The Source To Sink Analysis Of Paleogene And Cretaceous In Chunguang Oilfield,Junggar Basin

The Paleogene and Cretaceous of Chunguang Oilfield in the Junggar Basin is a potential series of strata for exploration in recent years.At present,due to which experts know little about the direction and composition of the source,sedimentary microfacies and sand body distribution characteristics,the lack of effective methods in predicting sand body have hindered the exploration and development of Chunguang oilfield.Based on the theory of “source-to-sink” system,seismic sedimentology,sequence stratigraphy and modern sedimentology,this paper adopts corresponding research techniques to carry out comprehensive research on the Chunguang Oilfield.In this thesis,the isochronous stratigraphic framework of the Paleogene and Cretaceous in the Chunguang oilfield is established.From the strata of bottom to top it is divided into 6 third-order sequences,including 13 fourth-order sequences.The sequence stratigraphy is well correlated with stratigraphic sand groups.The sequence development model of the Paleogene and the Cretaceous is “onlap of lower strata and truncation of upper strata”.By investigating the basement rock characteristics of the Paleogene and the Cretaceous in the Chunguang exploration area and the surrounding area,the ratio of thickness of sand bodies to thickness of strata and the Zircon U-Pb Dating,it is clear that there are two sources outside the basin in the Chunguang Oilfiled,one is the Early Paleozoic and Paleoproterozoic acidic volcanic rocks and sedimentary rocks in the northern foot of the Tianshan Mountains on the south side of the Chunguang Oilfield,and the another one is Late Paleozoic granitoids and basic and ultrabasic magmatic rock in the Zaire Mountains on the northwest side of the Chunguang Oilfield.By applying the layer flattening technique,decompaction correction,denudation restoration and the restoration of paleo-water depth,the paleo-geomorphology of the Paleogene and Cretaceous is reshaped.And then the four early Cretaceous gullies on the slope are identified and described in quantification.Based on core,logging,seismic and other data,the sedimentary facies types such as fan delta,braided river delta,gravity flow and lake are identified in the Chunguang Oilfield.The fan delta are mainly deposited in the southern C50 well area.The braided river deltas are mainly deposited in northeast and south-central area.The lacustrine facies and density flow deposits are developed in the C103 E well area in the eastern part of the Chunguang Oilfield.The source and sink systems of the Paleogene and Cretaceous in the Chunguang Oilfield are established and coupled.The dynamic models of the source to sink are summarized as follows: The main source of the SQh?1 to SQh?4 sequence is mainly a single local source(North Tianshan)source of eroded gully source-sink system.SQs to SQa?3 sequence deposition period is a single or mixture source localized area conversion source mode to slope type source to sink system.In different sequence periods and source to sink system,the main developmental coupling modes are different.There are mainly single local source(North Tianshan Granite)-conduit(wide and deep gully valley)-sink(near source coarse-grained fan delta),regional mixture source(mixed granite)-conduit(Wide-slopes)-sinks(relative to the source of small and medium-sized near-source braided river delta-slump fan)and other coupling modes.