Naturally Ordered Abundant Semigroups in Which Each Idempotent Has a Greatest Inverse

The aim of this article is to study naturally ordered abundant semigroups in which every idempotent has a greatest inverse. After obtaining some characterizations, their structure is established.     

Homogenization of a pseudoparabolic system

Pseudoparabolic equations in periodic media are homogenized to obtain upscaled limits by asymptotic expansions and two-scale convergence. The limit is characterized and convergence is established in various linear cases for both the classical binary medium model and the highly heterogeneous case. The limit of vanishing time-delay parameter in either medium is included. The double-porosity limit of Richards' equation with dynamic capillary pressure is obtained.     

Structure theory of naturally reductive spaces

In this paper we show that every naturally reductive space can be obtained by an explicit construction. This allows us to write a general formula for any naturally reductive space from which we prove a reducibility and isomorphism criteria.     

川西坳陷中段须家河组致密砂岩气藏成藏模式探讨

通过分析流体包裹体均一温度和砂岩碳酸盐胶结物氧同位素数据,并结合沉积-埋藏史,研究须家河组流体活动特征,进行储层致密化分析. 在此基础上,结合烃源岩演化、储层致密化、流体活动等研究,探讨川西坳陷须家河组致密砂岩气藏成藏模式. 认为：须家河组具有形成“连续型”气藏的地质条件,砂岩持续致密化,自烃源岩沉积后持续生烃,流体包裹体的显微观测也表明油气充注在持续进行. 据此认为,须家河组气藏成藏模式是“前期边致密边成藏,后期裂缝发育成藏”.     

LBM simulation of fluid flow in fractured porous media with permeable matrix

To analyze and depict complicated fluid behaviors in fractured porous media with variably permeable matrix, an integrated discrete computational algorithm is proposed based on lattice Boltzmann method (LBM). This paper combines with the external force model and statistical material physics to effectively describe the feature changes while the fluid passes through the fractures within the permeable matrix. As an application example, a two dimensional rock sample is reconstructed using the digital image and characterized with different feature values at each LBM grid to distinguish pores, impermeable and permeable matrix by stating its local physical property. Compared with the conventional LBM, the results demonstrate the advantages of proposed algorithm in modeling fluid flow phenomenon in fractured porous media with variably permeable matrix.     

Numerical study on transient flow in the deep naturally fractured reservoir with high pressure

According to the experimental results and the characteristics of the pressure-sensitive fractured formation, a transient flow model is developed for the deep naturally-fractured reservoirs with different outer boundary conditions. The finite element equations for the model are derived. After generating the unstructured grids in the solution regions, the finite element method is used to calculate the pressure type curves for the pressure-sensitive fractured reservoir with different outer boundaries, such as the infinite boundary, circle boundary and combined linear boundaries, and the characteristics of the type curves are comparatively analyzed. The effects on the pressure curves caused by pressure sensitivity module and the effective radius combined parameter are determined, and the method for calculating the pressure-sensitive reservoir parameters is introduced. By analyzing the real field case in the high temperature and pressure reservoir, the perfect results show that the transient flow model for the pressure-sensitive fractured reservoir in this paper is correct.     

Non-Markovianity in the presence of multiple thermal environments via collision model

By means of the collision model, we study the non-Markovianity of an open quantum system S being coupled to M thermal reservoirs. In our model, each reservoir is modeled as a chain of ancillas whose intracollisions account for the occurrence of non-Markovian dynamics. We show that by incorporating M reservoir ancillas into the system, the non-Markovian dynamics of S can be embedded in the extended system that experiences a completely Markovian dynamics. The number M of involved reservoirs can thus be identified as the memory depth and determines the degree of the non-Markovianity. In the equilibrium case with identical temperatures for all the reservoirs, we show that though the non-Markovianity is proportional to M in the zero and relatively low temperature regimes, in the relatively high temperature regime such proportional relation holds only for the weak intracollisions of the reservoir ancillas. In the nonequilibrium situation, we examine the effect of temperature difference of reservoirs on the non-Markovianity. Focusing on a simple situation with two reservoirs, we observe that the nonzero temperature difference has a significant impact on the non-Markovianity.     

赞比西河水资源调度

研究了赞比西河水资源的调度决策问题。赞比西河上的卡里巴大坝年久失修,赞比西河管理局给出了3种方案:维修、重建或用多个大坝代替现有的卡里巴大坝。通过查阅赞比西河相关资料及沿岸的地形地貌信息,首先确定了11个大坝的地理位置及每个大坝发电机组的装机容量,目标是满足水库附近居民及工农业的用水和用电需求;其次,根据投入产出比对管理局提出的3种方案进行了评价,以确定最优决策方案;最后,基于多坝替代系统建立了梯级水库的水资源调度模型,利用坐标轮换方法分别对平水年、丰水年和枯水年进行了水资源调度。模型的敏感性分析表明调度方案模型是稳健的,建立的调度模型符合实际,使得多坝系统水管理能力增强。     

Numerical Calculation of Flows and Long-Range Transport of Contaminants in Lowland River Reservoirs

Flows and contaminant transport in the Novosibirsk reservoir are calculated on the basis of a two-dimensional (plane) nonstationary model with Saint Venant's equations. The model allows for the presence of a large number of islands. Coefficients of horizontal exchange (dispersion) are calculated by the formula taking into account dynamic velocity at the bottom. Numerical implementation of the model employs a semi-implicit conservative finite-difference TVD scheme on a distributed grid and procedures allowing for the flow past these islands. Model examples of calculations and computation results for dynamics of long-range transport of contaminants along the Novosibirsk reservoir are given.     

Calculation of tracer travel times in fractured geothermal reservoirs

A new method is presented for calculating the time taken for tracer to move between wells in a fractured geothermal reservoir. The reservoir model considered is a two-dimensional confined layer, but many wells and a background regional flow can be included. Also, either a straight or dog-leg, finite length, high permeability fracture can be included. The fracture can alternatively be considered as a barrier to lateral flow. The flow field is represented by complex potentials which are used to accurately calculate the streamline locations and tracer travel times are evaluated by numerical integration along the streamlines. The methods developed are used to model the dispersion of tracer produced by large-scale differences in the flow paths along which the tracer travels from the release well to the observation well(s).Notation C _d concentration, kg m^-3 - C dimensionless concentration - C _obs dimensionless concentration at the observation well - f dimensionless distance between the injection and production wells - h _d fracture half length, m - h dimensionless fracture half length - H reservoir thickness, m - Ln(·) complex algorithm - M mass of tracer released, kg - n porosity, dimensionless - N _b number of streamlines calculated for blob release - N _f number of subdivisions for the high permeability fracture - N _w number of streamlines calculated for injection well release - ¢P _d complex potential, m² s^-1 - P dimensionless complex potential - Q _c characteristic well volume flow rate, m³ s^-1 - q _p production well volume flow rate, m³ s^-1 - R _c characteristic length, m - t _d time, s - t _b dimensionless response start time - t dimensionless time - t _td tracer travel time (without dispersion), s - t _t dimensionless tracer travel time - u average fluid velocity, ms^-1 - v _d background fluid speed, m s^-1 - v dimensionless background fluid speed - x _d Cartesian coordinate, m - x dimensionless Cartesian coordinate - y _d Cartesian coordinate, m - y dimensionless Cartesian coordinate - (·) Dirac delta distribution - _d velocity potential, m² s^-1 - dimensionless velocity potential - angle from the positive x axis to the direction of the background flow - _d stream function, m² s^-1 - dimensionless stream function - complex number - circle mapped to the fracture by the Joukowski transformation - region occupied by the blob - complex number - p production/observation well - r release well