Engineering
and
Design
BOREHOLE VIEWING SYSTEMS
1
.
Purpose
.
The
purpose
of
this
pamphlet
is
to
identify
the
types
of
data that
can be
obtained
from borehole viewing systems, describe the
equipment that is presently available for use, and list where the
equipment is available
.
2
.
Applicability
.
This pamphlet applies to all field operating
activities having civil works and military responsibilities
.
3
.
Background
.
Borehole television and camera systems provide an extra
dimension in obtaining borehole information and determining in situ rock
conditions
. Advantages for television systems are direct viewing,
immediate analysis, variable focusing, and concurrent records
. Borehole
camera surveys can provide color photography, 360 degree viewing area,
portable equipment, and high resolution images
. The Corps of Engineers
pioneered development and use of the NX borehole camera and is currently
believed to be the only source for the 360 degree radial-view camera
.
Television cameras and other systems are more recent developments
.
4
.
Description of Equipment
.
Characteristics of different viewing
systems are listed in Table 1 for comparison of critical features and
possible limitations
.
a
.
Television Systems
.
The television system uses a closed circuit
television camera and the image of the borehole sidewall is viewed on a
television monitor
. Most borehole television systems are composed of a
probe containing television electronics or camera equipment, a
combination lowering device and cable drum, and a control console
.
Television systems currently available for FOA's use are listed in
paragraph 8
. Features of most television systems include the alternative
use of an axial (downhole) or radial (sidewall) lens
. Some systems have
the capability of direct viewing, on the monitor, of a compass-clino-
meter
. Views may be transferred to a videotape for future
interpretations
. The videotape can also be used to record voice comments
as the boring walls are viewed
. In addition, a depth indicator located
on the console may be programmed to appear on tape, providing continuous
location of the probe in the borehole
.
DEPARTMENT OF THE ARMY
EP 1110-1-10
DAEN-CWE-S
DAEN-MPE-D
Pamphlet
No
. 1110-1-10
US Army Corps of Engineers
Washington, D
. C
. 20314
21 May 1982
