The Structural Analysis Of Maigaiti Slope Of The Tarim Basin

Maigaiti slope of the Tarim basin is located in the southern of the Bachu uplift.At present,the Bashtop oilfield,Bird Mountain gas reservoirs and Hetian River gas field are found in the working area.But its evolution and structural chracterristics are still not very clear,In particular,different periods of fault development and reservoir distribution are still very weak.Using the topic of "The structural analysis of Maigaiti slope of the Tarim Basin",around the core scientific problems of "the structural interpretation and evolution analysis of the Maigaiti slope using the tectonic evolution and the dynamics process as the main thread,on the basis of researching the reservoir development and distribution,exieting seismic data,combined with the technical difficulty of the working area,this artical carries out a precise interpretation of the key areas,and analysis of the tectonic evolution of the study area.Especially,comprehensive utilization of the precise interpretation of seismic data,regional geology,drilling data,this artical analysis and summaries the plane tectonic evolution of the characteristics and the reservoir distribution of characteristics.Through the research of geophysical feature,innovating the geophysical integrated interpretation and research techniques,realizing the precise reservoir prediction rather than geological speculation.And finally reveal the distribution of reservoir in the context of multi-period tectogenesis,And at last provide the basis for the optimization of oil and gas exploration targets.From west to east,Maigaiti slope constructs with six tectonic zones as follows:Selibuya tectonic belt,Kangxi tectonic belt,Himi tectonic belt,Mazhatage tectonic belt,Bird mountain tectonic belt,and Madong tectonic belt.The research of the fault structure of Mazhatage makes new progress:the unconformity sueface located at the top of the anticline of Mazhatage is the reflective horizon of T6,from the well sections through the wells of M2,M7,M5,M401,we can see that the strong reflective horizon in shallow areas is also T6 horizon.Mazhatage tectonic belt consists of three fracture structures:Manan and Mabei fault constitute the basement-involved type of strike-slip extrusion fault;the thrust faults along the bottom of the cream of the Paleogene salt bed from Maigaiti slope to Bachu uplift,along the ancient near the bottom of that department;the thrust faults along the middle of the Cambrian sault layers from Maigaiti slope to Bachu uplift.Madong tectonic belt constructs with five rows from the north to east,and each row constructs a large thrust sheet,the middle of the Cambrian sault layers as the main nappe detachment from the northwest to sourtheast,Thrust faults broken down into the middle of the Cambrian salt layers,up to breaking the first Ordovician.Hanging wall developed the propagation fold.Anticline core integration of the overlying strata is Carboniferous horizons.Silurian-Devonian horizons from the two wings to the core of the anticline gradually thinning until the tip off.Selibuya tectonic fault began in the period of late Hercynian,the tectonic activity intensified in the period of Himalayas.This fault has the double structural characteristics of strike-slip.According to drilling data,the thickness of the Lower Permian is very different.The thinnest area where located in the well of Ba3 is 62m,but the west side of the slope where located in the well of Q3 is 362m.The large thickness differences explain the uplift amplitude variations,they also explain that Selibuya fault may have sarted its ativities.The Bird Mountain fault is a slippage breaking thrust fault from south to north along the Middle Cambrian salt layers.And with the south of the reverse thrust,together constitute a "Y" font.The deep fault in the Bird Mountain belt may be superimposed on the new tectonic activities,resulting in the folds of the overlying strata deformation.In the northern part of the Maigaiti slope,in a ancient karst gentle slope-depression landform position,Karst reservoirs are under development and filling material in a serious condition.But the karst slope where Karstification is well developed is more conductive to karst reservoir development.Seismic reservoir prediction showed that:In the southern of Manan 1 well,the reservoir located in the slope region of ancient karst landform is developed.In the region of Madong area,the reservoir is mainly distributed in the fault zone.The reservoir and the superimposed figure of faults show that the reservoir is related to the fracture closely in this region.