Well databases allow exploration teams to challenge assumptions

Exploration risk offshore Norway should become easier to gauge, following the release of newer well data by the Norwegian Petroleum Directorate, which has now established a two-year release policy.

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Both the old and newer information can be accessed by subscribing to the Target Norway database and analytical software, the latest venture from Aberdeen-based Asset Geoscience.

This consultancy, formed by ex-BP geologists in 1995, has provided a similar service for the UKCS for the past two years, acting as data release consultants to Britain's Department of Trade and Industry Oil and Gas Directorate.

The databases, which are updated regularly, can be manipulated by the user or the Asset Geoscience team to assess the percentage of successful or unsuccessful wells drilled in any geological province or stratigraphic horizon on the two continental shelves. According to the consultants, the analysis can improve exploration teams' understanding of the value of undrilled acreage owned by themselves or other companies. It also helps them challenge assumptions concerning well success rates, and to instigate new ideas for the location of future wells.

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Upper Juarassic success rates by area (Original map produced using the Target-PetroView Link).
Click here to enlarge image

The Target system can be used to generate maps showing stratigraphic horizons overlain with well results, such as successes or failures, untested hydrocarbon columns, flow rates or volumes discovered. Target can also produce a variety of graphs, covering for example cumulative volumes and success rates over time. New graphs added to the package this year include pool size distribution and reserves breakdown by horizon or operator. The pool size distribution, says Technical Director Alistair Gray, "allows you to evaluate the percentage chance of exceeding a certain discovery size within a play."

This can be undertaken for various time periods to illustrate how the probability has changed throughout a play's history. There may be a decline over successive time periods, but there can also be step changes in technology and thinking, which lead to new areas of an established play being opened, such as the relatively recent discoveries in the Central North Sea HP/HT province.

Because well data release in the UKCS has a five-year cut-off point, Asset Geoscience has also just added a UKCS non-released wells module covering the past five years' activity. This module is based on non-DTI publications of well results.

Target is built in MS Access, with a direct link to Arthur Andersen's PetroView for mapping of statistical or well data. The company is now looking to extend its database services to other regions, such as Brazil, the Gulf of Mexico and the Caspian.

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