Sandstone matrix stimulation

Sandstone matrix stimulation is considered as one of the major challenges in the oil and gas industry. Most of sandstone acidizing jobs do not meet the required design because of the complexity of sandstone mineralogy. There is no standard mineralogy of sandstone reservoirs; it varies from one location to another. In the petroleum engineering domain, usually, the variation in mineralogy is not considered and field operation goes with the standard acid recipe provided by service suppliers. In this chapter, sandstone mineralogy will be described in detail and examples of the mineralogical composition of sandstone reservoir as wells as outcrops will be provided. Possible damaging mechanisms and the reactions between different fluids and minerals are summarized. Different acidizing techniques, formulation, and ingredients are presented as well. Moreover, the recommended various acid additives for successful acid jobs are explained. Part of this chapter also addresses the required laboratory evaluation tests along with the acid treatment design for field applications. Finally, the acid stimulation applications for both unconventional and geothermal sandstone reservoirs are discussed with some supporting field case.