岩浆活动对渤中19-6潜山油气成藏的影响

Influence of Magmatic Activity on Hydrocarbon Accumulation in Bozhong 19-6 Buried-hill in Bohai Bay Basin

摘要:

渤海湾盆地是中国东部重要含油气盆地。2018年中国东部最大整装凝析气田—渤中19-6气田的发现，一举打开了渤海湾盆地深层天然气勘探的新领域，展现了油型盆地天然气勘探的巨大潜力。渤中19-6构造带具有上油下气的分布特征，为了研究该构造带油气的成藏机理，从烃源岩生排烃史、构造热演化史、岩浆活动、流体包裹体显微荧光与测温技术等方面系统分析渤中19-6构造带油气成藏史，深入研究其形成机理，认为：渤中19-6构造带凝析气田不同深度的包裹体具有相似的盐度和均一温度分布范围，且不同深度的均一温度主峰温度相同，均表现为高于地层的温度，显示了油气充注属于事件性成藏，具有穿层、瞬时、高温的特征；渤中19-6构造带岩浆活动发育，岩浆侵入加速了有机质的成熟，促进了烃源岩生排烃作用，烃源岩在短时间内大量形成凝析油气；渤中19-6潜山构造带早期形成的古油藏，受新构造运动的影响，向上调整为渤中19-4油田，同时构造活动造成岩浆上涌，伴随的超临界状态幔源CO₂液体，加速了油气运移过程，凝析油气快速充注进入渤中19-6潜山圈闭，形成现今的渤中19-6凝析气田。

关键词:渤海湾盆地;渤中凹陷;渤中19-6构造;成藏过程;岩浆活动

Abstract:

Bohai Bay Basin is an important oil-bearing basin in eastern China. The discovery of Bozhong 19-6 gas field， the largest integrated condensate gas field in eastern China in 2018， has opened up a new field of deep gas exploration in Bohai bay Basin， showing great potential of gas exploration in oil-type basin. The Bozhong 19-6 structure belt has a unique distribution characteristic of oil accumulation in shallow part and gas accumulation in deep part. The hydrocarbon a ccumulation period and adjustment process in buried hill reservoir was investigated using a suite of hydrocarbon generation and expulsion history， tectonic thermal evolution history， magmatic activity， characteristics of fluid inclusions， microfluorescence determination and temperature measurement technology by taking Bozhong 19-6 structure belt as an example. The results show that ： The inclusions in the condensate field in the Bozhong 19-6 structural belt have similar distribution ranges of salinity and homogenization temperature at different depths， and the main peak temperature of homogenization temperature at different depths is higher than that of the stratum temperature， which indicates that the oil and gas charging belongs to the event accumulation， which has the characteristics of layer penetration， instantaneous and high temperature.The magmatic activity developed in the Bozhong 19-6 tectonic belt. The magmatic intrusion accelerated the maturation of organic matter and promoted the hydrocarbon generation and expulsion of source rocks， and the source rocks formed a lot of condensate oil and gas in a short time.Bozhong 19-6 buried structure belt， the early formation of the ancient reservoir is affected by the new tectonic movement， adjusted upward for Bozhong 19-4 oilfield， magmatic upwelling activity， with the mantle-derived CO₂ supercritical state of liquid， speeding up the process of oil and gas migration， condensate oil and gas rapidly filling into Bozhong 19-6 buried hill reservoir， forming Bozhong 19-6 gas field.

Key words:Bohai bay Basin;Bozhong depression;Bozhong 19-6 structure belt;accumulation process;magmatic activity