We have also found it to be very beneficial, particularly for older fields, to summarize a well history profile for each well. This should include a summary of the mayor events in the life of that well. Productiona and plots for each of that well's completions should be transferred to this file, along with well bore schematics, gas and fluid analyses and any other material deemed important.

Sand Level Organization

Once correlation and mapping is complete, copies should be made of the electric and porosity logs for each productive sand in each well. San top and base should be marked on each copy. Sand counts are also extremely helpful. the geologist should then furnish sand data sheets for each productive sand in the field. These sheets should include a minimum of measured and corrected sand tops and bases for each well, all pertinent fluid contacts, and gas, oil and water counts, as shown in Figure 1. If directional wells are involved, a true vertical thickness data sheet should also be created. these sheets should contain the required data to prepare all TVT calculations. These data include bed dip and azimuth for each well, in addition to bore hole angle and azimuth.

Reservoir Level Organization

Further sorting of the field and sand level data should now be made on a reservoir basis. These data include production tabulation and plots, bottomhome pressures, sidewall cores, log copies and fluid analyses. This sorting can be done in a "packet" format using one file per well, or in a book format separated by tabs.

Copies of maps should be made for each reservoir, including structure tops and bases, net sand and net pay isochores. Color and symbols can be applied if desired. Historic should be included, and isochores should be planimetered and documented. Also, a reservoir "well status sheet" which lists all completed wells in the reservoir with their cumulative production, perforations, production dates and very brief remarks conerning that well's status (currently producing, watered out, pressure depleted, etc.) are helpful. An example of this sheet is presented in Figure 2. At this point, average reservoir volumetric parameters need to be calculated using your company's accepted method. For example, average porosity and permeability can ne determined by averaging log data or side wall core data.

With all available information pertinent to each reservoir now organized in its own complete "packet" format, engineering analysis and manipulation, such as extrapolation of well and reservoir summary production plots and volumetric calculation can be performed with maximum efficiency. Once the most appropriate reserve methodology is selected, it is necessary to thoroughly document the reserve numbers in a "discussion" format.

The final result of this method od data organizaiton will be found invaluable in making daily operaitonal decisions. Far less effort will be required for special projects such as reserve updates and financial planning applicaitons.

Subsurface Consultants & Associates, Inc. offers a variety of software, including RESPACK (Reservoir Package System). Rogers & Elston Inc. a firm associated with SCA, has developed the software package. This package is an oil and gas reserves analysis and reservoir packet organization software which performs may of the aformentioned organizational tasks. When data is stored in such a digital format, new information can be easily and quickly incorporated into the existing database.

RESPACK's convenient parameter input results in a presentaiton quality output of fifteen calculated and informational reservoir forms. These include complete oil and gas volumetric calculations, SITP conversions, BHP corrections to datum, BHP/Z calculations, true vertical thickness corrections, water saturation calculations and averages, sidewall core averages, and volume calculations from input planimeter units. Informational forms include data inventory, sand data, oil and gas test data, oil and gas well status, and reserves summary.

RESPACK provides a cost effective, compact and organized method for maintaining, using and updating reservoir information. This package currently operates with Lotus 1-2-3, Release 3.1+ or later versions. A microsoft Windows version will be available in February 1994.

A free demonstration diskette is available through SCA.