The schematic diagram shown above presents the majority of the issues which need to be considered in developing a multiphase tieback. These issues are divided into the colour coded subgroups Energy, Integrity, Delivery, and Overall. If you wish more information directly on corrosion, for example, click on the word ‘Corrosion’ to take you to the guidelines on this subject. Click on the titles ‘Energy’, ‘Integrity’, ‘Delivery’, and ‘Overall’ in the diagram above to move you to the relevant page which lists the related issues.
Ti eb ac k Gu i d el i n es The schematic diagram shown above presents the majority of the issues which need to be considered in developing a multiphase tieback These issues are divided into the colour coded subgroups Energy, Integrity, Delivery, and Overall If you wish more information directly on corrosion, for example, click on the word ‘Corrosion’ to take you to the guidelines on this subject Click on the titles ‘Energy’, ‘Integrity’, ‘Delivery’, and ‘Overall’ in the diagram above to move you to the relevant page which lists the related issues overall production system optimisation field development architecture selection interaction of slugging & pipe fittings separator performance interaction with facilities performance separator pressure setpoint piping layout pressure loss relief and blowdown slugcatcher design drag reduction flowrate change temperature loss slugging (steady state) slugging(transient) multiphase boosting multiphase metering liquid inventory corrosion wellhead shut-in pressures pressure loss temperature loss slugging in horizontal wells interaction with reservoir performance interaction of slugging and risers pigging severe slugging prevention gas & dense phase export oil & condensate export hydrate control wax deposition erosion ashphaltenes artificial lift method selection sand/solids transport scale desposition gas lift system stability well testing pvt sampling pvt characterisation Energy Integrity Delivery Overall Use of these guidelines The schematic diagram shown above presents the majority of the issues which need to be considered in developing a multiphase tieback These issues are divided into the colour coded subgroups Energy, Integrity, Delivery, and Overall If you wish more information directly on corrosion, for example, click on the word ‘Corrosion’ to take you to the guidelines on this subject Click on the titles ‘Energy’, ‘Integrity’, ‘Delivery’, and ‘Overall’ in the diagram above to move you to the relevant page which lists the related issues go to Front Page Energy Issues Provision of sufficient pressure to transport required flow rates of hydrocarbons from reservoir to process • Pressure loss in flowlines • Drag reduction • Separator pressure setpoint • Slugging in horizontal wells • Pressure loss in wells • Gas lift system stability • Artificial lift method selection • Interaction with reservoir performance • Remote multiphase boosting go to Front Page Pressure Loss in Flowlines Appraise, select, define Principal reasons for investigating: to ensure the basic flowline system design is adequately sized to cover the range and uncertainty of flows over field life Secondary reasons for investigating : • to ensure that revisions to design to manage changes in reservoir predictions, temperature management, and additions from other fields, are checked for adequate size Upstream Technology Group contacts: Key data requirements: Phil Sugarman (Sunbury), Norm McMullen (Houston) • flowrate vs BHFP through life data; completion data; PVT data (black oil - bubble point, oil viscosity, three Business Unit contacts: stage flash data; condensate - full compositional description); proposed slugcatcher/first stage separator Nathan Barrett, Peter Bradley (Wytch Farm) pressure; specification of any artificial lift devices; route dimensions (length, topography) Contractors/consultants with relevant experience: Key work activities: • use a steady-state multiphase simulator to model well and flowline network to give pressure loss and velocity data as a function of flowrates Key output: • recommendations of line size[s] for the field flow line network go to Front Page Software packages: MULTIFLO (inhouse BP Amoco VAX), PIPESIM, PIPEPHASE, PROSPER/GAP Information on Intranet: Separator Pressure Setpoint Appraise, select, define Principal reasons for investigating: to ensure an adequate pressure drop is available from sand face, through the wells and flowlines [and risers], to the first stage separator, for the required flow rates through field life Secondary reasons for investigating : • to optimize this pressure, taking into account both reservoir performance and processing efficiency Key data requirements: • reservoir pressure and production rate as a function of time; gas-oil ratio as a function of pressure and temperature; range of expected pressure drop from sand face to separator as a function of flow rates, tubing and line sizes; compression costs as a function of flowrates, separator pressure and required export or reinjection pressure Upstream Technology Group contacts: Phil Sugarman, Bryn Stenhouse (Sunbury), George Shoup (Houston) Business Unit contacts: