engleski

Using of Ordinary Kriging for indicator variable mapping (example of sandstone/marl border)

There is plenty of opportunity to work with indicator variable in petroleum geology. It means that each task where we can define two possible results (binary approach), the most often expressed as 1 (true) and 0 (false), can be finally presented as indicator value. Furthermore, the reservoir facies analysis is just one of such problem that could be very good analyzed with such tool. In Croatian part of Pannonian basin system, the majority of reservoirs are presented by sandstones, that gradually have been changed in marls laterally as well as toward the top and the base of the reservoir. The analytical goal in this paper was lateral facies change, i.e. the mapping contours of permeable reservoir part. We used the well data to define indicator variable presented as 1 for reservoir described by sandstone, and with 0 for the reservoir in dominantly marl type or pure, basinal marl. Interpolation by hand (very popular in the past) located transition line on the half distance between 1 and 0 values. But, present-day approach is obligatory based on computer mapping. It is why we tried to use advanced technique of Ordinary Kriging to interpolate indicator values, trying to reach approximately ‘half-distanced’ facies line. The successfully results are presented in this paper.

Ordinary Kriging; indicator variable; sandstone; marl; facies transition

Rad je objavljne u posebnom izdanju časopisa "Naftaplina" (knjiga 56/10) posvećenom 5. međunarodnom znanstveno-stručnom skupu o naftnom rudarstvu, održanom 2009. godine u Šibeniku.