An Assessment of Completion Efficiency Comparing Actual Production Results to NMR Predicted Rates in the Rocky and Ammunition Fields - Oklahoma

Abstract

These two fields in Washita County, Oklahoma present extensive traditional log interpretation problems. The wells contain a variety of sandstone reservoirs, including Britt, Boatwright, Cunningham and Schneberger. Each provides unique log interpretation issues. A clear definition of log derived porosity is extremely difficult for these reservoirs in the best of circumstances. Permeability is also an issue. Well to well correlations are unreliable due to the variability within the formations. In many cases, the expectation for the performance of the well was subject to little science and much conjecture. In order to arrive at effective porosity and an estimate of permeability, NMR logs were added to the traditional logging program. At the time of logging, the technique employed for analysis of this log relied heavily on work done in the area. Parameters for analysis of a specific reservoir in a specific area were held constant with raw measurements of the tool considered to make changes to the base model. The Bray-Smith permeability model was applied to present estimates of permeability utilizing only the data generated by the NMR device. This paper attempts to compare the results of this new permeability measurement technique with the production actually observed from this field. We will compare and contrast the results of three methods of developing permeability from NMR measurements. These will all be compared to the actual results achieved in the wells in the Rocky and Ammunition fields in Western Oklahoma.