Artificial gamma (density) curve: the coal seam has obvious abnormal reflection;Apparent resistivity curve: the coal seam is relatively low amplitude anomaly, and the sandy mudstone is high amplitude reflection;Natural gamma curve: the coal seam is relatively low amplitude, but the sandy mudstone is high amplitude.Graduation picture does not explain the above explanation is a bit simple, trouble to explain a little bit more,Sit back and wait
Of course, the value of the logging curve is also an important means to determine the coal seam: for example, the value of density in the coal seam in about 1.3-1.4, the sound wave value of about 370-410 s/m, PE value of about 0.35-1.5, etc.. You read the value of your value to the log.
The coal seam has the obvious characteristic in the well logging curve: "four high" characteristic: the resistivity is high, and the change scope is big, the sound wave time difference is big, the transmission speed is slow, the compensation neutron is big, the well diameter enlargement is big
As well as the "four low" characteristics: low natural gamma, low compensation density, low cross section, low acoustic impedance, and dark color;
