Study On The Stratigraphic Correlation Of Qianjiang Formation In The Upthrown And Downthrown Sides Of Qianbei Fault

The structure feature of Qianbei fault zone is complex,and the formation of oil and gas geological conditions are suitable for secondary and pramary reservoir,where is a favorable area of various composite oil and gas reservoirs in the Qianjiang depression zone,and also is a important potential area for oil and gas exploration.Qianbei area includes the south of Jingmen Depression,the south of Lexiangguan uplift,the south of the Hanshui depression,the steep slope belt,the eastern slope belt,the cliff slope zone and the western slope zone.The downthrown side of Qianbei fault zone structural overall appearance features of the "three depression,two loins and two slope",and the tectonic pattern of each layer has obvious inheritance.Based on the lately-processed seismic data,it was precious interpreted the tectonic,so it can find out the fault section and low order faults distribution characteristics.Analyzed and described the formation potential area north of the ancient landscape restoration,tectonic evolution,sedimentary system and typical reservoir,indicating the type and direction of oil and gas exploration,which can improve the practical basis for the exploration of oil and gas in Qianbei fault zone.In this paper,according to the characteristics and details of the structural structure of the study area which is based on the 3D exploration of the whole-layer system,it guided by the theory and method of tectonics and geophysics,comprehensive application of seismic,geology,drilling and logging data.Based on the digestion and absorption the research of previous studies,describe faults and explain structure.This paper describes the internal structure of Qianbei fault zone and finds out the structure and tectonic characteristics of the middle and western segments of Qianbei fault zone and the developmental characteristics and developmental history of Qianbei fault zone,and the evolution history of the upthrown side has been solved.The regional tectonic setting and tectonic evolution of Qianbei fault zone are defined.A detailed analysis of the causes of "Jinsha red walls",it can guide to understand the reservoir formation model of Qianbei fault zone.The feature of typical wells dissected and analysis.After the above analysis,the main results and understanding of this study are as follows:(1)The tectonic belt of Qianbei fault zone is the product of the superposition and reconstruction of the multi-stage tectonic movement in the ancient and middle and new Cenozoic.The activity period of the submerged Qianbei fault can be divided into 4 large periods of activity,the 4 large periods of activity are the right-hand slip period,the strong subsidence period,the left-slip and strike-slip period.(2)The results show that the uptake plate of Qianbei fault zone is continuously uplifted at the end of the sedimentary stage of the Jingsha Formation and has been eroded for a long time until the end of the Jinghezhen Formation began to accept the deposition.So the product of the upthrown side under the action of continuous uplift is defined,and there is no possibility of the deposition of the Qianjiang Formation.(3)That falling plate of Qianbei fault disk is formed in Jingsha Formation deposition period.The secondary fault occurred and constituted the reverse "Y" structure,which formed the two grade fault slope break.The second-level faults take over the early control basin fracture and started the strong activity,thus control the lower part of the latent subsurface sediments.The middle fault block is caused by the large difference settlement rate of the fault on both sides.Leading off the clamping blocks left in the ramp and formed "concealed fault block".(4)Through dissected and analysis the typical oil wells,it is revealed that the sedimentary period of Eq1 of this area is a set of red strata with the development of pebbly sandstone,and it is a near-source accumulation fan with drought condition.The reservoir development is a good condition for hydrocarbon accumulation.The analysis shows that the potential reservoir has better exploration potential,and the oil layer is gradually thickened from west to east.