The Prospect Evaluation Of Oil And Gas Exploration In Yunlong Sag Of Chuxiong Basin

In this paper,the geological conditions of Yunlong Sag are analyzed in detail by geological and drilling data,It is concluded that there are several sets of effective source rocks,the Cambrian,Devonian and Upper Triassic hydrocarbon source rocks are the main source rocks in the region.The source rock is mainly composed of shale,and has the characteristics of large thickness and wide distribution.Based on the previous research results,the ground facies data are used to improve the lithology paleogeography.The reservoirs are the Upper Triassic dry Haizi Formation and the reclamation group,followed by the Jurassic,Cretaceous and Paleozoic reservoirs.The rock type is mainly sandstone.The regional cap rocks are the Lower Jurassic-Lower Cretaceous and Upper Cretaceous-Paleogene strata,which have a large thickness and a good sealing property.The direct cap rock develops in the Paleozoic strata.On the basis of horizon calibration,the interpretation of seismic data in Yunlong sag is carried out,and the quality of seismic data in the area is evaluated.Data quality assessment results from the layer point of view,the Ordovician reflection layer seismic data quality is better,more stable lateral,the overall quality is better than the Triassic and Cambrian seismic reflection layer,and the Triassic is worst.From the plane point of view,the quality of seismic data in complex area is worse than that in simple structure,and the exposed area of surface sand and mudstone is better than that of limestone.In the same lot of the upper and lower layers of seismic data quality change is also great,both shallow and deep poor situation due to deep shallow shallow difference,which may be with the area of tectonics,strata development is more complex and have a greater relationship.Based on the results of seismic interpretation,the structure and fault of Yunlong sag are studied.Yunlong sag on the plane was north-south distribution,with north-south shallow deep deep characteristics of the overall west slope of the asymmetric depression.According to the results of seismic data interpretation,the traps in the area are good,and four local structures are developed from west to east: Daxi Yi anticline,Faust anticline,Tongdong tectonic and small terrane anticline to seismic T? reflection layer Statistics,trapping area of 390km2.The distribution of the fault in Yunlong sag is strong,and it is mainly distributed in the north-south and north-east direction.A small amount is the northeast of the east,and the same period of development is not the same.There are three main types of faults in the formation of the fault: one is the long-term development of the fault,from the Paleozoic development so far,such as the Pudu River fault;one is mainly developed in the late Yanshanian fault,most of the region Fracture;another is mainly developed in the Himalayan fault.It is concluded that most of the faults in the area are formed in the late Yanshanian period,and this fault can not destroy the structure.And the rupture of the long-term activity and the rupture of the active period of the hillslift period have a damaging effect on the structure.In terms of the nature of the fault,the main thrust of this area is mainly thrust fault,both the strike-slip fault and the reverse fault.According to the scale of the fault,the role of the area will be divided into three levels of fault.The results show that the late Yanshanian period is the main formation period of the tectonics,and the strike-slip fault in the hilly period has a damaging effect on the preservation of the traps.The conservation conditions of the area were studied in detail from the aspects of cap rock conditions,hydrogeological and magmatic fracture activities,and the factors affecting the preservation conditions were selected to quantitatively evaluate and divide the Yunlong sag Effective storage unit,the Yunlong sag is divided into three different preservation unit.Which save the middle of the North to save the better conditions for the region,the preservation of the Northeast to save the middle of the region,the southwest of the preservation unit for the preservation of poor conditions.Based on the results of the effective preservation unit evaluation,the north and north of the Yunlong sag are the prospect of oil and gas exploration according to the geological conditions of oil and gas,trap conditions and so on.After the hard study,we have made the following achievements:1.Yunlong sag is a north-south asymmetric depression controlled by two boundary faultsThe western boundary of the Yunlong sag is the eruption-the middle-dry fault(Yimen fault),the eastern boundary is the Pudu River fault zone,the northern boundary is the Aurora exposing area,the southern boundary is the Ordovician,the Devonian exposed area,Is a two-sided rupture control was north-south distribution,southeast high northwest low asymmetric oblique.2.Tectonic deformation of Yunlong sag is affected by tectonic movement of Yanshan night curtain and Himalayan two periods.The late Yanshan tectonic movement is mainly from east to west squeeze-strike slip,forming north-south thrust-strike-slip fault and associated crooked anticline and north-east thrust fracture.The Himalayan tectonic variation is mainly driven by the left-lateral strike-slip along the north-south fault,and the compressive stress mainly comes from the west,The tectonic movement of the Himalayan period further strengthens the late Yanshan tectonic structure and has some modifications to the pre-structural traps along the active faults.3.The Cambrain system in Yunlong sag is shallow shelf faciesAccording to single well facies analysis,Yuncan 1 well field geological survey and analysis of radioactive elements,at the same time,combining previous research results,completed the yunlong sag of Cambrian system sedimentary facies revision work,thinking Cambrian system in Yunlong sag for shallow shelf facies4.Good preservation conditions is the area of oil and gas accumulation of the important conditionsYunlong depression is located between the Pudu River fault and the strong active zone of the Yimen fault,and the fault activity is caused by the fracture activity,which is easy to be connected with the denuded surface and the deep fault formed by the tectonic movement in the area,leading to the destruction of the reservoir.Therefore,the preservation of good conditions is the area of oil and gas exploration area favorable area.5.Quantitative evaluation and division of the depression within the favorable preservation unitAccording to the actual situation of this area,the 11 preservation elements of the evaluation of the effective preservation unit were screened,and the favorable preservation unit of the depression was quantitatively divided by comprehensive evaluation.6.A comprehensive study that the central region is a favorable place for oil and gas accumulationThe central structure of Yunlong North in the middle of Yunlong sag,the western fault structure of Yunlong West and the three tectonic tectonics of Xiaoqingshan fault are formed in the late Yanshanian period.The Lower Cambrian,Lower Devonian and Upper Triassic are the main source rocks.The reservoirs are the Upper Triassic dry Haizi Formation,the reclamation group(T3g + s)and the Paleozoic,Jurassic-Lower Cretaceous and Upper Cretaceous-Paleogene strata,and there is also a direct cover of the Paleozoic.The central tectonics of the central part of Yunlong Sag has good oil and geological conditions such as raw,drainage,transportation,poly,and so on.Comprehensive evaluation is a favorable gathering area for oil and gas exploration.