Standard Wireline Data Processing
Science operator: JOGMEC/NRCan/AURORA
Hole: Mallik-2L38 (re-entry)
Location: McKenzie Delta, Northwest Territories, Canada
Latitude: 69° 27' 40.71" N
Longitude: 134° 39' 30.37" W
Logging date: March, 2007
Total penetration: 1310 m (from kelly bushing)
Permafrost depth: 640 m
Casing depth: 103 m (508 mm), 677 m (340 mm), 1288 m (244 mm)
Kelly bushing: 9.29 m above sea level. Depth reference for all logs.
Ground elevation: 1.36 m above sea level.
Gas hydrate zones: 891-920 m, 931-993 m, 1010-1032 m, 1040-1056 m, 1060-1110 m (from kelly bushing)
Lithologies: Sand, silty sand, and sandy silt with various amounts of clay.
The logging data was recorded by Schlumberger in DLIS format. Data were reviewed at the Borehole Research Group of the Lamont-Doherty Earth Observatory in November-December 2020.
| Tool string (pre-drilling) | Run |
Top (m) |
Notes | ||
AIT/MCFL/TLD/HGNS/CMR |
|
|
677 |
|
|
AIT/MCFL/TLD/HGNS/CMR |
|
|
open hole |
|
|
| Tool string (main logging, open hole) | Run |
Top (m) |
Notes | ||
1. HRLA/AIT/GPIT/PPC/EDTC/EMS/SP/RtScanner |
|
677 |
|
||
|
|
open hole |
|
||
2. CMR/APS/ECS/MCFL/PPC/HNGS |
|
|
|||
|
|
|
||||
3. FMI/SonicScanner/PPC/EDTC |
|
No original acoustic data available. |
|||
|
|
No original acoustic data available. |
||||
4. AIT/MCFL/TLD/HNGS/SP |
|
|
|||
5. MrScanner/HGNS/EDTC |
open hole |
||||
open hole |
|||||
| Tool string (cased hole) | Run |
Top (m) |
Notes | ||
SonicScanner/EDTC |
1288 |
No gamma ray data available |
|||
SonicScanner/EDTC |
1288 |
No gamma ray data available |
NOTE: AIT/MCFL/TLD/HGNS = Platform Express
Mallik-2L38 was originally drilled and logged in 1998 to a total depth of 1150 m (from kelly bushing). The 2007 plan was to re-occupy the 2L38 cased section, use the abandonment cement below the casing shoe at 677 m as a kick-off plug to establish a side track. A new hole close to the old one in formation undisturbed by oprevious drilling would then be drilled. However, due to the lack of sound cement plugs inside the old casing it was impossible to kick off the new well and as a result the original hole was redrilled and deepened to 1310 m. Production tests were conducted after casing the lower part of the hole and more logging was carried out before and after the production tests.
In summary, logging operationsat Hole 2L-28 were conducted in three phases:
1) before deepening the original hole (cased to 677 m)
2) in the deepened hole (open hole)
3) after casing the lower part of the hole (before and after production tests).
Depth match. No depth matched was necessary due to the excellent correlation between runa.
All logs depths are referred to the kelly bushing, which was 9.29 m above sea level.
Environmental
corrections. None was applied to the resistivity and gamma ray logs but some corrections may have been applied previously.
Sampling rates:
- acoustic data: 15.24 cm (SonicScanner)
- caliper data: 15.24 cm (EMS, FMI, PPC), 2.54 cm (PEX)
- density data: 2.54 cm (TLD)
- gamma ray: 15.24 and 5.08 cm (EDTC, HGNS), 15.24 cm (HNGS)
- geochemistry: 15.24 (ECS)
- inclinometry: 15.24 cm (GPIT)
- magnetic resonance: 19.05 cm (CMR), 15.24 cm (MrScanner)
- porosity: 15.24 and 5.08 cm (APS, HGNS)
- resistivity data: 7.62 cm (AIT, RtScanner), 5.08 cm (HRLA, MCFL)
- spontaneous potential: 15.24 cm
Acoustic data. No original (including sonic waveforms) data was included in the available dataset (DLIS files). The sonic data included in LogDB are the result of processing performed for the client by Schlumberger.
The quality of
the data is assessed by checking against reasonable values for the logged
lithologies, by repeatability between different passes of the same tool, and by
correspondence between logs affected by the same formation property (e.g. the
resistivity log should show similar features to the sonic velocity log). The data at the Mallik hole is of excellent quality.
Gamma ray logs
recorded through the casing should be used only
qualitatively, because of the attenuation of the incoming signal.
Hole diameter was recorded by the caliper on the TLD-PEX (HCAL) and EMS tools (HD1, HD2, HD3), the Power Positioning Caliper tool (HD1, HD2, HD3) and the FMI (C1, C2).
A null value of
-999.25 may replace invalid log values.
Additional information about the drilling and logging operations can be found in the Geological Survey of Canada Bulletin 601 (https://doi.org/10.4095/291751).
For questions about the logDB database, you may direct your questions to:
Cristina Broglia
Phone: 845-365-8343
Fax: 845-365-3182
E-mail: Cristina Broglia
Tanzhuo Liu
Phone: 845-365-8630
Fax: 845-365-3182
E-mail: Tanzhuo Liu
Gilles Guerin
Phone: 845-365-8671
Fax: 845-365-3182
E-mail: Gilles Guerin