Experience

• Modelling of pipeline networks and review of the effects of network changes on compressor station operations.
• Modelling of centrifugal compressors and gas turbines in Mirade proprietary software suites.
• Aerodynamic modelling to determine the effect of revised system pressure regimes on compressor performance.
• DGS (dry gas seal) operating review.
• Integrated system modelling of multiple compressor stations and pipeline networks to determine optimum pressure regimes which took account of variations in demand, NTS and interconnector pressures, as well as network capacities and machinery capabilities (compressor and driver).
• Identification of demand and supply pressure ranges which would result in more challenging machinery operating conditions. Development of strategies to mitigate such effects.
• GT (gas turbine) fuel gas flows and costs calculations across a wide range of operating scenarios.
• Development of optimal operating strategies to minimise GT running hours and fuel gas consumption.
• Review of further asset operability improvement and OPEX reduction opportunities.

• Review of boroscope inspection reports, machinery operating histories and changes to ancillary equipment to determine an initial list of possible root causes.
• Development of plan for more-detailed investigations including GT strip-down at OEM’s facilities, specialist laboratory testing of components and control system reviews.
• Full GT strip-down witness and supervision on behalf of GT operator.
• Materials review.
• Review of control system parameters and sequences across steady-state operations, start-up and shut-down.
• In-depth cause and effect analyses across core engine, control system and ancillary plant to determine causes of component failure.
• Development of detailed plan of actions required to avoid recurrence of failure as well as to ensure improvements in ongoing GT health at operating site.

• Modelling of asset including centrifugal compressors, gas turbine drivers, process plant and wells (using Mirade proprietary simulation packages). Alignment to machinery vendor and plant operations data.
• Mean line aerodynamic analysis of stages within compressor section to develop revised performance map limits.
• Interrogation of machinery operating conditions in detail across a wide range of future process demands.
• Simulations of steady-state options to avoid machinery operating limits through adjustment of compressor and plant set-up and control.
• Steady-state option select based upon criteria such as machinery health, operability, maximum gas rates and implementation schedule.
• Review of DCS and anti-surge control system parameters to determine means by which operations team can avoid compressor limits and ensure health of machinery.
• Review of transient operating conditions and additional specific machinery health concerns.
• Risk assessment of operation through transient conditions and development of risk mitigation strategies.
• Guidelines for operations teams providing specific machinery and plant operating limits and instructions (both steady-state and transient) as well as methods to monitor key parameters and ensure machinery health.
• Methods developed by Mirade protected machinery without reducing maximum gas rates.

• Simulations of compression train operation under revised process conditions to determine extent of shift in machinery operating parameters from design intent. Simulations made using Mirade proprietary modelling packages.
• Assessment of key machinery health metrics to identify areas of concern.
• Compilation of risk factors with a review of each.
• Development of action plan.

• Peer review to ensure robustness of process simulator calculations.
• Review of effects of deviation of process operating conditions from original machinery design intent.

• Detailed review of design, build and maintenance history of machinery to identify causes of increased rotordynamic sensitivity.
• Reviews of ADRE data for start-ups and steady-state operation.
• Site surveys of machinery and associated plant.
• Project planning and management to ensure engagement and motivation of relevant parties – including compressor vendor.
• Witness of critical factory build activities during machinery overhauls / upgrades.
• Root cause analysis.
• Development of action plan.

Review of third-party project work related to:

• Feasibility of rewheeling within limitations imposed by existing casings and skid architecture as well as revised process conditions.
• Feasibility of operation of an existing centrifugal compressor at markedly different molecular weight; including the effects on performance envelopes and discharge temperatures.
• Planning for the development of a high pressure acid gas re-injection compression system with its associated technical and project challenges.
• Scheduling of FEED and detailed engineering as well as machinery tender and purchase.

• Reviewed ECLIPSE-produced production profiles including well rates, FTHPs, choke values and manifold pressures.
• Through more effective alignment of upstream and compression operations, reduced the compression power across the profile and enhanced installed driver power utilisation.
• Made compression selections for a number of options including a full aerodynamic analysis across the life of field for each design to quantify whether it benefited from the inclusion of a gearbox.
• Reviewed each option and determined the optimum solution having analysed them for achievable profiles, CAPEX and OPEX (fuel gas and CO2 taxation), frequency of machinery changes required to accommodate declining arrival pressures through time, ease of control (well control, manifold pressure and anti-surge), availability, flexibility to accommodate new production streams in the future, turbine loading / emissions and ultimate arrival pressure achievable.