Contractors/consultants with relevant experience: Key work activities: • use iteration, preferably in a software package, to investigate the influence of separator pressure set point on system equipment requirements, export compression, and thereby the influence on costs, production rates, and recovery go to Front Page Software packages: HYSIS, PROSPER/GAP/MBAL Information on Intranet: Pressure Loss in Wells Appraise, select, define Principal reasons for investigating: to ensure the basic well/flowline system design is adequately sized to cover the range and uncertainty of flows over field life Secondary reasons for investigating : • check revisions to system design following changes in reservoir predictions, and possible additions from other field developments Upstream Technology Group contacts: Key data requirements: Phil Sugarman, Simon Bishop (Sunbury), • flowrate vs BHFP through life data; completion data; Norm McMullen (Houston) PVT data (black oil - bubble point, oil viscosity, three stage flash data; condensate - full compositional description); proposed slugcatcher/first stage separator Business Unit contacts: pressure; specification of any artificial lift devices Contractors/consultants with relevant experience: Key work activities: • use a steady-state multiphase simulator to model well and flowline network to give pressure loss data as a function of flowrates Key output: • recommendations of line size[s] for well tubing and the field flow line network go to Front Page Software packages: MULTIFLO (inhouse BP Amoco VAX), PIPESIM, PIPEPHASE, PROSPER/GAP Information on Intranet: Artificial Lift Method Selection Select, define Principal reasons for investigating: to identify the most appropriate option(s) for adding energy to, or reducing the pressure drop through, the well/flowline system Secondary reasons for investigating : • ensure revisions to design due to changes in reservoir predictions and facilities design, are also compatible with the selected artificial lift options Upstream Technology Group contacts: Key data requirements: Phil Sugarman, Paul Fairhurst, Simon Bishop (Sunbury), • flowrate vs BHFP through life data; completion data; Norm McMullen, Dan Yee (Houston) PVT data (black oil - bubble point, oil viscosity, three stage flash data; condensate - full compositional description); proposed slugcatcher/first stage separator Business Unit contacts: Schiehallion (Doug Wood, Dyce), Angola (Leofric Studd, pressure; full specification of artificial lift devices Sunbury ) and chemicals Key work activities: • screen the wide variety of possible artificial lift options for those which may genuinely be applicable to the conditions of the system under investigation • use a steady-state multiphase simulator to model well and flowline network to give pressure loss data as a function of flowrates with the inclusion of various combinations of ‘artificial lift’ systems, including, but not limited to gas lift, electric submersible pumps, multiphase boosters, drag reducing agents, partial processing • evaluate the economic benefits of the various combinations, including installed costs, operating costs, costs of intervention, and value of additional go to hydrocarbon production Front Page Contractors/consultants with relevant experience: Software packages: MULTIFLO (inhouse BP Amoco VAX), PIPESIM, PIPEPHASE, PROSPER/GAP, REO, BOAST Information on Intranet: UTG Enhanced Productivity team Enhanced Productivity Multiphase Boosting Appraise, select, define Principal reasons for investigating: to determine whether remote multiphase boosting [with or without phase separation] is a potential alternative to more conventional energy addition or pressure drop reduction schemes Secondary reasons for investigating : • to specify the detailed requirements for the multiphase boosting technology for the given application Key data requirements: • gas, oil and water flowrates through life data; required pressure increase; gas volume fraction at pump inlet conditions; likelihood and magnitude of slugging upstream of the booster Upstream Technology Group contacts: Andrew Humphrey (Sunbury), George Shoup (Houston) Business Unit contacts: ETAP, Cusiana Key work activities: • • determine which of the multiphase boosting schemes are liable for the application, as affected by flow rates, gas volume fraction at inlet, pressure addition requirement, and work into the field development architecture considerations present the range of required operating characteristics to the multiphase boosting vendors Contractors/consultants with relevant experience: Bornemann, Leistrizt, R&M Tri-Phase, Framo, Sulzer, Ingersoll-Dresser Software packages: Information on Intranet: http://ut.bpweb.bp.com/pf/multiphase/mpb/default.htm Multiphase Boosting Copy of BP Amoco Net.url go to Front Page Drag Reduction Select Principal reasons for investigating: to determine the potential for drag reducing agents to be used to reduce pipe size specifications, or de-bottleneck existing systems Secondary reasons for investigating : Upstream Technology Group contacts: Helen Kerr, Lawrence Tebboth (Sunbury) Key data requirements: • gas and liquid hydrocarbons