Copyright 2006, Offshore Technology Conference This paper was prepared for presentation at the 2006 Offshore Technology Conference held in Houston, Texas, U.S.A., 1–4 May 2006. This paper was selected for presentation by an OTC Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Offshore Technology Conference and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Offshore Technology Conference, its officers, or members. Papers presented at OTC are subject to publication review by Sponsor Society Committees of the Offshore Technology Conference. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the Offshore Technology Conference is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of where and by whom the paper was presented. Write Librarian, OTC, P.O. Box 833836, Richardson, TX 75083-3836, U.S.A., fax 01-972-952-9435. ABSTRACT

Petrobras has converted the VLCC tanker Felipe Camarão into FPSO P-50 in order to operate in the Albacora Leste field, Campos Basin, offshore Brazil. FPSO P-50 is one of Petrobras largest offshore platforms, with a processing capacity of 180,000 bopd, 6 million m3/d of gas and an injection capacity of 35,000 m3/d of water.

Based on Petrobras experience from the conversion of 10 other FPSOs/FSOs, in the last 10 years, the FPSO P-50 project was developed taking into account the concepts of operability, constructability, and modularity, which resulted in several improvements on the systems and facilities installed on board. Some of the technical challenges involved in the FPSO P-50 project that will be addressed in this paper are listed below:

Material Selection: detailed material selection analysis for the process plant due to the presence of CO2 in the oil;

Gas Compression: 3 x 2 million m3/d Centrifugal Moto-compressors, driven by Variable Speed Drivers;

Gas Treatment: CO2 removal plant; Injection System: Sulphate Removal Unit; Offloading systems: Double Discharge System

with 2 Hydraulic hose reels installed at the bow and stern;

Marine Systems: Use of ring-shaped pipe-racks and submerged cargo pumps;

Chemical Injection System: Centralized filling and distribution system.

The main objective of this paper is to describe the technical challenges faced by the project team and the solutions adopted for the FPSO P-50 project.

INTRODUCTION Albacora Leste Field The Albacora Leste field was discovered in March

1986 by the wildcat 1-RJS-342A. This 600-km2 field lies 125 kilometers off the coast of Rio de Janeiro, at water depths from 800 to 2,000 meters. The field is comprised primarily of Miocene turbidite sandstones (Reference 1).

The Field Development comprises 16 subsea production wells producing 180,000 bopd through individual bundles to FPSO P-50, located at a 1,240-meter water depth. The water injection, totalizing 35,000 cubic meters, will be achieved through 14 subsea wells.

After processing and treatment in the FPSO, the oil is stored inside the tanks and later exported to shore by dedicated shuttle tankers. The compressed gas is exported through a 10-inch gas pipeline up to a subsea Pipe Line End Manifold (PLAEM) that is connected to an existing fixed platform through a new 20-inch diameter pipeline. From this fixed platform, the gas is sent to shore through the existing Campos Basin gas network.

FPSO P-50 P-50 shown at Figure 1 is a former VLCC from

Petrobras fleet that was converted to production from 2002 to 2005. The FPSO arrangement is modularized as shown at Figure 2, with separated modules for Gas Compression, Gas Treatment (De-hydration and CO2 Removal), Crude Separation, Manifolds, Electrical Generation, Electrical Utilities, Non-Electrical Utilities, Water Injection & Sulphate Removal, Flare System, Pipe-racks, Offices&Control and Quarters. Construction of the modules was granted to four different Contractors. The ship conversion and the final modules Integration Contract was assigned to a fifth Contractor.

The objective here is not to give a full description of all P-50 systems, which would make this paper overly extensive, but rather to focus on some critical systems where lessons learnt from Petrobras previous projects (Reference 2) resulted into a modification in the concepts adopted. We will here focus on the FPSO process plant and utilities, since the FPSO Marine Systems and the ship conversion were already thoroughly discussed in a paper previously presented in OTC (Reference 3).

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Albacora Leste Field Development—FPSO P-50 Systems and FacilitiesF.E.N. Brandão, C.C.D. Henriques, L.B. Rende, L.C.R. de Barcellos, and C.R.B. de Oliveira, Petrobras

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TECHNICAL CHALLENGES IN P-50 PROJECT P-50 Material Selection Process

The Albacora Leste Field’s characteristics motivated the review of the material selection philosophy for the FPSO based on the feedback obtained from similar projects in the Campos Basin. First, the oil samples showed the presence of CO2 (from 2.47% to 5.6% mol) in the crude composition, as well as a high level of chloride. Secondly, the required separation temperature of 110ºC resulted in a limitation of the material and coatings that could be used in the plant.

During the Front-End Engineering Design stage of the project, we decided to implement a decision tree analysis for each stream of the process plant, in order to decide the most suitable material for all piping and equipment of the plant. The decision tree created considered the following corrosiveness limits as decision points:

a) Chloride content above 50 ppm, for any BSW% (percent of basic solid and water on stream);

b) Partial CO2 pressure above 7 psig, and possibility of condensation;

c) Value fluid temperature above 90ºC on equipment, which prevents the use of internal coating.

There was also a singular situation of temperature up to 110ºC with presence of chloride and indication of special material. The opportunity to use special material to decrease the weight of large and heavy equipment, such as the separation vessels, was considered. Taking into account the information from several sources, including papers and manufacturer’s home-pages, a decision to make use of duplex stainless steel in the critical equipment was indicated.

It was necessary to create one decision tree for streams with oil, produced water and gas, and another one specifically for the gas stream, as shown in figure 3.

The analyzed systems were: Oil Processing and Treatment, Gas Compression, Booster Gas Compression, Gas Dehydration (Glycol), CO2 Removal, Fuel Gas, Desander, Produced Water, Water Injection and Seawater Lift, Flare System, Heating and Cooling Water. For a better assessment of CO2 corrosion and others sources, the plant was subdivided into 13 branches. The sequence presented was in accordance with P&D flow direction:

a- From inlet lines at platform to production & test manifolds.

b- From outlet production heater to production separator.

c- Oil treatment. d- Produced water systems. e- From production separator outlet gas to inlet of

first gas cooler. g- Gas coolers material h- All pipe branches between outlet gas coolers and

inlet gas scrubbers i- All pipe branches between outlet gas scrubbers

and inlet gas coolers j- Pipe branch between outlet of last gas coolers and

TEG contactor towers

k- Scrubbers and TEG contactor towers l- Condensate lines from TEG contactor towers to

production separators m- Condensate lines from scrubbers n- Gas dehydration system & dry gas system The equipment data were collected and filled in a

worksheet with some key process parameters, such as pressure, temperature, CO2 percent mol, oil and water flow of all fluid in & outlet. The worksheet allowed the calculation of partial CO2 pressure and BSW%. and was prepared and organized by systems, including several cells with links and formulae prepared to take the decision in accordance with the conditional precedence established by the decision tree. The Maximum Oil, Maximum Produced Water and Maximum Produced Gas conditions were considered for the material selection analysis. The worksheet showed different proposals of material to be selected; obviously some constructive constraints had to be taken into account to guide the final selection decision. The final situation can be observed on column “Cases” showed in figure 4.

