Abstract
Texaco conducted a successful surfactant/polymer flood in a 60-acre [24 ha] portion of the Salem Benoist reservoir in Salem, Illinois, in 1981. This pilot used a brine-tolerant petroleum sulfonate surfactant system blended in injection brine followed by a xanthan mobility control polymer in fresher water. The oil recovery over the seven year life of the flood was 487,050 bbl [77 435 m3]. This represents 45% of the oil remaining in the total thickness or 73% of that from the more permeable lower interval where most of the surfactant flowed.
Since this successful project, Texaco has continued to improve enhanced oil recovery surfactant systems. We have developed novel, brine tolerant surfactants based on the renewable resources lignin and tallow amine. This paper describes the laboratory work leading to a surfactant system which has been recommended for field testing. The laboratory work includes blending, interfacial tension measurements, and corefloods in Berea and reservoir cores.
Our novel lignin amine surfactant systems perform better in long corefloods than the field tested petroleum sulfonate system. Their costs are approximately 40% lower than the petroleum based system, and this lower cost has a major impact on project economics. The lignin amine system can be applied at a crude oil price of about $21/bbl while an equal amount of the petroleum sulfonate requires about $32/bbl for the same return on investment.
The type of lignin based surfactant system described in this report has applicability in all fields where conventional petroleum-based surfactants have been used. Their much lower cost means that they can be used economically at lower crude oil prices.
