Additional Arbuckle Reserves Developed Below Original Completion Depth in Stratified Reservoir
Authors: Mulling Claud A. , Ireland W.C. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
This paper was prepared for the 42nd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Oct. 1–4, 1967. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.
Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
New life has been given the 30-year old Edwards Field by development of Arbuckle reserves below the original completions. The first well deepened in June, 1966, had an initial potential of 460 BOPD. Subsequent work has developed reserves in several additional wells.
The Edwards Field Arbuckle formation consists of a series of dolomite and shale beds correlative from well to well. The correlation has made possible construction of true structure maps on zones within the reservoir. True structure roughly parallels the top of the Arbuckle in a large portion of the field, but considerable divergence occurs between true and unconformable structure in localized areas.
Original completion techniques and consideration of true structural relief had left oil trapped within the Arbuckle section. The Edwards Field wells were originally completed open hole a few feet into the Arbuckle without general knowledge of the zoning situation. Oil above the original common oil-water contact but below impermeable barriers has been developed by deepening old holes.

Introduction
In the 1930's and early 1940's, original completions in the Kansas Arbuckle dolomite reservoir were made without true knowledge of the stratification within the formation. Well logging tools, and techniques, were not perfected then as are common to today's industry. During those "boom" years, the main criteria to operational success was completion of a 3,000-barrel per day potential oil well as quickly and cheaply as possible by drilling only a few feet into the top of the Arbuckle formation.
This paper discusses the developments in one Kansas oil field for the exploitation of additional reserves based on the premise of stratified, or zonal, conditions existing in a heterogeneous dolomitic reservoir. This field is the Edwards Field, located in T17S, R8W, Ellsworth County, Kansas, and a portion of the so-called Geneseo-Edwards trend (Figure 1). Outstanding deepening successes have occurred in the Edwards Field proper, but only limited successes have been obtained in other portions of the Geneseo-Edwards trend. However, structural correlations have been made between nearly all wells deepened in the entire area.
Thus far, 14 wells have been deepened, and one new well drilled for lower zone Arbuckle reserves. Seven of these deepening jobs have been considered successes. The first well deepened in the C, E/3, NE/4 of Section 28 (Figure 2) produced 460 BOPD, no water, after completion in a new zone 35 feet below the original total depth. One year after deepening, this well still has a productivity of 132 BO and 576 BW.