composition; water cut as a function of time; flow line predicted flowing velocity, pressure loss, and required reduction in pressure loss; flow regime if multiphase Business Unit contacts: Key work activities: • • use a multiphase simulation software package to assess the possible reduction in line size, or increase in flow rate, associated with the performance of the available drag reducing chemicals assess the influence on the value of the produced hydrocarbons if the drag reducing chemicals stay in the product Contractors/consultants with relevant experience: Conoco Du Pont Software packages: Information on Intranet: http://upstream.bpweb.bp.com/ut/default.asp?id=195 Drag Reducing Additives Copy of BP Amoco Net.url go to Front Page Slugging in Horizontal Wells Define Principal reasons for investigating: to estimate the effect on productivity from long slugs generated in horizontal wells propagating up the more highly inclined sections Secondary reasons for investigating : • to manage the risk of damage to electric submersible pumps from varying loads during slug flow Key data requirements: • well inflow performance as a function of length; horizontal well section topography, and deviated well section geometry Key work activities: • • determine the mean and likely maximum slug sizes which could be generated in a horizontal well section, and determine the possible pressure/flow rate variations at the wellhead as a result Use data to evaluate separator/slugcatcher requirements ensure the specification for any electric submersible pumps includes an estimate of the frequency of slugging, the magnitude of the fluid density change, and the proportion of field life over which such a flow regime is expected go to Front Page Upstream Technology Group contacts: Phil Sugarman, Paul Fairhurst (Sunbury), JJ Xiao (Houston) Business Unit contacts: Matthew King (Wytch Farm) Contractors/consultants with relevant experience: Multiphase Solutions Inc (Houston) Software packages: OLGA Information on Intranet: Slugcatcher Design Select Principal reasons for investigating: to ensure the design of the first vessel downstream of the flow line and any riser can handle the predicted surges in flow rate from slug flow and system transients Secondary reasons for investigating : Key data requirements: • predicted range of slug size, velocity and frequency for steady-state conditions through field life; maximum expected slug from transient operations Upstream Technology Group contacts: Phil Sugarman (Sunbury), George Shoup (Houston) Business Unit contacts: Key work activities: • • • • • determine the surge volume required to cope with all possible slug deliveries, initially by steady-state calculation, and eventually by full dynamic model assess options for slugcatcher design, including vessel or finger, or subsea caisson ensure control system is written to control on flow rate and allow the level to vary try to restrain the process designers from using this vessel as a phase separator ensure that the process designers are aware of the residual flow rate variations that are inevitable even if controlling on flow rate go to Front Page Contractors/consultants with relevant experience: Multiphase Solutions Inc (Houston); Software packages: MULTIFLO, PIPESIM, OLGA, PETRA Information on Intranet: Severe Slugging Prevention Select Principal reasons for investigating: to determine the necessity for ways of preventing the occurrence of severe slugging, and to specify one or more appropriate measures Secondary reasons for investigating : Key data requirements: • likelihood of low flowrates operation, and typical low flow rates; gas and liquid densities; flowline length, topography and diameter; riser height and diameter Key work activities: • • use a flow regime prediction model to determine the area of the severe slugging regime for the specified geometry assess options for managing severe slugging, including avoiding low flow rates, riser based gas injection, riser top choking valve, Shell severe slug suppression device, re-specifying line diameter, changing flow line route to riser base go to Front Page Upstream Technology Group contacts: Phil Sugarman (Sunbury), George Shoup (Houston) Business Unit contacts: Doug Wood (Schiehallion) Contractors/consultants with relevant experience: Multiphase Solutions Inc (Houston); Software packages: MULTIFLO, PIPESIM Information on Intranet: Effect of Flowrate Change Select Principal reasons for investigating: to predict the surge volume and outlet flow rates resulting from an inlet flow rate increase, to feed in to design of slugcatcher/separator and the subsequent process equipment Secondary reasons for investigating : • to put necessary constraints on commercial negotiations concerning rate of flow rate increase Key data requirements: • flowrates through life data; gas and liquid hydrocarbons composition; anticipated flow rate ramp up ranges, especially those fixed in sales contracts Upstream Technology Group contacts: Paul Fairhurst (Sunbury), George Shoup (Houston) Business Unit contacts: Key work activities: • • • • use a transient multiphase simulator to run a flow rate condition to steady-state, and