The Study Of Reservoir Geological Character In Upper Es₄ Submember Of The Lai64 Block In Qingnan Sag

The Lai64 Block in Qingnan Sag is located in the intersection of the Dongying Depression and Qingdong Depression, and its main oil-bearing strata is the upper Es4 submember. There is only 13 exploratory well in this area, So the degree of exploration is low. But the thickness of dark mudstone and industrial oil flow in the Es4 reservoir are all proved that it has considerable exploration potential.This paper takes theories of structural geology, reservoir geochemistry, reservoir and geophysical exploration technology for guidance. The research on geological character and reservoir-forming regularities of upper Es4 member are based on seismic data, logging data,g- eochemistry data etc, which is the foundation of prediction to favorable exploration target. Main research achievements are as follows:According to the interpretation of seismic data, the most of faults are 4-stage fault and their active phase is paleogene. In the neogene the fault activity had been ended.It Using the biomarker to correlate oil-source between the source rock and discovered reservoir, which the results showed that oil in lai64 well is from the oil-source of the upper Es4 member , while the oil stain in lai62 well is from low-mature source rocks at the top of the upperEs4 member.Because the affection of sedimentary facies, the substance characteristic in three structural belt is different, and the subatance of resevior in the northern steep slope zone and the southern ramp belt is better than that in the cenral sag.The resevior can be divided into upper segment chunhuanzhen and lower segment chunhuazhen, the upper segment is distributed in the northern fan delta area, while the lower segment is distributied in northern underwater alluvial fan, turbidite fan in central sag and beach bar sand in the south area. It has cleared out the rules of favorable resevior's vertical and horizontal distribution by using of the results of wave impedance inversing and seismic attribute analyzing.The rich oil source , favorable reservoir-cap configuration, favorable trap position and the better assemblages between the trap formation periods and the accumulation period are the favorable conditions of the hydrocarbon accumulation in Lai64 block, which based on the achievement of structural and reservoir study defined the potential exploration.The exploration are the underwater alluvial fan between lai78 sides well and lai64 well, the turbidite fan which is located in lai64 well , the northern fault zone and beach bar sand in lai61 well.