Gas Compression and Treatment Systems P-50 Gas Compression proved to be a challenging

system from the Front-End Engineering Design phase up to the Construction and Assembly stages of the project. P-50 presents one vapor recovery unit (URV) and three main gas compression trains, in order to meet the gas lifting demands for production purposes, as well as for exportation and internal consumption. The total Compression capacity is 6 million Nm3/day. At the peak of gas production, it is expected that, for short periods, all 3 trains will have to run at the same time.

The compressor trains present a unique arrangement which increases the life time of the equipment.

The three compression trains are, each one, driven by 13 MW electrical motors. The Compression System will be the most important electrical energy consumer of the platform, resulting in the largest generation plant ever installed in a Petrobras FPSO.

The main compressor trains also count with seal gas system, with a completely independent nitrogen generator package, thus avoiding the use of process gas when sealing the compressors. Those nitrogen generators are located in the same compressor modules, and their use avoids loss of gas at seal leakage vents.

Main Compression System The main Compression System of FPSO P-50 is

located at two frontal modules on the vessel (Figure 2), one presenting two compressor units and, the other, presenting one compressor unit and the electrical systems, such as electrical filters, power transformers and speed control of the electrical motors that drive the compressors. Each compressor train has been designed to operate independently from the others, with two trains running and one standing-by, in normal operation (except for the gas peak condition). The Compression System is designed to take the gas leaving

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the oil & gas separators at 785 kPa and deliver gas at a little higher pressure than the exportation one, at 19614 kPa. This gas can then be injected in the production wells, as gas lifting delivered to internal consumers or exported. The gas from the Separators goes to one common safety gas knock-out drum and then flows to a cooler and a scrubber vessel to remove condensate, and finally, to the compressor. This ensures a reasonably dry gas passing through this equipment. This arrangement is repeated in three stages (low, intermediate and high pressures), until the final necessary output pressure is achieved. A fourth cooler at the end of compression process cools the output gas from the unit. The basic main compression system diagram is depicted in figure 5.

The static equipment pieces for the gas process are shell-and-tube coolers and scrubber vessels with demixers. Each compression train, indeed, comprises the following equipment:

• Low and intermediate pressure compressors, centrifugal type, mounted on a back-to-back arrangement, in the same bundle, one compensating the axial efforts of the other, with a nitrogen gas sealing system

• High pressure compressor with balancing piston to provide axial effort compensation, also with a nitrogen gas sealing system

• Gearbox • Electrical synchronous motor, air pressurized,

cooled by water/air interface, with 13,7 MW of required power

The auxiliary equipment of the compressor trains are: • Lubricating system console for compressors and

motor bearings, with two pumps (main/standby), plus one emergency pump

• Nitrogen generation package to furnish seal gas, and a seal gas distribution system

• Variable Speed Driver system – VSD, based on static frequency converter – SFC

• Harmonic Filters Once the driver is an electrical motor, all the energy

necessary to compress the gas (up to 19614 kPa) is obtained from the main electrical generation system of this platform. Some interesting details on the electrical driver system are explained in next section of this paper.

Compression Modules Layout From the point of view of the physical arrangement,

P-50 presents the unique characteristic of having the compressors located at the upper floor, while the coolers are located at a mezzanine and, the lower floor, in the scrubber vessels. This arrangement reduces the retention of condensate or water into the compressors, when it is not running, thus preventing it from corroding its internal parts.

This characteristic also reduces the condensate arresting to the compressor. However, the lubricating oil system must provide enough pressure to the oil to reach the upper floor where the machines are located. For this

reason, and the fact that there will be no rundown tank for the compression trains, the lubricating oil consoles count on three pumps (one on stand-by) and on an emergency pump that must be always ready so as not to cause the compressor unit to shutdown. This emergency pump is automatically tested at every 72 hours. The physical arrangement of the compression modules showing the equipment pieces is shown in figure 6.

Definition of Compression System Configuration In order to choose the Compression System

configuration, it was defined at first that the system would be built using variable-speed, machine driven compressors. Such machines would be gas turbines or AC electrical engines with Variable Speed Drivers (VSD). As the expected gas compression capacity would be high (6 Mm3/day), that meant that the compression power demand would also be high, directly impacting the Generation System concept. This point led Petrobras to make a technical and economical study to define the best configuration for both systems together. After a previous analysis of the possible configurations that could be used, we decided to study deeper and compare the following configurations:

• Option A: three turbo generators and three 2 Mm3/d turbo compressors;

• Option B: four turbo generators and three 2Mm3/d motor compressors;

• Option C: four turbo generators and four 3 Mm3/d motor compressors (S/P layout);

• Option D: four turbo generators and two 3 Mm3/d motor compressors.

Technical & economical analysis made for these four options considered plant global life cycle cost and sensitivity & risk analysis. To accomplish such work, recognized mathematical modeling and software tools were used to reach the desired conclusions.

The issues analyzed in the system life cycle cost study were capital investment, O&M cost and production losses due to machines unavailability. As this study works with probabilistic and statistical calculations, OREDA data base was accessed, and so it was Petrobras own historical machines failures data base, four year long fed. Analysis results showed that option B was a reasonable choice, despite not being the lowest global cost. High capital investment cost was compensated for lower O&M and unavailability rates.

Risk & sensitivity analysis considered financial losses due to gas burning and oil & gas pricing variation. This analysis has been essential for system layout definition, once its results indicated a large advantage to option B, mainly when considering the gas price trends. Thus, the choice for four turbo generators and three 2 Mm3/d motor compressors was made, mainly due to the produced gas use maximization and lower O&M cost, when compared to the other three options.

