Fabrication of new crystalline materials with atomic-level control. To understand charge ordering and screening in mixed valence oxides, this oxide superlattice has been designed, synthesized, and then spectroscopically characterized at the atomic scale using scanning transmission electron microscopy. In the false color elastic images, white stripes are layers of LaTiO3; purple stripes are SrTiO 3. Small images show individual atomic layers-in the topmost principal-component-filtered image, pink is lanthanum; light purple is strontium; and green is titanium.(From "Artificial Charge-Modulation in Atomic-scale Perovskite Titanate Superlattices," A. Ohtomo, D. A. Muller, J. L. Grazul, H. Y. Hwang, Nature, 419, 378 (2002). Reprinted by permission from Macmillan Publishers Ltd: Nature.) Directing Matter and Energy: Five Challenges for Science and the Imagination A Report from the Basic Energy Sciences Advisory CommitteeChair:John Hemminger (University of California, Irvine) U.S. Department of Energy December 20, 2007Prepared by the BESAC Subcommittee on Grand Challenges for Basic Energy Sciences Co-Chairs:Graham Fleming (Lawrence Berkeley National Laboratory and University of California, Berkeley)Mark Ratner (Northwestern University) CO M M I T T EE M EM B ER S BA S I C EN ERG Y S C I EN C E S A DV I S O RY CO M M I T T EEChair: S U B CO M M I T T EE O N G RA N D C H A LLEN G E S F O R BA S I C EN ERG Y S C I EN C E SCo Chairs: TA B LE O F CO N T EN T S G RA N D C H A LLEN G E S F O R BA S I C EN ERG Y S C I EN C E Sthe information stored in the Library of Congress could be contained in a memory the size of a sugar cube. Ultimately, if computations can be carried out at the atomic or sub-nanoscale levels, today's most powerful microtechnology will seem as antiquated and slow as an abacus.For the future, imagine a clean, cheap, and virtually unlimited supply of electrical power from solar-energy systems modeled on the photosynthetic processes utilized by green plants, and power lines that could transmit this electricity from the deserts of the Southwest to the Eastern Seaboard at nearly 100-percent efficiency. Imagine information and communications systems based on light rather than electrons that could predict when and where hurricanes make landfall, along with self-repairing materials that could survive those hurricanes. Imagine synthetic materials fully compatible and able to communicate with biological materials. This is speculative to be sure, but not so very far beyond the scope of possibilities.Acquiring the ability to direct and control matter all the way down to molecular, atomic, and electronic levels will require fundamental new knowledge in several critical areas. This report was commissioned to define those knowledge areas and the opportunities that lie beyond. Five interconnected Grand Challenges that will pave the way to a science of control are identified in the regime of science roughly defined by the Basic Energy Science portfolio, and recommendations are presented for what must be done to meet t...

The formulation of a black-oil or compositional fully coupled surface and subsurface simulator is described. It is based on replacing the well model in a conventional reservoir simulator with a generalized network model of the wells and facilities. This allows for representation of complex wellbore geometry and downhole equipment. The method avoids the inefficiencies and/or inaccuracies of other coupled models, in which wells and facilities are treated as separate domains or in which the global system is not solved simultaneously. Example cases demonstrate the performance of the model for cases with simple and segmented wellbores (with and without facilities).

The formulation of a black-oil or compositional fully coupled surface and subsurface simulator is described. It is based on replacing the well model in a conventional reservoir simulator with a generalized network model of the wells and facilities. This allows for representation of complex wellbore geometry and downhole equipment. The method avoids the inefficiencies and/or inaccuracies of other coupled models, in which wells and facilities are treated as separate domains or in which the global system is not solved simultaneously. Example cases demonstrate the performance of the model for cases with simple and segmented wellbores (with and without facilities).

