Engineering and Engineering Management

Peritus reviewed the Field Development Plan (FDP) and the Pre-Project Scope of Work (SoW) for a large LNG development, to support our client in its endorsement of the project and ultimately ensure a successful progression towards FID. Peritus provided advice to enable our client to (a) make informed decisions (b) understand the key risks and opportunities associated with the development and (c) positively influence the project team to maximise the value of the project to all stakeholders.  Peritus offered direction in the following areas:

• Ensure the work performed in the Pre-Project phase is focused on (a) The requirements to pass through the decision gate from Pre-Project to Basic Engineering, (b) Key Decisions that require completion prior to entering Basic Engineering, (c) Focus Areas that require work in the Pre-Project phase to enable the completion of decisions in later phases and (d) Risks / Opportunities for which mitigation / realisation strategies are required
• Peritus identified and prioritised the Key Decisions relating to the facilities aspects of the project.
• The major facilities risk areas were identified as were opportunities for value addition.
• Peritus suggested a range of assurance reviews and value improvement practices (VIPs) that would typically be expected within a Pre-Project phase

The client was considering offshore and nearshore FLNG options for the development of the remote Gas Fields offshore PNG.  Peritus performed a technical overview of the development concepts evaluating FLNG technology status and applicability to development, potential for aggregation with other fields and assessed overall development complexity.

Following a significant gas discovery in an onshore remote location, Peritus’s client requested to investigate potential to maximise the Estimated Ultimate Recovery (EUR) and demonstrate the technical viability of the additional recovery.  The area of investigation focused on development options that could maximise extending tail end production beyond that described in the original Field Development Plan.  A range of late life recovery options was examined, including (a) infield compression (b) 3rd party tie-in and (c) overcoming turndown constraints.  The activities included:

• Development of a simplified integrated production model considering reservoir performance (by client), flow assurance constraints (OLGA) and facilities limitations (HYSYS).
• The incremental recovery enabled by each option was assessed by comparing the production profile generated for each case against the reference case described in the FDP. A feasible late life scenario was consequently described, demonstrating the ability to increase the EUR by 22% over the reference case.
• Incremental Unit Technical Costs (UTC) were developed for selected cases for value comparison, which demonstrated the economic viability of the scenario described.
• The preparation of a Preliminary Field Development Plan for a nearby field to demonstrate the viability of 3rd party gas supply to the project. A portion of the stated increase in EUR requires such a 3rd party gas supply

The Gas Strategy Studies were focused around the development of gas discoveries in the existing producing basin in the vicinity of existing assets. The studies were structured to provide insights into the potential development options for the specific fields examined and to inform other gas development opportunities on the value drivers for a range of product streams such as;

• Conventional – Domestic gas, LNG – Mid Scale and Base Load Plants
• Alternative – Ammonia, urea and methanol amongst others

The studies developed preliminary technical definition, cost estimates, market analysis and economic analysis for the product streams across a range of reservoir outcomes. Consideration was given to the best use of existing infrastructure and operational presence in the region. A cohesive study of the impact of a range of CO2 compositions on the various development options considered the;

• Impact on drilling costs
• Impact on subsea architecture and materials selection
• CO2 removal options
• Geosequestration options
• Carbon permit requirements and free allocations under the Carbon Pollution Reduction Scheme (CPRS)

Peritus provided project management and engineering support for the Gas Strategy Studies, co-ordinating and controlling all scopes of work outside of exploration and subsurface appraisal. Activities included;

• Case development and screening
• Scope preparation, tendering and management for independent external study scopes
• Co-ordinating input from internal resources – subsea and pipelines, subsurface, drilling, marketing, operations
• Cost estimation and economic analysis
• Summary reporting and presentation
• Budget management

The Client wished to evaluate a third-party gas tie-back to existing infrastructure offshore Western Australia for processing (including liquefaction of natural gas) and for the storage and offloading of petroleum products.  Two development themes were investigated – robust cases that have a high technical certainty and minimal impact on existing facilities, and minimum functionality cases that may significantly reduce the development cost but have less technical certainty and/or may require more modifications on the existing facilities.  Options developed included MEG, Insulate and Blowdown and DEH with infield facilities and sub-sea tie-backs using DEH and anti-agglomerate LDHIs. Scope included Flow Assurance, process design, SURF and production facilities and CAPEX estimates.

