THERMOMAGNETIC MARKERS IN STUDIES OF THE RESERVOIR ROCKS

Thermomagnetic curves of reservoir rocks have been studied as markers of substance and reservoir rocks formation. In the temperature range of 400-530 °C it is observed an increase in the magnetization (maximum it is reached about 500 °C), then it goes the decrease in the magnetization of the newly formed magnetite, and it is sometimes visible the decrease in the magnetization of hematite (650-680 °C). The curves of the second heating differ more considerably, which depends on the content of Fe, sulfur, organic matter in samples. A series of the peaks are observed in the temperature range from 250 to 400 °C. These peaks are caused by magnetostatistical interaction of the generated pyrrhotine and magnetite. Since these minerals are formed into some aggregates, we observed temperature of Curie of pyrrhotine by the peak of the relative increase in the magnetization, caused by the transformation of magnetic and nonmagnetic sulfides into the magnetite (between 400 °C and 500 °C). This behavior is characteristic for the samples, which contain pyrite. Roughly, a quantity of pyrite can be evaluated on the decrease in the magnetization to ~400 °C. The presence of ferrous minerals, especially pyrite, not only decreases capacitive properties, but also it is the mineralogical factor, which influences the safety of the meta-stable phases of clay minerals