==== Geological Monitoring ====

On an exploration well the geological prognosis may be at best rather vague. Biostratigraphy adds certainty to the geological interpretation of drilled formations by providing stratigraphic control using principles and methods described elsewhere on this Wiki, primarily the identification of known “index fossils” to provide accurate calibration to standard timescales. Alternatively assemblages characteristic of known stratigraphic units onshore, or from other wells in a basin can provide useful tie-backs to those units. The stratigraphic prognosis of the well can be updated in real time and fed back into geological models in the office for updating.

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//Dr Ken LaBorde analyses samples for microfossils on board a rig, offshore Trinidad, drilling an exploration well.//

In these situations, normally, continuous 24-hour monitoring is not required and one biostratigrapher at the wellsite, working with the wellsite geologist is usually sufficient.