| Summary: | An inevitable consequence of deep drilling operations is that temperatures in the vicinity of a new borehole are always thermally disturbed. For most deep drilling technologies, the thermal disturbance is primarily due to heat exchange between the drilling fluid and the material surround the borehole. Although temperatures around a well eventually return to the undisturbed state, a measurable disturbance may still exist several decades after well completion. Thus, borehole temperature measurements must be 'corrected' if the undisturbed temperature distribution in the surrounding rock or ice is to be found. Undisturbed formation temperatures are of interest for a wide range of geophysical applications, including: regional heat flow studies, modeling hydrocarbon maturation in sedimentary basins, assessment of geothermal reservoir potential, interpretation of electric well logs, prediction of gas hydrate stability zones, permafrost characterization, and climate-change studies. This dataset consists of tabulated radial Green's functions Gr that can be used to assess the magnitude of the thermal drilling disturbance around a borehole during both the drilling and recovery phases. Tables are provided for the following types of boundary condition at the borehole wall: (1) Dirichlet - prescribed temperature, (2) Neumann - prescribed heat flux, and (3) Robin - a prescribed convective condition. When used in conjunction with the appropriate vertical Green's function Gz, 2-D drilling disturbance effects around a borehole can be computed. Although a simple analytic expression is available for Gz, a challenging numerical integration must be performed to evaluate the radial Green's functions Gr. The tabulated Gr values provided by this dataset are intended to alleviate the need to repeat these calculations. File "Gr_notation.pdf" describes the mathematical notation used in the dataset while "Gr_files.pdf' provides a description of the individual Gr files. A complete description of the Green's functions and their use for the drilling disturbance problem is provided by Clow, G.D., (2015): "A Green's Function Approach for Assessing the Thermal Disturbance Caused by Drilling Deep Boreholes in Rock or Ice", Geophysical Journal International, 203, 1877-1895, doi:10.1093/gji/ggv415. Recommended Citation: Clow, Gary D. (2015). Radial Green's Functions used to Correct Borehole Temperature Measurements for the Thermal Disturbance Caused by Drilling. UCAR/NCAR - CISL - ACADIS. Dataset. http://dx.doi.org/10.5065/D64F1NS6
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