The Division And Evaluation Of Hydrocarbon Accumulation System In Minfeng Area Of Dongying Depression

With the comprehensive utilization of data of geology, geochemistry, geophysics, laboratory analysis, testing and so on, application of petroleum geology, organic geochemistry, and other disciplines as theoretical guidance, drawing on the experience of reservoir system of ideas and methods , this paper systematically analyses the law of oil and gas accumulation of Minfeng areas from several aspects such as, the geological background, reservoir characteristics, accumulation conditions, accumulation process and the division and evaluation of accumulation system.Through the analysis of the source rocks'features including Es3z, Es3x and Es4s, this paper formulate a differentiation standard of sources in Minfeng areas. Utilization of the conventional geochemistry indicator and clustering analysis of mathematical statistics, this paper completes the work of correlation of oil-source, and clearly expounds the space of relationship between oil-source: the oil of Yanjia areas in Es3 and Es4 layers is from source rocks of Es4s, the oil of Yongan is from source rocks of Es4s and Es3x.This paper comprehensively analyzes the characteristics of sand body distribution, fracture system, unconformity distribution, combination of sand body and fault and transforming type in the whole region and sums up the relationship of characteristics and migration and accumulation of oil and gas. Utilization of a number of methods such as geological, geochemical, fluid properties and so on, this paper analyze the migration directions and path of fault zone of Yongan, carry out that oil and gas migration is the result of a variety of multiple transforming elements together acting; in the oil and gas migration, fault plays an important role in vertical transforming and accumulation; the match relation of fault and sand body decides the distribution of oil and gas.On the basis of obtaining the necessary key parameters of basin modeling, this paper established history of region of interest, including geologic history, thermal history, hydrocarbon generation history, expulsion history, and migration-accumulation history; simulates amount of the hydrocarbon generation-expulsion-accumulation of source rocks and obtained minimum coefficient of expulsion. With the characteristics of the formation stage of traps, hydrocarbon-generation history and bubble point pressure, this paper restores accumulation periods of this study area: at the end of Palogene and at the end of Neogene, different structural units have different accumulation periods. Utilization of visual flow-path simulation technology, this paper analyzes the characteristics of migration and accumulation of oil and gas and makes conclusion that the direction and amount of the streamline is under the control of the paleo-tectonic setting, hydrocarbon generation intensity and hydrocarbon areas. In the early period, the hydrocarbon generated is lower, Yanjia is the direction of hydrocarbon migration. in the later stage, the mount and scope of hydrocarbon generated expands, oil and gas is beginning to generate to the most part of the region.Combined flow-path simulation technology, the study areas of the accumulation system is classified into four parts: East of Shengtuo accumulation system, Yanjia accumulation system, Yongan accumulation system and East of Yongan accumulation system. Through the simulation, we master the allocation and potentiality of oil and gas resource of accumulation system. Yanjia areas is less explored and have larger potential exploration, proved reserves of Yongan town is slightly more than the average level of the Evaluation of the third Resource Assessment of Dongying depression. With the comprehensive analyses, We formulate the accumulation models of accumulation systems, and research the influence factors. Both of the accumulation systems are under the control of palaeostructure, abnormal pressure, the mount and scope of hydrocarbon generated. The key elements of Yanjia accumulation system are the match relation of sedimentary facies and source rocks, the construction form and physical properties of sandstone-conglomerate bodies. The key elements of Yongan accumulation system are faults developed in source and the match relation of fault and sand body.