孔隙结构对多孔介质渗透率的影响

1 Introduction
Porous medium's transfusion widely exists in petroleum exploitation, geotechnical engineering, groundwater exploitation and other engineering fields, so more and more people pay attention to the internal structure of porous media and flow characteristics. The internal structure of porous media are complex, their internal structural characteristics include pore radius, throat radius, pore ratio, pore tortuosity and other related parameters, pore-throat ratio as the main characteristics of fractured rock reflected in the internal structure of porous media filled, and greatest impact on the flow characteristics of porous media. Thus strengthening the internal structure of porous media will help to further understand the many properties of porous media flow, so as to provide relevant theoretical guidance for engineering activities. In recent years, with the deep study, porous medium's transfusion characteristic research starts from only pay attention to porosity to now pay more attention to its internal detail structure unceasingly the research. As early as 1856, French engineer H.darcy[1] did massive experiments, and summarized obtains relations between the seepage energy loss and the seepage velocity reciprocity namely for Darcy Law, it provides the elementary theory basis for afterward to study the porous medium the transfusion characteristic. With the deepening of the study and the level of research to improve, some scholars have begun to consider the internal structure of porous media, in 1952 Ergun [2] proposed the famous Ergun equation, and this equation had considered the relations between porous medium porosity and pore diameter, causing its structure and the actual porous medium structure tally. In order to reflect the real porous medium internal structure’s influence on transfusion characteristic, some scholars started introduce the pore throat to calculate porous medium transfusion formula, established pore throat model [3-4] , and introduced the pore throat parameter to this formula, the penetration coefficient which calculates with this model is more accurate. At present, mainly uses the physical test to determine the pore throat of the porous medium, but that require the test equipment demanding and time-consuming, expensive cost, and limited applications, so finding a simple and effective method of calculating pore-throat is essential. How to simplify calculates the porous medium the pore throat have become important research question,
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Nakayama et al [5] obtains some progress in particular diameter constitution porous medium penetration coefficient research, based on this and studied square granule filled fracture transfusion characteristic. Liu Jianjun et al [6] give a formula among penetration coefficient, porosity and the particle size of square granule filled fracture, and have confirmed formula correctness by the numerical simulation. He Yaoyao [7] combined the different diameter granule together to study the transfusion characteristic of porous mwk.baidu.comdium and has given related experimental formula. In this paper, based on previous studies, internal structure of porous medium simplified into four kind of regular granules, respectively is circular, square, hexagon shape and the octagon, given simple formula of these four kind of shape granules pore throat through mathematics inferential reasoning and the simplification, and confirms the formula reliability through the numerical simulation, so it provided one simple method for porous medium's transfusion computation.
Pore Structure Effect on the Permeability of Porous Media
HAN Peifeng1, LIU Jianjun2, HE Xiang 1. Institute of Poromechanics, Wuhan Polytechnic University, Wuhan, China, 430023 2. School of Civil Engineering, Southwest Petroleum University, Chengdu, China, 610500 hanpeifeng@yeah.net Abstract: Based on the actual shape of porous media, complex porous media can be simplified into four common rules for the shape of pore throat model. By simplifying the calculation, inferred these four kinds of regular shape pore throat model pore throat ratio simplification formula. In order to confirm the inferential reasoning formula is correct, four kind of regular pore throat models are established by using the finite element software, the inferential reasoning formula are substituted in the equation to calculate porous medium the penetration coefficient, contrasted the result and the tentative data we can discover some regulation through four kind of regular shape pore throat model data's contrast: Test results and calculation of derived results are in agreement, when the porosity is small, the experimental data and calculation of derived results agree well, when the porosity is large, the experimental data and calculation formulas are derived any deviation, but meet the requirements of engineering. Derived formula has changed the traditional pore throat ratio calculations rely on the test, and simplified calculation of the ratio of pore throat, saving cost and time conducive to pore-throat ratio in practical engineering application and promotion. Keywords: porous media, pore throat model, pore-throat ratio