PRM - Do it with Nodes!

Since full azimuth nodal acquisition has become the technique of choice for imaging below complex salt overburdens in the deep-water Gulf of Mexico, with more than 25 surveys acquired in the last 10 years, new high speed underwater communications technology is allowing the development of a “semipermanent” reservoir surveillance/Life of Field (LoF) capability using Ocean Bottom Nodes (OBN.)

Christened ZLoF this semi-permanent solution is a development of the Z3000 system that has delivered 98%+ reliability since its commercial introduction in 2005. ZLoF is designed to provide a highly cost effective alternative to cable based Permanent Reservoir Monitor (PRM) systems. Since the ROV deployed nodes are autonomous there are no cables to deploy/trench and there is no requirement to tie into a field’s production facilities all of which simplifies installation and significantly reduces costs.

With a 300 day active recording life and a 5 year on the seabed lifetime ZLoF allows, for example, 12 25 day surveys to be shot – Baseline + 11 Monitors – before node recovery. Node-on-node 4D has been shown to be extremely robust and it is expected that this semi-permanent system will enable frequent monitoring of reservoir integrity, injection rate optimization, improving water flood effectiveness and pressure maintenance.