Unplugging brine-submerged perforations
AssigneeShell Oil Company
InventorsEdwin A. Richardson, Walter B. Fair, Jr.
Life of this patent
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Abstract
Fluid passageways between a well borehole and a subterranean reservoir which are both plugged and submerged within relatively dense brine can be contacted with heat and oil solvent by arranging a nitrogen gas generating aqueous solution to be both reactive at the reservoir temperature and denser than the brine in the borehole and flowing alternating slugs of it and a liquid oil solvent into the zone to be treated.
Claims4
A well treating process, for bringing heat and oil solvent into contact with plugged fluid passageways which extend between the borehole and reservoir and are covered by a column of relatively dense brine, comprising:
- compounding a self-reactive heating solution which (a) consists essentially of an aqueous liquid solution of nitrogen-generating reactants arranged for yielding heat and gas at a significant but moderate rate at the reservoir temperature and (b) contains enough total dissolved solids to provide a solution density exceeding that of the brine in the borehole;
- flowing at least one slug each of said heating solution and a liquid oil solvent which becomes a hot liquid solvent for petroleum type compounds at the temperature yielded by the heating solution into the well at a flow rate and sequence such that (a) a significant portion of the heating solution sinks into the column of brine in the borehole and reacts to yield heat and gas that contact the plugged fluid passageways and (b) a significant portion of the oil solvent is heated by the reaction and is displaced into contact with the plugged passageways;
- and
- removing the resulting solution or dispersion of plugging materials in aqueous or oleaginous liquid by producing fluid from the well.
Dependencies are inferred from the claim text.