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Vapor Recovery System The vapor recovery system (URV), or gas booster

system, recovers the gas leaving the atmospheric oil & gas separators, a very rich gas with higher energy properties and increases its pressure to inject it in the main gas current. This gas can then be compressed with the rest of the gas produced in the system. The URV has one safety KO drum, followed by one cooler and one positive displacement, screw-type compressor which works filled with lubricating oil. Two vessels following the compressor dry the gas so it can flow to the safety KO drum of the main compression system. Those vessels have demixers that act as coalescing filters. The oil returns to the booster compressor in closed circuit. The compressor is driven by an induction electrical motor with a fixed speed (1800 rpm), and the capacity control is done by actuating a slide valve that increases or decreases the void space in the compressor. The auxiliary system of the URV is this lubricating oil system, including pumps and coolers, to avoid overheating the equipment. A very important variable is the output temperature and dew point of the gas, to avoid gas condensate at the discharge of the compressor. To achieve this during startup, fuel gas from the fuel gas system is used instead, while the oil is not at working temperature.

Control and Automation The equipment of the main compression trains, as

well as the ones of the URV, is monitored by temperature and vibration systems, and is locally controlled. Monitoring of the variables is allowed at the supervisory and control system (ECOS) of the platform. The compression is controlled by local PLC’s allowing it to quickly interlock and shutdown the system whenever needed. Those PLC’s also acquire data from the auxiliary systems in order to detect any unsafe condition and to interlock the system. They are also responsible for the startup and stop sequences, testing the lubricating oil pumps, etc. The control interface between the adjacent systems, however, becomes more challenging, as many signals come from other modules.

The main compression trains also have an integrated anti-surge and loading-sharing controllers net which monitors the operating point of each compression stage, avoiding the surge phenomena, acting on recycle valves of each compression stage, and also balancing the loading over each working gas compression train. It also controls the suction header pressure, reducing the flow to the flare system by increasing the compressor’s flow.

The main compression system also counts on multiplexers that allow the diagnostic of any transmitter instrument located at compression units by means of one maintenance station. The temperature and vibration system will also be connected to a computer running software which will allow the vibration analysis, frequency and disturbance characteristics, orbit tracing, and other complex-based algorithms in order to observe and monitor the performance of the trains during its lifetime and giving more input data for an effective

maintenance strategy, keeping the high availability of the machines.

Detailed characteristics of the electric driver

system Electric Motor: The driving of the main gas

compressors of P-50 is made by a system composed of synchronous motor, VSD and a group of transformers that feed the VSD with medium voltage, for each compression train, thus performing a total of three groups. This arrangement, with some small improvements, is the same as the one used on platforms P-43 and P-48, where this new concept was introduced.

The synchronous Motor that drives the compressors has a power of 13.7 MW and has 4 poles operating therefore with a nominal rotation of 1800 rpm. Another important characteristic of the synchronous motor is the two stator windings. These windings, one of those 30 degrees out-of-phase with the other, reduce the pulse torque caused by the motor feeding VSD arrival voltage which does not present a smooth sinusoid waveform. The motor is excited with alternating current, originated from the panel of the VSD.

Variable Speed Driver (VSD): The objective of the Variable Speed Driver is to control the motor speed and assist the compression gas flow demands, ranging from 10% to 105% of the nominal speed of the motor. Figure 7 shows a schematic diagram of the VSD.

The installed VSD is a Load-Commutated Inversor (LCI) and uses SCR´s in the rectification and in the inversion stages. The input rectifier is 24 pulses, with 4 inputs, where each one is 15 degrees phase delayed from the other, and with a voltage of 2060 Vac. Also, there are two outputs that pass through a 12 pulse inverter, with voltage varying from 0 to a maximum of 3520 Vac. The DC link between input and output stages of VSD comprises a reactor and works at 8900 Vdc. The voltage control is made in the rectifier (input stage), and the frequency control, which determines the rotation speed of the motor, is performed by the inversor (output stage). Due to the high power characteristics, this equipment presents internal cooling by water, in a closed system with a plate heat exchanger (water/water) external to the system. The VSD internal cooling water system presents a water de-ionization system, in order to avoid conductivity problems, such as electric discharges in the power circuits of the equipment. In this system, a portion of the water passes through a deionizer membrane, which keeps any ions present in the water. In the case the membrane becomes saturated, the conductivity of the water reaches a maximum value and it will cause a shutdown of VSD, and also of the gas compression unit.

Transformers: two transformers of double-output secondary, totaling 6 transformers, feed the four inputs of each VSD.

Even allowing the rectifiers to have 24 pulses, and depending on how the VSD´s are in operation, A with B or A with C, the phase delays make the system "see" a single, 48 pulse rectifier, and this reduces the level of

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harmonics generated by VSD´s. Those transformers are dry, with the windings cloistered in resin, and they do not have forced ventilation system or any other self-cooling system. The individual power of each transformer is 8992 kVA, totaling 17984 kVA for each VSD.

Harmonic Filters: The harmonics filters used in P-50 have the objective of reducing the level of harmonic generated by VSD´s, improving the quality of platform energy. Due to great power of VSD´s, the harmonic distortion level propagated to the electric distribution system of the platform is also quite high, making the THI (Total Harmonic Index) cross the maximum allowed level of 5%.

Constructively, the filters are simple, composed of capacitors, reactors and resistors. They are passive filters, tuned in the 5th and 11th harmonics, or 300Hz and 660Hz, which are critical frequencies in agreement with the study of the electric system of the platform, when two of the compressors units are in operation. There are three filter groups of 5th and 11th, each connected at one of the 13,8 kV busses, through a circuit breaker for each group.

Gas Treatment Gas treatment in P-50 basically comprises two

systems: CO2 Removal System, that gets the gas from the second Compression Stage and reduces the amount of CO2 from 5% to less than 2%, by means of a Amine (MEA) absorption; and the Dehydration System that gets the gas after the third stage and reduces the humidity to less than 1.54 lbs/m3, by means of a TEG (Tri-Ethylene Glycol) absorption process.

GENERATION SYSTEM

In P-50, due to the requested power of 13.7 MW for each compression train, totaling 41,1 MW, the Generation System had to be enlarged, when compared to previous projects. Adding the demand of the four water injection pumps of 3,9MW and other equipment, the generation system had to be designed with four turbo generators sets (one on stand-by), with 23MW each, resulting in an installed total power of 92 MW, not counting the 3MW of the auxiliary diesel generator.

