Artificial Fracturing of Cherokee Sands in the Gibson Pool, Cowley County, Kansas: ABSTRACT

Abstract

In order to present a background for the more specific data concerning the Gibson pool, some general information relative to the areal extent, stratigraphy, and history of oil and gas development of the Cherokee sands is necessary. The Cherokee sands of southeastern Kansas are confined to the Cherokee basin which is limited on the east by the Ozark uplift, on the west by the Nemaha arch, and defined on the north by the Bourbon arch. The basin is also considered to be a northern extension of Oklahoma's McAlester basin. The Cherokee sands, while widespread in this area, are not of the blanket type. In Cowley County, Kansas, which lies in the southwestern corner of the Cherokee basin, the sands are prevalent, but are concentrated in the western half of the county and on the astern flank of the Nemaha ridge. An area in which they are particularly abundant centers near Arkansas City which lies approximately 3 miles east of the Gibson pool. The Cherokee sediments which are lower Desmoinesian in age, while not the earliest Pennsylvanian rocks in Kansas, are the oldest represented in this area. Early Pennsylvanian seas were confined in southeastern Kansas by the Bourbon arch which isolated this area from the Forest City basin. The Cherokee section is made up predominantly of shales which, for the most part, are clayey or silty and micaceous. Fifteen coal beds and numerous sands have also been identified. The sands are lenticular and non-continuous, but because of their constant position in the Cherokee section, they lend themselves well to stratigraphic classification. Studies of the shales, coals, and sandstones indicate that they were deposited under cyclical conditions. There has been some controversy as to the true ori in of the sand lenses and also a great deal of confusion about the correct correlation and nomenclature. The term has been somewhat loosely applied to any sand encountered in the lower part of the Cherokee section. This has been particularly true of the Cowley County area and there is considerable doubt that any sands of Bartlesville age are actually present in this part of southeastern Kansas. End_Page 2610------------------------------ The development of oil and gas reservoirs of the Cherokee sands in southeastern Kansas may be defined into two major periods. One may be considered that period of development prior to the utilization of hydraulic fracturing treatments, while the other represents that period influenced by artificial fracturing. The first period may also be subdivided into several phases. The first commercial well drilled in Kansas was in 1860 near Paola. The outbreak of the Civil War discouraged any further venture such as this, but drilling was resumed following the war and exploration spread all up and down the Verdigris and Neosho Valleys. major impetus to the development of oil and gas in Kansas was provided by the discovery of the El Dorado pool in 1915 and the Augusta pool in 1916. generally ormal period of development followed with a slight decrease in activity to 1949. In the fall of 1950, the first artificial fracturing treatment was applied to the Cherokee sands in southeastern Kansas with excellent results. This started another near-boom and for the past 2 years the drilling activity has increased many-fold, resulting in many discoveries. One area in which the hydraulic fracturing of reservoir rocks has produced excellent results is in the Gibson pool, T. 34 S., R. 3 E., Cowley County, Kansas. The name has been utilized to identify the producing beds in the Gibson pool to conform to common usage in this area. However, it is believed the sand should be considered Red Fork or Burbank in age and that no true Bartlesville sand is present in this part of Kansas. The discovery well of the Gibson pool is Texas Company's Bryant 1 A, SE., SE., NW., Sec. 32, T. 34 S., R. 3 E. This well encountered a saturated sand superjacent to the Mississippian, but drill-stem testing of this zone recovered only a minor quantity of mud which was very slightly oil-cut. However, after pipe was set and the formation fractured, th Bryant 1 A was completed as a flowing well with a potential of 80 barrels of oil per day on March 3, 1952. Twenty-six new wells have been drilled within the new pool area and in many places the reservoir sand was found to be tight with low permeability and porosity conditions indicated by core analyses and drill-stem testing. However, fracturing treatment, both in the open hole and through casing, has resulted in obtaining some excellent wells, three of which have been given a maximum production rating. End_of_Article - Last_Page 2611------------