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

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.