利用导数的最大值进行试井分析

为了改进现代试井 Gringarten 图版计算均质地层时计算量大、计算步骤复杂等缺点,本文利用压力导数和时间乘积的最大值进行试井分析,组成一个新的图版,图版只有一条曲线,能保证 C(?)的连续性,该方法与现代试井方法相比简单的多.可与现代试井方法及常规方法联合使用,所得地层参数准确可靠。

Properties of Bentonite Enhanced Loess and Laterite

Loess and laterite distributed widely in the northern and southern China cannot be directly used as the natural barrier to isolate the solid waste because of their high hydraulic conductivity. In this paper, they are enhanced by bentonite to improve their hydraulic performance. The impact of bentonite content and water content on compressive strength of the compacted soil was investigated. The effects of bentonite content, water content, dry density and hydraulic gradient on the hydraulic conductivity were studied in detail. For the laterite and the laterite with 8% of bentonite, the experimental results of hydraulic conductivity can be applied in the engineering design. However, for the loess and the bentonite enhanced loess, those of hydraulic conductivity can not be directly applied in the engineering design because their hydraulic performance does not comply with the Darcy's law. These experimental results have to be carefully modified before application.

Rate decline analysis of multiple fractured horizontal well in shale reservoir with triple continuum

Multiple fractured horizontal well(MFHW) is widely applied in the development of shale gas. To investigate the gas flow characteristics in shale, based on a new dual mechanism triple continuum model, an analytical solution for MFHW surrounded by stimulated reservoir volume(SRV) was presented. Pressure and pressure derivative curves were used to identify the characteristics of flow regimes in shale. Blasingame type curves were established to evaluate the effects of sensitive parameters on rate decline curves, which indicates that the whole flow regimes could be divided into transient flow, feeding flow, and pseudo steady state flow. In feeding flow regime, the production of gas well is gradually fed by adsorbed gases in sub matrix, and free gases in matrix. The proportion of different gas sources to well production is determined by such parameters as storability ratios of triple continuum, transmissibility coefficients controlled by dual flow mechanism and fracture conductivity.

Experimental Study on Calculation of Hydro-Geological Parameters for Unsteady Flow

After the linear analytical method of unsteady flow theory is further improved,an innovative and faster algorithm is introduced.The water storage in a confined aquifer is derived from the water transmissivity coefficient and the water-pressure conductivity coefficient.The water transmissivity coefficient is approximated by a Taylorseries expansion of drawdown,and the water-pressure conductivity coefficient is obtained by the average drawdown.In this algorithm,the distance of the observation points from the pumping well must be short.When the distance is as short as the radius of the main pumping well,the data of the drawdown difference between the sidewall and the center of pumping well are difficult to measure,but the same results can be achieved based on the assumption that the drawdown difference approximates to the drawdown of the observation wells at a radial distance from the pumping well according to the algorithm.Without the help of charts,this algorithm is more concise and efficient,which has been verified by the test of water pumping project in Tianjin Binhai International Airport.

Progress in Ti_(3)O_(5):Synthesis,properties and applications

The crystal structure,physical,chemical and phase transition properties of trititanium pentoxide(Ti_(3)O_5)have aroused a broad range of research effort since the 1950s.Different crystalline forms(α,β,γ,δandλ)of Ti_(3)O_5 exhibit various properties.Particularly,reversible phase transitions betweenλ-andβ-Ti_(3)O_5 have been attracting increasing research interest,which brings new potential applications of Ti_(3)O_5 materials in the field of energy and data storage.More recently,Ti_(3)O_5 materials have shown excellent performance in trace detection,microwave absorption and virus adsorption,which has expanded its application fields.Here,the essential properties of different crystal forms of Ti_(3)O_5 are described in detail.An intensive overview of Ti_(3)O_5 preparation methods and applications is comprehensively summarized.

Determination of consolidation behaviour of clay slurries

The main objective of this study was to determine the consolidation behaviour of clay slurries.A finegrained clay with high consistency limits(W_L = 180%,w_P= 120%) was investigated using conventional oedometer and bench-top centrifuge tests.Results indicated that the slurry had an apparent preconsolidation(due to initial conditions,electrochemical interactions,tortuous drainage,and thixotropic strength) from e = 5.7 to e = 5.5 followed by virgin compression.Likewise,the low hydraulic conductivity(10^(-10)-10^(-12) m/s) was due to low porosity(small pore throats) and high tortuosity(long flow paths).Unlike consolidation of soils,the c_v and m_v decreased with increasing σ' but increased with increasing e and k.The data from the two tests correlated well in the range of σ' = 10-65 kPa,e = 5.5-3.86,k= 1.7 × 10^(-10)-5×10^(-11) m/s,F_c = 1-40 MN.New equations were developed to correlate the consolidation parameters(e,σ',k) with F_c.The deviation of k beyond 40 MN(e = 4.65) was due to deviation from the initial straight line portion of the settlement curve in the centrifuge test.

