Hydrocarbon Accounting and Shipping for LNG Plant

Angola LNG operate a liquefaction terminal at Soyo on the Angolan coast gathering gas from a range of offshore fields via a 500km pipeline network. In 2020, they were facing several issues with their legacy hydrocarbon accounting systems.

With their existing system no longer supported, Angola LNG were keen to find an evergreen solution which could be supported in-house. They selected EnergySys as a managed cloud-based platform where the subscription provides access to the latest version without additional upgrade costs or development impacts.

Accord were engaged by Angola LNG to re-implement the existing system using EnergySys and to train the Angola LNG IT team to support the system in-house. The transition from the unsupported system to EnergySys mitigated the risk that a critical system could fail and important information could be lost.

Accord established a small team who provided both domain knowledge and implementation expertise.

The existing calculation modules and reports were re-used as the basis for building the system whilst early workshops provided the opportunity for process improvement. Angola LNG were operating a number of external spreadsheets to carry out functions that could not be done in the existing system. During Design, Accord identified these external activities and incorporated them into the new build. Utilising decades of experience in the design, implementation and support of hydrocarbon accounting systems, Accord were able to revisit underlying business process assumptions and implement an easily extendable system to meet future business needs. 

The new system allows for ongoing change to the business processes which can be done quickly by the internal Angola LNG support team.

The system gathers data from 3 offshore blocks, a central processing facility including flare, fuel, Power Generation and Refrigeration measurement, a tank farm and domestic gas flows. Daily and hourly data is captured. Using this data, EnergySys calculates daily totals including Mass, Volume, Energy, Density, Heating Values, Wobbe Index for the required streams. 

Tank volumes are calculated from strapping tables, along with available storage of each tank and volumes available for loading. Produced physical properties at storage conditions can be established using GPA standards.

The system supports the sale of LNG, Propane, Butane and Condensate handling around 80 cargoes per year. On the shipping side, it is configured to handle split BoL’s for LNG, BoL’s for Propane, Butane and Condensate. This involves capturing all the required data to prepare a full documentation pack relating to each offload.

A key driver for our client was the ability to enhance the system internally without reliance on a single external product supplier. To support this aim, Accord delivered the following material:

• As-Build Design Document

• Business Process Workflows

• System & User Acceptance Test Specifications

• Training Videos and User Guides

• Fully functioning Production system with PI Connectivity

• List of all UAT & Enhanced Support defects identified and their resolution

This information has been successfully used by the operator support team, to provide first and second line support to their business users since April 2021.

Although Angola LNG perform the majority of user support and system enhancements, Accord provides a service for 3rd line support should the need arise. 

This allows Angola LNG to draw on Accord’s domain expertise and learn from other implementations to tackle more complex requirements.