Abstract

Considerable interest in chemical explosive fracturing has resulted in the derivation of mathematical reservoir models for explosive stimulations. Mathematical models are presented which describe the effects of a chemical explosive displaced into a producing formation and the characteristics of the drainage system within the formation after stimulation. The effects on formation permeability and fracture extension distances permeability and fracture extension distances for different types of formations are derived. Predicted over-all production improvement Predicted over-all production improvement ratios and the economics involved are also covered.

Introduction

In a recent article, a new technique of explosively stimulating the production of oil and gas wells is described by Weigelt and Laspe. The method involves the hydraulic or pneumatic displacement of a powerful slurried pneumatic displacement of a powerful slurried explosive far back within the fracture system of the pay zone. Upon detonation, which propagates through fissures as small as 1/64 in. propagates through fissures as small as 1/64 in. in width, high energy shock waves are initiated. These waves cause extensive rubblizing and secondary fracture generation at considerable distances from the original fissure. In addition, the large quantity of product gases generated by the explosion result in lengthening of the primary fracture system. The rubblized fragments, some of which are in the typical frac sand particle size range, are blown into the newly formed fractures to provide an autogenerated proppant.

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