The Research Of Stratum Characteristics And Restored Prototype Basin In Hami Depression

Although the research of tectonic evolution of Permian-Triassic in Hamidepression is not systematic，the exploration and outcrop data of Permian-Triassic，which were analyzed in recent years，shows that there are huge potential and greateconomic value to research the Permian-Triassic stratum. So the distribution rule ofdeep oil and gas reservoirs in Hami depression is hoped to be revealed by the study ofresidual stratum distribution，erosion thickness calculation and prototype basinrecovery，so as to realize the oil and gas breakthrough in Hami area earlier.According to the seismic、geological and well data which have been got，theresearch thoughts of this paper are as follows，first of all，the residual stratumdistribution characteristics of Permian-Triassic should be analyzed，then on the basisof the study of compaction coefficient，the original thickness can be recovered.Secondly the erosion thickness of Permian-Triassic is calculated by use of multipleapproaches comprehensively，and with combining the result of the stratum recovery，we can recover the prototype basin thickness. And at last，the migration of depocenterin Hami depression between Permian and Triassic can be cleared.Hami depression is a compressional superimposed basin which has undergonemany tectonic movements. And the multiple tectonic movements resulted in thedistribution characteristics of the Permian-Triassic stratum，and the serious erosioneither. Around the depression edge and boundary faults were denuded seriously，butthe center of the sags slightly. The erosion thickness of middle-upper Triassic was thelargest，the middle Permian was thinner than middle-upper Triassic，the lower Triassicwas the thinnest. And the erosion thickness was different between Huoshizhensub-sag and Sanbao sub-sag in different periods，at middle Permian the erosionthickness of Sanbao sub-sag was larger than Huoshizhen sub-sag，but at middle-upperTriassic Huoshizhen sub-sag was larger than Sanbao sub-sag. On the basis of the study of the original thickness and erosion thickness，withcombining the result of the tectonic evolution research，the prototype basin thicknessof Permian-Triassic in Hami depression was recovered，and also the migration rule ofdepocenter between Permian and Triassic was cleared. The result shows that，thethickness of middle Permian prototype basin distributed uniformly in the wholeregion，and there was a depocenter which located in the southwest of Huoshizhensub-sag.At the period of lower Triassic， the thickness of prototype basin inHuoshizhen was larger than that in Sanbao，and the depocenter moved to the southeastand the range expanded significantly. In general，the prototype basin thickness ofmiddle-upper Triassic was the largest，and the thickness in Sanbao was larger thanin Huoshizhen，there were three depocenters in this period，among which one locatedin Huoshizhen，and two located in Sanbao，as opposed to lower Triassic，thedepocenters moved to the northwest as a whole.