Abstract. The poster deals with the approach used for appraisal of marginal fields in deep water, presenting a recent case history.
After the field discovery and a first short term well testing, a feasibility study and a reservoir study were carried out, together with a series of parametric analyses, in order to identify the possible scenarios and to pinpoint the factors criticai for an economic exploitation of the field. The analysis showed that the condition for an economic development of the field was the capability to collect all the reservoir information necessary for deciding on the field development with a single appraisal well. For such a purpose, the following action plan was decided: o 3D seismic survey of the field area; o drilling of the appraisal well in two steps, first vertical drilling with continuous coring and DST's, then drilling o long term production test. the decision whether or not to develop the discovery will be based. risks and optimizing the field development design. of a properly oriented horizontal drain hole; The results of these activities have been used for an integrated multidisciplinary study of the field, on which This type of approach should enable the operator to reduce the delineation costs, while reducing economic APPRAISAL OF MARGINAL FIELDS IN DEEP WATERS: A RECENT CASE HISTORY Hydrocarbon potential of the deepwater area in the South Adriatic sea has been investigated since the late 70s, when AGIP drilled and tested the first well (Rovesti in 955 meters of water). Oil shows were detected and therefore, in the following years (early 80s) a second deep water drilling campaign was started.
The wells were located in water depths ranging from 400 to 1100 m and the drilling brought the discovery of several hydrocarbon accumulations.
However, although the results from this regional exploration activity were encouraging, the production technology available at that time was not yet capable to cope with the difficult deepwater conditions. Moreover, the envisaged solutions were too expensive, thus practically preventing an economic development of the reserves.
Therefore, in the following years a coherent multidisciplinary research programme was started, in order to develop the technologies required for an economic production of the discovered hydrocarbons.
After ten years of R&D work and about 100 million U.S.$ of investment, AGIP had available and ready for operational use key in-house developed technology and proprietary know-how related to the whole range of building blocks required for successfully coping with the different possible scenarios that an operator may encounter in deep waters. Consequently, in 1991 the feasibility of putting in production the deepwater fields in the Southern Adriatic was reexamined.
A screening study was performed, for evaluating the possible alternati