The generation trains arrangement was designed to guarantee 96% system availability.

As mentioned before, 5 different Contractors were in charge of P-50 construction and assembly. This contracting strategy required from the Electrical Generation System a high autonomy level, resulting in a design for the Generation Modules that requires few external needs to perform the work.

For energy optimization, in each turbine exhaust, it was installed a Waste Heat Recovery Unit (WHRU) that uses the high temperature exhaust gas for water heating, for the process plant.

For P-50 Generation System, the unit Classification Society required a complete 14t of tests. These tests were separated in two different steps. The first one, the String Test, took place in the Generation Modules

fabrication yard and the second one, the Full Load Test, was made at the final Integration Yard.

Technical System Description The P-50 main electric Generation System was built

in two modules, each one weighting around 1.500 ton and comprising two turbo generation trains, with independent auxiliary system for each one of them. The main equipment of the turbo generators are the following:

• Gas turbine (aero derivative type), 31370KW in the ISO conditions, bi-fuel, with nominal rotation of 6100 rpm in the power turbine;

• Gear box, that connects the turbine to the generator;

• 23MW electric generator, power factor of 0,8, 1800 rpm, 60Hz, 13,8KV, three-phase, type without brush, with refrigeration air-water.

All these equipment is monitored by a system of vibration measurement, axial displacement and bearing temperature, for the guarantee of machines readiness. These variables, together with other process variables, are input to a software piece that acquires the raw data and manipulate them to generate graphs in real time with the rotation orbit of the machines, the vibration frequencies specter, etc. This software will still be able to make complex calculations, as the determination of turbine heat rate, which is useful as a diagnostic and for predictive maintenance.

The 3750kVA (3000kW) Auxiliary Generator generates energy in 13,8kV and is connected to the medium tension bar. The Generator is driven by a 3140KW/12 cylinders diesel engine, 900rpm rotation, and has the main function to keep the electrical load supply to the platform when it is not producing and the load demand is low

In case of shutdown, the necessary power is supplied by the 1750kW power Emergency Generator that is also driven by a diesel engine, with 1820KW/16 cylinders and 1800rpm rotation.

An interesting characteristic of the 13,8kV panel is that its assembly is not in line, as the usual one, but in an "S" shape, because of room dimensions limitations, with the bus bars connection made through bars ducts leaving the panel superior part.

Control System Each module includes a local control cabin and an

engine control cabin (CCM). The CCM shelters the drawers of drive and protection of the auxiliary engines systems. In the local control cabin, the turbo generators control hardware is located divided in three main blocks:

Turbines Control Panel (TGCP); Main Generators Control Panel; Power Manager System (PMS).

The TGCP provides all the control and protection of the turbo generators, being responsible for the automation of the start-up sequence and trip of the turbo generators, fuel control, control of gas generator compression and power turbine speed.

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The MGCP is responsible for the protection, synchronism, parallelism and excitement of the generators.

The PMS manages the energy supply for loads, controlling the load sharing between the generators in parallel and answering for the load discarding, in case of greater demand than the power generation. This system shall present a fast response, in order to discard loads before the protection system of turbines or generators may cause unnecessary trip in the machines.

Auxiliary Systems Lubrication Oil System: The P-50 turbo generators

require two distinct systems of lubrication: synthetic oil (SLO) for the gas generator and mineral oil (MLO) for the power turbine, the reducing box and the electric generator. Mechanical drive pumps connected to the proper gas generator pressurizes the SLO. The MLO is pressurized by electric driven pumps. To increase the availability of the system, there are three pumps (one on standby and one for emergency). The MLO includes an emergency oil tank, the Run Down Tank, which is located in the highest module area, stores mineral oil. By the effect of gravity, the oil from the Run Down tank lubricates the machines without risk of damage, in case of system depressurization. In both lubrication systems, there is an equipment piece called oil vapor recuperating that filters the oil vapor generated by the bearing heating and brings the recovered oil back to the tanks. Not only does this equipment optimize the consumption of lubrication oil it also contributes for a cleaner operation of the turbo generators, since it prevents the oil vapor from being discarded to the atmosphere.

Fuel System: The gas generators of the electric generation system can be fed by both oil diesel or fuel gas. The proper gas produced and treated in the platform makes the combustible gas supply. Before being sent for burning, the gas is filtered for removal of condensate. The diesel supply is made by a main tank of the platform that receives the fuel from supply boats. Then, this diesel is treated by a cyclone, filtered and sent to daily consumption tanks (one tank for each turbo generator). The fuel consumption is monitored and sent to the performance calculation system, which is an excellent tool of analysis for predictive maintenance.

Air Filtering System: There is a filter box for each generation train. The combustion air is filtered in four stages: two demisters, one coalescence filter and one high efficiency filter. A part of this filtered air is directed through two fans for the hood ventilation. A gas sensor is installed in the filters boxes, to detect the undesirable presence of mixed inflammable gas in the ventilation and combustion air.

Hydraulic Start-up System Hydraulic engines connected to the gas generators

produce the turbo generators start-up. There are two Hydraulic Start-up skids for each pair of TGs, and each skid can start any one of those TGs.

String Test Petrobras and the EPC Contractor of the Generation

Modules made an agreement to perform, at the modules construction yard, a String Test to evaluate the operation of the turbo generation trains, its control system and auxiliary systems. In this test, all component systems of the modules were tested, simulating the final operational conditions of the machines. So, this kind of test is different from Factory Acceptance Tests, where each machine is tested separately in group of benches, with auxiliary systems that are not the same ones of the final package.

This test had the target to assess only the isolated operation of each train, taking into account neither the parallelism and synchronism between two or more turbo generators, nor the load split between them. Therefore, some control systems were not tested, amongst them the PMS and the MGCP. The test of these systems was forecasted to happen in the Full Load Test phase.

The equipment tested in the String Test was the following: Gas turbine; Electric generator; Gear box; All modules instrumentation; Couplings between turbine and reducing box and electric generating and reducing box; Gas Turbine Control Panel (TGCP), including vibration monitor and temperature of bearing system; Hydraulic Start-up system; Synthetic oil and Mineral oil Lubrication system, including the oil cooling; Liquid fuel system; Fuel gas system; Fuel air filtering and hood cooling system and Generator protection system.

