Products

Borehole Logging Systems

Induction Conductivity

H3I-453
H4I-453
HI-381
HI-453, HI-453E
HI-453F
HII-383
HII-453

Magnetic Susceptibility

HM-453, HM-383, HM-320
HM-453E, HM-383E
HM-100
HMM-453
HMG-453

Combined probes

HMI-453, HMI-453E
HRTIG-453

Other probes

BWS-50
HC-380
HC-380C
HC-453, HC-453a
HC-454
HRT-381
HF-380
HGSPR-380
HF-500
HN-453
HFN-381
HGG-453
HDG-453
HLG-382
HR-380 Glu
HR-380 P
HV-380 & HV-450

Other products

BLC-150, BLC-300
BHC-200
Geo set HDS-600
Portable Winches
Portable Logging System
Cameras

Accessories

AH-30, AH-150

Logging instruments

Lower - Upper Gradient Resistivity HR-380 Glu

General Two ways of resistivity of rocks measurement:

a) Standard Potential measurement. The distance between paired electrodes M and N is longer (1000 mm) and distance from the unpaired electrode A is small (see data sheet HR-380 P Potential).

b) Gradient Resistivity measurement. The distance between the paired electrodes M and N is short (200 mm). The unpaired electrode A is in longer distance (900 mm). When this type of measurement is used we distinguish between lower (RaG_I) and upper (RaG_L) gradient of resistivity (see pict.A and the diagram)).

The HR Glu is constructed for measuring of apparent resistivity Ra down the borehole whose value is a function of all true resistivities of the medium existing within the depth of investigation of probe including mud cake and invaded zone.

Lower - Upper Gradient Resistivity HR-380 Glu

Probe Parameters

Available in diameters 38 mm and 45 mm
Length 2000 mm
Weight 5,0 kg
Max. Working Pressure / Temperature 10 MPa / 75 °C
Power Supply 45 Vdc @ 120 mA

Excitation frequency is 81 Hz; Operated on one conductor cable. Output signal is in form of frequencies of pulses of amplitudes of 8V and widths of 6 µs (amplitude and width are adjustable).

Measurement

When winching the probe down, the electrodes for "Lower Gradient" are active and data are registered. After reaching the bottom of the borehole movement is switched to upwards the electrodes for "Upper Gradient" are active, Both curves ( RaG_u and RaG_I) will be drawn to one diagram. The probe is calibrated and the output frequency is directly proportional to the resistivity of measured rocks. The distance between electrodes can be designed in accordance with the customer's need.

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