PROCESS TO PRODUCE OIL OR GAS FROM A SUBTERRANEAN FORMATION USING A CHELATING AGENT

摘要

The present invention relates to a two-step process to produce oil or gas from a subterranean formation wherein in a first step the subterranean formation is treated with an aqueous composition containing a chelating agent selected from the group of glutamic acid Nu,Nu-diacetic acid or a salt thereof (GLDA), aspartic acid N,N-diacetic acid or a salt thereof (ASDA), methylglycine Nu,Nu-diacetic acid or a salt thereof (MGDA), and N-hydroxyethyl ethylenediamine Nu,Nu',Nu'-triacetic acid or a salt thereof (HEDTA) and wherein, in a next step, in the outlet streams from the subterranean formation the aqueous phase is separated from the non-aqueous phase.