Mobil Oil Corporation

Warren F Johnson

Joseph G Savins

Lawrence R Stowe

Bert J Warner

Melwyn L Mathis

A method for extending fractures in underground formations obtained by controlled pulse fracturing through the use of stabilized hydrogen peroxide solution. Controlled pulse fracturing causes radial fracturing near the wellbore. In order to extend these radial fractures further into the formation or reservoir, stabilized hydrogen peroxide is forced into the radial fractures. Stabilizing agents in the hydrogen peroxide react with metals in the formation causing the hydrogen peroxide to breakdown and form gas pressure sufficient to extend the radial fractures. Hydrocarbonaceous fluids are then obtained from the formation via the extended fractures which contact natural fractures in the wellbore.

Controlled pulse fracturing

The present invention relates to the in situ recovery of mineral values, particularly uranium, from subterranean formations that contain sulfur in organic or inorganic forms where the sulfur causes premature deletion of an oxidant and reduction in permeability of the formation. The adverse effects due to the presence of the sulfur in the formation are substantially reduced in accordance with the present invention by treating the formations with an aqueous solution of iron-complexing agent and then oxident to preferentially oxidize and solubilize at least a portion of the sulfur in the formation. The present process may be applied either as a pre-treatment process to be followed by a leaching process or simultaneously with the leaching process.

Process for recovery of mineral values from subterranean formations

Method and apparatus for mixing a gaseous oxidant (e.g., oxygen) and a lixiviant (e.g., an aqueous carbonate solution) at a downhole location before the oxygen-saturated lixiviant is injected into a formation to be leached. The invention involves establishing a mixing zone in the well by positioning a mixing means, comprising a housing, in the well at the downhole location. Lixiviant is flowed down the well and through a restrictive opening in the housing to substantially increase the flow velocity of the lixiviant. At the same time, gaseous oxidant is fed to the housing and is trapped therein by the increased velocity of the lixiviant and by packing material in said housing. The lixiviant flows through the trapped oxidant which, in turn, dissolves into the lixiviant to saturate same. Additional packing material is provided in the housing to remove undissolved oxidant from the saturated lixiviant before it is injected into a formation to be leached.

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Dallas, TX, United States of America

Warren F Johnson