COMPUTER AIDED NET PAY ISOCHORE MAPPING

Alan Cherry, Subsurface Consultants & Associates, LLC

Computer applications have revolutionized the way we handle complex geologic and engineering data.  Activities like seismic interpretation and well log analysis, for example, used to be very labor intensive, and are now routinely performed on a computer workstation.  Net pay isochore mapping, however, is largely still done the “old fashioned way” by hand.  There are many reasons for this; one being that existing software packages do not have a pre-built workflow to generate net pay maps, the other is that this work has routinely been performed by in-house reservoir engineers or 3rd party consultants who do not have access the workstation containing the data.

Once someone has learned and applied the principles of making net pay isochore maps by hand they should be able to move into the computer realm. Net pay isochore maps can be generated on the computer that rival or exceed the accuracy of those done by hand, and can be performed on most existing workstation software or other inexpensive (or free) tools.  Once generated, these maps can be efficiently updated and maintained.

The steps to build net pay isochore maps from existing data are discussed using an edge water reservoir as an example.  A computer aided methodology for handling the complexity associated with an uneven vertical distribution of reservoir quality rock within the wedge is presented.

AAPG Search and Discovery Article #90098©2009 AAPG Education Department, Houston, Texas 9-11 September 2009