• Devised a field development plan which included the client’s existing plans for the joint operation of reciprocating and centrifugal compression.
• Analysed data from existing ECLIPSE models in detail and used it to construct MBAL (reservoir tanks) and PIPESIM (wells and surface network) models. The PIPESIM model included field-aligned well-specific CGRs and WGRs, including correction of inflow performances for effects of water influx.
• Produced production profiles for various development scenarios and complemented them with CAPEX, OPEX and NPV analysis.
• Detailed reviews of reservoir inventories and pressures through time across the three reservoirs led to the introduction of new ideas for well development across the asset – extending plateau duration, enhancing post-plateau rates and greatly increasing cumulative gas produced.

• Worked in partnership with process engineering consultants on a project to expand the compression and processing capacity to afford the production of new well streams.
• Determined the increase in production rate achievable with feasible changes to machinery and plant in an offshore environment through detailed design reviews of compressor bundles and casings, gearboxes, electric motors and the platform’s power generation and distribution capacity.
• The recommended scheme involved rewheeling the compressors and replacing a gearbox and motor with increased power units while maintaining the same footprint and interface positions.
• Supported the practical implementation of the changes with API datasheets and close liaison with machinery OEMs

• With a multi-discipline team, determined the overall optimum solution required to maintain NGL plant entry pressure requirements across the remaining life of the asset.
• Investigated a very broad range of development options in detail (central-only compression, cluster-only and hybrid in addition to intrafield pipeline options as well as compression and driver types and power station options).
• Assessed each against many criteria including production profile adherence and enhancement, machinery / plant and multiphase pipeline operability, CAPEX / OPEX / NPV and risk to completion timescale.
• The recommended solution revised operating pressure philosophies for the three principal wellhead production streams – greatly reducing required power and CAPEX, enhancing management of pipeline liquids as well as allowing a phased introduction of compression facilities (reduced OPEX and enhanced NPV).
• Devised the development plan which included new compression trains and associated plant, separators, slugcatchers and intrafield multiphase pipelines.
• Ensured project continuity through the hand-over to FEED by producing detailed descriptions of machinery timetables (casings, rewheels, additional trains), suction / discharge manifold and segregation / commingling of production streams through time, operating philosophy for management of well / multiphase pipeline / machinery operations, control description, costings for major plant items ,H&M balances, API datasheets and plot plans.

• Used integrated asset modelling of new and existing facilities to determine new infrastructure required to add the Hatfield West reservoir to the existing gas storage asset.
• Investigated different well types, pipeline diameters and compression power options.
• Having determined the optimum power (through comparisons of peak rates, plateau rates as well as plateau duration and cumulative production achievable), reviewed CAPEX of variable speed electric motor vs. turbine drive, including the costs of grid connection.
• Developed a detailed action plan for Scottish Power, including; breakdown of CAPEX required, machinery purchase, sparing and service strategies as well as FEED project management to accelerate completion.

• Investigated various offshore and onshore compression reconfiguration options in detail to find the optimal solution that could accommodate future reduced flowing wellhead pressures, avoid overly low turbine loading and maximise operating efficiency to minimise CO₂ tax incurred.
• Referenced all economic calculations (sales revenue, CAPEX, fuel burn, CO₂ tax) to ‘do nothing’ case in addition to consideration of improvements in ultimate reserves recovery and field abandonment deferment.
• Used integrated asset modelling to determine the productivity of various options and identify the onset of system flow limits.
• Quantified the operational risks of long-term low power turbine operation through considering blow-off valve and guide vane operation as well as DLE combustion modes. Reviewed these against options for GG hardware modifications.
• Devised an introduction timetable for the recommended solution.

• Revamp of Rolls Royce Avon driven Dresser Rand gas lift compression trains made as part of the recommendations of the Claymore availability review in other project detailed below.
• Worked on a challenging compressor design that had to operate across a very wide range of molecular weights (start-up on import gas and operation on rich offgas).
• Performed analysis to determine head map shifts with different compositions to validate vendor proposals as well as changes to the surge line and requisite control functionality.
• Designs were also interrogated with respect to casing impeller number limits, head rise to surge, cooler and pipework temperature restrictions and the extent of offshore work required across options.

• Detailed investigation of operating capability of existing and rewheeled fixed-speed motor-driven Thermodyn compression trains under revised operating conditions.
• Simulations included JT cooling effects under recycle and careful consideration of low efficiencies achieved by the very low volume flow compressor.

• Simulated various compression options including rewheels, reconfiguration and the addition of a motor-driven booster.
• Produced production profiles for each option using a fully integrated model including multi-tank material balance gas-condensate reservoirs with aquifer support, wells, sub-sea tie-backs, topsides and compression trains.
• Investigated optimum timing of booster installation.
• Produced well schedules and resulting production profiles in accordance with well critical rates required to avoid well slugging.
• Produced rewheel datasheets

• Analysis of compression duty through time with a multi-tank material balance reservoir model with aquifer support, together with a highly complex well network and gathering system.
• Evaluated distributed (gas-engine-driven reciprocating) and centralised (GT-driven centrifugal) options.
• Conducted technical, CAPEX, OPEX and availability reviews of options, including rewheeling and re-staging timetables across a 40 year production profile.

• Used asset modelling to quantify the interaction between well performance and compressor load to find the optimum rewheel selections for these low volume flow machines.
• Modelled aerodynamic and overall compressor performances.
• Produced rewheel datasheets.
• Audited vendor rewheel designs.
• Produced production profiles for the rewheeled trains.

• Test plan and liaison with offshore commissioning and operations teams.
• Using UCPs in local control cab: Full-load test (forward flow on gas injection duty) and performance test on full recycle.
• Gas sampling.
• Performance analysis and report.

• Quantified factors restricting availability.
• Identified solutions.
• Developed implementation plan as well as operating strategies.

• Used integrated model to determine export and import compression requirements across campaigns for various machinery and well options.
• Identified the optimum compression power and number of wells.
• Investigated various compression arrangements and reviewed against their export/import profiles, capital cost, availability and operability.

• Reviewed attributes of series vs. parallel arrangements.
• Reviewed application of industrial and aero-derivative gas turbine drives, including performance at various speeds and ambient temperatures including emissions and field-operating and development histories of engines.
• Determined field gas compressor staging, casing and rewheel schedules to accommodate declining suction pressures through life of facility.
• Ensured sufficient turbine power will be available across a wide range of conditions including start-up at high ambient temperatures.
• Compiled machinery datasheets and specifications.
• Simulated deliverability of asset across seasonal temperature variations and declining arrival pressures through time.

• Investigation of possible rewheel options to optimise future operations.
• Aerodynamic simulations of existing and rewheel designs.
• Conducted simulations of operation of various designs at maximum turbine power and quantified benefits of each option.
• Technical meetings with OEM.

• Field testing of Solar Taurus driven Alice Chalmers compressor.
• Development and field alignment of model of entire facility from reservoir and wells, through machinery and process plant to NTS. Model then used by Scottish Power for forecasting production and injection rates.

• Used asset model to identify opportunities to increase injection rates, including compressor rewheeling, revised operating method and gas turbine upgrades. Recommended suitable turbine upgrade (GG and PT).
• Determined new offshore compressor designs that greatly increased design and operating efficiencies which, together with the turbine upgrades, led to significantly increased injection rates.
• Validated offshore upgrade proposal by quantifying increased flows across injection campaign using integrated asset model.
• Tested the trains during commissioning – see project listed separately above.

• Test plan and liaison with operations teams.
• Offshore testing in full recycle from local control cab.
• Aerodynamic design analyses.
• Performance test analysis.
• Rewheel design recommendations to accommodate declining well pressures.

• FAT (Factory Acceptance Test) witnessing engineer: Used test-stand data to calculate compressor performance and check against vendor-predicted data for MAN Turbo fixed speed motor driven booster compressor.
• Field testing in full recycle of MAN Turbo variable speed motor driven export compression trains following commissioning.

• Conducted matrix of aerodynamic simulations to determine the optimum shaft speed and interstage pressures.
• Took cognizance of driver power margins, balance-piston leakages and compressor discharge temperatures on staging and intercooling requirements.
• Ensured designs had adequate resilience under various operating scenarios.
• Completed audits of technical submissions from compressor vendors.

• Performance tested six offshore compression trains and supervised fluid sampling.
• Investigated effects of turbine flat-rating and compressor anti-surge control margins on train capacity.
• Conducted mass balances across asset, both from compression flows and powers as well as separator fluid sampling and GORs (gas oil ratios).
• Determined procedures required for installation of 130 and 161 series Avon gas generators across different engine bays.
• Investigated compressor orifice flow meter measurements and knock-out drum duties.
• Completed reliability and availability studies.
• Devised a detailed action plan of short, medium and long-term maintenance activities and procedures.
• Developed road map of compression improvement, upgrade and expansion options.

• Modelled existing and new satellite well networks and intrafield pipelines.
• Quantified the deliverability of centralised and distributed booster compression across 16 years of depletion.
• Determined optimum timing of introduction of booster compression and new satellite fields to maintain required plateau production.
• Determined strategies to significantly reduce the required compression power by optimising commingling pressures from low, medium and high pressure wells in conjunction with booster compression operation.
• Determined the optimum compression power, the number of trains required and number of compression stages through life of the field.
• Calculated length of plateau production and post-plateau production rates.

