EFFECTS OF THE HIMALAYAN MOVEMENT ON THE FORMATION OF OIL-GAS RESERVOIRS IN THE JIANGLING SAG

In the Jiangling Sag,there were intensive tectonic movements of the Himalayan cycle (mainly occurring as three phases),which exerted significant effects on hydrocarbon migration and accumulation.These effects appeared in following aspects:1)the strong compression stress derived from the Himalayan movement provided a great power for the expulsion of hydrocarbon from the Xingouzui Formation,with the three phases of the intensive Himalayan tectonic movement corresponding respectively to the three phases of hydrocarbon expulsion;2)the late phase of the movement changed the fluid dynamical conditions for the secondary migration of hydrocarbon,and thus tended to influence the direction and way for the secon-dary migration of hydrocarbon as well as the sites for hydrocarbon accumulation;3)the effects resulted in the decreasing of hydrocarbon-filling degree in structural highs,and led to the increasing in structural lows;4)the early and middle phases of the movement formed important structural conditions for hydrocarbon accumulation,while the late phase of the movement tended to adjust and change the early hydrocarbon reservoirs,and even destroyed them to reform some secondary hydrocarbon accumulation.