Formation Damage Prevention and Adsorption Studies of Nonionic Surfactants in Sandstone Reservoirs

The adsorption of chemical additives used in conjunction with matrix acid systems presents an obstacle to improved stimulation performance. The primary purpose of performance. The primary purpose of surfactants used in acid treatments is to reduce acid surface tension and contact angle and prevent acid/formation fluid emulsion. However, many of these chemicals adsorb rapidly in sandstone media, reducing their effectiveness in the formation. This study describes the laboratory and field investigation of various surfactant components and their adsorption properties in sandstone, A six foot long sandstone core apparatus provides the primary means for laboratory investigation. Various surfactant constituents such as ethoxylated nonyl phenols and linear alcohols are investigated phenols and linear alcohols are investigated for their adsorption properties. This data may be used to develop chemical additive systems which optimize chemical penetration in a sandstone formation. The primary results of this study include:Improvement in penetration of surfactants when linear ethoxylated alcohol is used rather than commonly used nonyl phenol ethoxylates.The C12-C13 alcohol with ethylene oxide ratios of 9 to 15 moles shows to moles shows to be the most effective formation damage prevention. P. 282