Integrated modelling of entire production network and topsides facilities for production optimisation of major oil and gas fields

Abstract

An oil company sought to identify bottlenecks in three of their main oil and gas production networks. It was desired to, therefore, develop the entire production network from wells, flowlines, intra-field and inter-field pipelines, and export pipelines up to the onshore terminal first stage separator/slug catcher, all in the transient multi-phase-flow oil and gas (OLGA) simulator. Furthermore, the detailed topsides facilities were separately modelled in a process simulator.

The OLGA and process simulator models were subsequently integrated, where the flow simulator model received boundary pressures from the topsides model and pushed through the mass flows of the individual phases into the process simulator. After field-matching and tuning the integrated models to the given field data, optimising the overall fields’ production and performance was carried out, powered by a market-leading optimisation engine. The main optimisation parameters were: wellhead choke openings; gas lift rates and allocations; and topsides operating conditions, facility constraints and control tuning parameters.

The network models were used to investigate the dynamic behaviour of wells and pipelines as well as surface process facilities equipment and control systems, with the aim to improve productivity of the entire field networks. The development of the integrated and dynamic well, pipeline and process models is part of company initiatives to facilitate the design and operational support tools for the company’s engineers.