Olefin Sulfonates for High Temperature Steam Mobility Control: Structure - Property Correlations

Abstract

Understanding the effect of the components of commercial olefin sulfonates on steam foam performance would aid manufacturing more cost-effective products. Commercial alkene sulfonates are a mixture of alkene sulfonate, hydroxyalkane sulfonate, and olefin disulfonate. The effect of these components, hydrophobe linearity, the position of the carbon-carbon double bond in the substrate (alpha-olefin compared to internal olefin), hydrophobe carbon number, and hydrophobe linearity on foaming properties and other properties of interest for enhanced oil recovery was studied. The connectivity index measure of chemical structures correlation with 121 C (250 F) foam stability provided a correlation coefficient of 0.98. Introduction Improved engineering concepts such as horizontal injection and production wells are improving oil recovery economics in steam enhanced oil recovery projects. The use of alpha-olefin sulfonates and other surfactants as steam foaming agents has been studied extensively at many laboratories. These studies include both laboratory tests and field pilots. The general consensus is that steam mobility control surfactants providing improved cost effectiveness are needed. The objective of this report is to describe structure property relationships of olefin sulfonates that aid in predicting their steam mobility control performance and identifying improved candidates with a minimum of laboratory screening studies. The results of original experiments are reported. In addition, previously published results are reconsidered from a surfactant structure - property perspective. Steam foam sand pack floods which serve as a basis for discussing the effect of hydrophobe carbon number and branching are described in references 3 and 4. Experiments of similar design have been described elsewhere. The connectivity index was originally developed to relate physical and biological properties of organic compounds to one or more connectivity indices, mXb. (m is the order of the connectivity index and b is the type.) The physical significance of the connectivity index is somewhat unclear but appears to depend on the topology of the molecule and therefore could be directly related to many physical properties. The connectivity index, I, is calculated using Equation 1: (1) wherein: I is the connectivity index d1 and d2 are the valence electrons (excluding those bonded to hydrogen atoms Appendix A provides a simple example, the calculation of the connectivity index of 1-butanol. The methodology used to calculate the connectivity index values for olefin sulfonates is also summarized. The first order connectivity index used herein tends to reflect the relative molecular surface area of the molecule and accounts for branching. Larger molecules have higher connectivity indices since they contain more atoms and bonds. As branching increases for a given number of carbon atoms, the connectivity index decreases indicating a more compact molecule. P. 91^

Simulation Studies on the Role of Lauryl Betaine in Modulating the Stability of AOS Surfactant-Stabilized Foams Used in Enhanced Oil Recovery

“…In this work, we have not investigated the impact of specific salt type and composition on foaming. Additionally, the branching of surfactants may also affect their interfacial properties. , These aspects are undoubtedly important in designing surfactant blends to stabilize foam. Investigations along these lines are part of our ongoing work.…”

Application of Sustainable Foaming Agents to Control the Mobility of Carbon Dioxide in Enhanced Oil Recovery

“…However, the chosen foaming agent should be sustainable, nontoxic and have less environmental disadvantages especially for the offshore field applications. Many screening studies to choose proper foaming agent have been performed by many scientists (Keeling, 1984;Maini and Ma, 1984;Borchardt et al, 1985;Heller et al, 1985;Suffridge et al, 1989;Hanssen and Dalland, 1990;Borchardt and Strycker, 1997;Mannhardt et al, 1998;Syahputra et al, 2000;Demin et al, 2001;Rojas et al, 2001;Marcano et al, 2009;Andrianov et al, 2011) but most of them used various petroleum based surfactant which potentially cause many ecological problems. In the recent years some reports are provided about sustainable surfactants that indicated they are already used in petroleum industry.…”