Effective matrix acidizing in carbonates using microemulsions

TLDR

Matrix acidizing is a technique used to enhance oil reservoir productivity by increasing rock permeability around the wellbore. The study seeks to uniformly penetrate acid into the formation porespace to improve well productivity. Acid mixtures of HCl for limestone or HCl/HF for sandstone are pumped at low pressures to avoid fracturing while dissolving the matrix. Partial dissolution of the matrix reduces flow resistance, increases rock permeability, and boosts oil production.

Abstract

The process of matrix acidizing of oil reservoirs is described. It is designed to improve well productivity by increasing rock permeability in the region surrounding the wellbore. As resistance to flow is reduced, oil can move more easily to the wellbore and production increases. A reacting mixture, usually containing HCI for limestone and an HCI/HF mixture for sandstone, is pumped into the well at pressures low enough to avoid fracturing the formation rock or to open existing fractures. The goal is to achieve a somewhat uniform radial penetration of acid into the formation porespace. Partial dissolution of the matrix can then take place, and rock permeability is increased.