Age 10505

Note: The source of the technical material in this volume is the ProfessionalEngineering Development Program (PEDP) of Engineering Services.

Warning: The material contained in this document was developed for SaudiAramco and is intended for the exclusive use of Saudi Aramco’semployees. Any material contained in this document which is notalready in the public domain may not be copied, reproduced, sold, given,or disclosed to third parties, or otherwise used in whole, or in part,without the written permission of the Vice President, EngineeringServices, Saudi Aramco.

Chapter : Process For additional information on this subject, contactFile Reference: AGE10505 R.A. Al-Husseini on 874-2792

Engineering EncyclopediaSaudi Aramco DeskTop Standards

Supply and Distribution

Engineering Encyclopedia Process


Saudi Aramco DeskTop Standards

CONTENTS PAGES

DISTRIBUTION SYSTEMS ............................................................................................................1

Flowlines and Trunklines...................................................................................................1

Pipelines.............................................................................................................................1

Master Gas System ............................................................................................................3

The Economic Incentive ..........................................................................................3

Network...................................................................................................................4

East-West Pipeline .............................................................................................................7

Importance...............................................................................................................9

Capacities of the East-West Pipeline .......................................................................9

Marine Transportation .....................................................................................................12

Terminals...............................................................................................................12

Shipping ................................................................................................................21

Export Patterns ......................................................................................................22

PLANNING AND SCHEDULING .................................................................................................27

Short Range Planning and Scheduling.............................................................................27

Planned Shutdowns ...............................................................................................28

Unplanned Shutdowns or Disruption ....................................................................28

Long Range Operating Plans ...........................................................................................29

Production .............................................................................................................29

Gas Recovery ........................................................................................................30

Supply and Distribution.........................................................................................30

Refining.................................................................................................................32

Downstream Integration ........................................................................................32



Saudi Aramco DeskTop Standards

MEASUREMENT OF HYDROCARBON .....................................................................................33

Need for Accuracy ...........................................................................................................33

Variables Affecting Measurement Accuracy....................................................................34

Volume Measurement ...........................................................................................34

Temperature...........................................................................................................36

Contaminants.........................................................................................................38

Pressure .................................................................................................................38

Ship loading ..........................................................................................................38

Ship Discharge ......................................................................................................38

GLOSSARY....................................................................................................................................39



Saudi Aramco DeskTop Standards 1

distribution systemsDistribution systems are required to transport oil and gas in an efficient, reliable, and controllable manner. Themajor systems used by Saudi Aramco are:

• Crude gathering and distribution systems

• Master Gas System

• East-West pipeline

• Marine transportation

Crude Gathering and Distribution SystemsSaudi Aramco has over 1,400 producing oil wells which must be connected to GOSPs which, in turn, areconnected to stabilizers, refineries, pipelines, and/or terminals.

Flowlines and TrunklinesThe first links in the chain of these facilities are the pipelines known as flowlines that carry the crude, which isstill under moderate to high pressure, from the wellhead to centrally located GOSPs. Two or more flowlines areoften connected into another pipeline, known as a trunkline, to carry the crude to the GOSP. Aramco has builtover 4,000 kilometers of flowlines and trunklines ranging from 4 to 24 inches in diameter for gathering andtransporting the oil to the GOSPs. (For offshore fields, much larger sized trunklines are used to carry the crudefrom well platforms to either offshore or onshore GOSPs.)

PipelinesAs the GOSPs are normally located away from the oil processing centers, a system of pipelines has beenconstructed to transport the oil from the GOSPs to processing plants like those at Abqaiq and then on to theloading terminals at Ras Tanura, Ju’aymah, and Yanbu.

Saudi Aramco operates 9,000 kilometers of hydrocarbon pipelines, excluding flowlines, ranging from 8 to 56inches in diameter.

Pumping facilities are located at gathering and distribution points throughout this pipeline system to provide theenergy input necessary for transporting the oil to the next step in its gathering and processing. Saudi Aramco’slargest pump station is located at Abqaiq, where six shipping pumps are driven by 12,500-hp steam turbines.




Major crude processing facilities, some of which have been discussed in previous modules, include thespheroids and stabilizers at Abqaiq, Ju’aymah, and Ras Tanura. In these facilities, the pressure of the producedcrude is reduced and escaping gases are collected, treated, and processed. The crude, at lower pressure withoutthe high volume of dissolved gas, is now ready for further processing and is pumped to a refinery, pipelinesystem, or export terminal.

Taken together, all of the component facilities described above are integrated in the Crude Gathering Network.The relationship of wells in several major fields to the GOSPs, stabilizers, refineries, and terminals is shown inFigure 1.

FIGURE 1. Crude Gathering Network




Master Gas SystemThis system was commissioned in 1982 to recover and make efficient use of the gas produced by SaudiAramco. The entire Master Gas System was developed and designed to implement the Kingdom’s plan to useits oil and gas resources as the base for industrialization and economic diversification.

Components of the system include tie-ins to over 60 GOSPs, three new gas processing plants at Berri,Shedgum, and Uthmaniyah, two NGL fractionation plants at Ju’aymah and Yanbu, and the necessaryinterconnecting pipelines.

