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51.
52.
地质条件约束下储层流动单元定量研究 总被引:2,自引:0,他引:2
由于流动单元定量研究中常用的数学方法不能反映储层的地质分布规律,采用了地质条件约束的研究思路,对塔中油田塔中11油藏志留系潮坪相储层进行了流动单元研究.在应用高分辨率层序地层学进行小层对比的基础上,首先确定储层内部的渗流屏障及连通体的分布规律,然后在连通体内部,综合采用基于孔渗的宏观参数FZI和微观参数R35建立流动单元的聚类样本和判别函数,对所有取心井和非取心井划分出流动单元类型.最后根据单井划分结果,在储层结构模型的约束下,优选随机建模方法对流动单元的分布进行横向预测,建立了流动单元分布的三维模型.实践证明,渗流屏障和连通体等地质条件控制下流动单元定量研究方法在潮坪相地层中有很好的应用效果. 相似文献
53.
Thomas Allen 《Boundary-Layer Meteorology》2006,121(3):475-490
The effect of variable roughness length upon the flow characteristics over hills is investigated. The changes considered herein cover a range of flow configurations such as the change from a forested (rough) valley with a moderately smooth hilltop to a grassy valley (smooth) with a “spiky” (rough) mountain top. The effect of moving the roughness with respect to the hill is also considered. Although many of the flow features change when the position of the roughness change is varied with respect to the hill these changes have very little impact upon the global properties used within orographic drag parametrization schemes. 相似文献
54.
金字塔沙丘地表气流场及其动力学过程研究 总被引:9,自引:7,他引:2
沙丘沉积构造指示及风洞实验结果表明:莫高窟顶金字塔沙丘形成于3组风向条件下(NE、SW及NW),是链状沙丘的一种变形、分离形式。从沙丘形态特征分析,三面体金字塔沙丘及其它复杂沙丘类型(线形、格状、多面体金字塔沙丘)之间存在某种内在本质的联系。即多信风条件下产生的风向组合,通过主、副脊(梁)的不同形式发育组合过程,形成适应于地表气流的地貌形态。同时认为:沙丘沉积构造及风洞实验相结合的综合研究比以往单一过程研究更为全面、系统、深刻。 相似文献
55.
Ignimbrites of the 13-ka Upper Laacher See Tephra were deposited from small, highly concentrated, moderately fluidized pyroclastic
flows. Their unconsolidated nature, and the prominence of accidental Devonian slate fragments, make these ignimbrites ideal
for clast fabric studies. The upper flow unit of ignimbrite M14 has characteristics typical of a type-2 ignimbrite. Layer
2a and the lower part of layer 2b of the flow unit have strong, upstream-inclined a[p] fabrics (a[p] means long particle axes
parallel to flow direction). Only clasts with a/b axial ratios of 2.5 or greater preserve good a[p] fabrics, whereas the a–b
planes of flat fragments dip upstream irrespective of axial ratio. The a-axis fabric becomes weaker, flatter, and more girdle-like
in the upper half of layer 2b. At one locality the a-axis fabric appears to rotate 40° up through the flow unit, suggesting
either shear decoupling of different levels in the moving flow or unsteadiness effects in a flow depositing progressively
at its base. The existence of similarly strong a[p] fabrics in layer 2a and the lower half of layer 2b appears inconsistent
with the common interpretation that ignimbrite flow units are emplaced as a plug of essentially non-shearing material (layer
2b) on a thin shear layer (layer 2a), and that the entire flow freezes en masse to form the deposit. The data suggest that,
if the flow froze en masse, it was shearing pervasively through at least half its thickness. Another possibility is that the
flow unit aggraded progressively from the base up, and that the fabrics record the integrated history of shear directions
and intensities immediately above the bed throughout the duration of deposition.
Received: 13 February 1997 / Accepted: 4 April 1998 相似文献
56.
A hybrid discrete-continuum approach has been presented in this paper to simulate water flow in the near and far fields of deformable fractured rocks. In the near field, the discrete model is used; while in the far field, the equivalent continuum model is employed. The discrete element method (with the static relaxation algorithm) is used in the near field and the boundary integral equation method in the far field. Along the interface of these two domains, both mechanical and hydraulic compatibility conditions are satisfied. Fully coupled hydro-mechanical analysis can be conducted in the combined near and far fields. Application to a dam foundation problem has demonstrated the capability of the developed approach. 相似文献
57.
The authors conducted a Rn222 survey in wells of the Larderello geothermal field (Italy) and observed considerable variations in concentrations. Simple models show that flow-rate plays an important part in the Rn222 content of each well, as it directly affects the fluid transit time in the reservoirs. Rn222 has been sampled from two wells of the Serrazzano area during flow-rate drawdown tests. The apparent volume of the steam reservoir of each of these two wells has been estimated from the Rn222 concentration versus flow-rate curves.List of symbols
Q
Flow-rate (kg h–1)
-
Decay constant of Rn222 (=7.553×10–3 h–1)
-
Porosity of the reservoir (volume of fluid/volume of rock)
- 1
Density of the fluid in the reservoir (kg m–3)
- 2
Density of the rock in the reservoir (kg m–3)
-
M
Stationary mass of fluid filling the reservoir (kg).
-
E
Emanating power of the rock in the reservoir (nCi kg
rock
–1
h–1).
-
P
Production rate of Rn222 in the reservoir: number of atoms of Rn222 (divided by 1.764×107) transferred by the rock to the mass unit of fluid per unit time (nCi kg
fluid
–1
h–1).
-
N
Specific concentration of Rn222 in the fluid (nCi kg–1)
-
Characteristic time of the steam reservoir at maximum flow-rate (=M/Q) 相似文献
58.
Many geothermal anomalies are intersected by vertical fault zones (narrow zones of fractured material with large effective permeability). These conduits are probably responsible for much of the upwelling of hot water from depth. This paper considers a shallow aquifer intersected by a vertical fault. The fluid flow in the aquifer is numerically modeled as a two-dimensional problem. It is observed that the temperature distribution in the aquifer is governed primarily by lateral flow of hot water supplied from the intersecting vertical fault and only secondarily by conduction. The numerical results also provide a possible explanation for the local temperature maxima and inversions occasionally observed in borehole measurements. The present model is an alternative to that based on mushroom-shaped isotherm distributions found in high Rayleigh number large-scale circulation cell calculations. 相似文献
59.
D. G. Day 《地球表面变化过程与地形》1978,3(3):319-326
Observations of stream behaviour during rainfall indicate that previous notions of a simple expanding and contracting network need review and refinement. In a small rural catchment near Armidale, N.S.W. changes in flowing stream length during rainfall have been depicted on flow length graphs which indicate a varied network response to similar rainfall amounts. Channel flow phenomena include discontinuous flow, the generation of flow points within the channel and movement of water downslope from saturated depression sources. Localized physical controls have a significant effect on stream growth which is a sensitive indicator of the catchment response to rainfall. During rapid changes in stream length total flowing length and discharge are highly correlated. A model of the pattern of network expansion and contraction involves several phases of flow contraction. 相似文献
60.
K. S. Richards 《地球表面变化过程与地形》1978,3(4):345-354
The nature of the flow in most natural streams is gradually varied rather than uniform. This is particularly true of streams with coarse gravel bed material organized into relatively stable riffle and pool features. In spite of this, there are few applications of the gradually varied flow models (e.g. the Bernoulli equation) to such streams. This paper presents some initial results of a simulation of flow patterns in two riffle-pool reaches, using an open channel flow profile computation method based on an equation defining an energy balance between successive cross-sections separated by an incremental distance. 相似文献