Permeability estimation from log-derived porosity II. Via co-kriging

In paper (I) (given at this meeting), the authors applied fuzzy regression to the problem of permeability estimation from porosity-log data. In this paper, they introduce another novel approach, co-kriging. Co-kriging is a multivariate geostatistical technique designed for characterizing joint spatial correlations between pairs of variables (log-derived porosity vs. core-derived permeability in the context of this paper). In other words, co-kriging yields estimates that use not only the information from direct measurements of the variables being estimated, but also the information from measurements of a second variable. Thus, co-kriging can be used to predict permeability at uncored wells. This is a powerful technique because they usually have more log data than core data. By making use of co-kriging they can make good use of the log-derived porosity data. Results of the study using the data from Chunchula field illustrate the power of this technique.