Hydrocarbon Accumulation Conditions And Favorable Block Prediction Of Fuyang Formation In Songbei Exploration Area

In this paper, by using seismic, drilling, heavy magnetic materials and collecting relevantresults, the characteristics of structural evolution and sedimentary formation developmentabout Songbei exploration area are analyzed. Through using experiment and evaluation ofsource rock, the development situation, geochemical index and distribution characteristics ofK1q and k1n1+2are studied, showed that most of blocks haven’t reached the mature stage, andoil generated can’t satisfy the largest residual hydrocarbon quantity, so all the13blocks can’tguarantee oil extraction outside. Oil-source correlation revealed that k1qn1source rock ofSanzhao sag supplied hydrocarbon for FY formation, and pointed out that hydrocarbonexpulsion threshold and peak were respectively1300m and2050m. According to thestructural evolution and materials hydrocarbon expulsion, and on basis of analysis ofhydrocarbon-expulsion evolution, the center of hydrocarbon-expulsion was indicated to movenorth gradually with layers depositing. Through simulating migration pathway with basinsimulation technology, the distance between exploration area and hydrocarbon-expulsioncenter was manifested lager than100km, belong to long distance migration range.Using drilling, lithological characters and physical property materials, and combiningwith single well sedimentary facieses analysis of key exploration wells, Fuyang reservoirmainly developing alluvial plain with fluvial facieses locally, and the distribution direction ofsandbody was near south-north and northeast, only in the south of Suihua sag andHaerbindong area presented near west-east. By using hydrocarbon evaluation methods, thispaper pointed out that the physical properties of FY reservoir were good, and porosity wasgreater than20%, permeability was larger than10×10-3μm2.Songbei exploration area was suffered intensely lifting and eroding through erosionrestoration technology, and only in Mulan and Binxian blocks, the thickness of k1qn1mudstone cap rock was more than100m. By using formation water analysis data, FYformation water was showed mainly NaHCO3type in north of Suiling anticline high belt,while CaCl2type in south and the eastern areas, and only in Hailun uplift belt andHaerbindong block, the formation water salinity was above5000mg/L，while in the restblocks2000~5000mg/L，which was not favorable for hydrocarbon preserving.Comprehensively using fuzzy comprehensive evaluation and hierarchy analysis tooptimize the13blocks of FY reservoir, and the results show that Haerbindong block is themost favorable for hydrocarbon accumulation, next were Binxian and Mulan block, and thespecifically favorable area locates the joint of Wangfu sag and Qingshankou-diaoyutai upliftbelt, covering about430km2.