• Conducted on-site performance testing and analysis of PGC trains.
• Quantified the effect of various phenomena on PGC throughputs.
• Following software analysis of data from initial platform visit, devised and supervised follow-up offshore testing to demonstrate the effect of capacity limiting phenomena identified by simulations. Demonstrated live how to greatly increase gas throughput.
• Developed action plans to greatly increase compression system flows through specific maintenance activities on existing machinery and associated plant.
• Investigated gas-liquid stabilities through the various knockout drums and quantified proximities to phase boundaries.
• Conducted aerodynamic analyses of PGC designs.
• Completed availability and reliability analyses of trains.
• Derived various PGC train upgrade & replacement options including rewheeling, turbine upgrades and full-scale replacement of trains.
• Investigated cost, space and weight implications of machinery upgrades.

• Through detailed modelling, demonstrated the proximity of operations at the new location to maximum speed, choke and recycle, for operation at various pressure ratios.
• Designed rewheel selections for three stages within proven tip speed limits while balancing head and volume flow attributes of impellers within aerodynamic limits and maintaining sufficient rotordynamic separation margins.

• Investigated potential consequences of prolonged operation at low turbine power, such as proximity of turbine operations to bleed-valve and VGV actuation boundaries for various aerodynamic speeds.
• Recommended operating strategies to enhance turbine availability, and ensured compliance with compressor operating envelopes.
• Made recommendations with respect to maximum head of compressor rewheel to ensure integrity of ancillary equipment.
• Investigated effect of head limitations on field deliverability.

• Minimised power consumption by identifying optimum interstage pressure and rated design speed.
• Quantified effects of balance-piston leakages on power.
• Validated equations of states for high pressures and high H2S content.
• Ensured designs benefited from solid centrifugal compressor design attributes to enhance performance retention in a challenging application.
• Investigated compressor operating conditions and motor loads with fixed speed and variable speed (fluid-coupling) selections.
• Determined motor loads.
• Conducted technical audits of proposals from compressor vendors.
• Reviewed technical attributes of vendor selections.

• Determined required centrifugal compressor maintenance/replacement strategy.
• Analysed separator capacities and produced offgas compression operating limits.
• Determined possible refinements of anti-surge control system set-points.
• Produced rewheeling and control system upgrade strategy and verified its suitability under present and future offgas loadings.

• Used modelling to quantify duty of new fixed-speed motor-driven booster centrifugal compressor under various operating regimes.
• Designed new compressor and proved performance in isolation and while running in parallel with existing Demag Delaval motor driven unit.
• Investigated existing and proposed infrastructure and control systems and their suitability in new arrangement.
• Detailed required changes to valving and control system to maintain adequate load sharing and operating stability.
• Devised suction pressure set points across production profile to optimise compressor operation with fixed speed drives.

• Site visits to quantify performance of various gas-lift centrifugal compression trains including MAN-Turbo, Dresser Clark and Solar turbine and motor-fluid coupling drives.
• Surveyed process conditions and their effect on compressor control.
• Quantified resilience of control systems and set points.

• Aligned integrated model of South Morecambe asset to field data, which included reservoirs, wells, processing and compression systems.
• Added newly drilled well in satellite reservoir and its tieback to the model.
• Devised operating requirements of rewheeled compressors across a production profile under various operating regimes and within power limits of installed turbines.
• Designed compressor rewheels for offshore and onshore compression units (Demag-RB211 and Dresser-Vectra trains).
• Produced data sheets for submission to OEMs.
• Conducted technical audits of various vendor selections, including reviews of their technical attributes to ensure alignment with required operating envelopes.
• Completed on-site software training of gas field operating staff.

• Investigated various casing arrangements and load/head sharing.
• Proposed and simulated various design options and quantified the effects on key compressor performance attributes.
• Audited vendor proposals and formulated design and selection recommendations.

• Evaluated operation and performance of existing RB211-24G driven Demag compression trains to verify need for rewheel.
• Developed model of entire facility including reservoirs, gathering systems, pipelines, compressors, turbines, and inert removal processes.
• Optimised rewheel selection to maximise power utilisation while avoiding recycle.
• Investigated options and strategies for future compression station reconfiguration and expansion.
• Determined optimum compression power across five-year period
• For future reconfiguration options, examined and quantified technical limits, capital cost, operational stability, plant disruption and reuse of existing plant.
• Identified compression revamp strategy.

• Investigated mechanical design including compressor performance indicators, speed matching of casings, tip speeds, material selections, and vendor’s experience list of high head impellers.
• Identified system constraints and their effect on operating envelope.
• Conducted extensive simulations of new design under various production regimes.

• Analysed process plant data to provide compressor performance evaluation of 2 x 7 MW variable speed electric motor driven Nuovo Pignone centrifugal trains.
• Modelled compression system to quantify capacity and process constraints.