Peritus were engaged in the early phase to undertake development planning and engineering work in support of the client for a deep water subsea (1200 m water depth) development requiring future compression facilities.  Peritus role was to develop the overall subsea architecture of immediate project requirements and subsequent field tie-backs.  Scope includes identification of a decision process, framing and executing the SU(R)F work associated with key decisions and documenting the concept screening and concept select activities. This includes development of philosophies and strategies, schematics and arrangement for subsea alternatives, CAPEX, present value and schedule development and HES and non economic screening to support the selected alternatives.  Development concepts included subsea architecture (and riser systems support) tied back to a new deep-water floating facility and an alternate development concept considering subsea compression.

The Peritus Scope considered all the activities required to define the subsea architecture including:

• Basis of design development
• Development of Scopes of Work for FEED and Execute
• Development of subsea architecture through an iterative process to converge towards a robust reference case
• Detailed field layout development
• Flowline preliminary mechanical design
• Subsea structure and tie-in spool definition
• Subsea control definition
• Pigging and pre-commission philosophy
• Installation strategy
• Class II Cost and Level II Schedule Development
• Detailed FEED Planning and budget preparation

Peritus Developed concepts for the tie-in of new fields (including production, MEG, controls and systems engineering) to existing subsea architecture. Tested technical viability of selected concepts, including consideration of flow assurance, intelligent pigging, start-up and other operational concerns.  Peritus compiled execution schedules and cost estimates for selected concepts and identified key risks and opportunities against each concept and provided a recommendation for the preferred concept.  This study was led by Peritus’ Field Development team in collaboration with Subsea Systems, Subsea Pipelines and Flow Assurance.

The client intends to develop several subsea fields located 60 -70 km away from existing infrastructure in water depth ranging from 125 m to 140 m.  Peritus performed a series of studies to determine how to tie the fields back to existing infrastructure, screening and developing technically robust reference cases on which cost estimates and schedules were built.  The technical evaluation included flow assurance, corrosion management, optimisation of subsea architecture, investigation of piggable wyes, installation methods, pipeline routing and onshore integration.  In ongoing support to the client for planning these fields, Peritus has updated this work over the years against new information or to further develop areas of the concept.

The client engaged Peritus to investigate upstream cost reduction opportunities for development of several remote, offshore, deep water, gas fields.  This study identified a range of robust solutions utilising traditional and new technologies for the challenging North West Shelf environment, in approximately 1,000m – 1,200m water depth, located approximately 175km – 300km from a suitable subsea tie-in location.  Areas investigated included alternate riser concepts, flowline and inline structures and towed flowline bundles.  Where new technologies proposed the assessment criteria applied was that should be deployable within the next 5-10 years.  The study team included Peritus subsea system and pipeline specialists to identify concepts, assess feasibility and develop cost building blocks appropriate for assessments.

The client had several potential development projects offshore Western Australia which by their nature have significant pipeline scopes and for which subsea pipelines comprise a significant element of the overall CAPEX.  Peritus were engaged to evaluate the opportunities for executing some subsea pipeline scopes of work by an alternative method to the conventional and expensive deep water pipelay vessels.  The method evaluated was to fabricate the pipelines onshore and then tow the suitably buoyed pipeline bundles to the project location for installation.  Peritus Subsea Pipelines and Floating Systems evaluated the opportunity for towed pipeline projects in the NWS, screening tow methodologies, developing engineering layouts and bundle cross-sections and utilising OrcaFlex to determine the required wall thicknesses suitable for managing fatigue through pipeline launch, surface tow, off bottom tow and normal operation.  Cost and schedule estimates were developed for onshore site set-up, procurement, onshore fabrication and offshore tow and installation.  Peritus identified an onshore fabrication location and established the feasible limits for surface and Controlled Depth Tow Mode (CDTM), based on pipeline fatigue.  The study presented costs and schedules that indicated a significant potential benefit to employing this fabrication and installation methodology, in comparison with conventional Slay

