Temperature and Pressure Ratings of Javelin and Dart Logging Tools

Temperature rating

In 2025, Vista Clara developed an electronics-based solution to improve the temperature rating of all Javelin and Dart downhole NMR logging tools, enabling reliable operation at borehole temperatures up to 85°C. This technical advancement significantly broadens the range of applications for Javelin and Dart tools, allowing them to accurately estimate hydraulic properties of subsurface formations under more demanding thermal conditions. This development supports stable performance in geothermal projects targeting shallow subsurface investigations, deep mining operations, and the evaluation of thermal energy storage systems.

Figure 1 below shows a heating experiment conducted on a Javelin Micro JPZ175D probe placed inside a custom-made oven. Silicon bags filled with vegetable oil were positioned around the sensitive zones of the NMR logging probe. NMR measurements were conducted while heating the probe to >100°C. Temperature along the length of the probe was monitored using electrodes positioned along its body.