1. Petro Data Mgt III- Facilities
Petroleum Professor
Collins Nwaneri

2. Introduction History about the origin of Oil:
The first oil well discovery was drilled by colonial Edwin Drake in 1859 in northwestern Pennsylvania.
The wells were shallow at less than 50 meters deep and produced oil were collected in wooden tanks.
After the oil discovery, oil replaced most other fuels for motorized transportation.
The automobile industry which was developed at the end of the 19th century, adopted oil as fuel.
Gasoline oil was essential for successful aircraft engine design.
Ships driven by oil moved twice as fast as their coal powered counterparts.
Gas was burned off or left in the ground.

3. Introduction
Pipelines were constructed to natural gas and the petrochemical industry increased production.
Refineries were built to divide the crude in fractions. Gasoline from crude was about % a century ago and with modern refineries, it can be up to about 70 % due to advanced reforming and cracking processes.
Afterwards, came the petrochemical industry at around the 1940’s, and chemicals were derived from petroleum and natural gas. Thereafter, plastics, rubber and several household goods were developed, amongst other products to date.

4. Facilities and Processes
Oil and gas facilities and systems are defined as per their use in the following oil and gas industry production stream:
Exploration: means the prospecting, seismic and drilling activities that occurs prior to a field development.
Upstream: Refers to all facilities for production and stabilization of oil and gas. Normally, for upstream this includes: wellhead, well, completion and reservoir only, and downstream of the wellhead as production or processing
Midstream: defined as gas treatment, LNG production and regasification plants, and oil and gas pipeline systems.
Refining: crude oil and gas, which includes condensate are processed into marketable products such as gasoline, diesel or feedstock for the petrochemical industry. Offsite storage tanks and distribution terminals are included in this segment.
Petrochemical: This are chemical products such as plastics, fertilizer from by-products of hydrocarbons. the

5. Exploration
Currently, this involves using surface geological mapping and advanced sub-surface surveying method such as passive seismic, reflective seismic, magnetic and gravity surveys to help identify potential hydrocarbon rocks.
In the past, surface indications such as tar seeps or gas pockmarks gave clues for shallow hydrocarbon locations.
Offshore wells typically costs between $10 to $100 million range.
Offshore rig leases are typically in the range of $200,000 to $700,000.
U.S onshore wells cost about $4 million. ( normally have lower production capacity)
A shallow wells at marginal fields can be drilled for as little as $100,000.
Therefore oil and gas companies carry out analysis on exploration data from this first drilled wildcat wells for good indication of source rocks and hydrocarbon potential, amongst other things such as probable down-hole pressure for safe drilling of other wells
Furthermore, if a find is made, additional requirement production testing, drilling appraisal wells, et.c , to determine the size and production capacity of a well before developmental wells are drilled.

6. Production
The following diag. is an overview of typical oil and gas production facilities:
Fig A: Oil and Gas Production Facilities

7. Production
The following diag. is an overview of a typical production facility. This varies in size and type.
Fig B: Oil and gas production overview
Disc…

8. Production
Many part of the processes in a production facilities are similar despite the oil and gas production rate per day.
The diagram in Fig. B shows production and test manifolds (called a gathering system in a distributed production) placed next to the wellheads. A gas oil separation plant (GOSP) that takes a well stream of hydrocarbon from natural gas, condensate and crude oil and unwanted elements such as water, salt, sand e.tc for separation.
Utility systems are not part of actual processes in facilities, but they provide the energy, water, air or other types of utility as needed in facilities.

9. Onshore
Onshore gas and oil production is economically viable with oil production capacity from wells as high as thousands of barrels per day. This is connected to a 1,000,000 barrel or more per day GOSP.
The oil product from this facilities are distributed by pipelines or tankers; and can also be stored.
Oil from the smallest reservoir can be collected in
holding tanks and transported for processing at the refinery via tanker trucks or railcar.
Gas gathering network can be large due to production from thousands of wells.

