Intended use and field of application
The Seismic recorder is intended for engineering seismics by near-surface section study based on up-hole velocity survey and vertical seismic profiling in the open hole at a depth of up to100 m.
The Seismic recorder can be used with various types of seismic impulse sources and vibrators. SCOUT-MSK provides digital seismic data recording in field conditions and monitoring of the main data acquisition channel specifications by means of in-built diagnostic facilities.
Configuration of the Seismic recorder includes
three-component borehole seismic surveying module with cable;
- pressure-control unit;
- recorder (BAR3-2);
- hand winch with ratchet;
- winch cable;
- guide with roller.
Brief functional characteristics of the recorder’s components
Borehole seismic surveying module with tree built-in electrodynamic geophones is intended for geophones displacement inside the borehole and their fixation at selected depths of up to100 m. Pressing of the borehole seismic surveying module to the sidewall of the borehole for more close contact is provided with the in-built controllable electromechanical device. Earth mechanical oscillations are transformed by geophones into electrical signals and are transmitted via the cable to autonomous recorder BAR3-2 for their digitization and recording.
The guide with roller, winch cable and hand winch with ratchet provide borehole seismic surveying module displacement inside the borehole at selected depths.
Pressure control unit (PCU) is intended for borehole module’s electric motor power management.
Downhole module
Recorder BAR3-2
Technical specifications:
|
Downhole module
|
|
Number of seismic channels
|
3
|
|
Geophone type
|
Electrodynamic
|
|
Geophone brand name
|
HT-5 (vertical)
HT-H-5 (horizontal)
|
|
Geophones layout
|
Three-component orthogonal with rigid fixation in relation to the downhole module case
|
|
Holding down device type
|
Electromechanical with direct current motor
|
|
Holding down device supply voltage
|
(27±3) V
|
|
No-load current
|
(200 – 500) mA
|
|
Latching current
|
(1±0,2) A
|
|
Holding down device full opening time
|
In less than 40 s
|
|
Holding down device dimensions:
Diameter
Length
Connecting cable length
|
57 mm
630 mm
125 m
|
|
Downhole module weight (without the cable)
|
No more than 6 kg
|
|
Downhole module operating temperature range
|
- 40 ?C ? +85 ?C
|
|
Sealing protection level according to GOST 14254-96 (MEC 529-89 CEI 70-1 EN 60529)
|
IP68
|
|
Recorder BAR3-2
|
|
Number of channels
|
3
|
|
Sample rate
|
0,25, 0.5, 1.0, 2.0, 4,0 msec
|
|
Timing accuracy
|
1 mcs
|
|
Maximum input signal
|
No less than 2500 mV
|
|
Frequency range
|
From 0 up to 1600 Hz
|
|
Common mode rejection
|
100 dB
|
|
Cross feed isolation
|
-120 dB
|
|
Dynamic range
|
140 dB
|
|
Total harmonic distortion
|
0,00035%
|
|
Maximum continuous autonomous recording
capability supported by on-board memory 32 Gb
|
640 h
|
|
Maximum continuous autonomous recording
capability supported by two on-board batteries
|
670 h
|
|
Gain constants
|
0, 12, 24, 36 dB
|
|
Input noise (10 – 125 Hz band)
|
No more than 0,17 mcV
|
|
Output data formats
|
SEG Y, SEG
|
|
Operating temperature range
|
40?C to +70?C
|
|
Geophone
|
|
Natural frequency
|
5 (±10%) Hz
|
|
|
Conversion ratio
|
98 (±5%) V/m/s
|
|
|
Open circuit damping
|
0,7 (±5%)
|
|
|
Coil resistance
|
1800 (±5%) Ohm
|
|
|
Distortion
|
No more than 0,2%
|
|
|
Frequency factor upper limit
|
No less than 250 Hz
|
|
|
Moving mass
|
15,8 g
|
|
|
Diameter
|
27,3 mm
|
|
|
Height
|
33,5 mm
|
|
|
Mass
|
105 g
|
|
|
Operating temperature
|
- 40 ?C ? +80 ?C
|
|
|
Pressure control unit
|
|
|
Input voltage
|
12 V
|
|
|
Output voltage
|
27 V
|
|
|
Peak current
|
2 A
|
|
|
Electrocution protection class
|
III
|
|
|
Seal rating
|
IPO50 (full dust protection, but moisture unprotected)
|
|
|