then increase the flow rate to a specified amount in a specified time increment record the maximum out flow rates and volumes of liquid and gas following the transient repeat for the range of flow rate ramps connect the transient multiphase simulator to a dynamic process plant simulator as the design work progresses to determine the effect of the surging on downstream process equipment go to Front Page Contractors/consultants with relevant experience: Multiphase Solutions Inc (Houston); Scandpower Software packages: OLGA, DSPICE, HYSIS Information on Intranet: Temperature Loss in Wells and Flowlines Select Principal reasons for investigating: to determine the requirements for protection against hydrate formation and wax deposition, and for process heating to break emulsions Secondary reasons for investigating : Key data requirements: • flowrate vs BHFP through life data; completion data; PVT data (full compositional description); proposed slugcatcher/first stage separator pressure; specification of flowline, seabed, water column and riser elevation and thermal characteristics Upstream Technology Group contacts: Carl Argo, Phil Sugarman (Sunbury ) , George Shoup (Houston) Business Unit contacts: ETAP (Tony Boyle) Key work activities: • • • • • use a steady-state multiphase simulator to model well and flowline network to give fluid temperature data as a function of flowrates and distance along pipe use a transient simulator to predict cooldown times from a variety of starting conditions use a fluid property prediction package to determine the hydrate formation locus on a pressure temperature diagram use a fluid property prediction package to determine wax deposition rates use fluid samples to determine emulsion forming tendency go to Front Page Contractors/consultants with relevant experience: Scandpower for cooldown Multiphase Solutions Inc, Flow Assurance Solutions Ltd for wax and hydrates Software packages: MULTIFLO, PIPESIM, PIPEPHASE, PROSPER/GAP for steady-state temperature OLGA for cooldown GENESIS, HYSIM, GUTS for hydrate prediction GUTS for wax prediction Information on Intranet: Piping Layout Select Principal reasons for investigating: to ensure the flowline and piping system design is correctly designed for slug flow, and any requirement for flow splitting is satisfactorily designed Secondary reasons for investigating : • to manage the risk of damage by external flows of wind or water Key data requirements: • slug characteristics - frequency, velocity, liquid holdup, for conditions through field life Key work activities: • • • • if any flow division is required, ensure design guidelines are followed calculate slug loads on bends as a function of liquid holdup and velocity, and pass information to piping stress engineers ensure piping layout design prevents any unsupported bends in the vicinity of nozzles into vessels determined likelihood of vortex induced vibration for unsupported sections subject to wind or current go to Front Page Upstream Technology Group contacts: Trevor Hill (Sunbury) Business Unit contacts: Contractors/consultants with relevant experience: Software packages: Information on Intranet: Multiphase Metering Select Principal reasons for investigating: to specify and commission appropriate remote and host multiphase metering systems for well test and/or allocation duties to: minimise CAPEX and OPEX: improve production data availability by more frequent or continuous measurement; improve accuracy and efficiency of production data acquisition Secondary reasons for investigating : Free up additional process capacity Key data requirements: • flowrates and flow regimes through life data; gas and liquid hydrocarbons composition; water cut and salts content as a function of time; measurement accuracy requirements; required mean time between failures; possibility of in situ measurement verification Key work activities: • • • • • • Upstream Technology Group contacts: Bill Priddy (Sunbury), Bob Webb (Houston) Business Unit contacts: ETAP, Colombia, GUPCO Contractors/consultants with relevant experience: Framo, MFI, Fluenta, Agar, ISA, Kvaerner, UK National Eng Lab assess the end user needs - surveillance/reservoir/well engineering determine the likely range of in situ volume flow rates to be measured, and of in situ gas volume fraction and Software packages: water-liquid ratio ESMER (Petroleum Software) assess options available commercially satisfying all the above requirements Information on Intranet: consider test of meters against test rig standards http://ut.bpweb.bp.com/pf/multiphase/mpmeter/default.htm arrange calibration of any meters existing in field Multiphase Metering against which the multiphase meters will be compared Copy of BP Amoco Net.url determine means of furnishing/sampling fluid property and PVT data through service life for calibration parameter setting and conversation of reporting units go to Front Page Gas and Dense Phase Export Select Principal reasons for investigating: to design an export system for gaseous or dense phase hydrocarbons to match projected production rates Secondary reasons for investigating : Key data requirements: • required gas export flowrates