The Tectonic And Thermal History Of Superimpose Basin

Study on tectonic and thermal history of basin is a important part in basin analysis and hydrocarbon exploration. The thermal state and thermal history of the basin nowadays are not only the objective exhibition in tectonic evolution, but can provide the significant physical parameter for space-time distribution of oil-producing situation of generating strata, hydrocarbon migration and reservoir. This thesis quantitatively studies the thermal evolution history of the basins with the systematical, integrated, dynamic and comprehensive study methods. From the plate tectonics, geodynamics and oil-gas bearing basin analysis fields, using the new results and recognitions of plate tectonics theory and superimpose basin as the guideline, the evolution of superimpose oil-gas bearing basins in western China and tectonic-thermal history, mature rule of generating rock are discussed by the combination methods of multi-branch of learning and multi-instrumentation. Select the Turpan-Hami basin and Santanghu basin as the important areas, the study principal line are the control of the basin formation, development and evolution to the thermal history. It can provide the important theory basis for the hydrocarbon exploration of the basins.The Turpan-Hami basin and Santanghu basin are all the intracontinental superimpose basins with complex evolution history, which are located between the Tianshan orogen and Altaides. The basins have experienced the superimpose and reformation of multiphase and multistage tectonic activitys, their development are controlled by two evolution system of Palaeozoic and Mesozoic-Cenozoic, showing a bound of community in dynamics and tectonic-thermal evolution.1. On the basis of the cognition to the basic geology condition of basins and unconformity, tectonic subsidence history study, it can analysis the stress state in the course of evolution and tectonic subsidence characteristics, as well as define the basin types in every epoch. It is indicate that the Turpan-Hami basin and Santanghu basin share the similar subsidence features like as fast-slowly- fast triple-line, reflecting their united regional stress field. The evolution of the basins can be devide three periods, including faulted basin in extending setting, depression basin in slight extending setting and intermountain basin in extrusion setting.2. By analysis the regional tectonic evolution setting, the discussion can be made on evolution history and dynamic system of Turpan-Hami basin and Santanghu basin. On the affect of paleo-Asia ocean and new-old Thetis structural domain, the two basinshave experienced multiphase extending, convergent and reformation of tectonic movement, showing tectonic features nowadays at last. The evolution of the basin can be devided several stages including of the formation of the basement, the evolution and the deformation etc. The evolution of Turpan-Hami basin and Santanghu basin were controlled by the evolution of orogen from Mesozoic, showing basin-orogen coupling features obviously.3. The study of thermal evolution to Tuha and Santanghu basins can be worked from two respects include tectonic thermal event(macroscopy) and thermal evolution in sedimentary stratum of basin(local). By the methods of volcanics isotope chronology, apatite fission track and inclusion thermometry, the regional tectonic thermal event can be discussed in Hercynian, Indo-Chinese epoch and Yanshan epoch. It is indicate that the affect of thermal event change from strong to weak and the regional background value depress gradually with the age become young. By using 'Mckenzie' model to simulate tectonic-thermal evolution and Ro, fission track etc. thermal index, the thermal history can be resumed intra-basins with the technics of Easyi?o% model and inverse modeling of fission track, stressly resolving the suitability and accuracy problems of thermal index. It is prove that the basins have experienced fast heating course in Permian, slowly cooling course in Triassic-Early Crataceous and primary steady course in Tertiary to nowadays. The geothermal gradient of the two basins have the characteristics of high in paleo and low nowadays. Their show the traits of high in east and low in west in Turpan-Hami basin and high in west and low in east in Santanghu basin as in the plane. Because of the different burial history and thermal evolution course of the basins, the generating rock can become mature and hydrocarbon accumulation in multiple phase.4. On the basis of the study in tectonic-thermal evolution in Turpan-Hami basin and Santanghu basin, the relation can be discussed between tectonic-thermal evolution of superimpose basin and maturity of oil source rock. It is indicate that magma thermal activity play the important role in maturity of oil source rock of Carboniferous and Permian. We can expound thermogene pattern in each evolution stage of superimpose basin by way of the Turpan-Hami basin and Santanghu basin and generalize the relation between tectonic-thermal history and hydrocarbon by means of contrasting thermal evolution history of several superimpose basin in western China.