The following external systems from the construction yard have been used:

Gas analyzers; Fuel gas temporary feed; Diesel temporary feed; Temporary ventilation tubing; Temporary hydraulic oil supply; Temporary air instrument supply; Temporary water cooling supply.

Evaluation Test Criteria: For the system acceptance, the machines design limits have been taken into account comparing the values verified in tests with equipment data. For the gas turbines, vibration values, bearing temperature, temperature and pressure of the lubrication systems were verified. The gas generator fuel control performance and the safety interlocking have also been analyzed. For the reducing boxes, vibration values and bearing temperature were checked and, for the generators, beyond vibration and bearing temperature, windings cooling systems, generators electric protection, electric power generated and safety interlocking were checked.

Another parameter checked, upon request of the Classification Society, was the tension and frequency variation levels of the generated electric signal related to sudden load variations as well as the liquid and gaseous fuel commutation. After these tests, additional verifications had been done through internal inspections of equipment critical parts and several filters, also being valid as system acceptance criteria.

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String Test Procedure: The test was divided in three different phases:

Test in stationary load conditions in operation: each turbo generator is charged with maximum load, 23 MW, for a one hour period, consuming liquid fuel and another one hour consuming gas fuel.

Test with load variation: the load demand for each generator is varied from 50% to 100%. The objective of this test is to check the machines speed control related to sudden load variations.

Fuel commutation test: the fuel is changed from liquid to gas fuel and then from gas to liquid, with machines in operation. This has the objective to test the machines speed control related to fuel commutation.

String Test Results: In general, the String Test ran well, confirming the satisfactory operation of the four turbo generation trains in all tests. Some small problems were detected during the tests, none of which critical for the system, but indicating the need for some design corrections or equipment maintenance. This can be considered the great profit of the string test that propitiated the early correction of the defects, in the modules construction yard, previous to modules integration, where more resources were available for corrective actions.

Full Load Test The Full Load Test has the purpose to verify the

parallel operation of the generators and their capacity in keeping their electric parameters (mainly the frequency) inside acceptable limits when sudden load variations occur. Moreover, this test verifies the turbines and generators protections functioning, regarding the requirements of the Classification Society. Related to the CO2 fire system of the turbine compartment, a test was performed for the performance of the cylinders witnessed and validated by the CS.

The Full Load Test comprises not only the main turbo generators, but also the medium tension electrical system main equipment, the main panel of 13,8kV, which present five input cubicles (TG's and Auxiliary Generator) and twenty eight output cubicles (loads) distributed in three bus bars (A, B and C), as well as circuit breakers of the bus bars interconnection and the auxiliary generator.

Parallelism must be tested between all four TGs and also the Auxiliary Generator, all connected; two of the TGs together with the Auxiliary Generators and the four TGs together. The load, in each test stage, must vary between possible minimum (40kVA) and 100% of the generation load in test. To verify the generation reaction in relation to sudden load variations, when the load reaches 100%, it is disconnected. The frequency transient should not be more than 10% and, in variation regimen, it should not be more than 5%. The load must be added in defined steps up to 100%, observing the load sharing between the machines that must not have variations of more than 15%.

The protection test should not only contemplate the generator electric protections (close-circuit, ground-fault, super excitement, sub excitement, etc), but also the turbine protections (over speeding, oil temperature, etc). These protection tests must occur before parallelism tests, so that during the latter, any fault can be treated without major problems, protecting the people and equipment involved in the tests.

INJECTION SYSTEM – Sulfate Removal Unit

The reaction between sulfate ions, present in injection seawater, and barium or strontium, from reservoir water, results in composites precipitation and scale formation. Consequently, reservoir and well surroundings become clogged, and equipment pieces – tubes, risers, surface facilities – present a lower performance, caused by obstructions, frequently needing a hard cleaning work. Moreover, the activity from sulfate reduction bacteria in the reservoir produces H2S, causing souring, with undesired consequences to oil composition and material corrosion. NORM (Naturally Occurring Material) can also be formed, if radio 226 or 228 are present in the reservoir, resulting in dangerous handling and discard operations. As an example, approximately 100 ppm barium sulfate precipitation, for 10000 produced water barrels a day, generates 287 tons of scaled material per year. One way to avoid these problems is to reduce sulfate concentration in seawater, before its injection, in a preventive action, almost eliminating sulfate as a source of scaling and souring, with some advantages in comparison to injecting chemicals in reservoirs and the associated difficulties concerning uniform distribution, instability under pH, pressure and temperature conditions, residual concentration monitoring and even damage to geological formations, specially in complex reservoir arrangements or high scale potential.

In the P-50 project, a sulfate removal plant allows for the reduction of sulfate content in seawater from its up to 2800 mg/l original concentration to 100 mg/l or less, with an approximately 96% efficiency. The SRU (Sulfate Removal Unit) is part of the injection water module, together with the Seawater Lift Pumps, electro chlorination equipment, coarse filters, deaerator, chemicals injection skid and injection pumps. Lift pumps, in a 2 x 100% configuration and 48000 m3/day flow, provide seawater from a 25-meter depth. The greater lift depth reduces oxygen, suspension solids and microorganisms concentrations, so the injection water system becomes less susceptible to corrosion and blockage. Electro chlorinator produces a sodium hypochlorite solution, from seawater, by electrolytic cells, injected in seawater lift pumps caissons, to avoid microorganism growth along the water injection system. Downstream, a basket coarse filter retains particles greater than 80 micrometers, before seawater enters the deaerator tower. Inside the deaerator, low pressure fuel gas flows against the seawater, physically reducing oxygen concentration in seawater to 0,1 ppm; then,

8 OTC 18242

oxygen content is chemically reduced to 0,01 ppm due to scavenger injection.

