EXPLOR Expert System for Oil and Gas Prospect Generation

R. Mark Maslyn

Oil and gas prospect generation involves three phases: data acquisition, mapping, and evaluation. EXPLOR is an expert system that automates the latter phases. The program's mapping routines are written in a high-level programming language for optimization. A backward-chaining PROLOG-based expert system is used in the evaluation phase.

Input data consist of well locations, status, target formation structure values, structure values from a second formation used for isopaching, target formation shows, geologic environment, and average size of the feature being explored for. The last value is used to determine show significance as a function of distance.

Since geologic exploration involves three-dimensional situations rather than the two-dimensional problems that most expert systems are designed for, EXPLOR uses grid values derived at 40-ac spacings across the map area. These values are compared with values at adjacent grid nodes to provide structural closure information.

Output includes structural leads with 3- and 4-way closure, stratigraphic leads, and leads derived from indirect evidence such as downward projected structure and favorable isopach trends. Prospect leads are output with graphic symbols on a prospect leads map, and individual prospect leads are detailed on an accompanying printout.

While EXPLOR may increase prospect generation productivity, the prospect leads--like other recommendations from expert systems--must be evaluated by experts, exploration geologists in this case, before further action.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.