Elliptical flow exists in the near vertical fracture area, or in anisotropic reservoirs, and the classical radial flow models cannot provide complete analysis for elliptical flow. This paper presents a mathematic model for gas elliptical flow in double porosity gas reservoirs. The differential equation of gas flow is written in Mathieu equation, so that the solution can be expressed also by Mathieu functions. The numerical calculation of relevant Mathieu functions , and its derivative is done to obtain the dimensionless pseudo pressure drop in Laplace space. Property sensitivities of double porosity systems including combination of , parameter related to anisotropy, storativity ratio , interporosity flow coefficient are studied by using the Laplace numerical inversion. The new solution not only includes factors considered for classic solutions in previous papers, but also incorporates the effect of reservoir anisotropy. It is kind of modification and supplementation to classic solutions.

Functionality of wood has to evolve with time to adapt to the emerging needs in society. In this work, endowing electrical conductivity to the insulating wood by adding graphene into the wood matrix to form a conductive wood-graphene composite (conductive wood) via a facile and environmentally benign fabrication technique. The rationale of fabricating conductive wood is of two folds: (1) The high suitability of wood as a renewable matrix due to its porous network and mechanically robust monolithic structure. (2) The need to explore reasonable strategy to adequately translate the properties of graphene from microscopic level to macroscopic level. The conductive wood is able to preserve both the natural features of wood (to function as mechanical scaffold) and the conductivity of graphene. An outstanding electrical conductivity (volume resistivity of 36.7 Ω·cm) is achieved for the conductive wood, while it can maintain a low bulk density of 0.44 g cm-1. More significantly, the conductive wood demonstrates a highly three-dimensional anisotropic conductivity that makes it a highly versatile conductor in various applications. Hence, this lightweight conductive wood may contribute towards a great electronic revolution and as an encouraging strategy to repurpose the function of wood in this new era.