Poisson’s Ration, Deep Resistivity and Water Saturation Relationships for Shaly Sand Reservoir, SE Sirt, Murzuq and Gadames Basins, Libya (Case study)

It is important to obtain relationships between the physical quantities, overburden and reservoir composition and fluid type. This is significant in the sense that if one property, e.g., electrical resistivity, can be more easily measured than Poisson’s ratio (PR). Therefore, later parameter can be estimated and defined against resistivity log data. In fact, these relations constructed by several wells data have been taken for each studied productive reservoir from different oil fields at different sedimentary basin, in Libya. However, comparison between calculated PR, measured deep resistivity and calculated water saturation content are using to a certain extent justification of reservoir conditions (tight zone).

These cross relations throw up the increase of PR range at low values of deep resistivity values and water saturation degrees, which present like a hyperbolic curves formed a two parts. The stable trend with constant PR values in hydrocarbon and clean intervals depths within a first part, while a shaly depth intervals act as a second part of the hyperbolic shape, which shows a scatter or cluster points indicates of water intervals and not a tight zone. Therefore, estimation of PR in shaly intervals in such these reservoirs are ranging above 0.3 up to 0.4.