through life data; gas hydrocarbons composition; required delivery pressure; requirement for exporting liquids as a dense phase; dewpoint and water content specifications Upstream Technology Group contacts: Phil Sugarman (Sunbury), Jim Best (Houston) Business Unit contacts: CATS, Miller Key work activities: • • • • use a gas pipeline hydraulics model to determine pressure loss as a function of diameter, and related compression and cooling requirements investigate line pack options assess options for transporting liquid as a dense phase pass specifications of pipeline to pipeline engineering group go to Front Page Contractors/consultants with relevant experience: Software packages: TGNET, HYSIS, MULTIFLO, PIPESIM Information on Intranet: Oil and Condensate export Select Principal reasons for investigating: to design an export system for liquid hydrocarbons to match projected production rates Secondary reasons for investigating : Key data requirements: • required liquid export flowrates through life data; liquid hydrocarbon density and viscosity; required delivery pressure; water content specifications Key work activities: • • • use a liquid pipeline hydraulics model to determine pressure loss as a function of diameter, and related pumping and cooling requirements assess and implement corrosion protection requirements pass specifications of pipeline to pipeline engineering group Upstream Technology Group contacts: Lawrence Tebboth (Sunbury), Dwight Reid (Houston) Business Unit contacts: Forties Pipeline System; BP Amoco Pipeline Company; TAPS Contractors/consultants with relevant experience: Software packages: TLNET Information on Intranet: go to Front Page Separator Performance Select Principal reasons for investigating: to ensure the separator design is suitable for the specified range of gas, hydrocarbon liquid, and water flow rates Secondary reasons for investigating : • to ensure appropriate solids removal facilities are available Key data requirements: • • flowrates through life data; gas and liquid transport properties [viscosity, surface tension, density]; emulsion characteristics, foaming tendency produced solids size range and expected flow rates [lb/’000 bbl] Key work activities: • • • use a separator sizing model to generate a vessel design with sufficient residence time for gas-liquid separation, and hydrocarbon liquid-water separation specify an appropriate inlet device, internals, and outlet devices to optimize the vessel size given the foaming and emulsion characteristics of the phases specify a sand wash system if significant solids are possible during field life Upstream Technology Group contacts: Brian Oswald, Helen Kerr (Sunbury) Business Unit contacts: Contractors/consultants with relevant experience: AEA Technology Software packages: PROSEPARATOR Information on Intranet: Separator performance and selection guidelines Separation Technology Area Sandwashing guidelines are available in the Multiphase Design Manual go to Front Page Overall Issues Issues affecting overall development concept, including fluid data requirements • Well testing • Field development architecture selection • PVT sampling • Overall production system optimisation • PVT characterization go to Front Page Well Testing Appraise Principal reasons for investigating: to provide information on reserves, reservoir barriers, well productivity, and to collect substantial volumes of fluids for characterisation of fluid properties and behaviours and to obtain mud free samples to check open hole samples Secondary reasons for investigating : • to provide pressure gradient surveys through the well to confirm the most appropriate pressure loss correlation Key data requirements: • estimate of likely production rate from the well to enable adequate sizing of separation and storage facilities Key work activities: • • • ensure that the drilling contract includes time and budget allowance for well testing, and appropriate separation and storage facilities on the vessel ensure that the gas and liquid metering facilities are adequate and properly calibrated Refer to PVT specialists for collection of PVT quality samples Upstream Technology Group contacts: Alan Stephen (Sunbury), Dave Bergman, George Shoup (Houston) Business Unit contacts: Contractors/consultants with relevant experience: Software packages: n/a Information on Intranet: Well Testing Technology Area Copy of BP Amoco Net.url go to Front Page PVT Sampling Appraise Principal reasons for investigating: to obtain adequate volumes of reservoir fluids for analysis to confirm fluid properties for reserves estimation, reservoir and facilities modelling Secondary reasons for investigating : • Geochemical analysis for basin modelling and prediction of fluids variation and compartments within the reservoir Key data requirements: • • reservoir/facilities uncertainties influence quality of samples required geochemist’s predition of, or knowledge of, fluid type (gas, oil, viscous oil) can influence sampling methods Upstream Technology Group contacts: Alan Stephen (Sunbury), David Bergman, Shen Tai-Lee (Houston) Business Unit contacts: Key work activities: • • • • • • • consult PVT specialists