Research On Tectonic Features And Hydrocarbon Accumulation In Majiatan Area Of Ordos Basin

The Majiatan Research Area is located at the junction of the western fault fold belt and the Tianhuan depression in the Ordos Basin.The tectonic in the area is obviously controlled by faults,and extremely rich mineral resources such as coal,oil and natural gas have been discovered.The geological tectonic in this area is complex and the tectonic activity is strong.Therefore,deepening the study of its structural characteristics is of great significance to the exploration and development of mineral resources in this area.The research direction of this paper is the precise interpretation of the tectonic,and then analyze the relationship between the tectonic features and hydrocarbon accumulation.Combined with the basic knowledge of seismic data interpretation,logging geology and tectonic geology that we have learned,and previous research results,based on the acquisition of 3D full-cover seismic data from the study area in 2004,using seismic fusion attributes,ant algorithm and mudstone smearing methods,through Geoeast and Traptester software to achieve the fracture characterization,crack prediction and fracture plugging evaluation.In the process of tectonic interpretation,in order to better enhance the ability to identify faults,seismic fusion curvature and coherence attributes were used to identify and determine different levels of faults in the study area,accurately implement the tectonic morphology of the target layer,To further characterize the overall fault system in the study area,a total of 61faults of various levels were depicted on the T_T77 layer in the study area,including 9 faults of level II;19 faults of level III;and 33 faults of level IV.Secondly ant algorithm automatic tracking technique to predict crack,fracture to obtain qualitative interpretation result fracture zone 219km²,cracks in fractured zones 97.6km²,three-dimensional visualization application and its spatial distribution characteristics obtained.Finally,a mudstone smearing coefficient method is used to quantitatively evaluate the sealing ability of the fault.The fault section where the target horizon T_T77 may have the capability of lateral sealing accounts for 82.3%of all the faults.The case of faults,fractures distribution characteristics and sealing ability of the fault,based on the actual drilling test data,the relationship between the tectonic of the study area and the distribution of hydrocarbon accumulation is analyzed:A flat area east wells are low-amplitude tectonic setting,The oil wells in the central tectonic belt are all high points in the faulted anticline area,with obvious features of tectonic reservoir control.The wells are in developmental cracks site,and good sealing near the fracture,indicating whether the fracture and fracture development sealing effect on the accumulation control action.