重复地震及其在人工探测中的潜在应用

本文研究了地球物理学家在重复地震（Doublet）研究方面取得的主要进展。针对天然重复地震数量少，区域分布有限，观测被动等问题，本文通过野外实验研究了人工震源信号的可重复性。由于人工震源位置已知，可随时主动激发，提出以此构建精确的人工重复地震，对于提高重复地震方法的可靠性与可行性具有重要意义，为进一步利用人工重复地震进行大尺度的地震探测奠定了基础。     

A 3D potential-based and desingularized high order panel method

In this paper, a novel high order panel method based on doublet distribution and Gaussian quadrature was adopted to deal with the potential flow problem. In the geometry representation we employed both the exact surface and NURBS surface form to construct the surface panel. These data were calculated directly from the mathematical shape definition. Furthermore, no fixed order of doublet density distribution was assumed on each panel. Not only the number of panels could be chosen, but also the Gaussian order of each panel. The numerical results for sphere, ellipsoid and Wigley hull demonstrated here indicated that the present method was adapted to the potential flow problem. Moreover, the NURBS surface geometry representation was capable of further potential flow optimal calculation.     

Reservoir lifetime and heat recovery factor in geothermal aquifers used for urban heating

Simple models are discussed to evaluate reservoir lifetime and heat recovery factor in geothermal aquifers used for urban heating. By comparing various single well and doublet production schemes, it is shown that reinjection of heat depleted water greatly enhances heat recovery and reservoir lifetime, and can be optimized for maximum heat production. It is concluded that geothermal aquifer production should be unitized, as is already done in oil and gas reservoirs.Nomenclature a distance between doublets in multi-doublet patterns, meters - A area of aquifer at base temperature, m² drainage area of individual doublets in multidoublet patterns, m² - D distance between doublet wells, meters - h aquifer thickness, meters - H water head, meters - Q production rate, m³/sec. - r _e aquifer radius, meters - r _w well radius, meters - R _g heat recovery factor, fraction - S water level drawdown, meters - t producing time, sec. - T aquifer transmissivity, m²/sec. - v stream-channel water velocity, m/sec. - actual temperature change, °C - theoretical temperature change, °C - water temperature, °C - heat conductivity, W/m/°C - _r rock heat conductivity, W/m/°C - _aC_a aquifer heat capacity, J/m³/°C - _aC_r rock heat capacity, J/m³/°C - _WC_W water heat capacity, J/m³/°C - aquifer porosity, fraction