| dc.description.abstract | The oil industry has been utilizing different acid systems, both organic and
inorganic, to stimulate sandstone and carbonate reservoirs. Among these, hydrochloric acid (HCl) is the most commonly used acid because it is cheap and efficient. In carbonate reservoirs, HCl is used by itself to decrease skin damage by creating conductive wormholes; whereas in sandstone reservoirs, HCl is mixed generally with hydrofluoric acid for stimulation of the reservoir.
Although HCl is widely used to increase hydrocarbon recovery from reservoirs, it has some drawbacks like high reaction and corrosion rates, especially in high pressure,high temperature environments. Therefore, an alternative acid system, which eliminates these problems while maintaining the advantages of HCl, is needed.
In a previous study, a new in-situ generated acid system was introduced for this purpose as an alternative to HCl at high temperatures, and its effectiveness was investigated. The objective of this study is to optimize the performance of this new acid system in Grey Berea Sandstone, Bandera Sandstone, Silurian Dolomite and Indiana Limestone. Elemental analysis of precipitates obtained at the end of aging cell tests will be investigated first. Coreflood experiments will be modified (flow rate, injected PV of acid, different additives etc.) accordingly, and results of elemental analysis of effluent samples and X-ray computed tomography (CT) of cores will be discussed. Finally, reaction type between the new acid system and carbonate (diffusion or reaction controlled) will be determined according to results of rotating disk apparatus (RDA) tests. | en |
