Key project decisions like field sequencing, plateau size, and design back pressures in a green gas field cluster development require a robust integrated system modelling. Given that most project decisions are made in economics domain, it is crucial to include the project economics within the integrated system modelling suite. This paper describes application of a workflow which integrates the subsurface, surface, costing and economics evaluation within the ambit of a single integrated modelling tool.
Typically network models are computationally intensive and project teams will only run them for few deterministic cases. The probabilistic analysis is performed at reservoir/field level, and they are combined to define deterministic (Low, Mid, High) case network models. However, this approach poorly captures surface-subsurface interactions and doesn't provide full solution space at the network level. Furthermore, to generate development options and scenarios, typically oversimplistic subsurface models are used that do not sufficiently capture liquid yield over time and water encroachment.
The proposed workflow does probabilistic simulations at network level to capture the full solution space. The workflow allows representation of project decisions and uncertainties under the same platform. Furthermore, representative modelling of reservoir architecture and fluid fractional flow allows more accurate prediction of liquid hydrocarbon and water which helps in robust facility design. Semi-automated nature of the toolkit allows generation of project economics for large number of sensitivities and scenarios in quick time. This approach is very useful where with only basic information fast analysis is required to start commercial negotiations, and in situations where good statistical coverage is more important than very detailed outcomes (even when detailed information is available) to support decsions.