The Economic IncentiveGas that is produced with crude oil is known as associated gas. This gas, which is held in solution in the crudeoil by the high pressure of the reservoir, is separated from the oil in the GOSPs and spheroids. Both thedepressured oil and the separated gas can be treated, processed, and exported. The gas contains four primarycomponents: methane, ethane, propane, and butane.

Before the Master Gas System was commissioned, gas from the GOSPs was generally flared, in which casethere was no opportunity to sell the gas.

Beginning in 1959, there was some low pressure NGL recovery from spheroids, crude stabilizers, tank farms,and refinery off gases. This gas was recovered for use as fuel. While the value of gas as fuel was significantlygreater than the zero value of flared gas, it was still much below the value that could be attained from upgradingthe gas to chemical feedstocks and LPG.

The Master Gas System, which cost several billion dollars to construct, was justified on three primary bases:

• As a cost effective source of feedstocks and fuel for a variety of domestic industries and utilities

• As a means to expand NGL exports to meet international demands

• As an opportunity to recover sulfur to protect the environment




Feedstocks and Fuel - Downstream industries and utilities could be built and operated using theseparated components of the gas as feedstocks and fuels. Methane is recovered and used as fuel forboth industries and utilities. The primary chemical feedstock is ethane, which is purchased by thepetrochemical plants at Jubail and Yanbu for the manufacture of ethylene, polyethylene, and glycol.Secondary industries, which use the products of the basic petrochemical plants as their feedstocks, arenow being developed. An example is the manufacture of plastic containers from the polyethylene.Not only does Saudi Aramco obtain a higher value for ethane as a petrochemical feedstock, but theKingdom achieves a higher degree of vertical manufacturing integration and self-sufficiency.

NGL Exports - The growing international market for NGL provided a natural attraction for SaudiAramco, which had little domestic demand for propane and butane.

The construction of NGL fractionation plants and terminals on both the Arabian Gulf and Red Seaensured a dependable source of feed to international markets and provided a measure of security andflexibility to Saudi Arabia.

Sulfur Recovery - Flaring of sour gas was reduced, and in many cases eliminated, as the gas wasrecovered and processed. This reduction directly reduced emissions of sulfur compounds to theatmosphere, providing a measure of protection for the environment.

Summary - The Master Gas System now provides a clean, low cost supply of fuel and feedstocks forthe domestic industrialization program, a dependable source of energy and feedstocks for internationalmarkets and strategic security and flexibility which ensures a secure supply to major internationalconsumers.

NetworkThe gas plants and NGL fractionation plants have important roles in the Master Gas System network. Thedetails of the operation of these plants have been discussed in a previous module. In this section, we willdiscuss their functions and effects on the Master Gas System.




Feed for the Berri, Shedgum, and Uthmaniyah gas plants comes from the sources shown in Figure 2.

Gas Plant Feed Rate Source of Feed

Berri 400 mm SCFD Berri Field

Shedgum 1.5 mm SCFD Shedgum GOSPs (Ghawar Field)‘Ain Dar GOSPs (Ghawar Field)Abqaiq Plants

Uthmaniyah 1.5 mm SCFD Uthmaniyah GOSPs (Ghawar Field)Haradh GOSPs (Ghawar Field)Harmaliyah Field

While continuing to use the same gas processing facilities, Saudi Aramco moved on to the secondphase of gas recovery, involving collection of associated gas from the production in the Safaniyah,Zuluf, and Marjan Fields in the northern sector, increased recovery from the Berri Field, and collectionof gas from the Khurais field in the interior.

FIGURE 2. Gas Plant Feed Sources




Future development plans include the development of non-associated gas, such as that from the KhuffField, as a back-up for the Master Gas System, and to continue the program of industrial development.

NGL Balance - NGL produced from Shedgum and Uthmaniyah is processed in the Ju’aymah orYanbu fractionation plants before being sold to downstream users. This balance and the role of theEast-West pipeline is shown in Figure 3.

FIGURE 3. NGL Balance




East-West PipelineThe pipeline, commissioned in 1981, consists of two parallel pipelines: one for crude and one for NGL. SaudiAramco manages and operates these two lines and also has the responsibility to operate the IPSA (Iraqi PipelineTrans Saudi Arabia).

The East-West Pipeline is the most advanced computer-monitored hydrocarbon pipeline ever built. Featuresinclude a supervisory control system located in the Central Dispatch Center in Dhahran. Here, the dispatcherreceives information from 38 locations along the line, which is transmitted back via microwave. The line isfitted with remotely controlled valves which can be operated from Dhahran in case of an emergency. The routeof the pipeline is shown in Figure 4.




FIGURE 4. Route of the East-West Pipeline




ImportanceThe pipeline is now a critical part of the distribution system for Saudi Aramco. The main functions are:

• Crude supply for local refineries. Both refineries at Yanbu, Pemref and YPR, rely on their feed supplyfrom the pipeline. This is a total of 470 TBD.

