渭河盆地天然气成因特征及其意义

Genetic characteristics of the natural gas in Weihe Basin and its significance

根据渭河盆地地热井气样分析成果,结合地质分析,发现渭河盆地地热井中广泛发现与上古生界煤系地层有关的热解-裂解煤型甲烷气及有机成因CO2气,区域地质和地震成果也佐证了渭河盆地基底存在上古生界地层.因此,前人认为渭河新生代盆地以渭河断裂为界,北部为下古生界,南部为元古界基底,不存在上古生界煤系地层基底的认识是不全面的,渭河盆地至少部分存在上古生界煤系地层基底.渭河盆地上古生界煤系地层可作为烃源岩,这为重新评价渭河盆地的油气地质前景提供了依据.

According to the gas sample from geothermal wells in Weihe Basin,combined with geological analysis results,it is held that there are the pyrolysis-cracking methane gas and the CO2 gas of organic genesis related to upper Paleozoic coal strata.Regional geology and seismic research results confirm that there are upper Paleozoic strata in the base of Weihe Basin.Therefore,the judgment of predecessors is not comprehensive that taking Weihe fault as a dividing line in Cenozoic Weihe Basin,its north is low Paleozoic,its south is proterozoic base,and there is not upper Paleozoic coal strata base in Weihe Basin.The research result in this paper proves that there is a part of upper Paleozoic coal strata base in the basin,and it can be as hydrocarbon source crock,which will be of important significance to the oil and gas geology prospects of Weihe Basin.