研究期間：10108~10207;Most contaminated aquifers below buildings have not been received proper attention due to the lack of appropriate means, as most site investigation techniques or in-situ remediation methods are based on vertical wells that are impractical to install below buildings. Such unattended contaminated aquifers present themselves as a threat to site remediation. As an alternative source zone, during the remediation process they can release contaminants to the surrounding areas so as to lower the overall remediation efficiency. Therefore, how to deal with the contaminated aquifers below buildings is an important issue. To enhance oil production, the directional drilling technique was originally developed to drill horizontal or slant wells in deep consolidated oil reservoirs. Over 15-year significant improvement, this technique renders drilling slant wells technically and financially feasible in shallow unconsolidated aquifers, on which many contamination sites locate. Using slant wells allows us to resolve the groundwater contamination problems below buildings, as they can be drilled at the perimeter of a building with an inclination angle into the contaminated aquifer. As a result, many available investigation or remediation techniques can be carried out in these slant wells. Aquifer heterogeneity is important to groundwater flow and contaminant transport. In order to determine aquifer heterogeneity below buildings, this project aims: (1) to develop the field technique of conducting the MLST in a slant well. This part will be performed through field experiments at a contamination site on an alluvial aquifer in southern Taiwan. In this site, a total of six slant wells surrounding an on-site building are available for the pertinent research activities. Field experiments will also be performed using slant wells in fractured formations available at the Xiao-Long-Di reservoir in mainland China; (2) to develop the data analysis method. First, the solution to a mathematical model properly simulating the MLST in a slant well will be determined for the non-oscillatory response as for the low-K cases and the oscillatory response as for the high-K cases. The solutions also have the potential to deal with the MLST in slant wells perpendicular to fractures in rock formations. The data analysis method will be derived based on these solutions. This research will extend the applicability of the MLST to the slant wells, and thus broaden our ability to characterize heterogeneity of aquifers below buildings as well as fractured formations where slant wells are drilled perpendicular to the inclined fractures.
