Abstract: Baijiahai-Wucaiwan area in eastern Junggar basin is characterized by multi-source and multi- stage hydrocarbon accumulations. This paper analyzes the essential conditions for forming dynamic system of hydrocarbon accumulation in this studied area in terms of the geologic structural setting. Through comprehensive analyses of geothermal field, pressure field, fluid potential and fluid chemical property, it discusses the relations among these factors and generation and expulsion of hydrocarbon, hydrocarbon migration and accumulation as well as time-space geologic process for reestablishing hydrocarbon accumulation. Based on study of the static and dynamic factors, a program for classification of the fluid dynamic system of hydrocarbon accumulation in Baijiahai-Wucaiwan area is proposed, that is, the system can be divided into an allogenic open system in Baijiahai salient and a self-source and semi-enclosed system in Wucaiwan sag,Such a classification offers new thoughts for further exploration in this area. In Baijiahai salient it is dominated by searching for multi-orientation oil/gas-filled or secondary reservoirs, while in Wucaiwan sag by finding self-source and self-reserved pools.

Key words: Junggar basin, dynamics, geothermal field, pressure field