| Unconventional oil and gas resource plays an increasingly important role in the world’s energy structure.It’s regarded as the transition energy in the process of changing from the conventional energy to green energy.Now the tight gas and tight oil become the focus of exploration and development. Among some Mesozoic and Cenozoic oil and gas basins in peripheral of Songliao basin, Yanji basin has a relatively larger vision of oil and gas resources for its special tectonic location. Focusing on the tight oil and gas, this paper makes a deep analysis to the tight oil and gas resource potential of Yanji basin. The research on its oil and gas geology makes a great significance to local economic. The evaluation of tight oil and gas resources is helpful to clear the area tight oil and gas prospects and guide the oil and gas exploration. It’s a challenge to evaluate tight oil and gas resource of a low degree of prospecting basin since no clear method specifications existed domestic and abroad. A reasonable and effective method is expected to be designed through this research which has the reference value for other regions also providing help to study Yanji basin deeply.Using geotectonics, oil&gas geochemistry, reservoir geology, sedimentology, petroleum geology and other basic theories as instructions, by comprehensively utilizing the field outcrops,well logging, mud logging, core and seismic data, etc., the characteristics of generation,storage and cap of Yanji basin are studied, the main controlling factors of hydrocarbon accumulation are determined. The quantity of tight oil and gas resources of the advantageous area is calculated by synthesizing three methods:hydrocarbon generation,resource abundance and volume.The results show that Dalazi formation first period, Tongfosi formation third period and second period are the main hydrocarbon source rock in Yanji basin.The main organic matter types are ⅡA~ⅡB secondary type is Ⅲ. Most areas entered the oil threshold and mainly in the mature stage. The main reservoirs are Longjing formation, Dalazi formation and Tongfosi formation. The lithology is given priority to with siltstone, packsand and medium sandstone. Main reservoir physical property is medium porosity and low permeability sandstone pore type reservoir. The preservation of the tight oil is affected by cap rock, tectonic activity, stratigraphic dip and hydrodynamic conditions. Favorable areas are selected by four principles: “source, reservoir, preservation but no migration” by the comprehensive analysis of tight hydrocarbon accumulation regularity. The oil resource is counted as 30×104t and gas resource is 2.3×108m3 in 4,5 favorable areas of in Yanji basin. |
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