AUTHORS: Di Cuia R., Riva A., Stefanelli R., Di Cesare L.
YEAR: 2006
Architecture of Carbonate Systems Through Time AAPG Conference – Mallorca (Spain)
An integrated review of all the available data acquired during over 25 year of exploration and production from a Jurassic carbonate reservoir in the Mediterranean Sea allow to review the previous geological model and open new perspectives to the exploration of undeveloped parts of the field.
Core analysis associated with electric and imaging log analyses were fundamental to identify, at the well scale, the vertical distribution of different lithologies, of depositional facies, of petrophysical properties as well as of fractures.
In this reservoir, petrophysical data confirmed that dolomites represent the main storage intervals of the reservoir while fractures guarantee the main fluid pathways. Thus the prediction of the distribution of dolomite bodies is a fundamental point for the evaluation of HC reserves.
The integrated analysis of all the subsurface data highlighted that dolomitic bodies can be correlated across most of the wells showing continuous distribution but variable thickness. They are limited to the carbonate platform top and absent in marginal and slope facies and they are present below an important paleo-karst interval. Dolomitisation was produced by the interaction of metheoric and vadose waters in association with the presence of carbonate island karst. It is possible that a secondary/minor mechanism for the formation of dolomites was related to some reflux processes.
The use of these concepts allowed to propagate the distribution of dolomite bodies over the entire platform. In this way new perspective for HC reserves were highlighted in the un-developed part of the field.