A portable borehole temperature logging system using the four-wire resistance method


ERKAN K. , Akkoyunlu B. , BALKAN E., TAYANÇ M.

JOURNAL OF GEOPHYSICS AND ENGINEERING, vol.14, no.6, pp.1413-1419, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 6
  • Publication Date: 2017
  • Doi Number: 10.1088/1742-2140/aa7ffe
  • Title of Journal : JOURNAL OF GEOPHYSICS AND ENGINEERING
  • Page Numbers: pp.1413-1419

Abstract

High-quality temperature-depth information from boreholes with a depth of 100 m or more is used in geothermal studies and in studies of climate change. Electrical wireline tools with thermistor sensors are capable of measuring borehole temperatures with millikelvin resolution. The use of a surface readout mode allows analysis of the thermally conductive state of a borehole, which is especially important for climatic and regional heat flow studies. In this study we describe the design of a portable temperature logging tool that uses the four-wire resistance measurement method. The four-wire method enables the elimination of cable resistance effects, thus allowing millikelvin resolution of temperature data at depth. A preliminary two-wire model of the system is also described. The portability of the tool enables one to collect data from boreholes down to 300 m, even in locations with limited accessibility.