Carbon Dioxide Gas Reservoir Characteristics And Its Special Relation With Gas Resource In The West Of Dongying Sag

The thesis is part of the item, research on the forming condition and accumulating model of carbon dioxide gas reservoir in Jiyang and Linqing Depression, supported by SINOPEC. Four carbon dioxide gas reservoirs have been discussed, which are Pingfangwang, Pingnan buried hill, Huagou and Gaoqing reservoir, and analyzed their relationship with magmatic rock, faults and the touched area between magmatic and carbonate rock.The following is the conclusions.Carbon dioxide gas reservoir in Pingfangwang is trapped in an antincline and has the bioherm-bank dolomite for reservoir layer and mudstone in Shasan segment for its cap formatiom. The value of 8 13Cco2 (PDB) is between -7.5‰ and -4.3‰, The ratio of 3He/4He is from 3.00 to 4.44, R/Ra is 2.14-3.21 in the reservior. So it belongs to the gas from mantle origion and secondly meybe the chemogenic gas in the rock.CO2 gas reservoir in Pingnan has buried hill for its trap and reservoir is limestone of mid Ordovician, and layer is aluminous layer in the bottom of Benxi Formation and mudstone and huge-mudstone in Shasan segment for covery. The gas in the reservoir with 6 13Cco2 (PDB) of -4.46~-5.90‰ is mixed gas of mantle and rock chemical origin, but majored in mantle origin.CO2 gas reservoir in the well Hua 17 is fault-blocked reservoir with sandstone in the lower part of segment and mudstone in mid of shasan segment.Gas reservoir with -3.35‰ of 6 13CCO2 (PDB) , 3.20 of 3He/4He ratio and 4.43 of R/Ra ratio is recongnized inorganic origin with much mixed Helium from mantle orgin.COi gas reservoir in Gaoqing area is kept in structure and lithology trap. It formed two suites of reservoir and cap assembles, which are the one of sandstone in lower part of Guantao Formation and mudstone in the upper part of Guantao Formation, and another of sanstone in lower part of Minghuazhen Formation and mudstone in its upper part. The reservoir shows 8 13Cco2 (PDB) with a value of -4.41‰ and the value of He between 358 ×10~6 and 847×10-6. According to chemical index of gas origin, it has the mantle origin.The CO2 gas reservoir in the area has intimate relationship with magmaintrusion,faults and the touched belt between the magma intrusion and carbonate rockin the special distribution.