New Concepts for Exploration in Tunisia

Abstract

Some parts of Tunisia have been explored by a fair number of wells; those parts are in semimature level of exploration. Other large zones are underdrilled; some have not been drilled at all, e.g., the northwest (due to tectonic complexity) and the southwest (due to technical difficulties in the Chott Jerid). Since the geologic problems are known (oil formation, migration, and trapping, and tectonic history), it is now the appropriate time for an exploration renewal. Separated by evaporites from the Mesozoic and Cenozoic cover, a heterogeneous basement with north-south discontinuities and east-west hinge lines was submitted to various stresses. The anticlinal features are generally related to salt migration, and they may be of three types: isopach recent anticlines, living structures with thinner series on the tops, and antiforms resulting from compressive shortening of thick depocenters. Many of these features are flower structures which evolved in relation with deep strike-slip movements. Some of them are salt domes and piercement structures. Only one well has been drilled in a transversal graben. As there are different types of grabens with various kinds of paleogeographic setting, these structural features and their external borders are a new set of objectives for further exploration. Except formore » few wells, no research has been conducted to explore stratigraphic traps.« less