银额盆地哈日凹陷多类型油气藏共生特征及其成藏机理

近年来,银根—额济纳旗盆地哈日凹陷发现了多种类型油气藏,证实其有较好的油气勘探前景,但该凹陷油气地质条件极为复杂,特别是对多类型油气藏的共生特征及其成藏机理认识不足,限制了对油气分布规律的科学预测,制约了油气勘探的进程.基于对各类型油气藏的剖析,探讨多类型油气藏共生特征及其成藏机理,预测油气分布,分析勘探方向,以期为该...

Symbiotic Characteristics and Hydrocarbon Accumulation Mechanism of Multi-type Oil and Gas Reservoirs in the Hari Sag,Yingen-Ejinaqi Basin

In recent years， a significant amount of oil and gas reservoirs have been discovered in the Hari sag of the Yingen-Ejinaqi Basin， which proves that the area is a good prospect for oil and gas exploration. However， due to the complex geological conditions， in particular， the lack of understanding of the symbiotic characteristics and hydrocarbon accumulation mechanism of multi-type reservoirs， the scientific prediction of oil and gas distribution is severely limited， which restricts the process of oil and gas exploration in this area. Based on the analysis of various types of oil and gas reservoirs， this paper discusses the symbiotic characteristics and accumulation mechanism of multi-type oil and gas reservoirs， predicts the distribution of oil and gas， and analyzes the exploration direction， providing the basis for exploration decision-making and deployment in the study area. The study shows that there are many types of oil and gas reservoirs， such as dolomitic mudstone biogas reservoir， limestone mudstone gas reservoir， limestone mudstone oil reservoir， sandstone oil reservoir， and volcanic rock gas reservoir， for which the K₁y， K₁b2， and K₁b1 source rocks are the main source rocks， and their oil and gas accumulation has “near source and within source” characteristics. The reservoirs are characterized by the coexistence of oil and gas reservoirs， conventional and unconventional reservoirs， and structural and lithologic reservoirs. The study of the oil and gas accumulation mechanism shows that the lack of an effective migration pathway is the main reason for “near source accumulation and in source accumulation”， the difference of thermal evolution degree of the main source rocks in different structural positions makes the oil and gas exhibit the distribution characteristic of “up oil and down gas”， and the development of a multi-type effective reservoir leads to the situation of “multi-type oil and gas reservoir symbiosis”. We predict that the cumulative oil and gas bearing area of various reservoirs in the study area is 381 km2. The calcareous mudstone gas reservoir， as the actual field of discovered reserves， is the main direction for future exploration， the sandstone reservoir is a potential field of expanding exploration results， making it the secondary direction， and the volcanic gas and calcareous mudstone oil reservoirs， as a beneficial supplement to the joint exploration of multiple types of oil and gas reservoirs， are the third potential direction.