Inducing flowback of damaging mud-induced materials and debris to improve acid stimulation of long horizontal injection wells in tight carbonate formations

Abstract

A method for treating an open-hole horizontal water injection well in a tight reservoir rock formation to remove undesirable materials such as formation-damaging polymers and chemical residues from pipe dope from the formation surface and adjacent formation pores prior to an acidizing treatment includes maintaining the drilling fluid pressure on the injection zone to induce flowback of formation fluid which is produced at the wellhead located at the earth's surface, where it is monitored for a reduction in the undesirable materials. In the event that the formation pressure is insufficient to produce formation fluid flowback, a nitrogen-lift is introduced at a predetermined location in the adjacent vertical well that will reduce the drilling fluid pressure to induce production of formation fluid at the wellhead.