Effects of Mechanical Aeration on the Compaction and Hydraulic Conductivity of a Grassy Sward

In a golf course located at El Kantaoui, Sousse, Tunisia, this study was carried out over a sandy soil grassy sward to investigate the effects of mechanical aeration （perforation of the sward with an aerators machine called ＂Vertidrain＂） on its compaction and hydraulic conductivity. For this purpose, many soil cores were extracted using a 1.6 e.g. m effective width Verti-Drain aerator equipped with hollow spades spaced 65 e.g. mm apart. Aeration was performed at a rate of 350 holes/m2. Soil resistance to penetration and permeability were determined at the initial state before aeration as well as 10, 20, and 30 days after aeration. Compared to the initial state, the results showed that mechanical aeration greatly affects the grassy sward ground by reducing its resistance to penetration as 35% and 43% decrease in penetration resistance were noticed at 5 e.g. cm depth 10 and 20 days after aeration, respectively. Also, resistance to penetration decreased by 41% and 48% at 15 e.g. cm depth during the same two periods of time with a relatively constant moisture content. However, soil resistance to penetration at 5 and 15 e.g. cm depths only decreased by 21% and 26%, respectively. Regarding the soil hydraulic conductivity measured after aeration, a significant improvement at the 1% level with the method of variance analysis, was observed compared to that at the initial state （4.9 e.g. cm hl）. Indeed, the hydraulic conductivity was 12.5, 13, and 14.1 e.g. cm h-1 10, 20, and 30 days after aeration, respectively.

Responses of wind-induced internal pressure in a two-compartment building with a dominant opening and background porosity Part 2:Parameter analyses and design equations

Analyses of the effects of some parameters were performed to determine the admittance functions in a common two-compartment building with background porosity by the imposed excitation method.Variations of the magnification factors of fluctuating internal pressures were analyzed using 96 model cases under random fluctuating external pressure,and then corresponding design equations were fitted.The results show that the Helmholtz resonance peaks of the admittance functions in both compartments increase with increasing the area of windward or partition wall opening.With increasing the volume of the compartment with an external opening,the resonance peak in this compartment at the higher Helmholtz frequency significantly decreases,at the same time,the resonance peak in the other compartment at the lower Helmholtz frequency also decreases.With increasing the volume of the compartment with background porosity,both resonance peaks in this compartment at the lower and higher Helmholtz frequencies decrease,meanwhile,the resonance peak at the lower Helmholtz frequency for the other compartment also decreases,whereas the resonance peak at the higher Helmholtz frequency increases.Both resonance peaks of the admittance functions in the two compartments decrease with increasing the amplitude of fluctuating external pressure coefficients or reference wind speed.

Equation of state of CAS phase to pressure of the uppermost lower mantle at ambient temperature

The CAS phase is a major constituent phase for the continental crust and basaltic compositions at the P-T conditions of the Earth＇s mantle, and potentially plays an important role in the geodynamic processes related to slab subduction. Its equation of state has been investigated here at ambient temperature up to about 25 GPa by using a diamond-anvil cell and synchrotron Xray radiation. Its P-V data, fitted to the third-order Birch-Murnaghan equation, yield an isothermal bulk modulus （KT） of 185 （9） GPa and first pressure derivative （ KT^t ） of 7.2 （12）. If KT^t is fixed at 4, file derived Kr is 212 （4） GPa. Additionally, the CAS phase is strongly elastically anisotropic, with its a-axis direction much less compressible than c-axis direction： Kr-a ： Kr-c = 2.19.

Numerical study of ambient pressure for laser-induced bubble near a rigid boundary

The dynamics of the laser-induced bubble at different ambient pressures was numerically studied by Finite Volume Method (FVM). The velocity of the bubble wall, the liquid jet velocity at collapse, and the pressure of the water hammer while the liquid jet impacting onto the boundary are found to increase nonlinearly with increasing ambient pressure. The collapse time and the formation time of the liquid jet are found to decrease nonlinearly with increasing ambient pressure. The ratios of the jet formation time to the collapse time, and the displacement of the bubble center to the maximal radius while the jet formation stay invariant when ambient pressure changes. These ratios are independent of ambient pressure.

Controlling Thermal Conductivity of Few-Layer Graphene Nanoribbons by Using the Transversal Pressure

We study the thermal transport of few-layer graphene nanoribbons in the presence of the transversal pressure by using molecular dynamics simulations. It is reported that the pressure can improve the thermal conductivity of few-layer graphene nanoribbons. This improvement can reach 37.5% in the low temperature region. The pressure dependence of thermal conductivity is also investigated for different length, width and thickness of few-layer graphene. Our results provide an alternative option to tuning thermal conductivity of few-layer graphene nanoribbons, b-arthermore, it maybe indicate a so-called pressure-thermM effect in nanomaterials.

Interface-induced warping in hybrid two-dimensional materials

Two-dimensional hybrid materials consisting of heterogeneous domains have been of great interest. Using empirical molecular dynamical simulation, we show that the morphology of such hybrid 2D materials can extend into the third dimension via strong warping intrinsic to the interfaces between the domains. The interface warping stems from the compressive stress in the domain with a larger lattice constant and even penetrates into the stretched domain. Based on classic plate theory, we analytically quantify the amplitude, wave length and penetration depth of the interface warping as functions of the lattice mismatch, achieving good agreement with the simulations. Moreover, we propose that periodically placing pentagon-heptagon dislocations along the interface can eliminate the warping in the 2D material and such defective interface can be more favorable than the warped one over a critical domain size, which is consistent with recent experimental observations. Our results suggest that the interface warping in 2D hybrid materials should be considered in further exploring their promising properties.

SENSITIVITY OF DARCY'S LAW TO DISCONTINUITIES

The authors investigate the sensitivity of hydrostatic pressure of flows through porous media with respect to the position of the soil layers. Indeed, these induce discontinuities of the porosity which is a piecewise constant coefficient K of the partial differential equation satisfied by the pressure u and it leads to the computation of the derivative of u with respect to changes in position of discontinuity surface of K.The analysis relies on a mixed formulation of the problem. Preliminary numerical simulations are given to illustrate the theory. An application to a simple inverse problem is also given.