• Crude supply for other nearby refineries. Tankers lift crude oil from the Yanbu Terminal to refineries inRabigh and Jeddah, totaling 385 TBD.

• Crude export via the Yanbu Export Terminal of up to 2,700 TBD.

• Supply of NGL to the Yanbu NGL plant up to 300 TBD.

• Supply of ethane to YANPET via Yanbu NGL plant for polyethylene manufacture.

• Supply of fuel gas for local Yanbu usage via Yanbu NGL plant.

Capacities of the East-West PipelineThe Crude Oil Pipeline - This 1,200 km pipeline runs from Abqaiq to Yanbu. The 48-inch (122 cm)diameter line has a current capacity of 3,200 TBD of Arabian Light crude. It is looped with a 56-inchline between pump stations. This line has 11 pump stations from the East Coast and descends into theYanbu region from a 1,300-ft elevation.

An expansion project will boost the capacity to a total of 5,000 TBD and will provide tie-ins to allowshipment of Arabian Heavy in addition to Arabian Light crude. Figure 5 shows the planned capacitiesof the expanded East-West Crude pipeline as well as a schematic layout of a typical pump station.




NGL Line - This 1,170-km pipeline runs from Shedgum to Yanbu. The line varies from 26- to 28- to30-inch diameters. The current capacity is 300 TBD and is designed to permit expansion by 50% ifneeded.

FIGURE 5. Pipeline Schematic




Summary - A summary of the pipeline capacities is shown in Figure 6.

Name Terminals Capacity Size Remarks

East-West CrudePipeline

Abqaiq to Yanbu 3.2 MM bbl/day • 1200 km long

• 48-inch line

• Eleven pumpstations with 56-inch loopsbetween stations

• Flow is about4 mi/hr(6.4 km/hr)

• Super pumpproject to increasecapacity to5.0 MM bbl/day

East-West NGLPipeline

Shedgum to Yanbu 0.3 MM bbl/day • 1170 km long

• 26-, 28-, 30-inchline

• Readily expand to450 TBD

Iraqi-Saudi ArabianPipeline (l)

From Iraq to PumpStation #3 of East-West CrudePipeline

0.5 MM bbl/day 48-inch line • Iraq limited to350,000 bbl/day

• Iraqi crude is timesequenced (notmixed with Saudicrude)

New Iraqi-SaudiArabian Pipeline (ll)

Pump Station #3 ofEast-West CrudePipeline to Red Sea(20 km south ofYanbu)

1.6 MM bbl/day To be completed in1990

Tapline Ras Tanura toJordan

0.5 MM bbl/day • Built in 1948

• Averagethroughput (1986)was 70,000bbl/day (ArabianLight)

SUMED Ain Sukhna to SidiKerir

1.6 MM bbl/day Two parallel 42-inch lines

• Running at 70-80% capacity

• Ownership:

- PETROMIN 15%

- ADNOC 15%- Kuwait 15%- Qatar 5%- Egypt 50%

FIGURE 6. Middle East Pipelines




Marine TransportationMarine liftings are very important to Saudi Aramco as 80-85% of the crude produced is exported by ship. As aresult, Saudi Aramco has the largest marine terminals in the world.

Saudi Aramco also owns and charters many tankers, particularly VLCCs for crude transport.

TerminalsSaudi Aramco terminals are all characterized by ultra-large equipment. All terminals must handle largevolumes of hydrocarbon and must be capable of loading large tankers quickly and safely.

Due to the size and number required, the tankage at all terminals is a major investment. One large crude tankmay cost over $250 million.

Three terminals are used for loading ships with crude or other products. They are:

• Ras Tanura

• Ju’aymah

• Yanbu

Ras Tanura Terminal was the first marine terminal in Saudi Aramco and was commissioned in 1939.It has been expanded and updated to meet increased production requirements and to conform tomodern engineering standards. The Terminal now consists of

• 4 tank farms

• 18 loading berths

• 41 loading lines




The terminal layout is shown in Figure 7.

FIGURE 7. Ras Tanura Terminal Layout




The four tank farms store both crude oil and refined products, and are capable of loading them out totankers at a high rate. This is summarized in Figure 8.

Terminal North Terminal South Plant 59

Crude Product

Number of tanks 6 49 36 13

Total capacity, MMB 7

Tank size, MB 1,000 - 1,250 150 - 1,500 8 - 600 75 - 925

Loading rate, 1,000 bph 140 120 15 each line 20

Number of export gradesshipped

CrudeNaphtha

43

Products handled

GasolineKeroseneJet FuelWhite DieselBlack DieselFuel OilC3 LPGC4 LPG

xxxxxx

xx

FIGURE 8. Ras Tanura Tank Farms




Floating roof tanks are used for crude storage. These tanks minimize breathing losses and make thetank safer. As shown in Figure 9, the roof floats with the aid of buoyancy from the pontoons.

Refrigerated tankage is used for LPG. Economically, it is cheaper to store large volumes of LPG atlow pressure/refrigerated temperatures than at high pressure/ambient temperatures. Refrigerated, orcryogenic, tanks need to be fabricated with special alloys and techniques depending on the lowesttemperature used. Refrigerant is often the product itself being stored. A typical process flow diagramis shown in Figure 10.

