The Effect of Iron Bearing Minerals on Anionic Surfactant Retention in Chemical Enhanced Oil Recovery Applications

The scope of the paper is within chemical enhanced oil recovery. The goal of the work was to observe and quantify the adsorption/partitioning (reversible adsorption) of anionic surfactant molecules on the surfaces of positively-charged, iron-bearing clay minerals. The relationship between porosity, permeability and clay content is also observed and discussed. Siderite (iron carbonate) is mixed with silica sand to create homogeneous synthetic cores. The surfactant used is anionic. A set of synthetic sandstone cores were fabricated containing varying content of siderite. They were used in flow experiments while keeping the surfactant concentration fixed. After ensuring that the iron cations are in low valence state, surfactant is injected and the effluent is analyzed to qualify the adsorption. The adsorption retention was determined by comparing the surfactant mass injected to the surfactant mass produced by way of measuring the effluent concentration during the core flood. This experiment provides a measure on the amount of surfactant lost due to adsorption effect. By understanding the relationship between surfactant retention and the presence of positively-charged clay in the core samples; corresponding decisions can be made to maximize the effectiveness of anionic surfactant and minimize production costs.