overburden pressure

Large area field immersion tests on characteristics of deformation of self weight collapse loess under overburden pressure

大厚度自重湿陷性黄土场地湿陷变形特征的大型现场浸水试验研究

Compared with the results of conventional core analysis, under reservoir conditions ( net overburden pressure> 20MPa), porosity decreases about 3% to 10%, permeability increases about 12% to 70%.

与常规岩心分析结果相比，油藏条件下（净覆压大于20MPa）孔隙度约减小3%～10%，渗透率约减小12%～70%。

The low-permeability cores show stress sensitivity during the effective overburden pressure increasing.

低渗储层岩心在有效上覆压力增大的过程中会表现出较强的应力敏感性。

The formation pressure system includes the overburden pressure ( P0), formation pore pressure ( Pp), fracture pressure ( FP) and breakout pressure ( BP).

地层压力体系包括上覆岩层压力（P0）、地层孔隙压力（Pp）、地层破裂压力（FP）和坍塌压力（BP）。

The earth pressure acting on the tunnel is much less than overburden pressure if there is an initial tail void.

当隧洞衬砌与周围上体有一个初始间隙（盾尾间隙）时，土作经过位移和与结构发生相互作用，最后作用在衬砌结构上的土压力远小于原位土压力。

Traditional theory considered that the overburden pressure ( pob) is the sum of hydrostatic pressure ( pf) and framework stress ( pG), this may resulted in many mistakes.

认为上覆岩层压力（pob）等于流体静压力（pf）和岩石骨架应力（pG）之和，是不严密的，这可以导致许多错误。

Calculate the overburden pressure by density logging;

利用密度测井方法计算出上覆岩层压力；

Of the pressures, the one caused by the weight of overlying sediments, we call it overburden pressure, is the most obvious.

在这两种压力之中，由上覆沉积物重量造成的压力最为明显，我们称这种压力为上覆压力。

The results of laboratory tests showed that the apparent preconsolidation pressure of Shanghai clay is higher than the effective overburden pressure.

室内试验成果表明，上海粘土的准先期固结压力较天然有效上复压力大得多。

Experiment Study on the Piles in the Soggy Field of Loess Collapsible under Overburden Pressure

自重湿陷性黄土场地桩基浸水荷载试验研究

When porosity matches net overburden pressure with exponent relationship, the presented physical significance is clearer, the accuracy requirement can be met and the compressibility of rocks can gained automatically.

孔隙度与净覆压间按指数规律拟合时，代表的物理意义更为明确，既能满足精度的要求，又能自动得出岩石的压缩系数。NET技术思想和基于。

This paper had studied the law of sandstone reservoir pore volume which are changing with pressure, and the variation relationship for sandstone po-rosity in different cement types and effective overburden pressure.

本文对砂岩储集层孔隙体积随压力变化的规律，及其不同胶结类型砂岩孔隙度与有效上覆地层压力的变化关系作了研究。

The overburden pressure system is also introduced and it can supply sufficient overburden pressure for the core gripper.

同时设计了该夹持器的上覆压力系统，可在实验中提供足够大的上覆压力。

Investigation on characteristics of physical parameters under formation overburden pressure

地层上覆压力下物性参数特征研究

The research shows that the relationship between formation porosity, permeability and net overburden pressure is closely related to univariate quadratic equation;

结果表明：油层孔隙度、渗透率与净覆压的关系以一元二次方程最为密切；

Determination and Regression of Overburden Pressure Gradient

上覆岩层压力梯度合理计算及拟合方法

There are certain relations among overburden pressure, underlying fluid pressure and matrix stress, and different understandings of how to describe or depict them in the end.

上覆岩层压力与下伏岩层中的流体压力以及岩石骨架应力之间，存在着一定的关系。

ON COMPUTATION OF OVERBURDEN PRESSURE AND SETTLEMENT FOR LAYERED SOIL CONSIDERING SEDIMENTATION Ore bodies show different forms i. e. layered bodies of sedimentation and irregular bodies of replacement.

考虑沉积作用的成层地基自重应力与沉降计算矿体有沉积似层状和交代不规则状两种形态，主要围岩蚀变为硅化和铁白云石化。

The oil shale on the surface show opening foliation, abundant pore volume and low density because of less overburden pressure.

地表油页岩由于覆压减小等影响，页理张开、孔隙增加、密度减小。

The preconsolidation pressure in the upper soil layer is larger than the existing overburden pressure, and the soil is in an overconsolidated state.

沿线地基土上部土层中的前期固结压力p′c值大于覆盖土压力，处于超固结状态。

In this paper are derived the formulae for calculating excess pore water pressure of saturated sand foundation with or without overburden pressure and with four types of vertical drainage conditions during earthquake, and one example for calculating is given.

本文对砂基在表面作用或不作用上覆压力、具有四种竖向排水的条件下，推出了地震期间砂基内超静孔隙水压力的计算公式，并给出了一个算例。

Overburden pressure has a strong influence on permeability and pore structure.

上覆地层压力对渗透率及孔隙结构特征影响很大。

For BZ34-1 and BZ28-2 oilfields where the main oil reservoirs are unconsolidated sand, the rock resistivity data measured under overburden pressure is used in reserves evaluation.

渤海渤中34-1、渤中28-2等油田（主要含油层为疏松砂岩）储量评价中采用了覆压条件下岩石电阻率测量结果。

The paper also studied the effects of porosity, fluid saturation in diphasic medium ( water gas and oil gas) and change of overburden pressure on reflection wave AVO.

并且研究了双相介质（水气、油气）孔隙率、流体饱和度和上覆岩层压力变化对反射波AVO的影响。

On the basis of core experiment from Xiang-4 gas pool, the model of this pool porosity corrected by overburden pressure is founded, this method of measuring porosity corresponding to the traditional one may be used in reserves calculation.

通过在香四气藏岩心实验的基础上，建立了该气藏孔隙度覆压校正模型。该方法测定的孔隙度与传统方法相当，可以用于储量计算。

The flux of water and ion migration and the amount of deformation is decreasing with the elapsed time in the power law and with increasing in the overburden pressure and with temperature depression.

水、盐迁移通量及变形量随时间按指数规律衰减并随外载增大和温度降低而减小。

In this paper, a three-dimensional ( 3D) finite element ( FE) model is developed to simulate the behavior of soil nail considering the effects of overburden pressure and dilation.

通过建立一个三维有限元模型，研究土钉在不同上覆压力和剪胀作用下的土钉抗拔行为。

The research and application of permeability, porosity and net overburden pressure laws

孔隙度、渗透率与净覆压的规律研究和应用

Calculation of excess pore water pressure of saturated sand foundation with different vertical drainage conditions and overburden pressure

竖向不同排水条件和上覆压力作用下砂基超静孔隙水压力计算

Parametric analysis is carried out to investigate the effects of soil dilation and overburden pressure on the soil nail pullout resistance.

结果显示，当上覆压力较小时，剪胀角对抗拔应力的影响较小。