FIGURE 9. Floating Roof Tank




Refrigerated storage is also used in the NGL terminal. Typical pressure/temperature conditions inrefrigerated storage in Saudi Aramco are shown in Figure 11.

Service Pressure (psig) Temperature (°F)

C2 1 -125

C3 0.5 -45

C4 0.5 25

The capacity of tankers that can be accepted at Ras Tanura depends on the berth. Only the Sea Islandscan accept ULCCs of up to 520,00 DWT. The South and the North Piers accept product tankers, andthe North Pier can take RLPG tankers.

FIGURE 10. Process Flow Diagram for Refrigerated LPG Storage

FIGURE 11. Typical Refrigerated Tankage Conditions




A summary of the berthing capabilities is shown in Figure 12.

Berths and otherInformation

South Pier North Pier Sea Islands

Crude x x x

Product x x -

RLPG - x -

Total 4 6 8

Maximum tanker size,‘000 DWT

30 100 500

Water depth 32 42 85

Ju’aymah Terminal, 15 miles north of Ras Tanura, has one large tank farm connected to a largeloading system 7 miles offshore. This is shown in Figure 13.

FIGURE 12. Ras Tanura Loading Berths

FIGURE 13. Ju’aymah Terminal




Tankage consists of 19 tanks for crude oil and 3 for bunker fuel oil. The crude tanks are up to 1.5million barrel capacity, making them some of the largest floating roof tanks in the world.

The pumping, although on a large scale, is typical of many ship loading operations. The pump sets areshown in Figure 14 below:

FIGURE 14. Typical Shipping Pump Set




The booster pump is located close to the loadout tanks in order to obtain good suction. They are highvolume, low head pumps. The shipping pump is a high volume, high head pump and requires abooster pump in series on the suction side to provide adequate NPSH. They can be run in almost anycombination to provide a variety of flow rates. An example of this is shown in Figure 15.

Pumps Operating

Case A Case B Case C

Booster 13,000 HP

x x x

Booster 23,000 HP

x

Shipping Pump 116,000 HP

x x

Shipping Pump 216,000 HP

x

Load out rate, mb/hr 40 65 130

Control rooms are located both onshore and offshore. The offshore control platform is linked to an oilmetering platform for royalty gauging of crude exported and provers to test the meter accuracy.

FIGURE 15. Loadout Configurations




A tanker loading at Ju’aymah ties up to one of six single-point mooring (SPM) systems about 8,000feet from the metering platform. Each system has two 42-inch crude oil loading lines and one 16-inchbunkering line with loading rates up to 140,000 barrels per hour. The loading lines from the oilplatform to each SPM buoy lie on the sea bottom. The lines from the buoy to the tanker float. Thetanker crew lifts them aboard with a ship hose boom after the tanker ties up to the SPM buoy. Waterdepth exceeding 100 ft can berth the largest tanker afloat today.

Yanbu Terminal is both a crude oil and an NGL terminal. Arabian Light crude arrives by pipelineand is distributed to Pemref, YPR, and export tankage. Crude for export is stored in 12 large-diametertanks totaling 12.5 million barrels and can be loaded on board ship at a rate of 150,000 barrels perhour. The crude berths have a 120-ft water depth and can accommodate tankers up to 500,000 DWT.Layout of the terminal is shown in Figure 16.

The NGL terminal stores and loads out ethane, propane, butane, and naphtha. Products are loaded outto 2 berths at 30 mb/hr. The LPG is stored in refrigerated tankage.

FIGURE 16. Yanbu Crude Oil Terminal




The relationship of the Yanbu NGL Plant and Terminal with surrounding industries is shown in Figure17 below.

ShippingSaudi Aramco has its own fleet of crude carriers which it owns and operates through a subsidiary company.This fleet is expanding with new VLCC additions planned for 1993, 1994, and 1995. This is shown in Figure18.

Status Number MDWT

Present Fleet 7 230-418

Additions:

199319941995

246

300300300

FIGURE 17. Yanbu NGL Plant and Surrounding Industries

FIGURE 18. VELA Fleet




In addition to these tankers, VELA also charters 10-15 VLCCs and 10-15 ULCCs. VLCCs have been chosenfor most of the fleet. They achieve most of the economics of scale associated with bulk carriers, but are stillable to berth at most locations. VLCCs can be used where the draft of the receiving port permits. Thedifferences between VLCCs and ULCCs are shown in Figure 19.

Statistic VLCC ULCC

MDWT 160/320 320/550

Draft, ft 65 75

Length, ft 1145 1240

Beam, ft 170 227

Typical Cost, $ million

-Single-hulled-Double-hulled

100120

Not available

Charter rates, $’000/day 30-40 35-45

Almost all the large tankers being newly constructed are VLCCs as their flexibility outweighs the slightly lowertransport costs of the ULCC. Note that Saudi Aramco is buying only VLCCs to add to its fleet, but it doescharter ULCCs.

