RE: OPL 226... Everything you need to know!16 Jul 2020 15:57
Just following up on your post RK regarding this bit:
'Because the 3D seismic is correlated with known geology we can be sure with a high degree of certainty where the oil, water contact is and how much is there.'
This is the one bit that stuck in my mind when trying to join some dots previously. It centres on one word I saw in one of the presentations, 'resistivity'. The presentation, which had quite a bit on the seismic, mentioned, 'note the high resistivity'. Looked it up;
'High resistivity is a characteristic of the presence of hydrocarbons and low resistivity is indicative of water. However, log analysts could not differentiate between rocks containing hydrocarbons and those with no porosity because both exhibit high resistivity. Even when hydrocarbon-bearing zones were identified using resistivity tools, the volume of hydrocarbon could not be determined without a porosity measurement.' https://www.slb.com/-/media/files/oilfield-review/defining-porosity.ashx
'Resistivity is the measurement of fluid conductivity and the formation. Conductivity is the reciprocal of Resistivity. Surveys are carried out in various oil and gas fields and then Resistivity logs prepared are studied. These Resistivity surveys help in creating a three-dimensional structure of the hydrocarbon formation below the surface. This helps in identifying oil and gas reservoirs with high chances of trapped oil and gas in the geological formations.' https://www.petropedia.com/definition/3244/resistivity
So to expand on why we have a 'high degree of certainty' we know what the porosity is from the drill and we also know that the resistivity measurement is high, therefore we can indeed see what is oil and what is water.
ATB