Geostatistical Modeling of Mississippian Limestone Garfield County, Oklahoma
Robert Holman and Priyank Jaiswal
Understanding the petrophysical and lateral facies changes of the Mississippian Limestone in the Anadarko basin is paramount for hydrocarbon exploration. The ultimate goal is to be able to predict petrophysical properties of the rocks away from the immediate vicinity of the borehole using methods such as seismic. Using geostatistiacal methods we show how porosity and other rock attributes can be predicted within a 3D seismic cube. Preliminary results have indicated that the key in geostatistical prediction is well-to-seismic calibration. After a correlation has been established between a log property (e.g., porosity) and a seismic attribute (e.g., amplitudes), the log property can then be extrapolated with the seismic attribute in multiple ways including Regression-Kriging, Kriging with external drift, Co-Kriging etc. The robustness of the extrapolation method is assessed through blind tests. Meaning, that as statistically generated surfaces are created, portions of the data will be withheld from the initial analysis to determine how well the algorithms are able to predict those points. The norm is to generate multiple realizations with any given geostatistical methods. The individual realizations are probability distribution (PD) maps. The key, in the end, is to put the individual PD maps in context of the geology with help of supplementary data such as cores and outcrops. A few questions that we are attempting to answer through our research include how porosity is related to a deposition environment and how fractures are related to facies.
AAPG Search and Discovery Article #90176©AAPG Mid-Continent Meeting, Wichita, Kansas, October 12-15, 2013