Export PatternsThe scheduling of marine transport of crude oil and hydrocarbon products is continually optimized. Majorconsiderations are the material to be exported, restrictions due to port or product availability, tanker route,discharge port limitations, and transportation economics.

FIGURE 19. Comparison Between VLCCs and ULCCs




Exports - In 1990, a total of 2,350 ships were loaded at Saudi Aramco terminals. These shipstransported over 17 billion barrels of crude and 193 million barrels of NGL to markets worldwide in1990. The distribution of products is shown in Figure 20.

FIGURE 20. Distribution of Saudi Aramco Exports in World Markets




Additional exports of intermediate and finished products from the Saudi Aramco refinery at RasTanura and from the export refineries at Jubail, Yanbu, and Rabigh are not included in the figures citedabove. Product exports are shown in Figure 21.

Gasoline 64 TBD

Naphtha 136 TBD

Distillates 315 TBD

Fuel Oil / Asphalt 264 TBD

Total 779 TBD

Restrictions - Tanker loading at any of Saudi Aramco’s terminals must take into account a number offactors, including several that deal with the terminals themselves, such as product availability, loadingrate, berth availability, and draft. A summary of these factors is shown in Figure 22.

Terminal Products Available Loading Rate(TBH)

Berths (No.) Draft (ft)

Ras Tanura

Sea IslandsNorth PierSouth Pier

Crude, ProductsCrude, NGLProducts

140120 (crude)

20

864

85-9042-5032-33

Ju’aymah

SMBsLPG Jetty

Crude

NGL

140

30

6

2

120

N.A.

Yanbu

Crude OilTerminal

NGL Terminal

Crude

NGL

150

30

2

2

120

120

FIGURE 21. Product Exports, 1990

FIGURE 22. Restrictions at Saudi Aramco Terminals




Additional restrictions come from the tankers themselves, including

• Draft required when fully loaded

• White or black oil cargo carrier

• Ability to segregate multiple products

Still further complicating the matter is the route the tanker must take to reach its destination. This mayrequire a comparison of the volume delivered in a large vessel traveling around Africa to Europe with ashorter voyage for a smaller vessel that can pass through the Suez Canal.

Considerations at the proposed discharge port are virtually the same as those at the loading terminal.

After all the matters discussed above have been considered, the optimum combination is proposedbased on overall transportation economics.

Economics - Generally, the larger the tanker, the lower the cost to transport per barrel of crude orproduct. As mentioned previously, Saudi Aramco charters VLCCs (up to 320 DWT) and ULCCs(320-550 DWT vessels) but is purchasing only VLCCs because of their added flexibility compared toULCCs.

The economics of a voyage are based on several items including the cost to operate the ship on a dailybasis, time required for the voyage, and the timing required for product delivery. Comparison ofshipping options leads to the optimum choice. A variety of vessels are compared in Figure 23.

Category MDWT Draft (ft) Speed(knot)

Length(ft)

Beam (ft)

General Purpose 16.5 32.6 15 556 72

Medium Range 25 38.0 16.5 710 93

Large Range I 45/80 39.5 16.5 755 108

Large Range II 80/160 55.2 15.8 855 133

Very Large CrudeCarrier (VLCC)

160/320 65.6 16 1145 170

Ultra Large CrudeCarrier (ULCC)

320/550 75.4 15.3 1240 227

FIGURE 23. Tanker Size - Sample Vessels




Two additional economic factors are of importance to the vessel and terminal decision. The cost ofcrude at Yanbu is $0.35/bbl greater than at the Gulf terminals due to pipeline tariff and terminal pilotcharges. Also, the cost of potential delays, which must also be paid should the vessel be unable to loador unload upon arrival in port, must be considered. The cost of any delay is known as demurrage.Typical demurrage rates are shown in Figure 24.

Vessel Size (DWT) $/Day

20,000 4,000

40,000 9,000

65,000 15,000

120,000 25,000

225,000 45,000

400,000 80,000

FIGURE 24. Sample Daily Demurrage Rates




PLANNING AND SCHEDULINGShort range planning and scheduling is required within Saudi Aramco to ensure continuity of crude and productsupply and in order to maintain planned production rates and objectives. Planning and scheduling generallyinvolves the solution of complex problems in order to arrive at an optimum mode of operation for theinterrelated systems operated by Saudi Aramco.

Short Range Planning and SchedulingSaudi Aramco has a special department called OSPAS (Oil Supply Planning and Scheduling) to organize:

• Gas supply and distribution

• Oil supply and distribution

• Refinery NGL planning

• Terminal planning

• Engineering

These divisions work directly with field units such as GOSPs, pipelines, terminals, and plants to gather data andimplement plans.