The SRU is essentially composed of booster pumps, fine filters, packages of sulfate removal membranes vessels, and a cleaning skid for the membranes. In order to provide enough pressure for the water to pass through fine filters and membranes, the SRU has two sets of 3 booster pumps each (one on stand by), rated for a 3000 kPa discharge pressure. There are four fine filters, each pair for two packages of membranes vessels, one filter for operation and the other as stand-by. The fine filters, cartridge type and 5 micrometers absolute, represent a last particles barrier for membranes and are responsible for specifying SDI and TDS in membranes inlet flow. Nanofiltration membranes separate sulfate from seawater, retain bacteria and particles larger than 10 angstroms in average, but allow the passage of other ions, such as chlorine and sodium, which are important to keep the reservoir salinity equilibrium. Six membranes modules are inserted inside each vessel. The vessel inlet flow, after passing through membranes, will result in two outlet currents, each with 50% of the inlet flow, the LSW (Low Sulfate Water) current, to be injected, and the HSW (High Sulfate Water) current, to be discarded overboard. The set of vessels is configured in a 2:1 array, with the double amount of vessels in first stage, compared to the second stage. First stage LSW is mixed with second stage LSW, first stage HSW becomes inlet flow for second stage, and second stage HSW is discarded overboard. Based on this arrangement, the system works with a 75% recovery rate.

In P-50, there are four vessels packages, functionally independent, each one with 44 vessels in the first stage and 22 vessels in the second stage, resulting in a 36000 m3/day LSW plant, from a 48000 m3/day inlet seawater. In order to obtain better performance in sulfate reducing and prevent membranes damages, it is very important to chemically treat the seawater along the system upstream membranes, injecting oxygen scavengers, biocides and anti-scaling products, to eliminate oxidizers agents which attack membranes structure, bacteria and scaling, respectively. SRU whole system is controlled by specific instrumentation and valves, in an essential role, related to LSW production, membranes protection against oxidizers and reverse flow, leakage detection and cleaning operations. A cleaning skid is used to clean membranes periodically, being composed of two tanks, where cleaning solutions are prepared, one heater for each tank, which provides ideal temperature to improve cleaning solution efficiency, a pump to send the solution to membranes and a cartridge filter, 5 micrometers absolute as fine filters, downstream pump, as a protection for membranes against the presence of particles in cleaning system. Two types of cleaning can be performed, alkali or acid, for biological and inorganic fouling, respectively.

Finally, the deaerated, treated and dessulfatized seawater is injected in 14 injection water wells by multiple stage centrifugal injection pumps, arranged in a

cluster of 4 pumps (one on stand by), rated for 20000 kPa discharge pressure.

MARINE SYSTEMS

In the P-50 project, all the marine systems connected to the cargo and ballast tanks, such as the cargo, auxiliary, loading and inert gas systems have their main headers built in a ring shape (Figure 2) instead of the traditional fishbone configuration seen in most FPSOs. In this concept, the piping is installed in two parallel piperacks located over the longitudinal bulkheads of the ship which reduces the amount of transversal lines over the main deck, improving the arrangement of the platform. Another advantage of this concept is that it is intrinsically redundant and it gives more flexibility to the operation, allowing simultaneous cargo transfer operations.

In P-50 cargo tanks, 1,100 m3/h dedicated hydraulic submerged cargo pumps were installed, one in each wing tank and two in the larger central tanks. This concept eliminates any kind of communication between the tanks, an obvious advantage in terms of safety of the ship. The elimination of the cargo and ballast valves inside the tanks also brings benefits for the operation and maintenance of the platform.

OFFLOADING SYSTEMS

In the FPSO P-50 project, Petrobras choose, for the first time, a reel system to retrieve and store the offloading hose instead of the chute system, where the hose is stored in a cradle, located alongside the deck, as used on all previous Petrobras FPSOs. The advantages of the reel system have been thoroughly discussed in a paper previously presented at OTC (Reference 3).

P-50 presents two Offloading Stations: one at the FPSO bow (Figure 8), and the other at the stern (Figure 9), each one able to export up to 7200 m3/h of oil. This double station configuration is necessary because P-50 is moored to a fixed azimuth by a spread mooring system. Each Offloading Station (bow and stern systems are identical) basically comprises:

Hydraulic Reel; Hawser Winch; Chain Stopper; A Hydraulic Power Unit to power the Reel and

Hawser Winch. Each Reel with 8-meter diameter and 8.5-meter width

stores a 220m-long, 20-inch double carcass floating hose at one layer with 8 turns. Between the hose and the Reel piping, a quick release device was installed to allow the immediate disconnection of the hose in case of emergency. In front of the reel there is a spooling device that makes the operation of hose retrieval and spooling easier, even in crossed current conditions. The reel is also equipped with an environmental protected control cabin, from where the operation of both the Reel and the Hawser Winch is conducted.

The Hawser Winch presents two compartments: one to store the hawser itself and the other for the chafing

OTC 18242 9

chain. The equipment is also equipped with a quick release and spooling devices.

Each group formed by Hydraulic Reel, Hawser Winch and Spooling Devices use one HPU (Hydraulic Power Unit) with two 90 kW electric drivers for usual service, and 12 kW emergency electric driver.

Additionally, for the case of unavailability of the main Offloading System, there is an Alternative one, beside each Offloading Station. The Alternate System is composed of an Auxiliary Winch that can pull 16 or 20 inch floating hoses from the sea, through a chute, and connect the hose to the Offloading piping.

As P-50 will be the first Petrobras FPSO to use an Offloading Hose Reel in the Campos Basin, a lot of care was taken during the design and fabrication of the system. The F.A.T. (Factory Acceptance Test) of the Reels, Spoolers and Hawser Winch was witnessed by Petrobras and confirmed all the operational parameters expected for the system, such as the reel speed, normal and emergency pull load capacity, hydraulic pressure levels, etc.

CHEMICAL INJECTION SYSTEM

Due to the toxicity of the chemical products used in oil processing and the amount of gallons of these products normally handled in offshore platforms, the risk of accidents is always considerable. Then, the P-50 Chemical Injection System was designed considering a centralized filling and distribution system in order to increase the safety of the activities of receiving and handling such chemical products.

The amount of containers for chemical products, hydraulic fluid and lubrication oils will be reduced in P-50, by the option of transporting the products in larger containers with capacity from 500 to 5000 liters.

Normally, the existence of different gallons and containers of chemical products in an offshore production platform demands internal load maneuvers in the platform decks to allow first the receiving and later the correct positioning of the containers for product transference to the fixed tanks. In P-50, the products manipulation will be safer, since the platform fixed tanks will be directly supplied with products stored in large containers. One flexible hose will link the container or gallon of chemical product and the rigid supply line to the fixed tank to be fed. A connector that may be quickly actuated and the opening of two valves allow the transference of the product by gravity, preventing the operator to come in direct contact with the dangerous chemical products.

