| The study area is located in the northeast of Eastern Liaohe depression, which has good oil/gas exploration prospect. The multiple episodic tectonic events and volcanic activities resulted in complex structural style, reservoir and oil/gas pool distribution. Aim at the difficult in oil exploration, by using high-resolution sequence stratigraphy and basin analysis theories, the dissertation has been carried out based on the integrated analysis of geological and geophysic data and reservoir inversion researches. The major achievements are as follows:1. In terms of high-resolution sequence stratigraphy, the Eogene section from Shayi to Dongsha members has been classified into 4 third order sequences and 20 fourth order sequences in the Hongxing area. The 4 third order sequences are correctable through out the study area and the high-resolution sequence framework has been established for the correction of strata.2. The depositional systems identified in the Eogene include fan-delta system of the Shayi member and the fluvial deltaic system of the Dongying Formation. Several dominated sedimentary facies have been recognized, such as sub-distributary channel, delta front mouth bar, interdistributary bay and delta front sand sheet an so on.3. The structural styles, fault characteristics and their spatial distribution have been revealed through 3D seismic interpretation and structural mapping. The study area is a complicated anticline composed of Jiazhangsi fault and its associated faults. The main fault shows as a steep, lower-normal and upper-reversion fault on the seismic profiles. Faults combination exhibit several different structural styles, such as flower type, "X" or "Y" type, and the area underwent the early dextral transtension and late sinister transpression.4. The control of tectonic evolution and volcanism on sediment filling has been discussed in this paper. The syndepositional faulting in Eogene are tensional or transtension. The Jiazhangsi fault and NNE associated faults controlled the subsidence center and sandbody distribution. volcanism restrained the distribution of sandbodies.5. The logging criteria for recognition of oil, gas and water beds have been established in the study area. Reevaluating 34 present wells based on this criteria, we discovered 16 oil/gas layers in 4 wells, increasing new oil reserves 33×10~4t and gas reserves 6×10~8m~3.6. The gas and oil pool distribution has been documented through the analysis ofplay formation and tectonic activity. It is pointed out that Jiazhangsi fault zone is the favorable zone where structural traps and litho-stratigraphic traps are prone to exist. The deep, early developed subsidiary fractures, control the development of hydrocarbon pools. Generally, these fractures were terminated at Esi, and hydrocarbon concentrated in the middle of Esi where is in the way of hydrocarbon transport. This is the distribution regularity of hydrocarbon pools in the middle of Esi. The trend of hydrocarbon transport and accumulation is from bottom to up and from south to north. In the western of Jiazhangsi fault, lens-type lithologic reservoirs are liable to come into being. But in the eastern, the reservoirs mainly are structural and lithological updip. On the basis of foregoing research, we predict 10 favorable targets concluding structural and structural-lithologic reservoirs. Some have been proved by continuous exploration drilling and gained good economical effects. |
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