Is Field Geology a Jolly?: how a dying practice in onshore exploration could have saved us time and money

Field geology was conducted extensively in the past to determine the elements of a ‘new’ petroleum system. In onshore fold belt environments, surface anticlines and their stratigraphic components defined the primary drilling targets. Subsequent seismic acquisition attempted to improve subsurface target delineation following either success or failure tests. Field campaigns slowly became sample and dip gathering  tasks along seismic lines and surface geological mapping sensu stricto, begun to disappear. Interest for the latter further dropped after oil or gas production was established and exploration/appraisal begun to rely on seismic alone . Since trap is the biggest risk in many fold belts seismic is now the primary de-risking data, despite its marginal quality and many pitfalls in these settings. Geological maps used to calibrate seismic have not been substantially upgraded for years in many fold belts, despite new remote sensing technology that could efficiently be used for this exercise.  With some examples from Colombia and PNG I try to highlight the cost effectiveness of field geology, as it still helps us avert drilling surprises or costly blunders altogether.