Introduction to Oil & Gas9th Week LectureByAP Dr Nasir ShafiqCivil Engineering DepartmentPipe Lines and Tankers

Learning objectivesThe objectives of this chapter is to give the basic understanding of the means of transportation of hydrocarbons, which are:Pipelines, andTankers

Learning outcomeAt the end of this chapter, students should be 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 to transport (move out) from one part of the world to the other.Why?How?

Why?

Oil & Gas value-chain

Why oil & gas are moved out?Natural gas and crude oil must be moved from the production site to refineries/gas processing plant and from there to consumers/end-users. Earlier slides show the worldwide oil & gas trade movement according to the consumption and demand in various countries/region.

How oil & gas are moved out?These movements (crude and/or refined products) are made using a number of different modes of transportation. Crude oil and refined products are transported across the water in barges and tankers and/or underwater pipelinesOn land crude oil and products are moved using pipelines, trucks, and trains.

How oil & gas are moved out?Similarly pipelines are used to move gas from 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 in areas not served by pipelines, the gas is liquefied to reduce its volume. When the gas is liquefied, it shrinks to l/600 of its gaseous volume.

Crude oil tanker

Oil pipeline

Oil pipeline

Pipelines DefinitionA pipeline system is defined as a pipeline section extending from an inlet point (may be an offshore platform or onshore compressor station) to an outlet point (may be another platform or an onshore receiving station).

Pipelines Definition

Pipelines types, classification and categoriesPipelines can be categorised as:Onshore, andOffshoreThe onshore and/or offshore pipelines have THREE (3) types:Trunk or gatheringTransmission or transportationDistribution

These lines are used to transport oil from field pressure and storage to large tank where it is accumulated for pumping into the long distance called trunk line.Gathering pipelines typically consist of lines ranging from 4- 8 inside diameter, operating pressure is higher than oil flow lines.Pipelines: Types

Gathering system throughput varies widely depending on:Number of field storage tanks.The producing capacity of well in each field.

Pipelines: Types

From large central storage, oil is moved through large diameter, long distance pipeline called trunk line to refineries. Pump are required at the beginning of the trunk line and pumping stations must also be spaced a long the pipeline to maintain pipeline pressure at the level required to overcome friction, change in the elevation and other losses.Trunk Lines

Crude trunk lines operate at higher pressure than gathering systems. These lines are made of steel and individual sections are joined by welding. These lines are almost buried below ground surface are coated externally to protect against corrosion.

Trunk Lines

Transmission/TransportationTransportation Pipelines - Mainly long pipes with large diameters, moving products (oil, gas, refined products) between cities, countries and even continents.

Transmission/TransportationThese transportation networks include several compressor stations in gas lines or pump stations for crude and multi-products pipelines.The large diameter may range from 24 to 60 inchesExample Trans ASEAN line

Distribution LinesDistribution Pipelines - Composed of several interconnected pipelines with small diameters, used to take the products to the final consumer. Feeder lines to distribute gas to homes and businesses downstream. Pipelines at terminals for distributing products to tanks and storage facilities are included in this group.

Distribution Lines

Oil PipelinesCrude oil is collected from field gathering systems consisting of pipelines that move oil from the wellhead to storage tanks and treatment facilities where the oil is measured and tested.Oil pipelines are made from steel or plastic tubes with inner diameter typically from 10 to 120 cm (about 4 to 48 inches). Most pipelines are buried at a typical depth of about 1 - 2 meters (about 3 to 6 feet).From the gathering system the crude oil is sent to a pump station where the oil delivered to the pipeline.

Oil PipelinesThe pipeline may have many collection and delivery points along route. Booster pumps are located along the pipeline to maintain the pressure and keep the oil flowing usually flows at speed of about 1 to 6 m/s. The delivery points may be refineries, where the oil is processed into products, or shipping terminals, where the oil is loaded onto tankers.

Oil PipelinesA pipeline may handle several types of crude oil. The pipeline will schedule its operation to ensure that the right crude oil is sent to the correct destination. The pipeline operator sets the date and place when and where the oil is received and when the oil will arrive at its destination. Crude oil may also move over more than one pipeline system as it journeys from the oil field to the refinery or shipping port. Storage is located along the pipeline to ensure smooth continuous pipeline operation.

Natural Gas PipelinesNatural gas pipelines are used to move gas from 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.For natural gas, pipelines are constructed of carbon steel and varying in size from 2inches (51mm) to 56inches (1,400mm) in diameter, depending on the type of pipeline.

Natural Gas PipelinesThe gas is pressurized by compressor stations and is odorless unless mixed with an odorant where required by the proper regulating body. Most natural gas pipelines operate using a complex have become so automated that they are capable of operating under command of a computer system that coordinates the operation of valves, prime movers, and conditioning equipment.

Pipelines ComponentsPipeline networks are composed of several pieces of equipment that operate together to move products from location to location. The main elements of a pipeline system are shown in the figure on the next slide.

Pipelines Components

Pipelines ComponentsInitial Injection Station - Known also as Supply or Inlet station, is the beginning of the system, where the product is injected into the line. Storage facilities, pumps or compressors are usually located at these locations.

