Simulation software and other tools that visualise numerical models are indispensable to the offshore oil and gas sector, enabling operators to simulate complex and potentially hazardous operations and processes, and ensuring safety, efficiency, and cost-effectiveness.
Accurate and precise simulations of oil and gas processes act s highly sophisticated training systems that replicate the environment and operations of an offshore rig, providing a controlled, risk-free setting where they can use equipment, initiate operational procedures, and make critical decisions.
By combining hardware and software, these tools create realistic virtual scenarios of key offshore operations, including drilling, safety protocols, emergency response, and equipment handling, all with detailed graphics and real-time simulation.
These can be customised to suit every stage of offshore production, from greenfield (conceptual, pre-FEED, FEED, and detailed engineering phases) to brownfield (life extension, engineering critical assessment, integrity management, fitness-for-service, and decommissioning).
Each segment of the production process – the interconnected systems working to bring hydrocarbons from the reservoir up a well and through pipelines to the refinery – can be simulated, and is particularly useful for understanding the behaviour of sensitive subsea infrastructure and processes required for offshore production.
Reservoir simulations replicate the way fluids move and interact with the reservoir over time and under various production and injection scenarios.
Common simulation applications for reservoirs include field development planning, production forecasting, and reservoir management.
These provide a deeper understanding of the reservoir’s dynamics before the first well is drilled, and also allow the tracking of reservoir performance over time, identifying bypassed oil and planning interventions such as infill drilling or enhanced oil recovery.
Well performance, behaviour and interaction with the reservoir are also often simulated, using geomechanics and structural mechanics analysis to evaluate the stability of the wellbore, and the soil-structure interaction on the strings of the well system.
Typical applications are global drilling analysis, bore stability, subsidence assessment, and wellhead fatigue.
Subsea equipment modelling assesses the structural strength of the equipment as well as functionalities such as sealability, connection mechanisms, foundation stability, and thermal insulation, with code-based analysis undertaken from the pipe to the entire network.
Similarly, pipelines (subsea umbilicals, risers and flowlines, or SURF) are treated extra cautiously as they represent the longest system of barrier between the production fluid and the subsea environment.
Simulation of pipelines is used to target optimised system designs that can operate under dynamic forces, such as bending, tension, compression, torsion, corrosion, erosion, buckling, and fatigue.
SURF simulations include pipelay analysis, riser fatigue, pipe walking and buckling, and vortex-induced vibration.
Finally, and perhaps most importantly, topside simulations are crucial for addressing the engineering and operational challenges associated with floating production storage and offloading (FPSO) facilities.
These platforms are floating factories loaded with inflammable fluids in harsh offshore environments, where they face corrosion from salty humidity and vessel motion from storms and waves, not to mention the logistics of incoming and outgoing workers and components for repairs.
FPSO simulations encompass topside structure analysis, global anchoring system analysis, gas dispersion modelling, and piping analysis.
The complexity achieved through simulations of oil and gas processes is evident in the advanced three-dimensional geological modelling of reservoirs. This modelling characterises the geometric shape of the reservoirs and aids in determining their distribution, quality, and internal configuration.
It is essential to accurately model the various oil and gas subsystems and understand how they interact within a broader process. This interaction can be simulated using finite element analysis and computational fluid dynamics.
Simulations of integrated operations and the holistic view of oil and gas processes they provide are invaluable for optimising production, fostering teamwork, and improving overall operational coordination.
Training simulation modules have limitless potential, with customisation options for targeted training, multi-user capability for team training, high adaptability to modifications, and flexibility with both remote and in-person training.
By developing a base framework for simulating oil and gas production systems, operators can then expand on this framework to integrate relevant subsystems and test alternative methods and strategies.
An example is the framework built by Petrobras to simulate production systems, which integrated reservoir flow assurance and economic models to optimise subsea layout and FPSO placement, and determine the net present value (NPV) of each alternative, among other operational and financial metrics.
The framework also incorporated the best reservoir drainage plan, FPSO facility location, and the subsea layout for each alternative.
The result was a reduction in the time needed to evaluate project alternatives and an improvement in interdisciplinary synergies, which enhanced economic returns.
Petrobras noted automation of the workflow reduced the time required to evaluate alternatives by 60 per cent. It was also highly efficient in finding better production system designs, increasing the project’s economic return.
Petrobras said: “Economic results obtained through the integrated simulation of each alternative were easily traced back to the inputs that were considered common premises, helping assure consistency in the comparison of alternatives.
“The simulation framework allowed for a quick and easy selection process of the production system alternative that optimised economic returns.
“NPV was chosen as the determining criterion between the alternatives – the alternative with a higher NPV was not the one with lower capital expenditure or higher cumulative oil production.
“The interaction between the disciplines permitted the identification of synergy gains, since all the constraints considered in the optimisation process were visible on the same framework.”
