Introduction to Oil & Gas9th Week LectureByAP Dr Nasir ShafiqCivil Engineering DepartmentPipe Lines and Tankers
Learning objectivesThe objectives of this chapter is to give thebasic understanding of the means oftransportation of hydrocarbons, which are: Pipelines, and Tankers
Learning outcomeAt the end of this chapter, students shouldbe able to demonstrate the following: Difference between a pipeline and a tanker and their application for transportation of hydrocarbons. Different types of pipe lines and the respective application. Different kind of tankers and their purposes
Produced Oil & Gas are required totransport (move out) from one part of the world to the other. Why? How?
Proved oil reserves at end 2008Thousand million barrels
Proved natural gas reserves at end 2008Trillion cubic metres
Why oil & gas are moved out?Natural gas and crude oil must be movedfrom the production site to refineries/gasprocessing plant and from there toconsumers/end-users.Earlier slides show the worldwide oil & gastrade movement according to theconsumption and demand in variouscountries/region.
How oil & gas are moved out?These movements (crude and/or refinedproducts) are made using a number ofdifferent modes of transportation. Crude oil and refined products are transported across the water in barges and tankers and/or underwater pipelines On land crude oil and products are moved using pipelines, trucks, and trains.
How oil & gas are moved out?Similarly pipelines are used to move gasfrom the field to consumers. Gas produced from onshore and offshore facilities is transported via gathering systems and inter- and intra-state pipelines to residential, commercial, industrial, and utility companies.
How oil & gas are moved out?In order to transport natural gas inareas not served by pipelines, the gasis liquefied to reduce its volume. When the gas is liquefied, it shrinks to l/600 of its gaseous volume.
Pipelines DefinitionA pipeline system is defined as apipeline section extending from aninlet point (may be an offshoreplatform or onshore compressorstation) to an outlet point (may beanother platform or an onshorereceiving station).
Pipelines types, classification and categoriesPipelines can be categorised as: Onshore, and Offshore The onshore and/or offshore pipelines have THREE (3) types: 1. Trunk or gathering 2. Transmission or transportation 3. Distribution
Pipelines: TypesThese lines are used to transport oil fromfield pressure and storage to large tankwhere it is accumulated for pumping into thelong distance called trunk line.Gathering pipelines typically consist of linesranging from 4″- 8″ inside diameter,operating pressure is higher than oil flowlines.
Pipelines: TypesGathering system throughput varies widelydepending on: Number of field storage tanks. The producing capacity of well in each field.
Trunk LinesFrom large central storage, oil is moved throughlarge diameter, long distance pipeline called trunkline to refineries.Pump are required at the beginning of the trunkline and pumping stations must also be spaced along the pipeline to maintain pipeline pressure atthe level required to overcome friction, change inthe elevation and other losses.
Trunk LinesCrude trunk lines operate at higher pressure thangathering systems. These lines are made of steeland individual sections are joined by welding.These lines are almost buried below groundsurface are coated externally to protect againstcorrosion.
Transmission/TransportationTransportation Pipelines - Mainly longpipes with large diameters, movingproducts (oil, gas, refined products)between cities, countries and evencontinents.
Transmission/TransportationThese transportation networks includeseveral compressor stations in gas linesor pump stations for crude and multi-products pipelines. The large diameter may range from 24 to 60 inches Example Trans ASEAN line
Distribution LinesDistribution Pipelines - Composed of severalinterconnected pipelines with small diameters,used to take the products to the final consumer.Feeder lines to distribute gas to homes andbusinesses downstream. Pipelines at terminals fordistributing products to tanks and storage facilitiesare included in this group.
Oil PipelinesCrude oil is collected from field gathering systemsconsisting of pipelines that move oil from the wellhead tostorage tanks and treatment facilities where the oil ismeasured and tested.Oil pipelines are made from steel or plastic tubes withinner diameter typically from 10 to 120 cm (about 4 to 48inches).Most pipelines are buried at a typical depth of about 1 - 2meters (about 3 to 6 feet).From the gathering system the crude oil is sent to apump station where the oil delivered to the pipeline.
