Abstract

Development drilling for gas from Upper Morrow sandstones in the Reydon Field, Roger Mills County, Oklahoma, and Hemphill County, Texas, has yielded a 60% success ratio. Development risk is high because these Upper Morrow sandstones exhibit a complex prodeltaic depositional environment. Reservoir prodeltaic depositional environment. Reservoir pressures exceeding 12,500 psia and temperatures pressures exceeding 12,500 psia and temperatures of + 280 degrees F. in the 15,000' range also create high drilling costs. Inasmuch as potential reserves are estimated to be greater potential reserves are estimated to be greater than 15 Bcf per well, development of these reservoirs still offers excellent economic return for investors.

Introduction

Deep drilling for hydrocarbons in the Anadarko Basin provides the petroleum industry with a new frontier for the discovery and addition of much needed fuel reserves. However, geological and operational risks associated with newly found deep reservoirs are severely magnified such that wildcat success does not necessarily assure typical development success. Development of gas from Upper Morrow sandstones in the Reydon Field is an example of successful drilling in spite of many problems associated with the geology and operations.

The Reydon Field exhibits a complex depositional environment of Upper Morrow sandstones which makes definition and predictability of the reservoir rock difficult. predictability of the reservoir rock difficult. In addition, Upper Morrow reservoirs at Reydon are abnormally high pressured, exhibit higher than normal temperatures and contain scale producing fluids which create hostile drilling producing fluids which create hostile drilling and production conditions. Proven and potential reserves, however, outweigh the increased risk and have afforded an excellent investment opportunity for those willing to assume this risk.

GENERAL

Location - Reydon Field is located in T 13 and 14N, R 26w, Roger Mills County, Oklahoma west and west southwest of the townsite of Reydon, Oklahoma and extends across the state line into the eastern sections of Block Z-1-ACH and B and H and W Survey and Block C-G and M and MB and A Survey, Hemphill County, Texas. The field has been variously designated West Reydon, Northwest Reydon and Viking Field (Hemphill County, Texas), but for purposes of this paper the entire area is referred to as the Reydon Field.

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