Pipelines ComponentsCompressor/Pump Stations - Pumps for liquid pipelines and Compressors for gas pipelines, are located along the line to move the product through the pipeline. The location of these stations is defined by the topography of the terrain, the type of product being transported, or operational conditions of the network.

Pipelines ComponentsPartial Delivery Station - Known also as Intermediate Stations, these facilities allow the pipeline operator to deliver part of the product being transported.Block Valve Station - These are the first line of protection for pipelines. With these valves the operator can isolate any segment of the line for maintenance work or isolate a rupture or leak.

Pipelines ComponentsBlock valve stations are usually located every 20 to 30miles (48km), depending on the type of pipeline. Even though it is not a design rule, it is a very usual practice in liquid pipelines.The location of these stations depends exclusively on the nature of the product being transported, the trajectory of the pipeline and/or the operational conditions of the line.

Pipelines ComponentsRegulator Station - This is a special type of valve station, where the operator can release some of the pressure from the line. Regulators are usually located at the downhill side of a peak.

Pipelines ComponentsFinal Delivery Station - Known also as Outlet stations or Terminals, this is where the product will be distributed to the consumer. It could be a tank terminal for liquid pipelines or a connection to a distribution network for gas pipelines.

Pipelines InstallationOnshoreBuriedOverheadHanging

Buried Lines

Overhead Lines

Overhead Lines

Pipeline Bridge

Pipelines InstallationOffshoreOn sea floorBuried into a trench

Offshore Pipelines Installation

Offshore Pipelines Installation

Offshore Pipelines Installation

Pipelines InspectionCrude oil contains varying amounts of wax, or paraffin, and in colder climates wax buildup may occur within a pipeline. Often these pipelines are inspected and cleaned using pipeline inspection gauges pigs, also known as, scrapers or Go-devils.

Pipelines Inspection

TankersOil tankers, also known as petroleum tankers, are ships designed for the bulk transport of oil. There are two basic types of oil tanker: the crude tanker and the product tankerCrude tankers move large quantities of unrefined crude oil from its point of extraction to refineries.

TankersProduct tankers, generally much smaller, are designed to move petrochemicals from refineries to points near consuming marketsCrude oil tankers are used to transport crude oil from fields in the Middle East, North Sea, Africa, and Latin America to refineries around the world. Oil tankers are often classified by their size as well as their occupation. Tanker sizes are expressed in terms of deadweight (dwt) or cargo tons. The smallest tankers are General Purpose which range from 10 to 25,000 tons.

Tankers Types and CapacityThe 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 2billion 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 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.

Tankers Types and CapacityThe average age of the fleet was 11.9 years.68% of the vessels are double hull ships.Tankers move approximately 2billion 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 ArchitectureOil tankers generally have from 8 to 12 tanks.Each tank is split into two or three independent compartments by fore-and-aft bulkheads.The tanks are numbered with tank one being the forward most. Individual compartments are referred to by the tank number, such as "one port", "three starboard", or "six centre."

Tankers ArchitectureA cofferdam is a small space left open between two 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 connected to a tanker's cargo lines. Some larger tankers have two pump-rooms. A pump-room generally spans the total breadth of the ship.

Tankers Architecture

Tankers Architecture

Tankers Architecture (Hull Design)

Tankers Architecture (Hull Design)A major component of tanker architecture is the design of the hull or outer structure. A tanker with a single outer shell between the product and the ocean is said to be single-hulled.Most newer tankers are double-hulled, with an extra space between the hull and the storage tanks.

Tankers Architecture (Hull Design)Hybrid designs such as double-bottom and double-sided combine aspects of single and double-hull designs.All single-hulled tankers around the world will be phased out by 2026, in accordance with the International Convention for the Prevention of Pollution from Ships, 1973.

Tankers: Architecture (Hull Design)In 1998, the Marine Board of the National Academy of Science conducted a survey of industry experts regarding the pros and cons of double-hull design. Some of the advantages of the double-hull design that 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, andbetter protection in low-impact collisions and grounding.

Tankers: Architecture (Hull Design)The same report lists the following as some drawbacks 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 used worldwide by the offshore oil industry to receive oil from nearby platforms and store it until it can be offloaded onto oil tankers.A similar system, the Floating production storage and offloading unit, or FPSO, has the ability to process the product while 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-down oil tankers, but can be made from new-built hulls.

Floating, production, storage and Offloading (FPSO)Shell Espaa first used a tanker as an FPSO was in August 1977. An example of a FSO that used to be an oil tanker is the Knock Nevis.These units are usually moored to the seabed through a spread mooring system.A turret-style mooring system can be used in areas prone to severe weather.This turret system lets the unit rotate to minimize the effects of sea-swell and wind.

Tankers Floating, production, storage and Offloading (FPSO)

LNG TankersTankers equipped with pressurized, refrigerated, and insulated tanks are used to transport natural gas liquids and liquefied natural gas (LNG). Natural gas is liquefied at the destination point and transported by special LNG cryogenic tankers to its destination. At the delivery point the LNG is re-gasified and charged into a gas pipeline system.

LNG TankersIn order to liquefy the gas its temperature is lowered to -259F (-162C).Natural gas is kept in refrigerated and insulated tanks to maintain in its liquefied state during transport.