montara & plover formations, page-104

JL & SE

Here my attempt to y'r question in simple words.

Reservoir pressure/connectivity can b established by calculating its permeability. Since we are dealing with Plover/Montara Sandstone, this rock has pores - thro' which the trapped fluid (oil, condensate, gas or water) flows.

The ease with which this fluid flow is attributed to the formation pressure & the size of the pores. At a depth of 3000m, u have a lot of overburden rock, so obviously there will b pressure caused by tectonic forces, however here they are measuring the in-situ pressure.

This pressure is measured by dropping a sophisticated tool (called Sonde' in French). It expands & presses hard against the openhole wall (8.5 inches diameter) & a valve opens to allow fluid to flow into the small chambers within this probe at the same time recording the pressure. Pressure is maintained all the time & fluid sample is collected for analysis. The chamber is kept open for a duration & then closed thus recording the pressure & capturing fluid samples.

Using this tool one can also find out the direction the fluid is flowing in. The fluid sample is analysed in lab so u could see its the same oil with identical properties like Specific Gravity (API), Color etc.

Thats what NXS are intending to do, when they try to correlate pressure data from Crux & Libra. Once they have this data they can actually tell whether Libra is connected to Crux or is part of a separate structure.

Hope this helps.

cheers