Development of Emulsified Acid System using Organoclays

Matrix acidizing technique is used to enhance the production of hydrocarbons from a reservoir, especially in low permeable reservoirs and in the case of formation damage. In carbonate reservoirs, acid stimulation jobs are challenging due to the acid's strong reactivity with the formation. Thus, the ability to create wormholes will be limited. Wormholes allow hydrocarbons to be produced by flowing into the wellbore. Emulsified acids system helps to overcome this challenge by reducing face dissolution. Recently, Pickering emulsions have attracted attention due to their easy preparation and enhanced stability features. In Pickering emulsions, solid microparticles that localize at the interface between liquids are used as stabilizers instead of surfactants. The preparation of emulsified acid system (EAS) is a complex process sensitive to several parameters governing the properties/feature of the emulsified system. The parameter includes mixing the aqueous and oleic phase, the rotational speed, the time of mixing, and the quantity of emulsifying agent (organology). It requires performing several experiments to identify the proper procedure and optimum range of the parameters affecting the emulsified acid preparation of desired properties. In this study, several experiments were performed using three types of organoclays (OC) namely Claytone-SF (strong), Claytone-EM (medium), and Laponite-EP (weak). Thermal stability tests were carried out at room temperature, 80ºC, and 120ºC. Rheology tests were performed for the most stable emulsions. This study investigated the potential of using special nanoparticles as emulsion stabilizers instead of surfactants. A proper sequence of the component mixing and optimum range of the factors affecting the emulsion preparation and properties were identified. This work aims to study the parameters involved in the emulsified acid preparation and optimize them to obtain a stable EAS.