Type of service:  Dynamic Simulation Study
Inprocess client:  Major FPSO constructing and operating company
Year:  2021
Country:  Ghana, (other in Asia)


The challenge in context

An FPSO is a Floating Production Storage and Offloading unit designed to produce oil and gas by processing the fluids arriving from offshore wells, usually in deep-water environments. Therefore, the FPSOs have the capability to store the produced oil until a separate cargo offloads it from the FPSO tanks.

Such kind of operations provoke a certain vaporization of the lighter oil components, which occupy the space on top of the oil. Often, this gas contains droplets of oil as well that are carried over. Therefore, this gas is both a source of VOCs (Volatile Organic Compounds) when vented, and a leakage in FPSO’s oil production.

In this project, our client, one of the leading FPSO operating companies worldwide, contracted Inprocess to develop an approach to calculate the amount of VOCs during cargo tank operations. At present, the flashed gases on these regular operations are sent to atmosphere. The objective of the project was to study the amount of VOCs generated and their emissions from the FPSO tanks in order to evaluate the options for the recuperation of these gases through a compressor, that would result in a reduction of the VOC emission as well as on enhanced oil recovery. These analyses were carried out with the help of the simulation models already developed by Inprocess for the Operator Training Simulators in two of client’s FPSOs (one operating in Asian waters, and another one, operating offshore Ghana). The dynamic simulations helped to evaluate how much gas was vented and flared due to routine operation of the internal oil tanks


Inprocess solution

Inprocess built the dynamic model, replicated the operations, and calculated the gases flows and emissions. To increase accuracy, the steady state model was rebuilt in order to emulate better the oil physical properties at the rundown to replicate with higher level of detail the operation, based on the present operating conditions. Cargo tank load is executed in three or four days, which means a dynamic simulation must be able to run fast without losing accuracy.

Based on the accuracy of the models developed by Inprocess it was possible to:

  • Calculate emissions: in terms of CO2 equivalents, in accordance with the Intergovernmental Panel on Climate Change (IPCC) (dynamic simulation for the flash gas)
  • Calculate economic benefits: how many barrels of oil can be recovered due to not relieving these gases to the atmosphere (steady state simulation)


Results and Benefits

The dynamic simulation study carried out also served to the objective of calculating the benefits of recuperating that gas emitted during operations. This study for two FPSOs provided an analysis of the amount of gas that is vented and flared as a result of common operation of the internal oil tanks, based on dynamic simulation.

  • Reduced environmental impact
  • Generation of a 0.1% increase in barrels production during operation: significant long-term value
  • Possibility of replication in other offshore similar facilities


Inprocess Added Value

Inprocess offers an advantage over other companies because of its experience and expertise in dynamic simulation. It constitutes our core business, and we understand the value it brings to our clients. Moreover, it is important to highlight the great professionalism of the team and the knowledge transfer that we share with our clients in every project we develop.

The client requested Inprocess, for this job in particular, because we have worked together for many years on different projects and they are very satisfied with both the equipment and the results.

From Inprocess we recommend and support our client with advice on how to proceed with the best solution always focused on the benefit for the client.

In addition to all this, we always go the extra mile. In this case, the LP/MP Flash Gas Compressors were not working, we provided an extra hypothesis and analysis as to why this compressor could not start based on the historical data, equipment capacity, control valves size and the verification using the steady state and dynamic simulation. 

Interested? Don’t hesitate to ask for more information just completing the form below