Interactions of fluids during sandstone acidizing operations

Sandstone formations are very complex in terms of mineralogy; it consists of a variety of minerals with different properties, minerals such as carbonate, clays, feldspars, iron oxides, and other minerals. This complex mineralogy will make it very difficult to have an ideal stimulation fluid; hence several stages and fluids are used. This chapter will cover the interactions of different fluids and additives with rock minerals utilizing experimental and simulation aspects. The basic chemistry of sandstone acidizing and the composition and additives of sandstone acidizing fluids are covered. This chapter will shed light on the compatibility between different fluid stages and the fluid in the same stage. Acidizing fluids such as HCl, HF, corrosion inhibitors, and clay stabilizers is discussed. Fluid/rock interactions that may cause fines migration, clay swelling, fluid retention, fluid adsorption, variations in porosity and permeability, and wettability alterations are analyzed.