Steady-state filtration in a dome-shaped nonhomogeneous stratum

The article gives a solution to the problem of the three-dimensional filtration of a homogeneous incompressible liquid in a thick curved stratum. It discusses different variants of the change in the permeability and the porosity of the medium in a vertical section. In known work [1, 2], studies have been made of the filtration flows in homogeneous thin (i.e., with a vanishingly small thickness) curved strata.Translated from Izvestiya Akademii Nauk SSSR. Mekhanika Zhidkosti i Gaza, No. 2, pp. 168–172, March–April, 1973.     

Simulation of gas-condensate well blowout under permafront conditions

The blowout problem for a gas-conjugate condensate well is considered in a new formulation. The effect of the fluid flow in the well shaft on the temperature of the surrounding rock and the reaction of the surrounding permanently frozen rock on the flow regime in the shaft during the thawing process are simulated and studied under ordinary operating and blowout conditions.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 101–108, May–June, 1994.     

Nonequilibrium gas-condensate flow in a laval nozzle

A scheme is proposed which simplifies the algorithm and reduces the labor involved in solving the system of quasi-linear hyperbolic equations describing supersonic nonequilibrium two-phase flow in an axisymmetric nozzle.     

Analysis of characteristics of pressure curve in gas-condensate wells

This paper utilizes a flow equation with a sink item that describes the characteristics of pressure-time chart when the pressure is higher than the maximum condensate pressure.We have established a sink item to show the influence of accumulation of condensate liquid according to Duhamet Principle of Superposition,and introduced two coefficients for it:condensing strength R_D and condensing relaxation timeλ_D.This paper gives the principle and the quantitative expression of the well pressure influenced by condensate function in the flow equation.An analytical solution for an infinite system is obtained(constant rate).These results can be used to analyse the unsteady flow test of constant production.     

Steady-state solutions to Bentsen's equation

Based on experimentally observed phenomena and the physical requirement of a unique value of saturation at any location within a porous medium, a restrictive condition for a valid solution to Bentsen's equation is derived: ?² f/?S ²≤0. The steady-state solution to Bentsen's equation is shown to be identical to the Buckley-Leverett solution to the displacement equation, and the steady-state solution for the fractional flow is shown to be independent of the capillary number. It is proved that under steady-state conditions, the capillary term of the fractional flow equation in the frontal region does not depend on the capillary number. Therefore, the unrealistic triple-valued saturation profile of the original Buckley-Leverett solution resulted because the capillary term was in-appropriately neglected. The break-through recovery efficiency,Τ _bt , is shown to be a function of the capillary number. As the capillary number decreases, the break-through recovery efficiency increases and the maximum value ofΤ _bt can be obtained asN _c → 0. The Buckley-Leverett solution is the limiting solution asN _c → 0.     

Steady-state whirling motions of thin filaments

The steady-state whirling motion of linear elastic filaments under self-weight with rotary excitation at one end and free at the other is examined; specifically, the effect of bending rigidity is investigated both theoretically and experimentally. Similarities between the problem of a perfectly flexible string and filament with non-negligible bending stiffness are exploited in identifying the possible modes of oscillation. The theoretical predictions have been compared with the experimental results for thin filaments with different bending rigidities to demonstrate the effect of bending directly.     

三线性滞回系统的稳态响应

提出了一种三线性滞回阻尼模型。用Krylov-Bogoliubov缓变系灵敏法研究了正弦型激励下单自由度三线性滞回系统的稳态响应。当本文的三线性模型退化为双线性模型时。本文结果与Caughey的结果是一致的。研究结果还发现。这种系统的稳态解总是稳定的，没有振幅的跳跃现象发生。但在激振力力幅达到一定值时能够发生无界响应。此外还发现，稳态振动达到峰值振幅时滞回面积（即最大滞回面积）对峰值振幅的比值和激振力力幅成正比。这个结论与双非线性滞回系统的相应结论是一致的。     

Steady-state countercurrent flow in one dimension

Two phase countercurrent steady-state flow through permeable media in one dimension is discussed. For steady-state countercurrent flow in water wet porous media, a saturation profile is predicted with the water saturation decreasing in the direction that the water phase is flowing. The de la Cruz and Spanos equations predict that the Muskat relative permeability curves for countercurrent flow will be less than the Muskat relative permeability curves for steady-state cocurrent flow. This result has immediate implications regarding the use of external drive techniques to determine relative permeabilities based on the Buckley-Leverett theory and Muskat's equations. These equations and current experimental evidence involving countercurrent flow indicate that Muskat's equations do not adequately describe the multiphase flow of immiscible fluids.     

Steady-state response of a binon-linear hysteretic system

The steady-state responses are analyzed for a binon-linear hysteretic system using the method of slowly varying parameters. It is shown that the triple-valued and quintuple-valued response curves exist in this system in certain parameter ranges. The stability is studied for the steady-state responses. The results obtained show that the unstable region of response is divided into two regions in certain parameter range, and the distance between the two regions goes to infinity as the value of non-linearity parameter goes to zero.     

Deep bed filtration model for cake filtration and erosion

Many phenomena in nature and technology are associated with the filtration of suspensions and colloids in porous media. Two main types of particle deposition,namely, cake filtration at the inlet and deep bed filtration throughout the entire porous medium, are studied by different models. A unified approach for the transport and deposition of particles based on the deep bed filtration model is proposed. A variable suspension flow rate, proportional to the number of free pores at the inlet of the ...