Despite depths of only 4000-6000 feet in the Medina/Clinton formations, significant crushing of Ottawa sand was documented due to narrow achieved widths. A review of 20 years of fracturing results showed convincingly that higher proppant concentrations resulted in greater EUR.
Over the past thirty years, the Medina sandstones have been the primary drilling target in northwestern Pennsylvania. Numerous operators have drilled and completed thousands of wells in this tight gas sandstone. As fracturing technology has evolved, many different types of treatments have been utilized; from “slickwater” fracs containing small volumes of sand pumped at low densities, to crosslinked gels carrying high volumes and densities of sand, to linear gels with widely differing sand volumes and densities, to nitrogen foams also transporting varying volumes and densities. While everyone agrees that Medina wells need to be stimulated in order to be productive, there are as many opinions as to the most successful technique as there have been operators. Often, these opinions are based upon conjecture with no comparative supporting data.
The Cramerven/Cooperstown field located in Crawford, Mercer, and Venango Counties provides an opportunity to review the history of Medina stimulation as well as compare the results of different frac styles. Wells in this field have been extensively analyzed and production tracked in order to determine the optimal stimulation technique. Although variability due to geologic differences can greatly affect the results of individual wells, large populations of wells have been compared in order to minimize the effect of this variability.
This paper will present a discussion of the historical stimulations performed in this field, compare stimulation design to Estimated Ultimate Reserves, provide background on the design and development of the treatments utilized, and finally, present an analysis of the current design based upon production decline analysis.
Author(s): Jim Fontaine, Universal Well Services, Inc.; Len Paugh, Jim Watson, Great Lakes Energy Partners, L.L.C.
Paper Number: SPE 78701