Abstract:

Absorbed hydrocarbon (acidolysis hydrocarbon and pyrolysis-desorbed hydrocarbon) technique has displayed favorable affection in normal oil and gas geochemical exploration. In this paper, based on the soil absorbed hydrocarbon test conducted in Muli area in Qinghai, the analysis of the characteristic value and the distribution features of the geochemical anomaly reveals that hydrocarbon annular anomalies is consistent with the detected mineral area, the spatial distribution of which is controlled by underground resources. According to the analysis of the methane carbon isotope, the origin of soil absorbed hydrocarbon anomaly is proved to be pyrolysis, which has the similar thermogenic characteristics with gas hydrate. The experimental results indicate that the soil heat-release hydrocarbon technology applicable to the geochemical exploration of gas hydrate can delineate the hydrate deposits region, which could be the supplement of other geochemical exploration methods.

Key words: pyrolysis-desorbed hydrocarbon, gas hydrate, permafrost region, Qinghai