Harpoon®
HIGH-RESOLUTION IN-SITU MEASUREMENTS OF SOIL MECHANICAL AND HYDROGEOLOGIC PROPERTIES
- Lower cost and higher confidence compared to soil sampling and laboratory analysis
- Perfectly correlated magnetic resonance and CPT data
- Data immediately available for engineering analysis
- Decreased project risk and increased data confidence from combined NMR and CPT data.
- For use on land or on the seafloor
Harpoon® Overview Video
Harpoon® Testimonials
Direct Measurement of Hydrogeologic Properties
Harpoon® provides high-resolution (5cm) measurement of volumetric water content and porosity in the native formation via stepped or continuous modes. Harpoon® NMR measurements are directly sensitive to the pore size distribution, which provides a new and enhanced mode for sediment classification.
Harpoon® NMR measurements can differentially estimate the bound and mobile water content, and provide quantitative estimates of hydraulic conductivity up to 3000 m/day (10000 ft/day). Harpoon® technology provides more reliable estimation of bulk density as compared to conventional lab tests, especially for sands where sampling methods tend to create large disturbance to the samples.
Soil Mechanical Properties
Harpoon® utilizes detachable Cone Penetrometer Test (CPT) cones that are commonly used in land and seafloor geotechnical investigations including investigations for development of offshore wind turbine foundations and cable routes. CPT measurements are used to determine the geo-mechanical engineering properties of soils and delineate soil stratigraphy.
The Magnetic Resonance Advantage
Harpoon® incorporates NMR-based technology that uses the same physics as medical MRI. This technology provides inherently non-invasive detection of water in sediments, using static and alternating magnetic fields to polarize and excite hydrogen in the native formation fluids outside the zone of disturbance from drilling. The initial amplitude of the NMR signal observed after this perturbation is linearly proportional to the volumetric fluid content, or the total porosity if the formation is saturated. NMR relaxation times are strongly correlated with the size of the pore space and are used to distinguish between water bound in small pores from more mobile water in large pores and fractures.
Physical Specifications
Sensor Length = 1.65 m
Sensor Max Diameter = 48 mm
Push rod type: 36 mm OD or 45 mm OD
Marine logging cable with 8 conductors
Max push force = 100 kN
Cone: 15 cm2 cone (multiple vendors supported)
- Tip resistance
- Pore pressure
- Sleeve friction
- Tilt angle
NMR Sensor Specifications
Dual Frequency with NMR sensitive zone diameters of 12.5 cm and 15 cm
Echo Spacing = 0.5 ms
Vertical Resolution = 5 cm
Data outputs:
- Volumetric water content (total porosity)
- Bound/mobile water fractions
- Relative pore size distribution (sediment classification)
- Estimated hydraulic conductivity
Data Processing and Interpretation
Vista Clara’s full-featured data processing and analysis software allow users to see the NMR logging results in real-time while logging. Users can perform real-time data processing, quality control, and interpretation of hydrogeological and CPT measurements. The software allows users to control all aspects of data analysis from acquisition to visualization, to final reporting. The data processing software automatically imports corresponding CPT data for joint analysis with NMR results.
Harpoon® Applications:
Harpoon® enables high-resolution, continuous measurement of soil mechanical and hydrologic properties in single push.
Land-Based CPT+NMR
Nearshore/Offshore CPT+NMR
Harpoon® Datasheet
high-resolution, continuous measurement of soil mechanical and hydrologic properties in single push
Harpoon® technology combines CPT and in-situ nuclear magnetic resonance (NMR) measurements in a single CPT-deployed tool