Geological applications of computers and geomathematics to petroleum exploration and exploitation are described and evaluated under the following headings:

1. Data storage and retrieval;

2. Summarization of data;

3. Data analysis;

4. Search techniques;

5. Resource estimation.

Data storage and retrieval systems form the backbone of most exploration programs. These files have grown in content and sophistication from small, highly specialized collections of project-oriented data to enormous, generalized data bases containing a variety of subject matter. The impetus for development of storage/retrieval systems has been the tremendous expansion of available information and the need to make information quickly available to geologists. In general, the nature of the information stored has encouraged the continuation of traditional exploration methods. With the data bases of much larger scope now becoming available, applications not possible prior to their development became possible, that is, the data base itself generates new applications. Prime sources of information are commercial and government agencies augmented by in-company collection on special projects.

Summarization and presentation of data by computer means has evolved in direct proportion to hardware and software advances. Beginning with simple listings by line printers, systems have evolved to the point where on-line video or hard copy displays are being produced directly by the working geologist. Sophisticated mapping routines, coupled with base-map programs, provide quick visual displays of data base information in the form of contour maps, facies maps, lithology logs, cross-sections and production statistics. Hardware and software advances are certain to increase the sophistication of techniques in this area of application.

Analysis of geological data by mathematical and statistical procedures does not appear to have gained as widespread usage in exploration activity as the variety of available methods would suggest. Most effort has gone into the development of mapping procedures which do receive routine usage. Trend-surface analysis, for example, is extensively used by many explorationists. But such methods as factor-analysis and pattern-recognition are rarely used outside research laboratories. Simulation of geological models, another technique of much academic promise, appears not to have caught on as an exploration tool. Simulation of reservoir performance is, of course, routinely used by engineers.

Interest in the development of probability based search models is on the increase. The exact nature and amount of routine use is, however, shrouded in secrecy. Several recent publications suggest that search model methods have received a great deal of research and have become fairly sophisticated. Although one of the first publicized geomathematical exploration methods (Dowd, 1961), early applications have not apparently proven successful enough to warrant widespread acceptance by working geologists.

Resource estimation of pools, basins and nations by means of mathematical models has developed into a major science in its own right. One such analysis by the Geological Survey of Canada has affected federal government energy policy. A variety of methods, ranging from rather simple probability models to extremely complex systems is used, but the final verdict as to their effectiveness has not been reached. A model specifically designed for petroleum and gas occurrence has not been developed as is the case with the mineral evaluation game.