Abstract: Niger Delta - The Eastern Deep Offshore Integrated Methodologies Towards Petroleum System Definition

Guyotte, E.; F. Clement; D. Dubucq; E. Caillet - Elf E&P

Blocks 222 and 223 are located on the southeastern part of the Niger delta, Nigeria. They are operated by Elf with Chevron, Exxon and Canadian Petroleum as partners. The blocks cover the transition zone between the shelf to the North and the slope to the South where turbiditic deposits are identified. An integrated approach had to be applied in order to try and increase the probability of success on prospects of this new potential petroleum province.

A decisive step is the use of a modeling software for simulating hydrocarbon generation and migration from source rock to trap. Comprehensive reservoir and pressure prognosis as well as structural interpretation are required as an input, in addition to geochemical data.

Seismic attributes developed by Elf research provide new insights into the delineation of sedimentary bodies (shelf, straight or meandering slope channels and slope fans) acting as potential drains and oil bearing reservoirs.

The proximity of the deltaic thrust belt results in a rather complex structural style; normal and reverse faults may be active simultaneously and structural inversion is common. In this context, hydrocarbon charging is predominantly vertical along fault planes and shale domes. The trapping mechanisms associated with the turbiditic systems in the area are therefore primarily structural, although a stratigraphic component is always superimposed.

The presence of hydrocarbons is ascertained by cross-checking the model with seismic indicators derived from specific processing tools, including in-house technology, directed at enhancing amplitude and various other attributes. It is now possible to apply this methodology in an automatic and fast manner throughout a 3D volume of seismic data, including AVO analysis.

This comprehensive approach integrating new tools, new concepts and experience helps to reduce the risk factor inherent in the exploration of such a frontier environment.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil