The Research Of Sedimentary Facies And The Prediction Of The Formation Lithology Trap In Chunguang Block Of Chepaizi Arch,Junggar Basin

Chunguang block is located in the western margin of Junggar basin Chepaizi area, close to Xiaoguai oil field and Hongshanzui oil field. It is an oil and gas accumulation zone,which has multiple of strata and a variety of traps and various types of oil and gas. It has a good potential. Chepaizi Arch belongs to the secondary tectonic unit of West Junggar upthrust, northwest uplift. It formed in late Hercynian period. Now, the tectonic framework appears like a southeast pitch triangle Arch after Himalayan movement. Paleogene is the potential prospecting horizon in Chunguang block. Many scholars have studied the region, but these concepts are disrelation and lack of unified understanding, thus depositional system in the region is not clear. Commercial oil and gas flow wells have been discovered in the region, such as Chun50, Chun110E, Chun114E, Chun124E. At the same time, the Chun49, Chun50-2, Chun116E, Chun118E wells have show of gas and oil, characterized by the thick oil layer but with poor production effect. Therefore, oil and gas exploration in the region is difficult, and the characteristics of the accumulation rule is complex. So the study takes the Paleogene of Chunguang block as the research target. Through the fine interpretation of seismic data in the study area, combining with the core, geology, logging and testing data, on the basis of sequence stratigraphic classification and correlation in the region, the study aims to research the target horizon sedimentary facies types, sedimentary facies plane distribution and sedimentary evolution regular pattern. At the same time,the study launches evaluate scrutiny of Chunl 10E main well area and establishes formation lithology reservoir formation pattern, and predicts the formation litho logic trap and favorable development zone in the region. Finally the study puts forward the favorable target area. Basically the study achieves the following results and understanding:1.Integrated basin sedimentary tectonic setting, palaeogeomorphology feature, strata overlap orientation, seismic reflection architectural feature, sand-ground ratio and sand-thickness change regular pattern, the study maintains the provenance direction is from the north and northwest.2.With the combination of the analysis of outcrop、well drilling and seismic. The study divides two sequence of Paleogene(E1-ESQ1/TST; E2-ESQ1/HST; E3-ESQ2/TST; E4-ESQ2/HST).3.Paleogene mainly develops braid river-braid river delta distributary channel sandstone reservoir facies. E1 mainly develops braid river. E2 and E3 mainly develops braid river delta. E4 mainly develops delta front with small scale. Through the evolution of sedimentary sequence and lithologic stratigraphic trap development regular pattern, the study realizes that E2 and E3 are more suitable for developing formation lithology trap.4.After careful dissection of the Chun110E well area in Paleogene, the study establishes delta subaqueous distributary channel lobes body geologic model. E2-E3 are subdivided into 5 cycle. On the basis of fine reservoir sedimentary contrast, clear five cycle profile distribution of sedimentary facies are clear. Proposed delta subaqueous distributary channel can form a lobes which constitutes delta front deposition; lobes body crossrange move, facies transformation in the updip direction, forming lithologic trap. A lobes body is an for independent lithologic reservoir. And multiple lobes body superimposed in the plane with reservoir laterally distribution.5.With the combination of sedimentary facies types and formation lithology reservoir development characteristics, using the "bright spot" technology, the study predicts the two favorable targets.