10. Onshore The following onshore unconventional plays can be exploited:
Heavy crude can be extracted by heating and use of diluents.
Tar sands can be strip-mined or extracted with steam. It should be followed processed to separate bitumen from sand.
Shale gas and oil have being produced by advances in drilling technology and hydraulic fracturing.

11. Offshore
A whole range of various type of structures are used offshore, and this depends on size and water depth.
More recent structures includes sea bottom installations with multiphase piping to shore and no offshore topside structure at all.
The following are examples of common offshore structures:
1. Shallow water complex: has several independent platforms with different parts of processes and utilities linked with a gangway bridge.
- Examples of individual platforms are wellhead, riser, processing and power generation platforms. (See Dia. A)
- Found in water depths of up to 100 meters
2. Gravity base: fixed concrete structures placed on the bottom with oil storage cells on the sea bed. (See Dia. B)
- Has a large deck with all parts of the process and utilities in large modules.
- Typically used for large fields I about 100 to 500 meters water depth about years ago.
3. Compliant towers: has flexible narrow towers attached to a seafloor foundation that can operate in deeper water depths unlike the fixed platforms. (See Dia. B)
- Typically used in about 500 TO 1000 meters water depth.
tow

12. Offshore
3. Floating production: All topside systems are located on a floating structure with dry or subsea wells. Examples are: FPSO (Floating Production, Storage and Offloading)
FPSO main advantage is that they are standalone structures and does not need external infrastructure such as pipelines or storage.
They currently produce about 10,000 to 200,00 barrels per day.
Typically tanker type hull or barge and can be used In water depths of more than 100 meters.
Wellhead or subsea risers used in some FPSO are centrally located for ease of rotation to point into winds, waves or current.
Anchors (positioning mooring-POSMOOR) or Thrusters (dynamic positioning-DYNPOS) can be used to hold FPSO in place on the water.
Most FPSO installations use subsea wells.
Main processes are placed on deck and hulls are used for storage and offloading to a shutter tanker. The hull can also be used for pipeline transportation.
In the future, FPSO with additional processing and systems, required for drilling, production and stranded gas LNF are planned.
One variation of FPSO is Sevan Marine design. (Circular hull has many characteristics of a ship-shaped FPSO, but does not rotate. (See Dia. D and C)

13. Offshore
4. Tension Leg Platform (TLP): consists of a structure held in place by vertical tendons connected to the seafloor by pile-secured templates. (See Dia. E2) - Held in a fixed position by tensioned tendons. - can be used in water depths of up to 2000 meters. 5. Semi-submersible platforms: have a similar design but without taut mooring. - Has more lateral and vertical motion and generally used with flexible risers and subsea wells. (See Dia. E1) 6. SPAR: They are single tall floating cylindrical hull, with a fixed deck. - cylinder hull does not extend to the seabed and is anchored to the bottom by cables and lines. (See Dia. F) - Used for water depths from 300 to 3000 meters. - can support dry completion wells and mostly used with subsea wells. 7. Subsea production systems: have wells located on the seafloor or seabed rather than the surface. (See Dia. G) - hydrocarbon is extracted at the seabed and “tied-back” to pre-existing production platform or onshore facility (depends on horizontal distance or offset). - After Wells are drilled, produced hydrocarbons are transported by undersea pipeline and riser to processing facilities. Allows for more production handling from more wells in a large area. - Used in water depths of 500 meters or greater. - cannot be used to drill, bit to extract and transport.

14. Common offshore structures
Dia. A
Dia. B
Dia. C
Dia. D
Dia. E1 & 2
Dia. F
Dia. G

15. Upstream Process sections
We will introduce the activities and processes after a producing wellhead in an upstream section.
1. Wellheads:
Sits on top of the oil or gas well leading to the reservoir.
Can be used as an injection well for water or gas injection into the reservoir for pressure maintenance to increase production.
Well is normally completed after drilling for flow of oil or natural gas to the surface.
Well flow from the wellhead is controlled by a choke.
Dry completion (onshore or deck of offshore structure)
Subsea completion below the water surface.
Wellhead structure (often referred as Christmas tree) should allow for production and work-over activities.
2. Manifolds and gathering:
Onshore, individual well streams are brought into the main production facilities over a network of gathering pipelines.
Used to select the best producing wells at anytime due to their well flow composition (oil, gas and water).

