FOAM OR VISCOSIFIED COMPOSITION CONTAINING A CHELATING AGENT

摘要

The present invention relates to a foam containing water, between5and 30wt% on total weight of the foam of a chelating agent selected from the group of glutamic aid N,N-diacetic acid or a salt thereof (GLDA), aspartic acid N,N-diacetic acid or a salt thereof (ASDA), methylglycine N,N-diacetic acid or a salt thereof (MGDA), N-hydroxyethyl ethylenediamine-N,N',N'-triacetic acid or a salt thereof (HEDTA), a foaming agent, and at least 25 vol% on total volume of the foam of a gas,and having a pH of between 2 and 5, to a viscosified composition containing water, between 5 and 30wt% on total volume of the composition of a chelating agent selected from the group of glutamic aid N,N-diacetic acid or a salt thereof (GLDA), aspartic acid N,N-diacetic acid or a salt thereof (ASDA), methylglycine N,N-diacetic acid or a salt thereof (MGDA), N-hydroxyethyl ethylenediamine-N,N',N'-triacetic acid or a salt thereof (HEDTA), and at least 0.01 wt% on total weight of the composition of a viscosifying agent,and having a pH of between 2 and 5, and to a process for treating a subterranean formation comprising introducing the above foam or viscosified composition into the formation.