Clemens T.,OMV |
Tsikouris K.,ICON |
Buchgraber M.,Stanford University |
Castanier L.,Stanford University |
Kovscek A.,Stanford University
SPE Reservoir Evaluation and Engineering | Year: 2013
The recovery of viscous oil can be significantly improved by injecting polymer solutions. The processes leading to increased oil production occur on a large scale-improving vertical and areal sweep efficiency-but they begin on a microscale. Micromodels with realistic pore geometries have been created. These micromodels were saturated with viscous oil, and the displacement of the oil by water and polymer solutions was investigated experimentally. Polymer injection reduced fingering compared with water injection and increased sweep efficiency accordingly. The micromodel pore-network geometry was digitized with scanning electron microscopy (SEM). The digitized model was used to perform computational-fluid-dynamics (CFD) simulation of the displacement processes. The displacement efficiencies and displacement patterns of the CFD simulations with water, polymer solutions, and polymer solutions after water breakthrough at the outlet end to displace oil were very similar to the results of the micromodel experiments. Then, the CFD simulations were used to investigate the displacement at the pore scale. Water injection leads to the creation of fingers along slightly more-permeable flow paths. The number and length of the fingers decrease if polymer solution is injected. Even for polymer injection after water breakthrough, the fingering is reduced, polymer solutions are diverted into less-favorable flow paths, and sweep efficiency is increased. CFD simulations can also be used to look into non-Newtonian fluid behavior at the pore scale. The polymers injected in the micromodel experiments exhibited shear-thinning behavior. On a pore scale, CFD simulations showed that the shear stress and viscosity of the polymer solutions accordingly are significantly lower in the pore throats than in the pores. Thus, the displacement efficiency of the polymer solutions is affected by the shear-thinning behavior. The CFD simulations are in remarkable agreement with the micromodel experiments and can be used to quantify the displacement processes at pore scale. Copyright © 2013 Society of Petroleum Engineers. Source
News Article | August 22, 2016
News Article | November 9, 2015
OMV AG is firming its traditionally strong ties with Russia. It recently agreed to participate with state-owned Gazprom in gas development in West Siberia and in a group led by Gazprom to expand the trans-Baltic Nord Stream gas pipeline.
But if you want to know how that compound is actually disrupting the bacterial walls, you need to be able to examine the bacteria cell's surface. Tools that probe these details usually need a flat surface, but bacteria are ellipsoidal. This was the dilemma facing a group of chemical and biomolecular engineers, led by Cornell associate professor Susan Daniel and colleague Matt DeLisa, the William L. Lewis Professor of Engineering. Their team devised a way to take bacterial outer membrane vesicles [OMVs] – shed from weak points on the membrane in nanometer-size particles – to create a planar representation of the bacterial outer surface. This was achieved, Daniel said, by recent doctoral graduate Chih-Yun Hsia and is detailed in a paper, "A Molecularly Complete Planar Bacterial Outer Membrane Platform," published Sept. 7 in Nature Scientific Reports. Other contributors included postdoctoral associate Linxiao Chen and graduate student Rohit Singh. The outer membrane of a bacterium is a protective barrier that contains proteins and liposaccharides important for the bacterium's function. And as bacteria evolve and become more drug resistant, gaining understanding of the outer membrane's role is crucial. OMVs are a great platform for study, Daniel said, because they are a molecularly complete representation of the cell membrane. Their latest work was a collaboration focused on understanding the functional role of the bacterial outer membrane and its constituents in the development of novel drug designs. To gain a better understanding of OMVs, however, they needed to be able to put one under a microscope to study the surface. For this work, the group chose E. coli, as it's among the best-understood bacterium. To flatten the OMV and study the outer surface, Hsia used a method previously reported by the group in dealing with mammalian cells: After the OMVs are deposited on a slide, a lipid material is added, which induces the OMVs to rupture into a flat sheet. When the edges of the lipid deposits come in contact with the spherical-shaped OMVs, those edges induce the OMVs to flatten out, face up like a parachute, into outer membrane-like supported bilayers (OM-SB). "It's fortuitous that the process happens this way because it means that the orientation of the proteins in the flattened OMV are the same as when it is still part of the original bacteria," Daniel said. "Now you have a flat bacterial surface, complete with all the constituents, and oriented properly so that you can monitor drug interactions and disruption with that surface." Hsia said this is the first time anyone's been able to create a molecularly complete planar representation of a bacterium. "Our approach actually contains all of the components of the E. coli, including the proteins," Hsia said. "All of our competing technologies are limited to just the lipid components of it, and that severely limits what your target is going to be." And with the deep understanding of E. coli bacteria, researchers can modify these OM-SBs, however they want to answer very specific questions. "If you wanted to just express a protein in E. coli membranes," Chen said, "you could put them into these OMVs and splat them onto a surface, and now you have a membrane protein in a lipid environment, in a platform that you could then use for biomicroscopy and a host of other things." Combining this approach with microfluidics, the group says, will lead to improved screening of compounds beneficial for future antibiotics design.
News Article | March 4, 2016
OMV AG will deemphasize growth of oil and gas production under a new strategy that safeguards cash flow, focuses a restructured downstream oil business on utilization efficiency, and restructures downstream gas operations.