54,645 research outputs found
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
Sequence-Dependent Effects on the Properties of Semiflexible Biopolymers
Using path integral technique, we show exactly that for a semiflexible
biopolymer in constant extension ensemble, no matter how long the polymer and
how large the external force, the effects of short range correlations in the
sequence-dependent spontaneous curvatures and torsions can be incorporated into
a model with well-defined mean spontaneous curvature and torsion as well as a
renormalized persistence length. Moreover, for a long biopolymer with large
mean persistence length, the sequence-dependent persistence lengths can be
replaced by their mean. However, for a short biopolymer or for a biopolymer
with small persistence lengths, inhomogeneity in persistence lengths tends to
make physical observables very sensitive to details and therefore less
predictable
Surface-induced near-field scaling in the Knudsen layer of a rarefied gas
We report on experiments performed within the Knudsen boundary layer of a
low-pressure gas. The non-invasive probe we use is a suspended
nano-electro-mechanical string (NEMS), which interacts with He gas at
cryogenic temperatures. When the pressure is decreased, a reduction of the
damping force below molecular friction had been first reported in
Phys. Rev. Lett. Vol 113, 136101 (2014) and never reproduced since. We
demonstrate that this effect is independent of geometry, but dependent on
temperature. Within the framework of kinetic theory, this reduction is
interpreted as a rarefaction phenomenon, carried through the boundary layer by
a deviation from the usual Maxwell-Boltzmann equilibrium distribution induced
by surface scattering. Adsorbed atoms are shown to play a key role in the
process, which explains why room temperature data fail to reproduce it.Comment: Article plus supplementary materia
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