PEACOCK, STEVEN G., BP Amoco Exploration; and JOHN A. PRITCHETT, BP Amoco Exploration

Abstract: Exploring In Frontier Areas With No Data - How Far Can You Go?

An efficient exploration process incorporates an understanding of how data and technology evolve through the exploration cycle of a basin, and tailors strategies to exploit both incremental and breakthrough learnings.A study of worldwide basins reveals common patterns of play type evolution that are linked to phases of data and technology acquisition.

This analysis itemizes factors found to impede new play generation, and advocates an exploration process that maximizes the use of sequential data acquisition. Examples of both evolutionary and revolutionary exploration applications are cited from the Gulf of Mexico and Angola basins.

Three factors were found to retard the quick recognition and capitalization of new basin plays: 1) Insufficient seismic quantity and/or quality to enable use of Direct Hydrocarbon Indicator (DHI) techniques. 2) Prevailing geologic models for non-brite plays which infer unattractive resource base and/or unacceptably high risk. 3) Unavailability of a specific technology needed to reduce play risks, or costs, to acceptable levels.

Individual strategies used to minimize these obstacles to basin development can be summarized into a four phase exploration process: 1) timely acquisition of appropriate seismic data, 2) achieving geographic expertise, 3) understanding causal mechanisms of pay distributions, 4) defining and filling key technical gaps.

Because DHI's often comprise the initial basin objectives, early acquisition of appropriate scale seismic data warrants priority consideration. Specifically, recent 3-D technology advances have proven to greatly reduce economic risks, justifying increased front end capital expenditures on area wide 3-D surveys.

With the progression to non-DHI objectives in the basin, geographic expertise, including data mastery and competitor analysis, becomes critical to the early recognition of developing play trends. Maximizing the use of incremental data input, including analogs, affords a competitive advantage in exploiting emerging plays.Alternatively, basin expertise enables recognition of exceptions to prevailing geologic paradigms, thereby nucleating breakthrough concepts.

As basin development progresses, the study of emerging pay patterns may reveal underlying causal mechanisms of hydrocarbon distributions.

Calibrated seismic and geologic models are developed and integrated into multi-scale, predictive, hydrocarbon systems model which is used to quantify exploration risks.

As conventional play opportunities in the basin wane, gap analysis is conducted to identify key technical challenges which, if solved, would render bypassed opportunities attractive. A focussed technical approach to solving key gaps may include leveraging academic and industry consortia. Once solutions are realized, implementation may lead to rapid capitalization of new play trends.

Examples from the Gulf of Mexico and Angola deepwater basins highlight how sequential data acquisition, as well as breakthrough technology, impacted exploration strategies in the two basins:

1) DHI Reliability: Initial basin assumptions that any "brite spot is a good spot" resulted in mixed drilling success in both basins. Inclusion of incremental rock property data/calibration, along with AVO technology advances, improved the differentiation of lithogy and fluid induced seismic anomalies, increasing the accuracy of the drill resource estimates.

2) Deepwater Reservoir Models: Conventional models maintained that reservoir risk in these clastic basins was generally proportional to depositional water depth. Incremental well data, from progressively deeper water penetrations, pointed to the extension of excellent reservoir rock out to abyssal plane settings. Calibration to seismic facies further reduced risks. The result was prospect viability in the Gulf of Mexico fold trends.

3) Seismic Depth Imaging Technology: Long standing geologic models of massively rooted salt stocks have, with the advent of 3-D prest imaging capabilities, given way to the recognition of large volumes of prospective subsalt section in the Gulf of Mexico and Angola basins.

4) Petroleum Systems Analysis:Advances in basin modeling technology, augmented by incremental basin calibration, afforded a competitive advantage in high-grading play opportunities in the Gulf of Mexico.As fluid flow and pressure models evolved, new potential was realized for previously condemned trends.This "bottom-up" exploration approach successfully augmented traditional seismic exploration methodologies.

5) Drilling Technology:The inability to economically drill and produce deepwater objectives has been a historic impediment to developing distal basin plays.Targeted technical solutions to this critical need have resulted in ever increasing water depth drilling records, opening vast prospective trends in both basins.

In summary, this paper suggests an exploration process that seeks to overcome obstacles to new play generation by tailoring basin strategies to successive phases of data availability.

AAPG Search and Discovery Article #90923@1999 International Conference and Exhibition, Birmingham, England