Peritus investigated optimising pipeline routes for a deep-water field, located within the Timor Sea, including options to export the gas and condensate reserves to one of the following:

• Timor-Leste based LNG plant
• Floating LNG facility
• Australian based LNG plant

The purpose of the assessment was to confirm there is a robust technical solution with manageable risk as the basis for a development plan.  Work included undertaking preliminary Flow Assurance studies for the recommended pipeline system concepts to establish the required pipeline diameters with confidence, and to highlight any flow assurance issues related to elements of multi-phase flow and production turndown conditions.  Studies included:

• Perform Flow Assurance studies to confirm the feasibility of exporting gas and condensate from the offshore field to onshore
• Undertake Cost Estimate from the offshore field to onshore, including looking to maximise the opportunity associated with existing infrastructure
• Perform a high-level evaluation of Onshore and Offshore MEG systems in relation to technical risk, cost, precedents (i.e. projects where this has been studied and adopted or alternatives used) and operational impacts/complexity and possible reduction in operability

Peritus scope of work was for the detailed design of a pipeline system to transport gas from several fields offshore Brazil to the mainland.  The pipeline is over 300 km in length, has a maximum diameter of 24 inches and originates in water depths over 2400 m. 

Peritus scope of engineering services included:

• Mechanical design
• Pipe soil interaction, including evaluation of existing geotechnical data
• Pipeline routing, including preparation of field layout, pipeline route drawings, alignment sheets and facilities approach drawings
• Bottom roughness assessment
• Pipeline fatigue assessment
• Free span assessment, including individual free spans as necessary and assessment of as-built condition
• Lateral buckling and walking assessment, including assessment of as-built condition and the design of buckle mitigation measures
• End expansion analyses
• Design of 5 No. PLEMs, including equipment, foundation, piping and structure design
• Design of 9 No. rigid tie-in/jumper spool pieces
• Procurement support of long lead items including connectors, valves, bends, wyes and tees
• FEA Analysis of forged tees, wyes and associated reducers

Peritus was engaged to execute the Detailed Design of an 8”, 18 km insulated pipeline and associated tie-in spool pieces.  The Peritus Scope of Work included:

• Pipeline route selection / alignment sheets
• Pipeline route finalisation and charting
• Insulation selection and specification
• Pipeline mechanical design
• Stability analysis
• Pipeline crossing design
• Tie-in spool design
• Material specification and MTO’s
• Detailed pipeline upheaval buckling analysis
• Installation analysis
• Dropped object analysis and protection design

Peritus detailed design scope was for four pipelines and the associated tie-in spools for offshore Gulf of Thailand at the northern tip of the Malay Basin.  The Peritus Scope of Work included:

• FEED Review
• Design Basis preparation
• Review / incorporate Transient Analysis
• Pipeline Routing and alignment sheets
• Pipe / Soil Interaction
• Pipeline Mechanical Design including expansion
• Stability
• Spans / Bottom Roughness / Intervention Design
• CP / Coating / Field Joint Design
• Protection requirements
• Tie-in Spool Design
• Riser and Riser Clamp Design
• Material Specification and MTO’s
• Detailed Pipeline Soil Interaction / Lateral Buckling Analysis and mitigation

The Project involved modification of existing facilities and development of a new riser platform bridge linked to existing facilities.  Peritus scope included Detailed Engineering Design of 24” x 75km Gas Export Pipeline System, tie-in spools and rigid risers including:

• FEED review
• Material and corrosion assessment
• Pipeline route finalisation and charting
• Pipeline mechanical design
• Pipeline crossing design
• Riser, riser clamp and tie-in spool design
• Material specification and MTOs
• Detailed pipeline lateral buckling analysis

The client required evaluation of riser solutions for a proposed new deep-water floating platform, including riser type options, platform location and layout of flowlines and risers in relation to existing facilities.  A screening exercise was undertaken to evaluate the applicability of various riser types (SCR, Lazy Wave SCR, SLOR) for the water depth and metocean conditions of the platform

location.  The riser evaluations showed a preference for large diameter Lazy Wave SCRs for the given location, water depth and expected wind/wave patterns.  The layout studies indicated that location of the platform, relative to existing infrastructure was crucial to optimizing the flowline routings and riser approaches.  Recommendations were provided on riser selection, platform orientation, platform location (and aspect) and riser approaches – all as suggested input to future detailed studies.

