吐哈盆地山前带构造岩相带及油气藏预测研究

This paper based on the example of mountain front tectonic belt of Tuha basin - a typical basin in west China, using geological, logging and seismic data, combining the two methods-comprehensive analysis of geological-geophysical data and numerical simulation together, studies the types of tectonic lithofacies and the mechanism of oil/gas accumulation in mountain front tectonic belt, and predicts favorable exploration areas. The tectonic lithofacies in periphery belt of compressional basin is systematically studied for the first time. The distribution and systematically analyzed with geological, logging and seismic data; the bury history of formations in the mountain front are restored with the back-stripping technique; the tectonic depression history of the mountain front is studied according to Airy Balanced Model; the tectonic evolution history is restored with the balanced section technique; according to the space composition of tectonic units and sedimentary systems of different geological time, the tectonic facies belt of the middle and lower Jurassic in the piedmont is divided into 12 types, and the controls of each type's tectonic lithofacies belt on the conditions of oil/gas generation, reservation and sealing are analyzed in depth. 3D numerical simulation and analysis is applied to the tectonic stress field in the hydrocarbon reservoir-forming-period for the first time. Because of the complex evolution of mountain front of Tuha basin, 3D numerical simulation of tectonic stress field in the hydrocarbon reservoir-forming-period helps to study the magnitude of the maximum principal stress, the minimum principal stress and the shear stress, the range and distribution of the principal stress, and controls of the upwards factors on the oil/gas migration and accumulation. Through the study on the oil-controlling fault's evolution, sealing mechanism and sealing history, the coupling of two effects of the fault-passage and sealing screen for oil/gas migration can be defined. Using the basic principle of petroleum system analysis, the paper systematically studies the hydrocarbon reservoir-forming mechanism and the time-space matching of the factors that affect the formation of reservoir, such as the space matching of active oil/gas matching of the active period of fault, the migration period of oil/gas and the formation period of trap. Through comprehensive analysis, the favorable exploration targets are selected in selected in the mountain front.