16. Upstream Process sections
Gas gathering systems can be metered at the individual gathering lines into the manifold.
Multiphase phase flows measurements can use flow-meter or be automated.
Offshore, dry completion wells on the main field center, feed directly into production manifolds. Outlying wellhead towers and subsea installations feed via multiphase pipelines back to the production risers
3. Separation:
Wells with pure gas can be taken directly for gas treatment and/or compression.
Wells with combination of gas, oil and water, with various contaminants must be separated.
Production separators come in different forms and design. (Classic variant is the gravity separator).
4. Metering, Storage and Export:
Most plants do not allow local gas storage.
Oil is often stored before offloading to shuttle tankers for further handling .
Offshore production facilities without direct pipeline store crude oil in base or hull then offloads to shuttle tankers for further handling.

17. Upstream Process Sections
Meters are used to monitor and manage natural gas and oil exported from production installation (i.e. oil and gas flow measurement)
The metered volume represents a transfer of ownership from a producer to a customer. (This is referred as custody transfer metering)
Custody transfer metering is used for sold product invoicing and also for production taxes and revenue sharing between partners.
Metering installations consists of multiple meter runs to accommodate full capacity range.

18. Upstream Stream Processes
5. Utility Systems: Are not used in hydrocarbon process flow, but provide service some service to the main process safety and residents i.e. electricity, water e.tc.

19. Midstream
This is normally made up of gas plants, LNG production and regasification, and oil and gas pipeline transport systems.
Fig. C

20. Midstream
Gas Plants:
Handle the separation of various hydrocarbons and fluids from pure natural gas to produce “pipeline quality” dry natural gas.
Natural gas is treated before it can be transported and sold.
Natural gas that is separated from crude oil, is normally made up of mixtures of ethane, propane, butane and pentanes.
Water, H2S, CO2, helium, nitrogen, et.c are examples impurities found in raw natural gas.
NGL “Natural gas liquids” (Associated hydrocarbons) are used in oil refineries or petrochemical plants and as sources of energy.
2. Gas Compression:
A means to push gas from gas separators outlets because of low gas pressure in order to move the gas through pipelines for transportation.
Examples of compressors are: Turbine driven compressors (use natural gas and turbines) and electric driven compressors.
Scrubbers (liquid droplets removal), heat exchangers, lube oil treatment e.tc are examples of equipments used in compression stations.

21. Midstream
3. Pipelines:
Measure anywhere from 6 to 48 inches in diameter.
Pipelines are normally inspected for corrosion and defects with “pigs”. Pigs intelligent robotic equipment used to test pipe thickness, roundness, check for corrosion, detect leaks, e.tc.
Export facilities normally have depressurization equipments, pig launchers to insert pigs and pig receivers to receive pigs in pipelines.
4. LNG liquefaction and regasification facilities:
Involves the cooling of natural gas at (-162 deg. C) into liquid form for transportation to other facilities when a pipeline is not available or it is not economical.
A regasificatiion terminal is at the receiving end for the LNG conversion into vapors for pipeline transportation.
Compressed natural gas (CNG) is mainly natural gas with methane that is compressed to liquid at normal ambient temperature.

22. Refining
They use a distillation column to separate crude into fractions of a defined range of products.
The quantity and quality of this end products depends on the crude used.
Refinery operations often include distribution terminals for product dispensing to bulk customers such as airports, gasoline stations, ports and industries.