To prevent containers damages from shocks or falls, cradles and bumpers were foreseen, to guarantee the safety during the containers handling operations. The easy visualization identification of cradles will be enough to guide the cargo handling staff to place each container near by the corresponding fixed tank supply line. The chemical products distribution through the injection points was designed considering the two philosophies:

For some products, the traditional dedicated dosage pump to each point of injection was kept.

For other chemical products the philosophy of a centrifugal pump was adopted with IRCD (Injection Rate Control Device) distribution for dosage in several points. Outflow transmitters had been installed in the IRCD to monitor the injections outflows or concentrations, optimizing the consumption of the involved products.

MODULES INTEGRATION

Due to the five EPC contracts strategy, P-50 Integration was a big challenge, from the detailing design up to the physical Integration. The inter-stage interface from the Compression Modules to the Gas Treatment Modules (built by another contractor) is an example of the complexity of the work. But the Electric and Automation integration of all modules to the Electrical Utilities Module and the Office&Control Module, respectively, was probably the most complex task during the detailing design.

Physical integration of the piping was made easily by the use of intelligent 3D modeling of all modules and the central pipe-rack. All the tie-backs were previously identified and measured.

The lift of the modules to the ship was made by the crane barge Kaisei, having broken the record of the heaviest lift ever made in Brazil (>1500 tons). The seating of the modules over the ship stools presented some problems due to differences in the as-built dimensions. These problems resulted in the need of a great deal of reinforcements in the modules supports. CONCLUSION

Years of experience operating FPSOs have produced a solid background for innovation in new projects. In P-50 design, this experience in converting 10 FPSOs allowed concept modifications in critical systems of the platform, such as the Compression, Marine, Offloading and Chemical Injection Systems. In order to minimize the risk of using new or modified concepts, factory and yard tests were carried out and witnessed by Petrobras, to guarantee that the equipment would perform as designed.

The innovations adopted in P-50 make this design a top of class FPSO conversion that will guarantee a reliable, safe and efficient operation.

ACKNOWLEDGMENTS

The authors thank PETROBRAS for permitting the publication of this paper. In addition, they acknowledge numerous colleagues from Petrobras who have helped to continuously improve our expertise on the management of big offshore projects. ABBREVIATIONS FPSO Floating Production Storage and Offloading VLCC Very Large Crude Carrier EPC Engineering, Procurement and Construction

10 OTC 18242

ECOS Estação Central de Operação e Supervisão (Central Station of Operation and Supervision)

URV Unidade de Recuperação de Vapor (Vapor Recovery Unit)

PLC Programmable Logic Controller VSD Variable Speed Driver O&M Operation and Maintenance KO Knock-Out THI Total Harmonic Index ISO International Standards Organization WHRU Waste Heat Recovery Unit CCM Central de Controle de Motores (Motor Control

Central) PMS Power Manager System. TGCP Gas Turbine Control Panel SLO Synthetic Lubrication Oil MLO Mineral Lubrication Oil CS Classification Society SRU Sulfate Removal Unit LSW Low Sulphate Water HSM High Sulphate Water P&ID Piping and Instrumentation Diagram HPU Hydraulic Power Unit REFERENCES [1] Saliés, J.B. et al “Albacora Leste Field: Challenges

Of An Ultra-Deepwater Development”, World Petroleum Congress 2002

[2] Mastrangelo, C.F. and Henriques, C.C.D. “Petrobras Experience On The Operation Of FPSOs”, International Society of Offshore and Polar Engineering – ISOPE 2000

[3] Santos, A.B., Henriques, C.C.D., and Pimenta, J.M.H.A., “Improvements Achieved in the Project of FPSO P-50”, Offshore Technology Conference OTC-2004.

[4] American Bureau of Shipping, Steel Vessel Rules, Part 4 – Vessel Systems and Machinery, USA, 2004.

[5] Vu, V. K.; Latapie, D. and Davis, R. A. “Barite Scale Prevention for Elf Angola’s Girassol Field Using Sulphate Removal Technology”, Deep Offshore Technology – DOT 1999.

[6] Heatherly, M. W., Marathon Oil Co; Howell, M. E., US Filter/WT; and McElhiney, J. E., Marathon Oil Co “Sulfate Removal Technology for Seawater Waterflood Injection”, OffshoreTechnology Conference – OTC 1994.

OTC 18242 11

Figure 1 - FPSO P-50 - 3D Model

Figure 2 - Cargo System Schematic Layout

12 OTC 18242

Figure 3 – Decision Tree for Materials Selection

1 - Petroleum, Gas and Produced Water

Chloride content above

50ppm?

Chloride content above

50ppm?

Carbon Steel

Coated Steel

Stainless Steel

Coated Steel

Duplex Steel

Carbon Steel

Coated Steel

Stainless Steel

Coated Steel

Duplex Steel

Coated Steel or Stainless Steel -

Operating temp.above 90ºC?

Coated Steel or Duplex Steel -

Operating temp.above 90ºC?

Coated Steel or Stainless Steel -

Partial Pressure of CO2 above 48.2kPag

(7psig)?

Carbon Steel or Coated Steel or Stainless Steel -

Partial Pressure of CO2 above

48.2kPag (7psig)?

Carbon Steel - Operating

temp.above 90ºC?

BSW above 35%?

Carbon Steel or Coated Steel or Stainless Steel -

Partial Pressure of CO2 above

48.2kPag (7psig)?

Carbon Steel - Operating temp.

above 90ºC?

Coated Steel or Stainless Steel -

Operating temp.above 90ºC?

Coated Steel or Duplex Steel -

Operating temp.above 90ºC?

Coated Steel or Duplex Steel -

Partial Pressure of CO2 above

48.2kPag (7psig)?

YESNO

NO YES

NO

NO NO

YES

YES YES

YES or NO

YES or NO

NO

NO NO

YES or NO

NO

YES

YES

YES

YESYES or NO

2 - For Gas

Condensation Probability?

Condensation Probability?

Carbon Steel

Carbon Steel

Carbon Steel

Coated SteelStainless

Steel

Partial Pressure of CO2 above 48.2kPag

(7psig)?

