Study On Tectonic Evolution And Its Controlling Effect On Hydrocarbon Accumulation In Lunnan Area

According to the characteristics of the Lunnan Lower Uplift Area of complex fracture system,multiple tectonic movements and fault controlled reservoir,this paper systematically analyzes the developmental characteristics of tectonic and stratigraphic.Meanwhile,the denudation of unconformable contact strata is restored and erosion characteristics are analyzed thoroughly.And then according to the reports of 3D tectonic evolution and balanced section construction,the paper analyzes the tectonic evolution in great detail.Combining with Petromod simulation results,the paper analyzes of reservoir evolution model in Lunnan area.Furthermore,controlling effect of fracture system on reservoir are analysed.The results of the paper show that:(1)With the results of tectonic evolution,tectonic activities are divided into eight stages.Basilar strike slip faults formed in the Caledonian.There is strong extrusion and a large area of round north and south by uplift and erosion in early Hercynian tectonic and late Hercynian period,while the formation was eroded and it formed two large anticlines(Lunnan anticline and Sangtamu anticline tectonic inversion)in the same time.Then,inversion of structures occurred in late Yanshan period.The last,in he Himalayan period,Kunlun Mountains and Tianshan thrusted to the inner basin,and stratum changed from North High low male into the North South high-low.(2)According to the simulation results of oil and gas system,the oil and gas accumulation mode is summed up to four times of oil and gas filling,one oil and gas destruction period and three times of oil and gas adjustment period.Giant paleo oil reservoirs in the Lunnan low uplift formed in the late Caledonian period and destroyed by the strong denudation of the Early Hercynian period.However,after the late Hercynian period,oil and gas recharge to Ordovician reservoir.The paleo oil reservoir moved upward to the Carboniferous and Triassic reservoirs,which formed secondary oil and gas reservoirs from the late Yanshan to early Himalayan period.Later,the oil and gas reservoirs were re-adjusted in the late Himalaya period,and they continued to move upward to the Jurassic strata and stored in the reservoir.(3)The effect of fracture system on oil and gas reservoirs is mainly in the control reservoir condition,transportation and accumulation conditions and reservoir distribution.The period of oil and gas migration and accumulation is controlled by the opening period of the large oil source fracture and the location of the large fracture controlled the location of hydrocarbon migration and accumulation.