at an early stage in planning the well ensure drilling plans includes the collection of reservoir fluid samples as a priority, in terms of time, budget, and attention to procedures If the well is not to be flow tested then mud type becomes critical, as open hole sampling procedures triplicate samples are required to prove sample validity measure pressure and temperature at which samples were obtained - and also ensure that reservoir temperature and pressure are measured ship samples to PVT contractor for analysis QC data and compare with analogue fluid data for open hole sampling, take mud samples go to Front Page Contractors/consultants with relevant experience: Software packages: Information on Intranet: Guidelines for taking fluid samples Fluids Sampling PVT Characterisation Appraise, select, define Principal reasons for investigating: to calibrate and validate models used to predict phase envelope and associated fluid physical properties Secondary reasons for investigating : Key data requirements: • • • • gas/oil ratio, stock tank API, gas gravity, field shrinkage factors, gas and liquid compositions to C36+ laboratory studies for equation of state tuning - CCE (at temperatures), CVD, Differential liberation including viscosity and effluent compositions, seperator test ashphaltene and wax contents cruide oil assay Key work activities: • • • from the input fluid data use a fluid property prediction software package and adjust the tuning factors until the software adequately predicts the measured fluid densities, gas-oil ratio, bubble point and other PVT data ensure that these predictions can be reproduced in all the software packages to be used for other analysis which include fluid property data requirements use the tuned Equation of State to simulate reservoir and facilities performance go to Front Page Upstream Technology Group contacts: Mike Roffey, Phil Sugarman (Sunbury), Sheng Tai-Lee, Dave Bergman, Norm McMullen (Houston) Business Unit contacts: Contractors/consultants with relevant experience: Multiphase Solutions Inc (Houston); Calsep; AEA Technology Software packages: GUTS, PVTOL, PVTsim, GENESIS, HYSIS, PVT (for PROSPER/GAP), Winprop Information on Intranet: Reservoir Fluids Includes information on fluids data uncertainty, GOR estimation, and a list of who to speak to on a wide range of fluids issues Field Development Architecture Selection Appraise, select Principal reasons for investigating: to determine the most appropriate layout of wells, flowlines, facilities, export methods, to meet targets for field development [CAPEX, rate of return, production rates, recovery factor] Secondary reasons for investigating : • to determine where new technology can make a substantial contribution to meeting the development targets Key data requirements: • expected well flow rates, and fluid characteristics, starting reservoir conditions, expected reservoir support mechanisms, metocean/terrain constraints, legislative requirements Upstream Technology Group contacts: Nigel Pollard (Sunbury), Tom von Aschwege (Houston) Business Unit contacts: Key work activities: • • study the benefits and difficulties, and costs, of various field development architecture options work the various issues in sufficient detail to be able to rank the options this will include the groups of multiphase issues [energy, integrity, delivery], as well as processing requirements, well intervention requirements, subsea equipment reliability…consider issues as a function of for your life also, including requirements for reservoir pressure support, water handling go to Front Page Contractors/consultants with relevant experience: Software packages: PROSPER/GAP, CRYSTAL BALL Information on Intranet: Overall Production System Optimisation Select Principal reasons for investigating: to ensure the as built system produces as much hydrocarbon as possible from the reservoir Secondary reasons for investigating : • to de-bottleneck before production commences Key data requirements: • reservoir details for input into multiple tank model; all completion details, including factors affecting inflow performance; all flow line specifications; process plant constraints Upstream Technology Group contacts: Simon Bishop (Sunbury), Norm McMullen (Houston) Business Unit contacts: Key work activities: • • build the Integrated Asset Model for the field assess opportunities to increase production by adjusting plant constraints, well productivity etc Contractors/consultants with relevant experience: Petroleum Experts Software packages: PROSPER/GAP/MBAL Information on Intranet: go to Front Page ...Use of these guidelines The schematic diagram shown above presents the majority of the issues which need to be considered in developing a multiphase tieback These issues are divided... flows over field life Secondary reasons for investigating : • check revisions to system design following changes in reservoir predictions, and possible additions from other field developments... rates, gas volume fraction at inlet, pressure addition requirement, and work into the field development architecture considerations present the range of required operating characteristics to