Petro-Log™
Petro-Log™ measures the formation where it sits. Density, natural gamma, resistivity, magnetic susceptibility and porosity logged continuously along the hole, at a resolution and consistency that sampling cannot match.
What Petro-Log™ answers
Petro-Log™ is in-situ formation characterisation by wireline logging: physical and chemical rock properties are measured directly in the borehole to produce continuous lithology, mineralisation and alteration proxies for geological, resource and material understanding.
Key answers
- LithologyRock type and mineralogy proxies from the combined log response
- DensityBulk density for tonnage, rock mass and stratigraphic correlation
- RadioelementsPotassium, uranium and thorium concentrations from spectral natural gamma
- ResistivityFormation electrical resistivity and conductivity
- Magnetic susceptibilityMagnetic mineral content and ground-truth for airborne and ground magnetic surveys
- Porosity & alterationPorosity, permeability, saturation and alteration halo response
Applications
- Mineral exploration
- Resource definition and grade control
- Coal and industrial minerals
- Quarry and construction materials
- Stratigraphic and civil ground models
What a Petro-Log run delivers
Petrophysics, from the Greek petra (rock) and physis (nature), is the study of physical and chemical rock properties. Petro-Log acquires those properties in-situ: a string of measurement tools is run in the borehole and the formation is measured where it sits, under natural stress, saturation and temperature.
What is the host rock, where does it change, how altered is it, where is the ore, and how strong is the ground around it?
- DistributionsMultiscale distributions of petrophysical properties along the hole
- LithologyRock mineralogy and formational processes
- ElementsElemental concentrations, including radioelements (K, U, Th)
- AlterationMetamorphic processes and alteration halos
- MechanicsMechanical properties that predict temporal behaviour of the rock mass
- OreOre presence and concentrations, predictive assay
- ReservoirPorosity, permeability and saturation
Interpretation, lithology blocking and machine learning classification are delivered by our geoscience team.
Petro-Log™ questions
Do logging tools map geology directly?
No. Logs measure physical properties, and geology is interpreted from them. Because each rock type has a characteristic signature, interpretation is usually straightforward once the logs are calibrated against core from one or two holes.
How is downhole logging data correlated with geology?
Logs are depth-matched to core, then the log responses are calibrated against logged lithology, assays or geotechnical tests. From there the same signatures are recognised in holes with no core, or used to block lithology automatically.
How do in-situ properties differ from laboratory measurements?
Laboratory tests measure a small sample after it has been removed from confining stress, dried or resaturated, and sometimes damaged in handling. In-situ logs measure the rock under natural stress, saturation and temperature, over a much larger volume. The two are complementary: lab tests calibrate the logs, logs extend the lab results along the whole hole.
Are the tools calibrated?
Yes. Every tool is calibrated against known standards before deployment, and calibrations are checked on site. Raw counts are converted to engineering units through documented calibration equations, and QA checks accompany every run.
What borehole diameters do the logging tools work in?
Our slimhole fleet is designed for exploration and mining diameters, from around 45 mm upward, and includes tools for larger water and geotechnical holes. Individual tools have minimum and maximum diameters; we match the suite to the hole.
Can Petro-Log data be used for machine learning?
Yes, and it is well suited to it: continuous, numeric, multi-parameter and consistently sampled. Our data science team uses expert rules and machine learning for lithology classification, alteration mapping and predictive assay.
More in the FAQ & glossary.