Abstract

The Gas Research Institute (GRI) has been sponsoring a three-well cooperative program with Ashland Exploration, Inc. (AEI) during the past two years evaluating the Devonian Shale and Berea sandstone formations in Pike County of eastern Kentucky. The COOP 2 was targeted to evaluate the Berea and was GRI's first comprehensive tight gas sand research project in the Appalachian Basin. The objective of the research was to use and apply technologies developed previously in other GRI research. This paper will summarize the integrated reservoir and hydraulic fracture descriptions determined from analyzing the data collected in this project. The results presented can be applied by operators to better understand the productive mechanisms in the Berea reservoir, to predict well performance, and to design completion procedures and stimulation treatments. The methodology can also be applied to other tight gas sand formations.

Introduction

In the Appalachian Basin, many wells are drilled and dually-completed in the Devonian Shales and a tight gas sand, which increases the chance for a successful well and maximizes the economics. The Shales and the various secondary completion targets are a large gas resource for the Appalachian Basin and the United States. Up to this point, GRI had not performed extensive research on the many productive tight sand formations in the Appalachian Basin.

GRI is currently sponsoring a three-well research program in eastern Pike County, KY with a cooperative industry partner, Ashland Exploration, Inc. (AEI). Fig. 1 shows a map of Kentucky and the research area in Pike County. This program targets the Devonian Shales and Berea tight sand formations, which are typically stimulated individually and then commingled. The research is important because operators do not routinely perform such detailed analyses on their wells. This site was chosen because many operators are active in this area, and there is excellent future development potential - i.e., the results will be useful in many new wells.

The three-well project has been in progress since mid-1991 and will be completed by mid-1993 (see Fig. 3). The Shales research in the COOP 1 and Berea research in the COOP 2 have been completed. The analysis results from the first two COOP wells will be used to evaluate the Shales and Berea formations in a third well (ED well) that has been farmed-out from AEI. The purpose of this paper is to summarize the major Berea research results in the COOP 2. The research results from the Shales in the COOP 1 will be addressed in a separate paper.

The primary objective of the Berea research in the COOP 2 was to transfer and apply technologies developed previously in GRI's Tight Gas Sands and Gas Shales projects to gain a better understanding of the Berea in the study area. This technology consisted of integrating reservoir and stimulation data to describe the pre- and post-fracture production from the Berea in the COOP 2. As a result of this work, we satisfied specific objectives such as identifying geologic production controls, developing log models to predict net pay, porosity, and stress profiles, and identifying potential modifications to completion and stimulation practices.

In this paper, we summarize the key results obtained from geologic, coring, logging, well testing, and fracture treatment evaluations performed in the COOP 2.

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