Table T6. Logging tools and their applications.
| Tool | Acronym | Tool string | Principle | Synthetic seismogram* | Lithology mineralogy† | Porosity | Geochemistry elements | Other | Sample
interval (cm) |
Approximate vertical resolution (cm) |
|---|---|---|---|---|---|---|---|---|---|---|
| Sonic: | ||||||||||
| Long spacing | LSS | FMS/sonic | Sonic travel time | G | F | G |
15
|
61
|
||
| Resistivity: |
|
|
||||||||
| Shallow focused | SFR | Triple combo | Spherically focused current | F | F | VG |
15
|
76
|
||
| Dual induction | DIT-E | Triple combo | Induced current | F | F | VG |
15
|
150 and 200
|
||
| Dual laterolog | DLL | Triple combo | Focused current | F | F | VG |
15
|
61
|
||
| Formation MicroScanner | FMS | FMS/sonic | Focused microcurrent | P | P | G | ‡ |
0.25
|
0.5
|
|
| General purpose | GPIT | FMS/sonic | Oriented magnetic field | P | F | ** |
0.25
|
1
|
||
| Inclinometer |
|
|
||||||||
| Neutron porosity | APS | Triple combo | Absorption of bombarding neutrons | P | F | VG | H |
5 and 15
|
30
|
|
| CNT-G | Geochemical |
15
|
46
|
|||||||
| Aluminum activation clay tool | AACT | Geochemical | Absorption
of bombarding neutrons |
P | F | P | Al, Mn |
15
|
46
|
|
| Induced gamma ray | GST | Geochemical | Capture of bombarding neutrons | F | VG | F | Ca, Si, Fe, S, |
15
|
46
|
|
| Spectroscopy | Ti, Gd, H, Cl |
|
|
|||||||
| Natural gamma ray | HNGS | Triple combo | Natural gamma-ray emissions | P | VG | K, Th, U | †† |
15
|
46
|
|
| Spectroscopy | NGT | FMS/sonic and geochemical |
15
|
46
|
||||||
| Bulk density | HLDS | Triple combo | Absorption of bombarding gamma rays | G | G | G |
15
|
46
|
||
| Temperature/ acceleration/ pressure |
TAP | Triple combo | Formation temperature tool acceleration pressure | ‡‡ *** |
1/s
4/s 1/s |
|
||||
| Caliper | LCAL | Triple combo | Hole diameter | P | ††† |
15
|
|
Notes: * = logs other than sonic and density can be converted to pseudosonic/density, based on known log responses to lithology and porosity. † = percentages of minerals with abundances >3% are determined from simultaneous inversion of several logs. Usefulness of tool for application: VG = very good; G = good; F = fair; P = poor. ‡ = detailed mapping of fractures, faults, foliations, and formation structures; analysis of depositional environments; formation dip. ** = magnetic reversals, stratigraphy, fault zones. †† = used for depth matching of logs. ‡‡ = heat flux, detection of permeable layers. *** = information on tool motion for eventual integration into heave compensation system. ††† = quality control for other logs. Blank spaces = no data.