23. Petrochemical
Petrochemical plants produce thousands of chemical products.
The main feedstock is natural gas, condensate (NGL) and other refinery by-products such as napthan, gasoil and benzene.
Petrochemical plants are divided into three main primary product groups as per their feedstock and primary petrochemical product.
Olefins: main source of plastics, industrial chemicals and synthetic rubber.
Aromatics: source of plastics, synthetic detergents and dyes.
Synthesis gas: used to make ammonia e.g. fertilizer and methanol. Also used in other processes such as Fischer-Tropsch process that produces synthetic diesel.

24. Reservoir and wellheads
There are 3 main types of convectional wells.
Oil well with associated gas.
Natural gas wells with little or no oil.
Condensate wells with natural gas and liquid condensate.
No need for artificial lift installation for most natural gas and condensate well.
Oil wells need artificial lift installation with decline in reservoir pressure during years of production.
Unconventional wells are created from tight reservoirs with low porosity and varying maturity that creates shale oil and gas, tight gas, heavy oil, etc.

25. Crude oil and natural gas
A complex mixture of various organic compounds. (Mostly alkanes and smaller fraction aromatics).
API gravity is a measure of the specific gravity or density of a particular crude.
Higher the API number (in degrees), the less dense (lighter) the crude and vise-versa.
Crudes from different fields and different formation within a field be similar in composition or largely different.
Crude oil is also characterized for undesired elements like sulfur.
Crude oil API gravities range between 7 to 52 (Most fall between 20 to 45 API gravity range).
Light crude (40 – 45 degrees API) may be the best, but the lighter the crude the Shorter and Less molecules it contains for high octane gasoline and diesel fuel production that are needed for maximum production by refineries .
Heavy crude (less than 35 degree API) has longer and bigger molecules that are not useful as high octane gasoline and diesel fuel without more processing.

26. Crude oil and natural gas
- API gravity is not used meaningfully for mixed crudes of different type and quality or different petroleum components, except for fluid density measurement. This is unlike, natural crude oil that has not being mixed, blended e.tc.
Heavy crude can be processed by cracking an reforming to reduce the carbon number in order to increase the high value fuel yield.
Natural gas:
Natural gas used by consumers contain almost entirely methane.
Wellhead natural gas is not pure.
Natural gas comes form three types of wells (Oil wells, Gas wells, and condensate wells).
The following are classification of natural gas per source.
Associated gas (Oil well)
Free gas ( gas expansion from oil) or dissolved gas ( dissolved in oil)
Non-Associated gas (gas wells or condensate wells with little or no oil)
Natural contains mixture of other hydrocarbons such as: ethane, propane, butane, pentane and impurities such as water vapor, hydrogen sulfide (H2S), carbon dioxide, helium, nitrogen and other compounds.

27. Crude oil and natural gas
Condensate:
- Made up of NGL (ethane, propane, butane, iso-butane and natural gasoline). They are sold separately and used as raw materials for oil refineries or petrochemical plants, as a source of energy and for enhance oil recovery.
They are also useful as diluents for heavy crude.

28. Reservoir and wellheads
The reservoir:
See section 3.2 (Discuss in class)
Exploration and Drilling:
See section 3.3 (Discuss in class)
The Well:
See section 3.4 (Discuss in class)
Wellhead:
See section 3.5 (Discuss in class)
Artificial lift:
See section 3.6 (Discuss in class)
Well work-over, intervention and stimulation

29. The Upstream Oil and Gas Process
This is a process that uses process equipment to take products from the wellhead manifolds and delivers stabilized crude oil, condensate or gas marketable products.
Components in the process are available to test products and clean waste products such as produced water.
See an example of a process on the Statoil Njord floater as shown on page 40. (Discuss)
A typical process is described from below:

30. Manifold and Gathering
Pipelines and risers:
This facility uses subsea production wells. (High pressure Wellhead with Christmas tree and choke on the sea bed).
A production riser (offshore) or gathering line (onshore) will bring the well flow into the manifolds.
The manifold line may include several check valves: choke, master and wind valves. This valves are slow and during a production shutdown, the pressure on the first sectioning valve that is closed rises to the wellhead pressure before the valves above can close. Why?
Note: Pipelines and risers are designed like this.

