IMPROVED ELECTRON TRANSFER AGENTS IN WELL ACIDIZING COMPOSITIONS AND METHOD

摘要

An acidizing composition and a method of acidizing a hydrocarbon bearing subterranean formation in the presence of ferric ions are provided. The acidizing composition includes a strong mineral acid solution, an electron donor agent, a primary electron transfer agent and a secondary electron transfer agent. The primary electron agent is a source of rhenium ions. The secondary electron transfer agent is a source of iodide ion or iodine. The electron donor agent and primary and secondary electron transfer agents function together to reduce ferric ion present in the mineral acid solution to ferrous ion which in turn prevents ferric hydroxide and/or free sulfur from precipitating out of the solution and reduces the formation of sludge in crude oil in the formation. The particular electron transfer agents used in connection with the invention function with virtually all known electron donor agents.