Sedimentary Facies Evolution Of The Jurassic Qugu Formation In Chepaizi Oilfield, Jungger Basin

Chepaizi oilfield lies in the southwest DaNi fault basin, the northwestern margin of Kelamayi DuanJie and the Hong-Che second-order tectonic units. It is a south-north ancient uplift as the main body, suffer from east-west and south-north fracture crosscut formed broken rank type structure. Reservoirs are mainly by fracture occlusions, tectonic lithology contro. The reservoir sedimentary rocks of the Upper Jurassic Qigu Formation is one of the main reservoir oilfields.The Jurassic Qigu Formation of Chepaizi reservoir, develop to now achieved good development effect generally. Because oil fields are located in areas geology tectonic characteristics complex, development, the group’s highest-ranking. The sand body lateral changes quickly in Jurassic, reservoir heterogeneity is serious, lithology and physical properties of reservoir in plus plane change big, making the difficult of exploitation increase, and face a geological problems increase gradually. Through a lot of fields and indoor research work,Paper study for petrological characteristics, and the sedimentary facies source direction, sedimentary microfacies, sandbodies distribution characteristics mode and small layers of exhibition and the system analysis of the Jurassic Qigu Formation in Chepaizi oilfield.Paper studies sedimentary clastic,sedimentary rock structures and compositions, structure characteristics, using heavy mineral percentage content and methods of sandstone exhibition throughgoing, considering the sediment source of northwest mainly from Zaire mountain and Chepaizi Uplift. Research areas are mainly develop alluvial fan facies and braided delta of nearly source, form mountain alluvial fan-braided delta of nearly source-lake sedimentary system. Reservoir main development in braided river distributary channel and phase (river stranded microfacies, heart beach microfacies), front branch river and phase and littoral and shallow lake beach and bar phase belt. Through the single well, even well profile of the sedimentary facies comprehensive analysis, the study area, the group which longitudinal and transverse sedimentary facies throughgoing characteristic, analyzed the sedimentary microfacies relative hydrocarbon accumulation of the influence,and the lithology reservoir of the control of the favorable facies belt is forecasted for oil exploration and exploitation, provides a strong basis.