31. Manifold and Gathering
Short pipelines are not a problem compared to long pipelines where a multiphase well flow may separate and form slugs(plugs of liquid with gas in between) that travels the pipeline.
Slugging can cause separation process upset and overpressure safety shut-down.
Slugging can be controlled manually by choke adjustment or by automatic slug control.
Also, areas of heavy condensate can form in pipeline .
At high pressure, plugs can freeze at normal sea temperature. (During production shut-down or long offsets)
Ethylene glycol can be injected to prevent freezed plugs)
The floater above as topside chokes for subsea, kill fluid which can be injected into the well before the choke.

32. Manifold and Gathering
Production, test and injection manifolds:
Check valves allow each well to be routed into one or more of several manifold lines.
At least one for each process train plus additional manifolds for test and balancing purposes. An example shown in figure 41 is a three manifolds: test, low pressure and high pressure manifolds.
Test manifold allows one or more wells to rooted to the test separator.
While the HP and LP manifolds will allow groups of HP and LP wells to be taken to the first and second stage separators, respectively.
Chokes help to reduce the wellhead flow and pressure to the desired high pressure (HP) and low pressure (LP) respectively.
Reservoir specialist define the desired settings for a well production at HP and LP at various production levels.

33. Separation Test separators and well test:
The purpose of a separator is to split flow from well stream that consists of crude oil, gas, condensates , water and various contaminants into desirable fractions.
Test separators and well test:
Test separators are used to separate the well flow from one or more wells for analysis and detailed flow measurement.
Takes place at the start of a well production and regular intervals afterwards (1-2 months)
Total and component flow-rates are measured at different conditions.
Slugs or sand are also determined.
Separated components are analyzed at the lab to determine hydrocarbon composition of gas, oil and condensate.
Test separators can be used to produce fuel gas for power generation when the main process is not running.

34. Separation
Production Separators: The example below is a gravity type:

35. Separation The following key points are:
Pressure reduction from the well by the production choke to HP manifold and first stage separator. Pressure is about 3-5 MPa and Inlet temperate between degree C.
Pressure is reduced in several stages.
Three stages allow controlled separation of volatile components. ( This is to achieve maximum liquid recovery and stabilized oil and gas and to separate water).
Retention period allows for gas to bubble out, water to settle at the bottom and oil to be taken from the middle.
At the crude entrance is a baffle slug catcher to reduce the effects of slugs (large gas bubbles or liquid plugs). Turbulence or Laminar flow, which is more desirable at this entrance and why?
Barriers are present to keep back the separated oil and water.
The Main control lopes which are the oil and gas level control loops controls oil flow out from the separator on the right and gas flow out from the top, respectively.
The control loops are operated by control systems and also function to prevent gas blow-by. ( This happens when low level oil causes gas to exit via the oil output, causing high pressure downstream).

36. Separation Second Stage Separators:
Liquid outlets from the separator are equipped with vortex breakers to reduce disturbance on the liquid table inside. (Helps prevent separated liquid from mixing with oil or water drawn in through the vortices.
Gas outlets are equipped with demisters, this are filters that remove liquid droplets in the gas.
Emergency valves (EVs) are sectioning valves that separate the process components.
Blow-down valves, allow excess hydrocarbons to burn-off in the flare.
Second Stage Separators:
Similar to the first stage HP separator and in addition to the output from the first stage. It receives production from the wells connected to the low pressure manifold.
Pressure is about 1 Mpa and temperature below 100 deg. C
A oil heater can be between the first and second stage separators to reheat oil/water/gas mixtures. (Makes it easier to separate water with high initial water cut and low temperature).

