Comparison of Magnetic Resonance Bin Distribution Permeability to Observed Production
The geology of the hydrocarbon productive formations in western Oklahoma varies greatly in composition. These range from formations plugged with salt; some detrital, arkosic formations; very fine grained, but productive environments to very clean and permeable formations. This variability presents a very difficult log interpretation problem since reservoir quality changes greatly from well to well and from formation to formation. Logging programs designed to extract specific answers about one formation are not always able to provide conclusions in other formations in the same well. Image logs were added as part of the logging program. Although significant geologic information was obtained, the ability to effectively discern productive horizons was not enhanced.
Magnetic Resonance Imaging Logs (MRIL) was added to the logging program to add another piece of data to the resolution of this problem. Initial results were inconclusive and the technique was discouraged for several years. The advent of the T2 bin distribution permeability equation gave rise to the idea of revisiting those data sets using that technique to evaluate the data.
This case study details the results of using T2 bin information for estimating productive capacity in several western Oklahoma wells and in several different horizons. We retrieved NMR data that was recorded several years ago and recomputed the permeability utilizing the bin permeability equation. We exhibit the permeability’s calculated productive capacities and compare them to the production rates observed in the wells.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009