Measure porosity & pore size (in saturated zone)
Measure saturation (in unsaturated zone)
Calculate permeability, bound vs free fluid
Distinguish between water, oil & gas
Does not require a nuclear source
High-resolution packer test infilling
Leach pad optimization
Tailings dam hazard analysis
Monitor dewatering progress
Well screen placement
Coal gas content
Grain size estimation
Above: Magnetic Resonance permeability log is shown in brown below, compared with 5 m packer intervals in light green. Dark green is NMR permeability averaged over the packer interval, and red is core permeability. As is evident, NMR permeability agrees well with packer tests, while offering much higher resolution. Above is the total porosity measured by NMR, subdivided into free fluid (blue), capillary fluid (yellow), and bound fluid (grey). Purple bars are porosity from core.
Above: NMR matches pump test results well; reads lower porosity than core due to lack of confining pressure in core analysis.
Above: NMR can measure free and adsorbed gas and oil content, with rapid turnaround as compared with traditional methods.
Measures water content (porosity) downhole
Uses a nuclear source
Cannot determine pore size or permeability estimate
Spinner and Heat-Pulse Flowmeter
Measure flow rates under ambient and pumping conditions
Locate in/out flow zones and rates
Spinner Flowmeter for high-flow or pumping conditions
Heat-Pulse Flowmeter for low-flow or ambient conditions
Above: Schematic illustration of hypothetical flow regimes measured under ambient and pumping conditions.
Above: The bar chart to the left and well schematic on the right, show inflow and outflow rates measured with Heat-Pulse Flowmeter under ambient conditions. The logs in the center show rates measured by Spinner Flowmeter under pumping conditions. The difference above and below each step in these curves are the inflow rates, shown in the bar chart to the right. Fluid temperature/conductivity logs also provide qualitative indication of inflow/outflow zones due to differences in fluid properties between inflowing formation water and borehole water post-drilling.
Fluid Temperature & Conductivity
Locate flow zones downhole via differences between inflowing formation water and borehole water post-drilling.
Combine with Flowmeter for flow confirmation (see above)
Identify fracture zones below water table
Image fluid flow with excellent depth resolution.
Contaminant plume migration
Leach pad flow pathways
Tailings dam saturation profiles
Above: Cross-hole resistivity profile of a low-resistivity anomaly, such as a contaminant plume, leachate flow pathway, or mineralization.