Sweeter E&P terms, Cretaceous Abiod chalk oil play lead to busier exploration in Tunisia. (petroleum exploration)

Sweeter E&P terms, Cretaceous Abiod chalk oil play lead to busier exploration in Tunisia

Tunisia's oil exploration and production industry is experiencing a boom of almost unprecedented proportions.

The catalysts are changes in the fiscal and legislative regime and a high success ratio in an exciting new exploration play, Upper Cretaceous Abiod chalk.

The foundation of this renewed phase of activity was laid in 1985.

The Tunisian government decided to liberalize the terms and conditions that apply to the hydrocarbon exploration industry, in order to encourage the search for reserves to replace those being rapidly depleted through increased industrial, commercial, and transport consumption.

It was expected at the time that Tunisia would become a net importer of oil again by the early 1990s.

Production from giant El Borma field was declining at around 5%/year in spite of an extensive secondary recovery program.

Terms sweetened

The initial amelioration to the fiscal and licensing terms was enacted in September 1985.

Before its effects could be perceived, the oil price had begun to spiral downwards and oil exploration budgets suffered large cutbacks.

It then became clear to the government that to compete for scarce exploration funds it would have to further improve Tunisia's position in the league table of countries in which oil companies would spend their increasingly precious exploration budgets.

By September 1987, a second revision to the legislation had been passed through the legislature easing the tax burden yet again and introducing the concept of the profit/investment ratio into the law.

The final piece in the jigsaw was enacted in 1990 giving further tax incentives and introducing more flexible licensing terms. In combination these changes began to attract a steady stream of applicants for open acreage but even so the net acreage under license was slowly decreasing.

Two discoveries

The discovery by Marathon in 1986 of 20 million bbl Ezzaouia field near the holiday island of Djerba began to change the industry's perception of Tunisia as a higly prospective and increasingly attractice country in which to explore for hydrocarbons.

Ezzaouia field came on stream in late November into production facilities (OGJ, Dec. 3, p. 40).

This new perception was reinforced in 1988 by AGIP SpA's discovery of Maamoura oilfield in the Gulf of Hammamet. The fields's reserves may be about 50 million bbl of oil.

The reservoir for this field is the Abiod chalk of Campanian/Maastrichtian age, which had not previously been considered as reservoir because of its low porosity and permeability.

However a flow rate of 3,300 b/d of oil was achieved from the second well on the structure, …