JMD-1 Compensated Density Probe | Geotech Instrument Co., Ltd.

PRODUCT PARAMETERS

A larger source distance is used to take into account both measurement sensitivity and statistical fluctuation error.
The method of using long and short source distance detectors to measure simultaneously can compensate for unfavorable factors such as mud cakes.

GET A QUOTE

Description

FAQ

Get A Quote

Description

Abstract

JMD-1 Compensated Density Probe is one of many nuclear logging methods. Its theoretical basis is the Compton scattering effect. It uses Cs137 as a gamma source. The energy of the emitted gamma rays is 0.661MeV. It does not react with the formation material to form electron pairs, but it will produce the Compton effect. By measuring and recording those gamma rays with higher energy, including gamma rays that have been scattered once or multiple times, the apparent density of the formation can be calculated.

Applicable Conditions

● Cased

● Bare hole fill with water or mud

● Bare Dry hole

Applications

● Exploration and quality evaluation of oil, coal, gas and other mineral deposits

● Determine lithology

● Measuring formation porosity

● Testing the cement cementing quality outside the production well casing

● Quantitative calculation of in-situ formation density

Features

● A larger source distance is used to take into account both measurement sensitivity and statistical fluctuation error.

● The method of using long and short source distance detectors to measure simultaneously can compensate for unfavorable factors such as mud cakes.

Specifications

Scattered gamma detector	Nal crystal + photomultiplier tube
Natural gamma detector	Nal crystal + photomultiplier tube
Radioactive source	Cs137, 3700MBq
Quantity parameters and range	Natural gamma: 1~32768cps; Long source distance count rate: 1~32768cpS Short source distance count rate: 1~32768cps; Density: 1~3.0g/cm3; Accuracy 3%
Signal output	Bipolar encoding

FAQ

In gravity exploration (SI), what is the unit of gravity? How to convert gravity units between SI and CGS?

What are gravitational field and gravitational potential?

What is the normal gravity field of the earth? What are the rules for the change of the normal gravity field with latitude and altitude?

① The normal gravity field of the earth: Assuming that the earth is a rotating ellipsoid (reference plane), the surface is glossy, the internal density is uniform, or it is distributed in concentric layers, the density of each layer is uniform, and the deviation of the shape of the ellipsoid from the geoid is very small, then the gravity field generated by the earth is the normal gravity field.
② The normal gravity value is only related to the latitude, the smallest at the equator and the largest at the poles, with a difference of about 50,000 g.u.; the rate of change of the normal gravity value with latitude is the largest at 45° latitude, and zero at the equator and the poles; the normal gravity value decreases with increasing altitude, and its rate of change is -3.086 g.u.. The main feature of the long-term change is the "westward drift" of the geomagnetic elements, both the dipole field and the non-dipole field drift westward, and have a global nature.

What is the relationship between gravitational field strength and gravitational acceleration?

What is gravity exploration?