Tall Oil Pitch in Chemical Recovery

Abstract

Abstract This paper describes a laboratory investigation of tall oil pitch as a potential alternative to petroleum sulfonate as a surfactant for chemical recovery. Tall oil pitch is a bottom product of tall oil fractionation that is based on a major by-product of the paper industry. It is inexpensive, substantially available, and derived from a renewable resource. It is a complex solid consisting of fatty acids, rosin acids, and unsaponifiables. Oil recovery in Berea sandstone cores has shown that final residual oil can be lowered to several percent by injecting properly formulated tall oil pitch solutions in high-salinity field water at 158 and 195°F (70 and 90°C). Tall oil pitch must be neutralized to achieve interfacial activity. Usual neutralization of tall oil pitch with sufficient alkali to balance the acid equivalence results in surfactant solutions unfavorable for chemical flooding. Alternative neutralization methods are shown to produce solutions that give better oil recovery and no plugging problem in core experiments. Tall oil pitch has low salinity tolerance, and the additionof NEODOL® 25-3S does not provide satisfactory interfacial activity, salinity tolerance, and temperature stability. Alternative methods of increasing field water compatibility of tall oil pitch slugs have been investigated. Good oil recovery has been obtained with slugs containing as much as 26,280 ppm total dissolved solid. Five different sources of tall oil pitch were studied. Oil recovery efficiency was shown to be parallel with the fatty-acid dimer content of the sample as determined by gel permeation chromatograph. Heat treatment of the pitch to increase the fatty-acid dimer content improves recovery performance. This finding is important not only in controlling the activity of tall oil pitch but also in providing new leads to what makes certain surfactant materials active.