally located source of high percentage. 3. Corrosive gas lift can increase the cost of gas lift operations if it is necessary to treat or dry the gas before use.
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