Abstract: Solving Geoscience Problems in the Coming Century by Integrating New Technologies and Different Disciplines
Bernard C. Duval
At the turn of the century, oil and gas exploration is becoming more difficult as petroleum provinces are attaining maturity. Thus the need to find more "subtle" new fields is critical. Geoscientists can make a major contribution, at technical and management levels, provided they take into account all parameters controlling petroleum systems, make the best use of available technologies, and are prepared to work within integrated teams. This trend can be illustrated by recent applications carried out in several types of basins.
The first application case is the Mahakam delta of Kalimantan, Indonesia. The use of sequence stratigraphy, and integrating well and seismic data at a regional scale, allowed the complete reconstruction of the basin history. It also recognized the controlling key parameters like regional and local seals, and new reservoirs like lowstand wedge sands in the distal part of the delta. Sedimentological studies in the modern delta, used as analogs for the Miocene delta, served to understand the distribution of mouth-bar sands and led to development of a new highly productive reservoir model. Regional work involving geochemical modeling, hydrodynamics, and the distribution of undercompacted high-pressure marine shales in the prodelta, has led to the understanding of the totality of the petro eum system and helped discover a new giant field in a mature area.
The second case, taken from an active operation in the Bongkot field, Gulf of Thailand, shows how detailed 3-D seismic interpretation is critical in identifying targets in a highly complex structural and stratigraphic setting (densely faulted trap with numerous thin fluvio-deltaic sands). Continued application of geosciences to all phases of an "upstream" operation--exploration, field appraisal, and development--resulted in a successful interplay with other disciplines (drilling, reservoir, engineering, and production).
The last example is taken from the west coast of Africa (offshore Cuenza Basin, Angola). The relationship between salt tectonics, and particularly "raft" tectonics, and the dynamics of the petroleum system is analyzed. The stratigraphic model controlling carbonate reservoirs is discussed, together with the interpretation of specially processed seismic data. Integrating biomarkers and isotopic geochemistry led to the understanding of the migration and segregation of oil vs. gas in the traps, and helped formulate an exploration strategy accordingly.
Although the lecture describes multidisciplinary approaches to petroleum exploration, the same concepts and methodologies are receiving increased attention in other areas where earth sciences are applied, like mining and environment.
AAPG Search and Discovery Article #90953©1995-1996 AAPG Distinguished Lecturers