OSPAS will work with other departments to ensure processing objectives are met. They will continuouslyreview:

• Maintaining adequate feed to all plants

• Maintaining liftings or product distribution for each plant so that it can continue at planned rates

• Maintaining supplies of product to downstream users and customers

• Maintaining adequate inventory for tanker liftings

• Rescheduling tanker liftings




Planning concerns can be caused by

• Planned shutdowns

• Unplanned shutdowns or disruptions

Planned ShutdownsThese are coordinated by OSPAS with all departments concerned. This will include:

• T & I’s

• Facility tie-ins that require a shutdown

• Regenerations of catalyst

As an example, a shutdown of the East-West pipeline for tie-ins may cause problems as follows:

• Yanbu tankage can supply the 4 refineries for 10 days only

• Production cutbacks at Abqaiq would be needed as the extra crude normally going to Yanbu cannot allbe routed to Ras Tanura and Ju’aymah

Unplanned Shutdowns or DisruptionThese are the most disruptive to planning and require immediate action. Typical examples are:

Reduced plant capacity - A fire at a plant may temporarily reduce capacity and flexibility.Sometimes it may result in many months down time before repairs or replacements can be made.

Crude ship delays may be caused by weather or late arrival. This may result in production cuts whichin turn affect:

• Master Gas System

• NGL availability

• Fuel gas sales

• LPG supply

When this occurs, gas-only fields like Khuff can reduce the associated problems.




Long Range Operating PlansSaudi Aramco prepares and updates its 5-year objectives on an annual basis. These include crude production,gas recovery, marketing strategies, flexibility, and downstream integration objectives. Evaluation of theseobjectives allows Saudi Aramco to identify the projects that are required for the implementation of theobjectives. Because of the scale of Saudi Aramco’s operations, most projects identified are large andexpensive. In this section, we will review a number of current objectives and the projects announced for theirimplementation.

ProductionFor 1992, a crude production target of 10 million barrels per day has been established. Comparison of thistarget with recent historical production is shown in Figure 25.

1992 Production Target 10.0 MM B/D

1989 Average Production 4.9 MM B/D

1990 Average Production 6.3 MM B/D

1990 Year-End Production 8.5 MM B/D

A number of projects have been identified that, when implemented, will allow Saudi Aramco to reach andmaintain production at this target level. Production was quickly increased from 5 million barrels per day inFebruary, 1991 to over 8 million barrels per day by starting production and restreaming mothballed facilities,such as

• 6 of 7 GOSPs restarted in Khurais field

• Upgrading of mothballed facilities in Marjan and Zuluf offshore fields which will eventually increaseproduction from these fields to a total of 1.5 million barrels per day

Longer term projects include development of the Arab Superlight fields south of Riyadh. The four fields:Hawtah, Dilam, Rabigh, and Nuayyim, will produce a combined total of 195 TBD by 1995.

Additional fields, such as El Haba, Saban, Watban, and Faudah are targeted for further development and will beproducing to the crude gathering systems by the late 1990s.

FIGURE 25. Crude Oil Production




Saudi Aramco is investigating new technology which may allow two-phase flow of crude and gas from theoffshore fields and which, if successful, would eliminate the need for expensive offshore GOSPs.

Exports of crude will reach 8.4 million barrels per day, matching the 10.0 million barrels per day productionlevel.

Gas RecoveryExpansion of the Master Gas System to recover gas previously not included in the system as well as gas fromthe restarted production facilities has also begun. Additional gas processing facilities may be required in thefuture.

Supply and DistributionMajor projects in the S & D area include those shown in Figure 26.

• East-West crude pipeline “superpump”project

– Increase capacity to 5.0 million barrels per day– Tie-ins to allow transport of Arabian Heavy in 48-inch line

• Yanbu crude oil terminal expansion

– Additional crude tank (1.5 million barrels)– Fourth loading berth– Expansion of existing berth to accommodate largest ULCCs (500 DWT)

• Additional crude ships

– 6 VLCCs on order– 6 VLCCs planned for 1995

• Domestic product supply

– Modification of Ras Tanura refinery– Processing agreements

FIGURE 26. S & D Projects




The modifications to the East-West crude pipeline and expansion of the Yanbu COT will greatly increase theKingdom’s flexibility and security in maintaining crude oil deliveries.

The domestic demand for products is expected to continue growing. The existing domestic refineries cannotmeet this demand without significant capital expenditures for additional processing facilities. The domesticsupply and demand forecast is shown in Figure 27.

Supply, TBD Demand, TBD

Gasoline

1985199019952000

150156156156

(Summer - Winter)

150 - 150160 - 170160 - 200165 - 230

Distillates

1985199019952000

320320320320

340 - 355345 - 390365 - 425380 - 460

Alternative for making up shortfall:

• Gasoline - Reforming (CCR)IsomerizationFCC

• Distillates - HDCIncreased crude runs

• Processing Agreement (Italian Refinery)Transportation costs:

Crude from Ras Tanura to Italy - $0.70/bblProducts from Italy to Ras Tanura - $1.20/bbl

The primary option for meeting increasing product demand is to modify and upgrade the facilities at the RasTanura refinery to increase premium product production without processing additional crude.

FIGURE 27. Domestic S & D Forecast




RefiningThe current project underway to upgrade the Ras Tanura refinery to a full conversion refinery will be one of thebiggest in Saudi Aramco history. Several major units will be added in four phases of this project, valued at $3to $4 billion.

Ras Tanura will become a major export refinery, able to supply Europe, the U.S., and Far East markets.

Units to be added include Vacuum Distillation, Catalytic Cracking, Alkylation, Isomerization Hydrocracking,Continuous Reforming, Hydrotreating, and Coking. These processes will be discussed in detail in Module 6,New Technology.

Downstream IntegrationSaudi Aramco has positioned itself as a major worldwide product supplier. The Petromin-Mobil Refinery atYanbu and the Petromin-Shell Refinery at Jubail are modern cracking refineries, producing large volumes ofintermediate and finished products.

Outside the Kingdom, Saudi interests have purchased 50% of Texaco’s refining and marketing system on theU.S. East and Gulf coasts, creating Star Enterprises.

In 1991, Saudi Aramco purchased 35% of Sang Yong Refining and Marketing in Korea. This purchaseguarantees an outlet for over 200 TBD of crude and strengthens Saudi Aramco’s position as a product supplier.




MEASUREMENT OF HYDROCARBONMeasurement of hydrocarbon volumes is, of course, the basis for calculating Saudi Aramco’s revenues.Measurement needs to be accurate and reliable despite the irregularities that frequently occur.

This section examines the economic incentive to improve measurement accuracy, the variables affectingaccuracy, and how they are measured and compensated.

Need for AccuracyMeasurement should be 100% accurate, but invariably it always has a small associated error. This small error,when applied to large volumes, represents an enormous amount of money. For example, the value of 1/2%error is shown for several Saudi Aramco volumes in Figure 28.

Type Million $ Per Year

Crude:

RT refinery feedEast-West pipelineTotal production

17110280

NGL exports 30

One crude tanker holds a multimillion-dollar cargo. The importance of accurately measuring its cargo isindicated by the value of 1/2% error in Figure 29.

Type $ Per Cargo

VLCC 200,000

ULCC 270,000

These values justify sophisticated facilities and rigorous procedures to improve measurement accuracy. As aresult, Saudi Aramco has staff groups dedicated to measurement and loss control. For example, the Meters andMeasurement Group at Ras Tanura Terminal is responsible for custody transfer and legal claims for shiploading.

FIGURE 28. Measurement Error of 1/2%, Million $ Per Year

FIGURE 29. Value of 1/2% Measurement Error, $/Cargo




Variables Affecting Measurement AccuracyThe following variables affect the quantity measured:

• Volume

• Temperature

• Contaminants

• Pressure

Volume MeasurementFinal volumes used for custody transfer are the result of a reconciliation between at least two volumemeasurements with corrections being made where necessary for temperature, pressure, contaminants, andgravity.

Independent arbitrators are often used to compute the official volumes/weights used in the custody transferbetween seller and buyer. Their typical duties are to witness measurements, ensure that sound measurementpractices are followed, and calculate or check the final quantities.

Tank measurement is a major method used both onshore and on board tankers. The volume can bemeasured by innage or outage gauging as shown in Figure 30.

FIGURE 30. Innage and Outage Gauging




This procedure requires that each tank be calibrated or strapped to be able to relate a liquid height witha volume. The liquid height can be measured by manual gauging or electronically (Remote TankGauging). The errors that may affect accuracy include:

• Fluctuating liquid level

• Tank distortions

• Liquid stratification

• Sludge buildup

• Water present

Meters provide dynamic measurement of hydrocarbon as it is pumped. Meters, whether they areturbine or positive displacement, require a proving system which is used to check meter accuracy andprovide a meter factor. The errors that may affect the accuracy of meter measurement may include:

• Line contaminants

• Pump cavitation – often at high rates from low tanks

Reconciliation between tank volumes and meter volume with the best equipment and procedures areless than 0.025%. However, discrepancies of 0.1 - 0.2% are often seen as a result of poor operatingpractices or inadequate maintenance.




TemperatureHydrocarbon expands as it is heated, so that gravity and volume must be corrected for temperature. A standardtemperature of 60 °F is adopted in the industry.

Similarly, API gravity will need to be corrected for temperature. A typical table of correction factors is shownin Figure 31.

API Gravity at Observed Temperature

38.0 38.5 39.0 39.5 40.0

Temperature, °°F Corresponding API Gravity at 60 °°F

120.0 33.5 33.9 34.4 34.9 35.3

120.5 33.4 33.9 34.4 34.8 35.3

121.0 33.4 33.8 34.3 34.8 35.2

121.5 33.3 33.8 34.3 34.7 35.2

122.0 33.3 33.8 34.2 34.7 35.2

122.5 33.3 33.7 34.2 34.7 35.1

123.0 33.2 33.7 34.2 34.6 35.1

123.5 33.2 33.7 34.1 34.6 35.1

124.0 33.2 33.6 34.1 34.6 35.0

124.5 33.1 33.6 34.1 34.5 35.0

125.0 33.1 33.5 34.0 34.5 34.9

Example: A sample of crude oil has an API gravity of 39 at 121 °F. What is the API gravity correct to 60 °F?

Answer: From the table, using 39.0 °API and 121 °F, the API gravity at 60 °F is 34.3.

