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Abstract

Applying technology to Devonian Shale wells can increase present value profit by $30,000 to $150,000 per well in a typical drilling program by improving stimulation treatment design and results. An intermediate level of technology application is best, costing $6,800 above what a typical operator currently spends. The key objective of the technology application is to optimize the stimulation treatment using a layered reservoir description with accurate formation properties. An accurate layered reservoir description minimizes inappropriate stimulation treatments, consistently resulting in treatments that are close to the optimal treatment.

Introduction

Over the last decade, the Gas Research Institute (GRI) has performed both laboratory and field research to develop improved completion, stimulation, and reservoir engineering technologies for Devonian Shale wells. 1-9 Existing technologies were adapted, where feasible, to solve shale-specific problems, and new technologies were created for items such as log interpretation and measurements of shale matrix porosity and permeability. A recent paper by Hopkins et al. 10 describes in detail how to apply these new technologies.

The new technologies improve the reservoir description by providing accurate estimates of reservoir properties for individual layers within the formations Several of the most important technological developments include the following.

Development of a shale-specific log interpretation methodology for determining net pay, porosity, and fluid saturations.

Identification and spacing measurement of naturalfractures using the bore hole camera and microresistivity devices.

New laboratory equipment and procedures for measuring matrix porosity and permeability.

Laboratory equipment and procedures for measurement of adsorbed gas content.

Development of stress profiles for the Devonian Shalesby conducting in-situ stress tests with nitrogen and using the results to calibrate full wave-form acoustic log data.

Pump-in/fall off pressure transient testing techniques(nitrogen slug tests) for measuring bulk permeability and fracture volume.

The purpose of this paper is to quantify the benefits of applying these technologies to Devonian Shale wells. Technology application increases profit through improved stimulation designs resulting from layered reservoir descriptions and accurate reservoir property estimates. We quantify the benefits using statistical formulae to compute the profit expected from a typical Devonian Shales well, both with and without technology application. We identify five reservoir properties most in need of greater measurement accuracy, and compare the expected profit from three levels of technology application to the expected profit from the current level of technology application.

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