The Study On Sedimentary Facies Of The 3th Member Of Peng Laizhen Formation In Chengdu Sag

Chengdu sag located in the middle part of Chuan xi depression,and it has successively experienced Indosinian movement,Yanshan movement and Himalaya Movement.There are some paleostructures,Which is conducive to the accumulation of Oil and gas.and these positive tectonics and slopes are potential oil and gas migration. The Peng laizhen formation gas reservoir is currently the main gas in Chuan xi depression with abundant remaining resources.,higher potential of exploration,so the 3th member of Peng laizhen stratum in Cheng du sag has large prospecting potentialIntegrated with field outcrop observation, core observation,3D seismic data to identify sequence boundary,then summarize the characteristics of different base-level cycles. Finally, established the sequence stratigraphy frame of Peng laizhen formation in the middle of the Chuan xi depression. Combined detrital composition analysis of sandstone with ZTR heavy index and other methods to analyze the source of supply in the 3th member of Peng laizhen formation in Cheng du sag, from what we can deduce that the source comes from Micang Shan orogenic belt and the middle part of Longmen Shan orogenic belt and. On the base of established sequence framework of Peng laizhen formation in Chuan xi depression, we studied the sedimentary system and sedimentary Facies.Research shows that the 3th member of Peng laizhen formation in Cheng du sag is shadow is shadow lacustrine-delta depositional system. Delta were of main facies in the 3th member of Peng laizhen formation, while the lake is limited. there are both the braided river delta and meandering river delta deposits, meanwhile the delta front is the main subfacies in the delta. The lacustrine facies mainly include shore-Shallow lake microfacies. On the basis of single well analysis, well-tie analysis Combined with the sand ratio data, we draw the plane distributive maps of sedimentary microfacies and give the sedimentary microfacies pattern. At the same time,we pay additional attention to JP25 sandstone units, and draw its plane distributive maps of sedimentary microfacies. All of which help us to define the distribution characteristics of sedimentary microfacies.At last, after analyzing result of the senior,this paper presented the sedimentation model of the 3th member of Peng laizhen formation in the middle of Chuan xi depression.This paper evaluates and predicts the advantage area to the 3th member of Peng laizhen formation reservoir based on the reservoir development factors in Cheng du sag. Research indicates that, in the 3th member of Peng laizhen formation of Cheng du sag,the better reservoir has extensive distribution,which Mainly distributed in Ma jing-Shi fang-Guang jin-Xin du-Luo dai regions; Medium reservoir is more widely distributed and has a large area distribution in Cheng du sag; Poor reservoir mainly distributed in the piedmont area of longmen mount.In the process of investigation and study, we concluded that:1、Research shows that the 3th member of Peng laizhen formation in Cheng du sag is shadow is shadow lacustrine-delta depositional system. Delta were of main facies in the 3th member of Peng laizhen formation, while the lake is limited. there are both the braided river delta and meandering river delta deposits, meanwhile the delta front is the main subfacies in the delta.2、The delta front is the main subfacies in the 3th member of Penglaizhen Formation of Chengdu sag.The braided river delta are mainly in Chong Zhou-Pi Xian area,and the braided river delta are mainly in the NE direction.3、Research indicates that, in the 3th member of Peng laizhen formation of Cheng du sag,the better reservoir has extensive distribution,which Mainly distributed in Ma jing-Shi fang-Guang jin-Xin du-Luo dai regions; Medium reservoir is more widely distributed and has a large area distribution in Cheng du sag; Poor reservoir mainly distributed in the piedmont area of longmen mount.