SIMULATION STUDY ON WATERFLOOD FRONT: BLOCK HADE OF TARIM OILFIELD IN NORTHWEST CHINA

Block Hade consist of a deep thin sandstone reservoir of two sub-layer reservoirs. The thickness is about 1.5 m for each layer. The two-layer “staircase” horizontal well is used for recovery. In order to determine water displacement front and edge water movement, tracer test is conducted in the reservoir. But the cycle of field tracer monitoring is about 150-360 days. This prevented the efficient monitoring of waterflood swept area and waterflood advance direction and velocity, after the cycle of tracer monitoring. Conservation of mass with respect to tracer flow and history performance matching of tracer enabled the study of water-flood front and edge-water advance. The simulation result is basically consistent with the monitored field tracer results. Therefore, numerical model can be used to conduct a longer monitoring period. It can make up for the disadvantage of the complexity of the tracer monitoring setup, its implementation, and time-consuming monitoring cycle. The water-flood front, water-flood swept area, advancing velocity and the predominant water injection direction can be obtained. Furthermore, it is possible to evaluate and predict the injection-production well interaction and can also provide a reliable basis to deploy reasonable flood patterns to enhance oil recovery

Optimal transfer of an unknown state via a bipartite operation

A fundamental task in quantum information science is to transfer an unknown state from particle $A$ to particle $B$ (often in remote space locations) by using a bipartite quantum operation $\mathcal{E}^{AB}$. We suggest the power of $\mathcal{E}^{AB}$ for quantum state transfer (QST) to be the maximal average probability of QST over the initial states of particle $B$ and the identifications of the state vectors between $A$ and $B$. We find the QST power of a bipartite quantum operations satisfies four desired properties between two $d$-dimensional Hilbert spaces. When $A$ and $B$ are qubits, the analytical expressions of the QST power is given. In particular, we obtain the exact results of the QST power for a general two-qubit unitary transformation.Comment: 6 pages, 1 figur

The Gentlest Ascent Dynamics

Dynamical systems that describe the escape from the basins of attraction of stable invariant sets are presented and analyzed. It is shown that the stable fixed points of such dynamical systems are the index-1 saddle points. Generalizations to high index saddle points are discussed. Both gradient and non-gradient systems are considered. Preliminary results on the nature of the dynamical behavior are presented

Phasor analysis of atom diffraction from a rotated material grating

The strength of an atom-surface interaction is determined by studying atom diffraction from a rotated material grating. A phasor diagram is developed to interpret why diffraction orders are never completely suppressed when a complex transmission function due to the van der Waals interaction is present. We also show that atom-surface interactions can produce asymmetric diffraction patterns. Our conceptual discussion is supported by experimental observations with a sodium atom beam.Comment: 5 pages, 6 figures, submitted to PR

Influence of Potamogeton crispus growth on nutrients in the sediment and water of Lake Tangxunhu

An incubation experiment was performed on Potamogeton crispus (P. crispus) using sediment collected from Lake Tangxunhu in the center of China, in order to determine the effects of plant growth on Fe, Si, Cu, Zn, Mn, Mg, P, and Ca concentrations in the sediments and overlying waters. After 3 months of incubation, Ca, Mg, and Si concentrations in the water column were significantly lower, and P and Cu concentrations were significantly higher than in unplanted controls. The effect of P. crispus growth on sediment pore waters and water-extractable elements varied. Concentrations of Ca, Mg, Si, Fe, Cu, and Zn were significantly higher, and P was significantly lower, than in pore waters of the control. Water-extracted concentrations of Fe, Mg, and Si in the sediments were lower, and P was higher, than in the control. Presence of P. crispus generally enhanced concentration gradients of elements between pore waters and overlying waters but not for P. The growth of P. crispus was associated with an increase in water pH and formation of root plaques, resulting in complex effects on the sediment nutritional status

High-gain weakly nonlinear flux-modulated Josephson parametric amplifier using a SQUID-array

We have developed and measured a high-gain quantum-limited microwave parametric amplifier based on a superconducting lumped LC resonator with the inductor L including an array of 8 superconducting quantum interference devices (SQUIDs). This amplifier is parametrically pumped by modulating the flux threading the SQUIDs at twice the resonator frequency. Around 5 GHz, a maximum gain of 31 dB, a product amplitude-gain x bandwidth above 60 MHz, and a 1 dB compression point of -123 dBm at 20 dB gain are obtained in the non-degenerate mode of operation. Phase sensitive amplification-deamplification is also measured in the degenerate mode and yields a maximum gain of 37 dB. The compression point obtained is 18 dB above what would be obtained with a single SQUID of the same inductance, due to the smaller nonlinearity of the SQUID array.Comment: 7 pages, 4 figures, 23 reference