Standard Wireline Data Processing
Science operator: Arkoma Production Company
Logging operator: Schlumberger, Welex
Hole: Cajon Pass (aka Arkoma) Federal 1-26
Location: Cajon Junction, San Bernardino Mountains, California
1303 ft S and 1745 ft E from NW corner of Sec. 26, Twp. 3N, Rge. 6W
Logging dates: February 14 and March 10, 1984
Elevation (kelly bushing): 1001.58 m (3286 ft)
Elevation (ground level): 997.3 m (3272 ft)
Total penetration: 1795.3 m (5890 ft)
Casing: 13 3/8 in at 154.5 m (507 ft)
Casing: 9 5/8 in at 400.2 m (1313 ft)
Lithologies: sandstone, granodiorite, granite, gneiss.
Sediment/basement contact: 658.4 m (2160 ft), from GR log.
The logging data was acquired by Schlumberger (Run 1) and Welex (Run 2) in LIS format in 1984. The Schlumberger data was originally available on 9-track magnetic tape archived at LDEO-BRG in 1987, when the CP-226 hole was drilled and logged. The Welex logging data below 594 m were manually digitized at LDEO-BRG in1987, from the blueprints produced by Welex. The available dataset does not include any Dipmeter acquired by Schlumberger or Welex or resistivity data acquired by Welex below 390 m. The dipmeter and resistivity data acquired by Welex are available in analog form only.
The available data were reviewed for quality control and formatted for upload onto the LogDB database at the
Borehole Research Group of the Lamont-Doherty Earth Observatory in March 2021.
| Log data | Top depth (m) | Bottom depth (m) | Casing depth (m) | Notes |
DIL (Dual Induction Tool)
|
154.5 |
Schlumberger logs |
||
BHC (Borehole Compensated Sonic Tool) |
154.5 and 400.2 |
Schlumberger / Welex logs, 3 intervals, spliced. |
||
GR (Gamma Ray Tool)
|
154.5 |
Schlumberger logs |
||
GR (Gamma Ray Tool) |
open hole |
Welex log, digitized |
||
CDL (Compensated Density Log) |
open hole |
Welex log, digitized |
||
CALI (CDL Caliper) |
open hole |
Welex log, digitized |
The Cajon Pass (formerly Arkoma) Federal 1-26 hole, located 4.3 km from the San Andreas Fault in the San Bernardino Mountains, was drilled by the Arkoma Production Company as a wildcat well. The hole was logged by Schlumberger in February, 1984. The logging suite included DIL/BHC/GR and HDT (High Resolution Dipmeter). After installing a 13 3/8 in casing at 154.5 m, the hole was deepened to a total depth of 1795.3 m and logged by Welex in March 1984. Logging consisted of DIL/GR, CDL and Dipmeter tools. The hole was subsequenly cased to a depth of 400.2 m with a 9 5/8 in. casing.
The quality of
the data is commonly 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).
Gamma ray logs recorded through the casing (above 154.5 m) should be used only qualitatively, because of the attenuation of the incoming signal.
A wide and/or irregular borehole affects most recordings, particularly those that require eccentralization and a good contact with the borehole wall (CDL). Hole diameter was recorded by the hydraulic caliper on the CDL tool . CP-126 is generally in gauge, showing values in the 8.5-10 in. range, with local enlargements generally not exceeding 12 in. A large washout, up to 22 in in diameter, occurs at 618-658 m, at what the sonic and resistivity indicate as the sediment/basement boundary.
A null value of
-999.25 may replace invalid log values.
Additional information about the Cajon Pass project is available at:
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/GL015i009p00945
https://link.springer.com/content/pdf/10.1007%2F978-3-642-73455-7.pdf
https://agupubs.onlinelibrary.wiley.com/doi/toc/10.1002/(ISSN)1944-8007.CAJONPS1
Questions about the data available on line can be sent to:
Cristina Broglia
Phone: 845-365-8343
Fax: 845-365-3182
E-mail: Cristina Broglia
Gilles Guerin
Phone: 845-365-8671
Fax: 845-365-3182
E-mail: Gilles Guerin