Identification of Source Rocks and Quantitative Evaluation of Accumulation Contribution in Residual Basin: Taking Pre‐Jurassic in the Tainan Depression, Turpan‐Hami Basin

powerful transformation after late tectonic movement. The tectonic settings and sedimentary filling of prejurassic is obviously different from that of the overlying strata, forming two sets of structural layers with large different tectonic deformation features. The Identification of source rocks and Accumulation contribution in PreJurassic Residual Basin are difficult to conduct because of the complicated tectonic evolution history. In this study, the Residual Basin tectonic development features and evolution history was confirmed through structural geology and seismic stratigraphy related theory, And original sedimentary environment of hydrocarbon source rock development was restored through core observation, rock samples analysisand combination of sedimentology and geochemistry. Based on Identification and prediction of source rocks, the accumulation contribution was evaluated by oil-source correlation and genetic method, and the hydrocarbon accumulation model was determined at the end. The results of the study indicate that: (1) From the core reveal source rocks on both sides of northern margin fault Kumu swell, we can see that Taodonggou has source rocks development in hrust fault hanging wall, no source rocks development in footwall, and it is best in top of hanging wall, bad in back limb, no source rocks development in western segment, showing that controlling-depression fault developed weaker in faulted period, activity characterized by strong east west weak characteristics. Because of the sliding friction resistance, an inverse traction characteristics appeared on the layer of rollover near controlling-depression fault of rift basin, concaving down along seismic event, arching upward in Central rift basin The characteristics of the lower beds downworping and the upper beds upwarping was formed(F.O. Marques, 2014; Li Wenyong, 2013; Marco Bonini), which was a common positive inversion structure. (2) In early permian, pre-jurassic was in Bogda Rift intensive stretching environment in the Tainan depression, Turpan-Hami Basin, forming a number of intracontinental rift,chasmic and half-graben basin. Its strata structure was stable, in the stage of continuous deposition, and layer mainly developed dark mudstone, which was the most important hydrocarbon source rocks layer in Turpan-Hami Basin pre-jurassic; With the movement of Late hercynian happened in late permian, the Jueluotak mountain uplifted, Bogda Rift began to return, part of normal faulting began to structure thrust inversion, and the layer of Yingyeer structural belts uplifted then was eroded, part of belts was missing. The layer of Wutonggou Formation was generally eroded depleted, part of Wutonggou layer was eroded, erosion thickness range from 0 to 100 meters, and denudation thickness center in central structural belt, presenting the radiated trend around. (3) The layer’s source rocks have a single facies belt, the main lithology is dark mudstone, the peak height of 20R-ααα-C27, 20R-ααα-C28 and 20R-ααα-C29 presents reverse ”L” type and contribution of terrestrial plant. The percentage composition of C27, C28 and C29 havelittle difference. The input of source rocks are mixed with terrestrial plant, phytoplankton and algae, and the content of tricyclic terpane and gammacerane are very high, Ts<

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