Matrix addizing

Foamed Matrix Acidizing. Matrix addizing is a stimulation treatment used to remove damage near the wellbore without deating a fracture. The process involves the injection of a reactive fluid into the porous medium at a pressure below the fracturing pressure. The fluid dissolves some of the porous medium and consequently increases its permeability. 

In dolomite, add spends differently than in limestone formations. The readion of HC1 with dolomite is rate-limited at formation temperatures under 50 °C. Wormhole development, which is common in limestone acidizing, is not charaderistic in dolomite addizing (32). As pores become connected during matrix addizing operations, dolomites form caverns. The use of foamed acid ensures that the acid is spent in the primary channels and allows deeper penetration. Foams are good acid extenders. Deeper penetration can be achieved with foamed add as opposed to an equal volume of nonfoamed acid. 

As previously discussed, the most common purpose of matrix addizing is to restore near-wellbore permeability in or through a damaged formation zone. Because it is bypassed, rather than directly removed, formation damage in a candidate for carbonate acidizing need not be acid removable by contrast, it does need to be add removable in a candidate for sandstone acidizing. 

This chapter discusses conventional procedures for matrix addizing procedures, as well as alternative and retarded acid methods, additives, and add placement. Appendix B includes examples of successful procedures using matrix acidizing. 

It is important to evaluate the effectiveness of every stimulation treatment. Evaluations of matrix addizing and add fracturing treatments are usually based on production increases or comparison with other wells. With matrix acidizing, comprehensive pretreatment and posttreatment well testing and interpretation are usually not economically justified. Comprehensive evaluation can be justified most of the time with acid fracturing and propped fracturing. 

Damage bypass (matrix acidizing and fracture addizing)... 

---