The goal of sandstone-matrix acidizing is to remove siliceous particles that are blocking or bridging pore throats. This is accomplished by injecting acid formulations containing hydrofluoric acid (HF) or its precursors because HF is the only common acid that dissolves siliceous particles sufficiently. Standard treatments include preflush and post-flush stages of hydrochloric acid (HCl) to minimize the potential for secondary precipitation. This paper presents experimental and field-case studies with a sandstone-acidizing treatment designed to retard the HF reaction rate and enable single-stage treatment.
Introduction
The goal of sandstone-matrix acidizing is to dissolve damage that blocks or bridges pore throats in the formation matrix, thus ideally restoring the original reservoir permeability.