37. Separation Coaleser: Electrical desalter: Third stage Separators:
This is the final separator, which is a two phase separator. (Flash drum)
Last heavy gas components boils out at this stage at atmospheric pressure (about 100 kpa)
If it is mainly gas production, remaining liquid droplets are separated out by a Knock-out drum (K.O .drum) , two phase separator.
Coaleser:
This is after the third stage, where oil goes to a coaleser for final removal of water. (water content can be reduced to below 0.1 %)
Electrical desalter:
Used to remove unacceptable amounts of salt from oil. (The salts can be sodium, calcium or magnesium that come from the reservoir water and also dissolved in the oil.

38. Separation Water Treatment:
The desalters can be placed after the first or second stage separator as per the GOR and water cut from the well.
Water Treatment:
Various equipments are used to clean or treat produced water. See the figure below:

39. Separation
A water treatment systems shown below has a sand cyclone, which removes most sand from the separators and coalescers. Which is further washed below it is discharged.
- Afterwards, the water goes to a hydocyclone, a centrifugal separator to remove oil droplets.
- Finally, the water is collected in a water-de-gassing drum. Dispersed gas rises away from oil droplets (by flotation), surface oil film is drained and produced water is discharged to the sea.
- Any recovered oil from the water treatment system, is recycled to the stage separator.

40. Gas Treatment and Compression
Gas train consists of several stages, each taking gas transfer from suitable pressure level in the production separators gas outlet, and from the previous stage.
See the diagram for a typical stage on page 48.
Heat Exchangers:
For the compressor to operate efficiently, gas temperature should be low.
The lower the temperature, the less energy will be used to compress the gas for a final pressure and temperature.
Gas from separators and compressed gas are relatively hot.( This due to thermodynamic balance).
Heat exchangers are used to cool the gas.
Two types of heat exchangers are Plate heat exchangers (See bottom picture on page 48) and Tube & Shell exchangers (See picture on page 49). Plate heat exchangers are made up of a number of plates where gas and a cooling medium pass between alternating plates in opposing directions. Tube and shell exchangers use cooling fluids (mostly pure water with corrosion inhibitors) placed in a shell.
It is important to plan the thermal balance for heat exchangers. (What is going to be used to conserve heat, how to handle excess heat and what material is used).

41. Gas Treatment and Compression
Scrubbers and reboilers:
- Scrubbers are used to remove mist & other liquid droplets from separated gas, water and hydrocarbon droplets from cooled gas in heat exchangers. (It is designed to remove small fractions of liquid from gas)
This is to prevent liquids from entering the compressors and eroding the compressor fast rotating blades. (Liquid must be removed from gas before it enters a compressor)
They are various types of gas drying equipment available. The most common suction (compressor) scrubber is based on dehydration by absorption in Triethylene glycol (TEG).
This scrubber consists of many levels of glycol layers.
(See picture on page 50 of a typical Glycol regeneration unit).

42. Gas Treatment and Compression
Compressors, anti-surge and Performance:
Compressors are used in many parts of the oil and gas process, from upstream production to gas plants, pipelines, LNG and petrochemical plants.
- They are different type of compressors, each with different characteristics such as: operating power, speed, pressure and volume.
Reciprocating compressors:
- Uses a piston and cylinder design.
- Used for lower gas compression and high reservoir pressure gas injection.
Screw compressors:
- Has two counter-rotating screws with matching profiles which provide positive displacement and a wide operating range.
- Used mostly in natural gas gathering.

43. Gas Treatment and Compression
3. Axial blade and fin type compressor:
- has up to 15 wheels which provide high volumes at a relatively low pressure differential . (Discharge pressure 3-5 times inlet pressure)
- Used in air compressors and cooling compression in LNG. Inlet flow of up to 200,000 m3/hour.
4. Centrifugal compressors:
- Used in large oil and gas installations.
- Has discharge pressure of up to 50 bars and inlet volume of up to 500,000 m3/hour.
- Compressors have full pressure range specifications and
most compressors will not cover it efficiently.
- For gas to pipeline pressure requirements (Lowest pressure is atmospheric , about 3 to 2 Mpa (30-50 bar) pressure is used.
- Reservoir reinjection of gas pressure requirement. (20 Mpa (200 bar) and higher. Why is this pressure higher than pressure for gas to pipeline?

