Effects of Organic-inorganic Interaction on Hydrocarbon Generation of Source Rocks in Bohai Bay Basin

Abstract:

In this paper， taking the Bozhong 19-6 gas field as an example and source rocks as the research object， the organic-inorganic interaction is studied to clarify the characteristics of source rocks in the Bozhong 19-6 structural belt and the effect of organic-inorganic interaction on the hydrocarbon generation and gas generation. Mudstone samples from more than 30 wells are selected for organic geochemistry， inorganic geochemistry， paleontology and other series analysis. The results show that， the source rocks in the study area are mainly partial humic organic matter，the paleontology is dominated by the higher plants of angiosperms and gymnosperms， and the humic amorphous forms are the dominant kerogen. The illite is the dominant clay mineral in the Bozhong 19-6 structural belt. A large number of humic amorphous forms have been enriched by physical adsorption and chemical bond bridging， and the organic matter is hydrogenated by clay minerals. In the late period， under the effect of illite， the source rocks mainly undergo decarboxylation reaction and thermal cracking to form a large number of short-chain hydrocarbons. Under the action of illite， the hydrocarbon production increases greatly， and then enriches， forming the wide distribution of condensate oil and gas.

Key words:Bozhong depression;types of source rocks;illite;organic-inorganic interaction