Independent document review for FPSO design documents included intact and damaged stability, longitudinal strength, motions, mooring system design, heading analysis, and model test report.

Independent Structural Integrity Management review of for an FPSO including Hull & Topside Inspection Reports, Assessment of Hull and Topsides Strength and Fatigue, Review of Swivel, Turret, Cantilever and Mooring System Life Extension reports, Review of Structural Integrity Management System.

Peritus scope was for the provision of floating systems engineering specialist support considering installing a large compression module onto an existing floating production system.  Scope included developing a Lifting and Installation Studies Scope of Work which involved:

• Reviewing relevant reference documentation to become familiar with the work done and identify the important issues to be addressed in a lifting and installation study,
• Develop the installation study SOW and coordinate with compilation of the all other contract exhibits and create a complete Tender package. Liaise with INPEX Contracting and procurement specialist to ensure appropriate processes are adopted.

Following development of the scope Peritus was responsible for coordinate the technical part of the third-party tendering process and conducted clarification meetings during Contractor proposal submission period and review contractors’ proposals.  After award Peritus were responsible to manage progress of the studies through regular progress meetings and answering of any queries.  After completion of eth work, Peritus were responsible for the development of the final summary report on the lifting and installation feasibility assessment

The client requested Peritus perform the riser analysis for a 4” workover riser in the Gulf of Mexico in 1712 feet of water. The project utilizes ENSCO’s drill rig 8505 with spread mooring. The scope included the global static and dynamic analyses of the workover riser to define watch circles and operational limits. Peritus’ scope included:

• Perform riser pipe sizing to confirm specified wall thickness and steel grade
• Establish riser stack-up, calculate riser weight and set applied top tension
• Perform riser strength analysis to define watch circles and operational limits and to determine if a stress joint is required at the transition from the riser package to the riser pipe string
• Perform riser VIV and wave loading fatigue analyses
• Provide technical support during offshore operation

Peritus was engaged to carry out the verification and clashing analysis for a flexible riser system in the Gulf of Mexico; in a water depth of 640 m. The development utilizes a Floating Production Unit (FPU) that is fitted with a Disconnectable Transfer System (DTS). Whilst the DTS is connected to the FPU the vessel will maintain its location using Dynamic Positioning (DP). However, in extreme weather conditions the DTS will be released from the FPU which will then withdraw from the location. Peritus was contracted to perform an independent riser interference assessment for the project and to aid in resolving comments and issues from Riser CVA regarding riser interference for the new Phase 2 production riser.  Peritus’ scope included:

• Dynamic strength analysis for production riser in the Connected and Disconnected conditions and in Emergency Disconnect
• Interference analysis to assess the potential of production riser clashing with adjacent risers, umbilical and the tether system
• Wave loading fatigue analysis for production riser
• Interface with Riser Certified Verification Agent (CVA)

Peritus were engaged by the EPC contractor to execute the riser design and analysis for a floating production system offshore Australia.  Located in water depths between 400 m and 600 and comprising of riser diameters between 6 to 24 inches, risers included export wet gas and condensate as well as import MEG.  The SCR Design Challenges comprised a complex combination of design conditions including:

• Large Diameter, Shallow Water, High Temperature
• Corrosive Fluids, Tropical Cyclones, Persistent Swells

The Peritus Scope considered of all aspects of the SCR design and engineering, including:

• Mechanical Design, Strength, Fatigue, Interference Assessment
• Installation Analysis, Engineering Criticality Assessment (ECA)
• Design of Riser Top Termination Joints, SCR Monitoring System