Process for producing or cleaning high pressure water injection wells

A process for controlling the build-up of sulfides, biomass and other accumulations within a water injection or oil-producing well having a pumped water injection stream, the process comprising the steps of

• (a) mixing the following feed streams:
• (1) a proton donor stream;
• and
• (2) a stream containing a chlorine dioxide precursor and water to thereby generate an aqueous solution of chlorine dioxide gas;
• (b) maintaining the resulting aqueous chlorine dioxide gas stream at a pressure sufficient to keep the chlorine dioxide gas dissolved;
• and
• (c) injecting under pressure the aqueous chlorine dioxide gas solution stream into the pumped water injection stream and thereafter under pressure into the water injection or oil-producing well.

A process for cleaning a producing well, the process comprising the steps of

• stopping the pumping of oil out of the well;
• selecting an oxidant reactive with hydrogen sulfide under downhole conditions;
• and
• injecting said oxidant under pressure into a pumped water injection stream and thereafter under pressure into a well containing hydrogen sulfide.

A process for cleaning an oil-producing or water injection well, the process comprising the steps of:

• generating chlorine dioxide gas;
• mixing the chlorine dioxide gas with water under pressure sufficient to form an aqueous solution of chlorine dioxide gas;
• raising the pressure above the aqueous solution of chlorine dioxide gas to wellhead pressure;
• and
• injecting under pressure the aqueous solution of chlorine dioxide gas into the well.

A process for facilitating the removal of biomass and other deposits from injection wells, the process including the following steps:

• generating chlorine dioxide gas in a liquid media to thereby form a solution of chlorine dioxide gas in the liquid media under a pressure sufficient to dissolve the chlorine dioxide in the media;
• providing a high pressure water stream;
• injecting the solution of chlorine dioxide gas into the high pressure water stream to thereby form a high pressure water-liquid media chlorine dioxide gas solution;
• directing the high pressure water-liquid media chlorine dioxide gas solution into a water injection well;
• and
• removing water and liquid media through a different well at a site remote from the site of the water injection well.