암반 내 유동 분석을 위한 시각적 투수도 정규화 기법의 활용

Abstract

This report presents the Transmissivity Normalized Plot (TNP) method, developed for the visual comparison and analysis of field hydraulic test data that reflect flow characteristics in fractured rock. This method is based on a derivative normalization approach that comple- ments traditional type curve analysis. Derivative data are normalized with respect to the dominant inner boundary condition and then converted into units of radial flow equivalent transmissivity. The resulting TNP expresses transmissivity as a function of time on a log-log plot, allowing for the visual comparison of hydraulic test data obtained under various conditions. For the case when the hydraulic test displays infinite acting radial flow (flat derivative), the transmissivity can be derived from the y-axis coordinate of the flat portion of the derivative displayed on the TNP. The basis for the visual evaluation of transmissivity is that during radial flow the derivative has a slope of zero and its vertical position in log-log coordinates is an inverse reflection of the transmissivity. When analyzing transient hydraulic test data from different field settings, the TNP technique enables visual comparison of similar formation responses in terms of both flow model characteristics and transmissivity magnitude. If normalized derivative curves from different tests converge in the late-time region, it suggests that the tests are capturing the same large-scale transmissivity and flow structure. This report outlines the fundamental concept and principles of the TNP method and examines its applicability through case studies covering a range of fractured rock environments and hydraulic properties. This TNP approach enables the visual integration and direct evaluation of various hydraulic test data within a single plot, and can be effectively utilized for constructing consistent conceptual flow models and accurately estimating hydraulic parameters.