Research On Developing Rules Of Hydrocarbon Accumulation Pools In Marine Face Formation Of Akekule Arch

Akekule arch lies in the southern part of Tabei uplift, Tarim basin, which is an old arch developed on the pre-Cambrian metamorphosed basement. Its development is mainly affected by the mid-late Caledonian Movement, early Hercynian Movement, late Hercynian Movement, Indo-Chinese-Yanshan Movement and Himalayan Movement. Among which,early Hercynian Movement and late Hercynian Movement have affected on the Ordovician formatiom predominantly. They have caused the fonning of the main fault belts, fractures and karstification in the Ordovician carbonate formation, which act an important role for the fonning of hydrocarbon accumulation pools.The petroleum controlling structures and hydrocarbon geology is systematically concluded and studied in this paper. According to the petroleum controlling structures, the finite numerical models of the Ordovician formation of Akekule arch are built up to imitate the petroleum controlling factors,which contain fluid potential, fracture developing extent and darcy velocity. The imitated tectonic stages contain early Hercynian stage, later Hercynian stage,Indo-Chinese-Yanshan stage and Himalayan stage.Through analysis of the imitated results of single stage and comparison of the imitated results of several stages,conclusions are gained as follow:the odovincian hydrocarbon pools are mainly formed in late Hercynian stage and Himalayan stage, whose distribution are chiefly controlled by the fault belts;the darcy velocity is controlled by the fracture developing extent;under the pushing of the unequall gravity force of the overlying strata,hydrocarbon presents the tendency that it generally flows from the deep slope to the top arch;the Odovincian accumulation pools in the axial region are filled with mixed hydrocarbon,which in the southeastern slope are filled with new hydrocarbon.The imitated results shows that the range around T750 well-S97 well and LN11 well-LN34 well are the favorable hydrocarbon accumulating areas in early Hercynian stage; the NE striking fault belts formed in early Hercynian stage and the nearly EW striking fault belts formed in late Hercynian stage are the favorable hydrocarbon accumulating areas in late Hercynian stage; the southeastern slope and the deep fault belts in the middle part of the arch are the favorable hydrocarbon accumulating areas in Indo-Chinese-Yanshan stage; the fault belts in the axial region of the arch are the favorable hydrocarbon accumulating areas in Himalayan stage.