Gas Collection and Compression System at Kalol GCS, Summaries of Thermodynamics

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REPORT ON TRAINING

IN

OIL AND NATURAL GAS CORPORATION LIMITED

SURFACE TEAM

AHMEDABAD ASSET

SUBMMITTED

BY: -

ACKNOWLEDMENT

Firstly, we would like thanks Mr. N. Khanduri for his great efforts in arranging our training at Ahmedabad asset under surface team. We would like to express our sincere thanks to installation managers of GGS motera KALOL,C.T.F, G.C.S,G.C.P, KALOL G.G.S VII , E.T.P, C.W.I.P, Nawagam C.T.F, Desalter plant, Artificial lift & security dept. 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

TOPIC PAGE NO.

GGS-MOTERA

DATE OF COMMISION: 29.03.

AREA OF INSTALLATION:

WELL PRODUCTION STATUS :

TOTAL WELLS CONNECTED-

TOTAL FLOWING WELLS-

TOTAL LIQUID PRODUCTION-40 m^3 /day WATER INJECTION WELLS- nil GAS INJECTED-20000 m^3 /day VESSELS: LOW PRESSURE SEPARATOR- (vol- 6 m^3 ) GROUP SEPARATOR- (vol-6 m^3 ) TEST SEPARATOR- (vol- 6m^3 ) VERTICAL SCRUBBER-(capacity-1.7 lacks m^3 /day) HORIZONTAL SCRUBBER-(capacity- 50000 m^3 /day) BATH HEATER- 1 NO.S TANKS OIL STORAGE TANKS- 3 NO.S (45 m^3 ) 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/cm^2 ) 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/cm^2 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 separation gas is directly sent to GAIL and oil goes to storage tank.

• LOW PRESSURE SEPARATOR

When the fluids coming out of the wells have pressure of about 1-2 kg/cm^2 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

 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 m^3 )  Small water tank- (capacity- 100m^3 )

KALOL GCS (GAS COLLECTION STATION)

INSTALLATION MANAGER : Mr.B.B.Patel ESTABLISHED IN : 1973 RECEIVING STATUS : Total Wells Connected- Total Working Wells- 13 Receiving pressure-4kg/cm^2 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

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 (SO 2 and HCl) removal efficiencies.

4. SEPARATOR  Functions at 4kg/cm^2  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 45m^3 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

SUPPLY FROM GCS

• 1. GGS Motera
• 2. KALOL GCS (GAS COLLECTION STATION)
• 3. GAS COMPRESSION PLANT (GCP)-KALOL
• 4. CENTRAL FARM TANK (CTF)-KALOL
• 5. GGS VII-KALOL
• 6. EFFLUENT TREATMENT PLANT (ETP)-II (KALOL)
• 7. CENTRAL WATER INJECTION PLANT (CWIP)
• 8. CENTAL TANK FARM (CTF) – NAWAGAM
• 9. DESALTER PLANT: NAWAGAM
• 10. WWTP-WASTE WATER TREATMENT PLANT
• 11. ARTIFICIAL LIFT (Ahmedabad)
• Methane(CH 4 ) 87. COMPOUND MOL%
• Nitrogen(N 2 ) 0.
• Carbon di oxide(CO 2 ) 1.
• Ethane(C 2 H 6 ) 5.
• Propane(C 3 H 8 ) 2.
• Water(H 2 O)
• Hydrogen bi sulfate(H 2 S)
• Carbon monoxide(CO)
• Oxygen(O 2 )
• I-butane 1.
• N-butane 0.
• I-pentane 0.
• N-pentane 0.
• Hexane 0.
• Heptane
• Octane
• Nonane
• Decane plus
• Helium(He)
• Argon

GAS SUPPLIED TO QUANTITY

IIFCO (Associated. Gas) 30000m^3 /day SAHAND-II (Natural Gas) 50000m^3 /day Bharat Vijay Mill(Sintex)(Associated Gas) 15000-20000m^3 /day RIL (Compressed Gas) 1 lacks m^3 /day Compressed gas to Grid 4.30 lacks m^3 /day Gurukul (Kalol) 300 m^3 /day Central Farm Tank (CTF) (Associated Gas) 1700m^3 /day

GAS COMPRESSION PLANT (GCP)-KALOL

INSTALLATION MANAGER : Mr. Rajesh Kumar DATE OF COMMISION: GCP-I: 26.02. GCP-II: 15.03. TOTAL CAPACITY : 5 lacks m^3 /day TOTAL COMPRESSORS: 10 6 in old plant and 4 in new plant Capacity (old) =3 lacks m^3 /day Capacity (new) = 2 lacks m^3 /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/cm^2 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 1st 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/cm^2 and because of compression temperature rises to 125^0 C so to low down the temperature to 40-45^0 C, compressed gas is sent to inter gas cooler. Now the cooled gas of 12-14 kg/cm^2 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/cm^2 pressure but temperature has again gone up to 145^0 C 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/cm^2 pressure is sent back to GCS. GCP FACILITIES

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-2100m^3 /hr
• Model- 14 X 8 X 5 2 RDH-
• 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 2 SO 4 so that pH of water is maintained. Then again this water goes to cartridge filter, so that if any filtration is left can be

 Two 11 KV sub-station  8 step down transformers