FIGURE 31. API Gravity Correction Table




Correction factors are applied to measured volumes to produce an equivalent volume at 60 °F. A table ofconversion factors is shown in Figure 32.

API Gravity at 60 °F

33.0 33.5 34.0 34.5 35.0

Temperature, °F Volume Correction Factor

120.0 .9725 .9724 .9723 .9722 .9721

120.5 .9723 .9721 .9720 .9719 .9718

121.0 .9720 .9719 .9718 .9717 .9716

121.5 .9718 .9717 .9716 .9715 .9713

122.0 .9716 .9715 .9713 .9712 .9711

122.5 .9713 .9712 .9711 .9710 .9709

123.0 .9711 .9710 .9709 .9708 .9706

123.5 .9709 .9708 .9706 .9705 .9704

124.0 .9706 .9705 .9704 .9703 .9702

124.5 .9704 .9703 .9702 .9701 .9699

125.0 .9702 .9701 .9699 .9698 .9697

Example: The volume correction factor for the crude oil sample that had an API gravity of 34.3 (corrected to60 °F) and was at 121 °F would be 0.9717.

Temperature can be measured accurately with a manual thermometer or electronic means. The errors that mayaffect accuracy are:

• Non-uniformity of temperatures in a tank or pipeline

• The hydrocarbon may be of unusual composition, for example, highly aromatic, and its expansion maynot be accurately represented by the normal tables

FIGURE 32. Volume Correction Table




ContaminantsOil is sold on a dry, solids-free basis. To correct the oil volume to this basis, the water and solids content mustbe measured. The difficulties in obtaining an accurate result are mainly in obtaining a representative sample.Special in-line samples are used to continuously sample the contents of a pipeline. Tests used are:

• Karl Fischer test for water

• B S & W centrifuge test for sediment and water

PressureWhere fluids are compressible, a correction may need to be made for pressure, for example, a fuel gas. Thestandard condition is one atmosphere.

Ship loadingWhere possible, meters are used for custody transfer if the shore tanks are floating, that is, if the tanks arereceiving products while the ship is being loaded. Three measurements of the sales volume are possible, asshown in Figure 33:

Ship DischargeNormally, the shore tanks are used to measure crude receipts. These receipts are typically 0.2 to 0.3% less thanthe loaded volumes. Losses of this type are known as In-Transit losses and can usually be reduced byimproving custody transfer procedures.

FIGURE 33. Three Methods of Measuring Volumes




glossaryberth Any place or area where a ship anchors to receive or discharge cargo.

booster pump A large pump with high volume and low discharge pressure, used to feed ashipping pump.

B S & W An abbreviation for Bottoms Sediment and Water, volumes of both of whichmust be discounted when calculating crude sales volumes.

cryogenic Refrigerated, using a cold liquid substance that is normally a vapor, forcooling.

demurrage The charge for detaining a ship beyond the time allotted for loading, unloading,or sailing.

distribution The network of systems for transporting any product from a source or point oforigin to an intermediate or final destination.

diversification The economic practice of investing in various segments of the businesseconomy, so that income is not totally dependent on one or two operations.

dock A fixed berth.

East-West Pipeline The crude and NGL pipelines that traverse Saudi Arabia from the easternprovince to Yanbu on the Red Sea.

flowline The lines used to transport crude from individual producing wells to trunklinesor GOSPs.

fractionation Distillation of crude or NGL to its component parts.

grass roots Used to describe a refinery built new rather than one expanded or modified.

innage The measure of product stored in a tank by the depth of product from the tankfloor to the liquid level.

Linear Programming(LP)

A type of mathematical model used to simulate process operations and toprovide guidance for economic optimization of the process operations.

MGS Abbreviation for Master Gas System, the overall system lines and facilities forrecovery, treatment, and fractionation of produced gas.

outage The measure of product stored in a tank by the space from the liquid level to adatum plate at the top hatch.

prover A system of meters used to check calibration of the primary delivery meters ata terminal or tank farm.

regeneration The process of restoring a catalyst to nearly new condition by removingcontaminants that inhibit the catalysts’ performance.

shipping pump A large pump with high volume and high discharge pressure characteristics, forloading crude or products onto a ship or to a pipeline.




SPM Abbreviation for Single-Point Mooring, where a ship ties up to load or unloadbut then can float around, as opposed to tying up at a fixed dock.

supply The available product to meet market demand.

T & I Abbreviation for Test and Inspection, when a process is shut down andcomponent parts opened and inspected for repair.

tanker An ocean-going ship for transport of crude, refined products, or LPG.

terminal A facility, generally consisting of storage tanks, delivery systems, and berthfacilities, at which a tanker receives or discharges cargo.

trunklines Secondary lines used to carry crude from producing wells to the GOSPs, madeup of flow from two or more flowlines.

ULCC A crude ship rated at 320 to 550 DWT.

vertical integration The economic practice of being involved with all the steps in production ofconsumer products; for example, crude production, transportation, refining, andmarketing of finished refined products.

VLCC A crude ship rated at 160 to 320 DWT.

Age 10505

Documents

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