Multizone monitoring well completion design in the GAB

Abstract

To provide the community with assurance that Santos GLNG operations are performed in a safe and responsible manner, the company has undertaken a major project to equip a large number of boreholes with multizone aquifer monitoring systems. These systems ensure aquifer water levels are monitored accurately.

To provide a cost-effective design that reduces the need for multiple wells and provides long-term data reliability, a packer and gauge system with full redundancy was designed and co-developed with Santos. The focus of this design was zonal isolation between aquifers, full redundancy and retrievability.

This extended abstract describes a project where a fully retrievable seven-zone system was designed, deployed and monitored. Although the swell packers used to isolate zones are a mature technology, this is the first application where they have been designed to be recovered from the borehole with a pull-to-release system.

The design and deployment was especially complex as both the retrievable packers and 14 pressure temperature gauges were deployed in a slim 4″ bore. The system was successfully deployed in the first quarter of 2014. A compact solar power surface acquisition system has also been integrated. It gathers and transmits the borehole data to an online portal. Santos is fully transparent with the data gathered and the local community is able to get this data from the online portal.