(162o) Using NMR to Characterize Brine/Crude Oil Emulsion Formation and Stability

This work provides specific information regarding the formation and stabilization mechanisms of brine/crude oil emulsions. Ultimately, this information will lead to a quantitative understanding of the relationship between drop size distribution and methane hydrate formation in crude oil emulsions. In this work, drop size distributions of brine/crude oil emulsions are measured and used to quantify the mechanisms that lead to emulsion formation and stabilization. Currently, experimental evidence in the literature shows that drop size distribution and stability of brine/crude oil emulsions affect methane hydrate blockage formation [Skodvin, T., "Formation of Gas Hydrates in Stationary and Flowing W/O Emulsions," Encyclopedic Handbook of Emulsion Technology, ed. Johan Sjoblom, 2001]. The formation of methane hydrate blockages is a significant problem in the petroleum industry, resulting in costs exceeding 500 million dollars annually. Therefore, this work provides specific data regarding brine/crude oil emulsion formation and stabilization mechanisms in order to improve the understanding of methane hydrate formation in brine/crude oil emulsions.

Previous work at Rice University has shown that nuclear magnetic resonance (NMR) is an effective tool to measure transient drop size distributions in brine/crude oil emulsions [Pena, A., "Dynamic Aspects of Emulsion Stability," Ph.D thesis, Rice University, 2003]. The stability of brine/crude oil emulsions is directly reflected in the transient drop size distribution. Therefore, NMR is currently being used in this work to gain information about the emulsions created from different crude oil samples by measuring transient drop size distributions. The emulsions have been formed with both a Rushton turbine mixing device and Couette flow. The Rushton turbine produces a turbulent flow field, while Couette flow results in the application of uniform shear to the emulsion samples. Our initial transient drop size distribution measurements indicate that the applied shear, mixing duration, and energy input affect the formation and stability of the emulsions. Also, flowing conditions as well as quiescent conditions in the time between measurements have been investigated. In addition, the surface relaxivity of the two brine/crude oil systems has been investigated using two different techniques, CPMG-PGSE and PFG-SE DE. Finally, experiments are currently being performed which quantify the effect of crude oil chemistry and temperature on emulsion formation and stability.