Recovering Oil From Shale With Nuclear Explosives
Authors: Lombard D.B. 
Published: December 2007

Nuclear explosives can be used to break large volumes of oil shale in place at depth, where deposits are thick. The diameter of the region (chimney) of shale broken by a nuclear explosion can be as much as hundreds of feet. The height is at least double the diameter. For example, a 20 kt detonation at a depth of 2,000 ft will break about 800,000 tons. Any problems associated with the radioactivity generated by a nuclear explosion in oil shale are expected to be manageable.

The probable size distribution of fragments of this broken shale has been estimated from photographs of roof falls in the Bureau of Mines oil-shale mine at Rifle, Colo. Calculations based on the theory of particle statistics lead to an estimated permeability of 3×10-5 to 3×10-4 sq ft, within the broken zone. The cost of breaking the shale with nuclear explosives would range from less than $.35 to more than $1.20/bbl of oil for recovery of 25 gal/ton, according to calculations for 100 and 20 kt explosions, respectively. Other costs, including mining or in situ retorting, and refining, are not calculated.

Basic features of a plan for in situ retorting are discussed. A relatively small-scale non-nuclear in situ retorting experiment is recommended. If successful, it would be followed by a nuclear explosion pilot experiment, from which detailed engineering criteria could be developed for using the nuclear techniques on a production basis.

Introduction

A nuclear explosion releases large amounts of energy in a short period of time. Ways in which this cheap energy source can be used for constructive and profitable industrial purposes are under active consideration. Early speculation about such possibilities began even before the world's first nuclear explosion in 1945. However, serious research on the subject did not begin until 1957, when the Atomic Energy Commission initiated the Plowshare program at the Lawrence Radiation Laboratory of the U. of California. Since that time, a number of technically and economically attractive engineering applications for nuclear explosives have been developed.

Canals, harbors, aqueducts, road cuts, and perhaps overburden stripping are among the works which can be accomplished as large excavations with nuclear explosives. The production of broken rock for large construction projects also has a good potential, where nuclear explosives buried more deeply would break just to the ground surface.

There are also a number of very exciting possibilities for completely contained underground nuclear explosions. Among these are:stimulating petroleum reservoirs;stimulating natural gas reservoirs;creating cheap storage for natural gas;creating underground space for the disposal of radioactive wastes or for the disposal, storage or conservation (for later use) of treated sewage wastes;leaching low-grade copper deposits;mining large, low-grade disseminated mineral ore deposits; andrecovering oil from oil shale. Before discussing the latter, we will examine a few technical facts about underground nuclear explosions and their particular effects which are related to oil shale.