Dissection Of Typical Stratigraphic Reservoirs And Physical Modelling On Hydrocarbon Accumulation Mechanism In The Northwestern Margin, Junggar Basin

Based on previous studies, the paper studied the type and distribution of stratigraphicreservoirs in Junggar Basin, and also studied the profile type and vertical structure ofunconformity and their impact on the oil and gas migration and accumulation of the studyarea. On the basis of anatomical analysis of typical stratigraphic reservoirs (stratigraphicreservoirs in Zhong32 region and Wu Qunan region) in the northwestern of Junggar Basin, thepaper established the physical simulation experimental model of stratigraphic reservoirsaccumulation mechanism of the area. Assisted by physical simulation experiments, the papergot a further understanding of the process of migration and accumulation of oil and gas alongthe unconformity, and slso got a intuitive analysis of the accumulation process and theformation mechanism of stratigraphic reservoirs.The types of stratigraphic reservoirs in Junggar Basin is diversified, the developmentalpatterns of unconformity have their unique space structure. According to their contributingfactors, the concept of " unconformity architecture body" was raised , and vertically dividedinto three layers: upper architecture body (mainly transgressive sands or bottomconglomerates), intermediate architecture body (weathering clay ,also known as weatheredmudstone layer), and the underlayer of architecture body (semi-weathering rocks, also knownas weathering-cracked zone). On this basis, the paper studied the relationship betweenunconformity architecture body and hydrocarbon accumulation. The results showed thatunconformity architecture body could play the role of capping, transporting and traping effectin the process of hydrocarbon accumulation.Used the experimental simulation devices, the experiments simulated the advantageous migration direction of oil and gas in the transport layers of unconformity architecture body,the experimental results showed that, the predominant pathway of oil and gas in unconformityarchitecture body is effected by the transport layer geometry, unconformity angle of dip,properties of transport layer, oil and gas migration rate and some other factors. Physicalsimulation on accumulation mechanism of stratigraphic reservoirs showed that, stratigraphicoverlap zones in high position were the favorable sites for formation of stratigraphicreservoirs, and unconformity architecture body was approved migration pathway for lateralmigration of oil and gas, the priority migration pathway of oil was the transport layers with agood physical property. The migration of oil had shown a significant heterogeneity both in thelayers of different structures and in the same structural layer. In addition, unconformityarchitecture body could not only served as a good channel for oil and gas migration, but alsoserved as the favorable site for hydrocarbon accumulation.