A Study Of Seismic Facies And Oil Accumulation In The Shahejie-Dongying Fomations In The Western Part Of The Wuqing Sag

The Damengzhuang sag and the positive structural zones around it in the Western of Wuqing Depression have not been a major breakthrough for many years. Because of less drilling data and low level of explorartion, the favorable reservoir facies and accumulation conditions are not clearly. So, using seismic facies methods to analysis the sedimentary facies, forecast the distribution of reservoir facies, and predict cookies-block through the study of accumulation conditions is an important guiding significance to oil and gas exploration.Eight kinds of seismic facies types are recognized. Combined with the corresponding relationship between sedimentary facies and seismic facies, the proportion of sandstone derived from seismic velocity-lithologic analysis, seismic facies are converted into sedi- mentary facies. The distribution of the favorable reservoir facies is clearly. The results indicate that:during Es3-Es2 deposition period,Yangcun slope developed shallow lake,delta, river sediments; Hexiwu developed shallow lake deposits during Es2 deposition period; downthrown block of Baodi fault developed alluvial fan deposits in Es2-Ed period, followed by the river-fan delta facies to the center of the sag except Ed period. Daliangzh- en belt was widely distributed by shallow lake in Es1 period, fluvial in Es2 and Ed period.The results of the study of accumulation conditions show that, source rocks are mature and high-mature now. the oil founded is from the lower part of Es3 source rock with highest hydrocarbon generation potential; reservoir physical property has the characteristic of middle-porosity,low and ultra-low permeabllity; the source rock below reservoirs assemblag is more favourable; hydrocarbon generation stage is later than trap formation period and well matched with migration; Daliangzhen belt, the downthrown block of Hexiwu fault and Baodi fault develops fault block reservoirs and faulted-nose reservoirs; Yangcun slope develops sand lens, structural lithostratigraphic, fault block, stratigraphic reservoirs, At last 15 favorable targets around the hydrocarbon kitchen were evaluated.