Over the last decade, three-dimensional (3-D) imaging and modeling of
the subsurface through time (4-D) have co-evolved and emerged as a
major research focus of the petroleum industry. Virtually all major oil
companies have independently recognized the need for 4-D petroleum
system models (also called basin models) because they:
- Organize data, allowing deficiencies or inconsistencies to be identified,
- Archive data (data loss due to personnel attrition and reorganization is a major cost factor),
- Facilitate visualization of geologic processes and communication with stakeholders, and
- Add value by converting static data into dynamic processed data and interpretations.
4-D petroleum system models can serve as evolving databases
that provide surface and subsurface geologic information for various
practical research needs. They allow users to figuratively look within
the earth to examine data, appraise the reliability of geological
concepts, models, or geochemical input, and extract needed information.
Major applications of 4-D geologic models include developing predictive
exploration and reservoir models, integrating sequence stratigraphy and
assessment units, predicting the extent and timing of petroleum
generation in source rocks, structural deformation that disturbs basin
architecture, migration pathways, and locations of potential traps and
accumulations, and analysis of risk based on different geologic,
geochemical, or fluid-flow assumptions. Thus, 4-D geologic models can
provide a basic geoscience framework to conduct and record a wide
variety of applied and basic research.
As petroleum becomes more difficult to find and reserves become
more difficult to replace, 4-D petroleum system modeling has grown
because it better quantifies the generation, migration, and entrapment
of the remaining resource. It also facilitates interpretation of the
stratigraphic and sedimentologic processes that are important to develop
a predictive sequence stratigraphic framework. Because of financial and
time constraints, large oil companies typically conduct 4-D modeling
studies only at scales to suit their immediate needs. These studies
commonly cover only the acreage held by each company and seldom cover
the full extent of each petroleum system. This knowledge gap represents
an opportunity for the proposed 4-D petroleum system modeling group at
Stanford because many domestic and international companies are willing
to supply data and expertise. Companies will benefit from Stanford
studies that extend 4-D interpretations beyond immediate concession
areas. For example, many oil companies exhaustively study postage-stamp
areas within basins, but 4-D modeling may not have been conducted over
the entire area (e.g., Gulf of Mexico, San Joaquin Basin, Permian Basin,
Los Angeles Basin, North Caspian Basin).
4-D petroleum system modeling is rapidly growing as a tool to
better understand subsurface migration, accumulation, and preservation.
The approach is strong as a tool to predict the pod of active source
rock, thermal maturity of the source rock, migration pathways, and the
timing of petroleum generation. 4-D modeling is currently less
successful as a means to predict volumes of trapped petroleum, their
detailed compositions, or the effects of secondary processes. However,
solutions to these questions could have major impact on the domestic and
world economy. 4-D modeling is a tool that will continue to attract new
users because of the potential for high-impact solutions to these
problems with respect to exploration, development, and assessment.
However, these questions are particularly amenable to the proposed
program at Stanford because to properly address them will require
coordinated, long-term research not generally undertaken by industry.