Oil PipelinesThe pipeline may have many collection anddelivery points along route. Booster pumps arelocated along the pipeline to maintain thepressure and keep the oil flowing usually flows atspeed of about 1 to 6 m/s.The delivery points may be refineries, where theoil is processed into products, or shippingterminals, where the oil is loaded onto tankers.
Oil PipelinesA pipeline may handle several types of crude oil. Thepipeline will schedule its operation to ensure that theright crude oil is sent to the correct destination.The pipeline operator sets the date and place whenand where the oil is received and when the oil willarrive at its destination.Crude oil may also move over more than one pipelinesystem as it journeys from the oil field to the refinery orshipping port.Storage is located along the pipeline to ensure smoothcontinuous pipeline operation.
Natural Gas PipelinesNatural gas pipelines are used to move gasfrom the field to consumers. Gas producedfrom onshore and offshore facilities istransported via gathering systems and inter-and intra-state pipelines to residential,commercial, industrial, and utility companies.For natural gas, pipelines are constructed ofcarbon steel and varying in size from 2 inches(51 mm) to 56 inches (1,400 mm) in diameter,depending on the type of pipeline.
Natural Gas PipelinesThe gas is pressurized by compressor stationsand is odorless unless mixed with an odorantwhere required by the proper regulating body.Most natural gas pipelines operate using acomplex have become so automated that theyare capable of operating under command of acomputer system that coordinates theoperation of valves, prime movers, andconditioning equipment.
Pipelines ComponentsPipeline networks are composed of severalpieces of equipment that operate together tomove products from location to location.The main elements of a pipeline system areshown in the figure on the next slide.
Pipelines ComponentsInitial Injection Station - Known also asSupply or Inlet station, is the beginning ofthe system, where the product is injectedinto the line.Storage facilities, pumps or compressorsare usually located at these locations.
Pipelines ComponentsCompressor/Pump Stations - Pumps forliquid pipelines and Compressors for gaspipelines, are located along the line to movethe product through the pipeline.The location of these stations is defined bythe topography of the terrain, the type ofproduct being transported, or operationalconditions of the network.
Pipelines ComponentsPartial Delivery Station - Known also asIntermediate Stations, these facilities allow thepipeline operator to deliver part of the productbeing transported.Block Valve Station - These are the first lineof protection for pipelines.With these valves the operator can isolate anysegment of the line for maintenance work orisolate a rupture or leak.
Pipelines ComponentsBlock valve stations are usually located every20 to 30 miles (48 km), depending on the typeof pipeline.Even though it is not a design rule, it is a veryusual practice in liquid pipelines.The location of these stations dependsexclusively on the nature of the product beingtransported, the trajectory of the pipeline and/orthe operational conditions of the line.
Pipelines ComponentsRegulator Station - This is a special type ofvalve station, where the operator can releasesome of the pressure from the line. Regulatorsare usually located at the downhill side of apeak.
Pipelines ComponentsFinal Delivery Station - Known also as Outletstations or Terminals, this is where the productwill be distributed to the consumer. It could bea tank terminal for liquid pipelines or aconnection to a distribution network for gaspipelines.
Pipelines InspectionCrude oil contains varying amounts of wax, orparaffin, and in colder climates wax buildupmay occur within a pipeline.Often these pipelines are inspected andcleaned using pipeline inspection gaugespigs, also known as, scrapers or Go-devils.
TankersOil tankers, also known as petroleumtankers, are ships designed for the bulktransport of oil.There are two basic types of oil tanker: the crude tanker and the product tankerCrude tankers move large quantities ofunrefined crude oil from its point of extractionto refineries.
TankersProduct tankers, generally much smaller, are designedto move petrochemicals from refineries to points nearconsuming marketsCrude oil tankers are used to transport crude oil fromfields in the Middle East, North Sea, Africa, and LatinAmerica to refineries around the world.Oil tankers are often classified by their size as well astheir occupation. Tanker sizes are expressed in termsof deadweight (dwt) or cargo tons. The smallesttankers are General Purpose which range from 10 to25,000 tons.
Tankers Types and Capacity The Large Range and Very Large Crude Carriers (VLCC) are employed in international crude oil trade.As of 2006: The world tanker fleet had 4,186 vessels with a carrying capacity of 358.8 Mdwt. 84% of the tanker fleet were owned by independent tanker companies. The average age of the fleet was 11.9 years. 68% of the vessels are double hull ships. Tankers move approximately 2 billion tons of oil every year. Second only to pipelines in terms of efficiency, the cost of tanker transport amounts to only two or three U.S. cents per gallon.
Tankers Types and CapacityThe Large Range and Very Large CrudeCarriers (VLCC) are employed in internationalcrude oil trade.As of 2006: The world tanker fleet had 4,186 vessels with a carrying capacity of 358.8 Mdwt. 84% of the tanker fleet were owned by independent tanker companies.
Tankers Types and Capacity The average age of the fleet was 11.9 years. 68% of the vessels are double hull ships.Tankers move approximately 2 billion tons of oilevery year. Second only to pipelines in terms ofefficiency, the cost of tanker transport amounts toonly two or three U.S. cents per gallon.
Tankers ArchitectureOil tankers generally have from 8 to 12 tanks.Each tank is split into two or three independentcompartments by fore-and-aft bulkheads.The tanks are numbered with tank one beingthe forward most.Individual compartments are referred to by thetank number, such as "one port", "threestarboard", or "six centre."
Tankers ArchitectureA cofferdam is a small space left open betweentwo bulkheads, to give protection from heat,fire, or collision. Tankers generally have cofferdams forward and aft of the cargo tanks, and sometimes between individual tanks.A pump-room houses all the pumps connectedto a tankers cargo lines. Some larger tankershave two pump-rooms. A pump-room generallyspans the total breadth of the ship.
Tankers Architecture (Hull Design)A major component of tanker architecture is thedesign of the hull or outer structure.A tanker with a single outer shell between theproduct and the ocean is said to be single-hulled.Most newer tankers are double-hulled, with anextra space between the hull and the storagetanks.
Tankers Architecture (Hull Design)Hybrid designs such as double-bottom anddouble-sided combine aspects of single anddouble-hull designs.All single-hulled tankers around the world will bephased out by 2026, in accordance with theInternational Convention for the Prevention ofPollution from Ships, 1973.
Tankers: Architecture (Hull Design)In 1998, the Marine Board of the National Academyof Science conducted a survey of industry expertsregarding the pros and cons of double-hull design.Some of the advantages of the double-hull designthat were mentioned include: ease of ballasting in emergency situations, reduced practice of saltwater ballasting in cargo tanks decreases corrosion,
Tankers: Architecture (Hull Design) increased environmental protection, cargo discharge is quicker, more complete and easier, tank washing is more efficient, and better protection in low-impact collisions and grounding.
Tankers: Architecture (Hull Design)The same report lists the following as somedrawbacks to the double-hull design: more expensive to build, more expensive in canal and port expenses, ballast tank ventilation difficult, ballast tanks need continual monitoring and maintenance, increased transverse free surface, more surfaces to maintain,
Floating, production, storage and Offloading (FPSO)Floating storage and offloading units or FSOs are usedworldwide by the offshore oil industry to receive oil fromnearby platforms and store it until it can be offloaded onto oiltankers.A similar system, the Floating production storage andoffloading unit, or FPSO, has the ability to process the productwhile it is onboard.These floating units reduce oil production costs and offer,mobility, large storage capacity, and production versatility.FPSO and FSOs are often created out of old, stripped-downoil tankers, but can be made from new-built hulls.
Floating, production, storage and Offloading (FPSO)Shell España first used a tanker as an FPSOwas in August 1977. An example of a FSO thatused to be an oil tanker is the Knock Nevis.These units are usually moored to the seabedthrough a spread mooring system.A turret-style mooring system can be used inareas prone to severe weather.This turret system lets the unit rotate to minimizethe effects of sea-swell and wind.
Tankers Floating, production,storage and Offloading (FPSO)
LNG TankersTankers equipped with pressurized, refrigerated, andinsulated tanks are used to transport natural gasliquids and liquefied natural gas (LNG).Natural gas is liquefied at the destination point andtransported by special LNG cryogenic tankers to itsdestination. At the delivery point the LNG isre-gasified and charged into a gas pipeline system.
LNG TankersIn order to liquefy the gas its temperature is loweredto -259°F (-162°C).Natural gas is kept in refrigerated and insulated tanksto maintain in its liquefied state during transport.