To interpret and optimize field performance of in-situ combustion, dominant chemical and physical mechanisms comprising the displacement process must be understood, and the influence of reservoir characteristics and operating procedures in determining swept areas of the reservoir must be established. This paper addresses important aspects of these factors via a numerical simulation study. Vaporization of the oil, changes in oil volatility due to coking, and changes in oil properties due to low temperature oxidation are shown to have considerable impact and need to be adequately modelled. The extent of fingering of the burned region due to high permeability layers and the dependence of fingering on vertical permeability are investigated. Various operating procedures that are evaluated include: reinjection of exhaust gases procedures that are evaluated include: reinjection of exhaust gases rich in carbon dioxide, simultaneous water-oxygen injection to control override, post-burn waterflooding, and selection of well spacing. Introduction Prediction of in-situ combustion field performance requires: Prediction of in-situ combustion field performance requires:understanding the relative importance of the constitutive chemical and physical processes that determine oil displacement in those areas of the reservoir that are swept, andmarket opportunities for the application of energy technologies and systems. understanding how fluid flow and reservoir characteristics determine swept volume. Although researchers have derived much information from one-dimensional combustion tube studies, results cannot be scaled up to predict field performance. Due to differences in length and time scales and difficulty in reproducing reservoir conditions, the relative importance of various mechanisms in a combustion tube is not the same as in a reservoir. Although bench-scale experiments have been used to investigate individual processes known to occur, the extent to which each process can affect field results, such as oil produced or oxygen required, remains to be determined. Although numerous field studies have been performed, results are far from comprehensive, reservoir peculiarities cloud results, and extrapolation of results to other fields is difficult. Numerical simulation programs have been developed to help understand and predict in situ combustion performance. The cost of running a predict in situ combustion performance. The cost of running a simulator that contains all applicable physics, however, is prohibitive, and much required experimental input is unavailable. prohibitive, and much required experimental input is unavailable. The goal of the present investigation is to determine which physical, chemical, and fluid flow processes can significantly physical, chemical, and fluid flow processes can significantly affect oil production, oxygen consumption, and time required for in-situ combustion. Such information will facilitate execution and interpretation of field projects and help determine which phenomena should be included in in-situ combustion reservoir simulators and/or deserve additional investigation. To do this, oil production via in-situ combustion was phenomenologically examined to determine which processes are occurring. To determine the relative importance of these processes, simulations have been performed, using ARCO Oil and Gas Company's in-situ combustion reservoir simulator, in which comparisons have been made between predicted field performance with and without the effects of each process. Processes addressed include vaporization of the oil, coking, low Processes addressed include vaporization of the oil, coking, low temperature oxidation, exhaust gas re-injection, gas override and possible control via water injection, and instabilities due to possible control via water injection, and instabilities due to vertical variations in horizontal permeability. Using this approach, an improved understanding of in-situ combustion has emerged. The current findings are for a light oil subjected to high oxygen concentration injection gases; generalization of the results, however, is expected to be straightforward.

The need for flexible and efficient multi-porosity, reservoir-simulation capabilities has never been greater. Much of the world's oil reserves are contained in highly variable fractured reservoirs. Moreover, there is now unprecedented interest in the simulation of unconventional gas reservoirs, where up to four porosity types may be required. This paper discusses the design of an N-porosity, full-featured reservoir simulator capable of handling these diverse scenarios. Essential to the design is the programming data-structure paradigm of the SubGrid. SubGrids represent collections of simulation nodes within spatial regions of interest and encapsulate all data and variables required. Any number of associated SubGrids may coexist, representing N-porosities. Inter-and intra-SubGrid connections may be arbitrarily specified. Because the linear solver operates on the associated SubGrids as distinct entities, the design has tremendous flexibility. For example, regions with simple connectivity, such as in dual-porosity, single-permeability models, can have simple pre-solver elimination performed while other regions with uniform intra-porosity connectivity require a merged SubGrid solution. The scheme efficiently treats regions with different numbers of porosities, levels of interconnectivity, and levels of implicitness. Applications may be applied across multiple reservoirs simultaneously. Treatment of missing "fracture" zones has always been an important feature in the dual-porosity, single-permeability simulation. The traditional approach is to treat the matrix within missing fracture zones effectively as though it were an interconnected portion of the fracture porosity. This preserves connectivity within the fracture-free zones and the more computationally efficient single-permeability solver pre-elimination step. A second missing "fracture" scheme is introduced, which differs in the way that the connections between the fracture and matrix blocks are computed at the boundary of fracture-free zones. Flexible transfer-function application and porosity dependency during equilibrium initialization are discussed. Computational DesignThe extension of the classic industry-standard, dual-porosity simulation scheme to more porosity types began with tripleporosity models (Abdassah and Ershaghi 1986;Lee et al. 1987). More recently, Fung et al. (2011) have demonstrated applications with Middle Eastern carbonates of up to three porosity types within their generalized multi-porosity scheme. Moreover, interest in the simultaneous simulation of four porosity types for unconventional gas reservoirs is now under active study (Andrade et al. 2011). This paper presents the design of our simulator with respect to the challenges of modeling multiple porosity types. Treatment of Multiple Porosities.Our reservoir data architecture expresses the simulation domain into one or many SubGrids, as depicted in Fig. 1. SubGrids are collections of structured or unstructured simulation nodes that ordinarily represent distinct and contiguous regions. ...