44. Gas Treatment and Compression
Compressors can be driven by gas turbines, electric motors and steam engines.
The main operating parameters for a compressor are flow and pressure differential. The product of both parameters defines the total loading.
For maximum flow in a compressor to be achieved there is a maximum pressure differential and maximum choke flow (Max. Q).
For a lower flow, there is minimum pressure differential and flow (Min. Q) before a compressor will surge.
See Diagram in Page 53 for the relationship between pressure differential and flow in a compressor and indication of constant speed lines (blue lines), maximum operating limits (orange lines) and surge domain (Area to the left of the surge line).
A compressor performance control aims to keep compressors operation close to the optimal set point without exceeding control outputs such as speed setting.
Anti-surge control protect the compressor from going into surge.
Set point adjustment used to increase surge margin due to rapid variation in loads.

45. Gas Treatment and Compression
Equal margin used to adjust set point for equal margin to surge between several compressors.
Model based control used to predict surge conditions and react faster to real solutions while preventing unnecessary recirculation.
The following systems are also employed to maintain compressors and prevent expensive repairs:
1.Load Management (Balance loading among several compressors)
2. Vibration (Vibration monitoring system used to identify vibrations in compressor that can lead to problems).
3. Speed governor (used to maintain efficiency and control rotational speed).
Compressors have lube and seal oil handling capability (used to lubricate high speed bearings and gas absorption to prevent gas leaks). Some have wet seals which also helps prevent gas leaks.

46. Oil and gas storage, metering and export
Storage, pumps and pipeline terminal equipment are the final stage before oil and gas leaves a platform.
Fiscal metering:
Used by partners, authorities and customers for calculation for payments, Invoices and taxes that is based on actual shipped product.
Custody transfer (Responsibility or title transfer) between producers and customers also takes place at this point.
A fixed or movable prover loop is installed for calibration in metering system for accurate readings.
Some Smaller installations still use dipstick and manual records, while larger installations have analysis and metering systems.
Liquid Metering: See a diagram of a liquid hydrocarbon (oil and condensate) metering system on page 55 .
-An analyzer is present in the system that provides data such as density, viscosity and water content.

47. Oil and gas storage, metering and export
-Pressure and temperature compensation is also present in the system.
Examples of liquid meters are turbine meters, positive displacement meters and coriolis mass flow meters.
Meters are calibrated for accurate measurements.
Gas metering: Similar to the liquid metering systems above except:
Analyzers measure hydrocarbon content and energy value (Unit in MJ/scm or BTU, Kcal/scf) and also pressure and temperature.
Examples of gas meters are orifice and ultrasonic meters.
Gas metering is less accurate than liquid, typically +-1.0% of mass.
There is no prover loop, and instrument and orifice plates are calibrated in separate equipment in gas metering system.

48. Oil and gas storage, metering and export
LNG is often metered with mass flow meters.
Meter measurements are taken at various points in oil and gas movement.
Storage:
Oil and gas from production sites can be piped directly to a refinery or tanker terminal.
Gas is difficult to be stored locally and it is sometimes stored In underground mines, caverns or salt deposit.
Production platforms offshore without pipeline store oil in onboard storage tanks to be transported by shuttle tankers.
Onshore, fixed roof tops are used for crude storage and floating roof for condensate. Rock caves are also used for storage.

49. Oil and gas storage, metering and export
Special tank gauging systems such as level radars, pressure or float are used to measure the level in storage tanks, cells and caves.
The level measurement is converted to converted to volume and compensated for temperature for standard volume.
A tank farm is made up of tanks that is used for hydrocarbon storage . (Area capacity of about 1 – 50 million barrels)
Marine loading:
A loading system consists of one or more loading arms/jetties, pumps, valves and metering system.
A tanker loading system is complex due to the volume involved and the interaction of several loading arms with the ballast system that helps to control the loading operation.
Tankers are normally filled in a sequence to avoid damage to the structure due to stress.