Special Steel or Coated Steel -

Operating

NO YES

NO YES YES

YES

NO

NO

P-122303A/B Crude Oil Inlet 57,3 941,4 2,5% 23,3 1190,3 59,9 4,8%BSW <

35% > 50ppmCoated Steel or

Special SteelCoated Steel or

Special SteelCoated Steel

(SHELL)Crude Oil Outlet 75,0 882,6 2,5% 21,8 1199,7 57,8 4,6%

BSW < 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Coated Steel

Design Condition 210,0 1471,0 2,5% 36,3 1190,3 59,9 4,8%

BSW < 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Duplex Steel

(TUBES) Hot Water --- --- --- --- --- --- --- --- --- --- --- ---

SG-122301A/B Crude Oil Inlet 75,0 882,6 2,5% 21,8 1199,7 57,8 4,6%BSW <

35% > 50ppmCoated Steel or

Special SteelCoated Steel or

Special SteelCoated Steel

Crude Oil Outlet 75,0 882,6 0,2% 1,8 1199,7 57,7 4,6%

BSW < 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Coated Steel

Gas Outlet 75,0 882,6 5,1% 44,7 0,0 0,0 0,0%BSW <

35% < 50ppm

Carbon Steel or Coated Steel or

Special SteelCarbon Steel Carbon Steel

Produced Water Outlet 75,0 781,0 0,2% 1,6 0,7 666,0 99,9%

BSW > 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Coated Steel

Design Condition 105,0 1471,0 5,1% 74,4 1199,7 57,8 4,6%

BSW < 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Duplex Steel

TAG Location T (ºC) P (kPa) CO2 (% mol)

Partial Press.CO2

(kPag)

Oil Flow (m3/h)

Water Flow (m3/h)

BSW % BSW Limit Chloride Chloride and BSW

Partial pressure of CO2

Temperature

Criteria (Max Oil Condition)

OTC 18242 13

P-122303A/B Crude Oil Inlet 54,4 941,4 0,2% 1,9 201,0 704,8 77,8% BSW > 35% > 50ppmCoated Steel or

Special SteelCoated Steel or

Special SteelCoated Steel

(SHELL)Crude Oil Outlet 75,0 882,6 0,2% 1,8 201,7 711,3 77,9% BSW > 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Coated Steel

Design Condition 210,0 1471,0 0,2% 2,9 201,7 711,3 77,9% BSW > 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Duplex Steel

(TUBES) Hot Water --- --- --- --- --- --- --- --- --- --- --- ---

SG-12230A/B Crude Oil Inlet 75,0 882,6 0,2% 1,8 201,7 711,3 77,9% BSW > 35% > 50ppmCoated Steel or

Special SteelCoated Steel or

Special SteelCoated Steel

Crude Oil Outlet 75,0 882,6 0,0% 0,2 201,1 36,5 15,4% BSW < 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Coated Steel

Gas Outlet 75,0 882,6 3,0% 26,1 0,0 0,0 0,0% BSW < 35% < 50ppm

Carbon Steel or Coated Steel or

Special SteelCarbon Steel Carbon Steel

Produced Water Outlet 75,0 781,0 0,0% 0,2 0,7 666,0 99,9% BSW > 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Coated Steel

Design Condition 105,0 1471,0 3,0% 43,5 201,7 711,3 77,9% BSW > 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Duplex Steel

Partial pressure of CO2 TemperatureBSW % BSW Limit Chloride

Chloride and BSW

CO2 (% mol)

Partial Press.CO2

(kPag)

Oil Flow (m3/h)

Water Flow (m3/h)TAG Location T (ºC) P (kPa)

Criteria (Max Water Condition)

P-122303A/B Crude Oil Inlet 59,9 941,4 1,3% 12,0 1055,6 249,3 19,1% BSW < 35% > 50ppmCoated Steel or

Special SteelCoated Steel or

Special SteelCoated Steel

(SHELL)Crude Oil Outlet 75,0 882,6 1,3% 11,2 1061,3 248,3 19,0% BSW < 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Coated Steel

Design Condition 210,0 1471,0 1,3% 18,7 1055,6 249,3 19,1% BSW < 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Duplex Steel

(TUBES) Hot Water --- --- --- --- --- --- --- --- --- --- --- ---

SG-12230A/B Crude Oil Inlet 75,0 882,6 1,3% 11,2 1061,3 248,3 19,0% BSW < 35% > 50ppmCoated Steel or

Special SteelCoated Steel or

Special SteelCoated Steel

Crude Oil Outlet 75,0 882,6 0,1% 0,5 1061,3 193,3 15,4% BSW < 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Coated Steel

Gas Outlet 75,0 882,6 4,1% 36,1 0,0 0,0 0,0% BSW < 35% < 50ppm

Carbon Steel or Coated Steel or

Special SteelCarbon Steel Carbon Steel

Produced Water Outlet 75,0 781,0 0,1% 0,5 0,7 666,0 99,9% BSW > 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Coated Steel

Design Condition 105,0 1471,0 4,1% 60,2 0,7 666,0 99,9% BSW > 35% > 50ppm

Coated Steel or Special Steel

Coated Steel or Special Steel

Duplex Steel

Chloride and BSW

Partial pressure of CO2

TemperatureWater Flow (m3/h)

BSW % BSW Limit ChlorideTAG Location

Criteria (Max Gas Condition)

T (ºC) P (kPa) CO2 (% mol)

Partial Press.CO2

Oil Flow (m3/h)

P-122303A/B Crude Oil InletCoated

SteelCoated

SteelCoated

Steel

(SHELL) Crude Oil OutletCoated

SteelCoated

SteelCoated

SteelDesign Condition

Duplex Steel

Duplex Steel

Duplex Steel

(TUBES) Hot Water --- --- ---

SG-12230A/B Crude Oil InletCoated

SteelCoated

SteelCoated

Steel

Crude Oil OutletCoated

SteelCoated

SteelCoated

Steel

Gas OutletCarbon

SteelCarbon

SteelCarbon

SteelProduced Water Outlet

Coated Steel

Coated Steel

Coated Steel

Design Condition

Duplex Steel

Duplex Steel

Duplex Steel

Max Gas

CASES

TAG Location Max Oil Max Water

Figure 4 – Worksheets for materials selection

Note1: for heat exchanger, duplex steel was selected due to the difficulty to manufacture an internally coated shell.

14 OTC 18242

Figure 5 - Basic block diagram for main gas

compression system

Figure 6 - Physical arrangement, main compression

system equipment.

Figure 7 – Schematic of the transformers/VSD/Motor of

the P-50 compressors

Figure 8 - Bow Offloading Station

Figure 9 - Stern Offloading Station