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    Subject: Reservoir Characterization For Small Fields

    Name: Letha Lencioni

    E-Mail: llencio@enron.com

    Date/Time: 3/4/98 8:32 AM


    I would like to generate some comments about appropriate levels of reservoir characterization for smaller fields. In our experience, what techniques have proven to be cost effective, what's too expensive, what just doesn't work?
    For example, I have been working on planning a waterflood project in a small updip area of a reservoir in which a waterflood was attempted in the 60's and 70's. The area is covered by part of a large 3-D seismic survey, but the structure and amplitude maps generated so far have not helped explain the poor waterflood response. How many of you have been able to conduct interference tests when you'd have to shut in 10% of your division's oil production for a month?
    What are some cost effective ideas that have worked for you in characterizing smaller reservoirs?

    1st Response

    Name: Mike O'Dell

    E-Mail: odell@gto.net.om

    Date/Time: 3/4/98 11:41 AM


    I've run across several cases where injectors and producers are just not completed in the same sands. Before embarking on any field tests, I suggest a thorough review of what you already know. Dig out the old waterflood records to see if there was ANY pressure or water cut response in ANY of the producers. You say your project is in an updip area. You don't mention the oil density, but possibly gravity forces dominated over viscous forces in the old waterfloods, and all the water went downhill.
    You mentioned a pressure interference test. These work well only in a limited class of problems. Run through some calculations to see what you would get in an ideal pressure interference test.

    2nd Response

    Name: Jeffry Hamman

    E-Mail: jghamman@marathonoil.com

    Date/Time: 3/6/98 6:20 PM


    I've seen some very valuable insight into the stratigraphic framework of reservoirs through seismic inversion. Many times amplitude extracts have been misleading because of impedance variations in the layer overlying the reservoir.