Flow through fractures
Flow through fractures
复制标题
DOI：
10.1029/wr017i001p00191
复制
发表时间：
1981-02
影响因子：
5.4
通讯作者：
C. Neuzil;J. V. Tracy
中科院分区：
文献类型：
--
作者：
C. Neuzil;J. V. Tracy
通过裂缝的流动通常被理想化为两个平行板之间的流动（平面泊泽维尔流）。平行板之间的开口或孔径是明确的，其与流量的关系是众所周知的。然而，岩石中的裂缝具有不均匀的壁和可变的孔径。提出了一种断裂流动模型，其中断裂由一组具有不同孔径的平行板开口表示。该模型导出了一个修正的泊泽伊方程，其中包含了裂缝的孔径频率分布。可采用任意孔径分布；为了简化计算和证明模型的性质，假设其分布为对数正态分布。即使假设了分布的解析形式，也需要两个参数来确定流量，而不是一个代表“孔径大小”的单一值。建立了裂缝在压缩（裂缝壁变形）和拉伸（裂缝壁分离）过程中孔径变化的模型，该模型约束了附加参数，并允许计算流量作为平均孔径的函数。平均孔径和流量之间的理论关系可以用来解释已发表的单个裂缝的实验室数据。
Flow through fractures is often idealized as flow between two parallel plates (plane Poiseuille flow). The opening or aperture between parallel plates is unambiguous and its relation to flowrate is well known. However, fractures in rock have uneven walls and a variable aperture. A model for flow in a fracture is proposed wherein the fracture is represented by a set of parallel plate openings with different apertures. The model leads to a modified Poiseuille equation for flow which includes an aperture frequency distribution for the fracture. Any arbitrary aperture distribution can be used; in order to simplify computation and demonstrate the properties of the model a log normal form of distribution is assumed. Even when an analytical form of the distribution is assumed, two parameters, rather than a single value representing ‘aperture size’ are required to determine flowrate. Models of aperture change for a fracture undergoing compression (fracture walls deforming) and extension (fracture walls separating) are developed which constrain the additional parameter and allow calculation of flowrate as a function of mean aperture. The theoretical relationships developed between mean aperture and flowrate can be used to interpret published laboratory data for single fractures.