The Study On The Sedimentary Microfacies And Favorable Sandbody Prediction Of Shahejie Formation In Wuqiang Oilfield, Raoyang Depression

In order to gain an even clear sight of the causes of formations, the distribution features and the control factors of the sandbody in southern part of Raoyang depression, this thesis has made a predictive study of the sediment microfacies and the favorable sandbody in Shahejie formation of Wuqiang oil field in Raoyang depression by synthesizing dates relating to seism,drilling,well logging and geochemistry and so on under the guide of sedimentology.Through methods like inspecting the rock cores,indentifying mineral thin-sections,analyzing the particle-sizes,and analyzing the well logging dates and so on and with the combination of the analysis of single well facies and profile facies,this thesis has studied the sedimentary character in Wuqiang oil field which shows that the Es2-Es3 in Wuqiang oil field in Raoyang depression are developed into fluvial/deltaic mainly and the provenance comes from Xianxian lobe in the east. The main developments of the deltaic deposits are depositional microfacies like distributary channels and backswamps on the delta plain,underwater distributary channels,interdistributary estuaries,mouth bars and sheet sandstones on the deltaic front,in which overwater and underwater distributary channels as well as mouth bars are the best reservoir beds. In the sedimentous period of Es3,it developed into regressive sequences which become thinner to the upward;in the sedimentous period of Es2,it developed into progradational sequences which become wider to the upward.Based on the basis of inspecting the cores and with the combination of indentifying mineral thin-sections,we have identified the soft-sediment deformations that have something to do with the effect of seisms.,the main types of which include all kinds of liquefied sand dikes,water-escape structures developing towards downward,load casts,ball-and-pillow structures,flamy structures,liquefied swing structures,pseudoconcretions,beads-shaped structures,pillow shaped layers and all kinds of leaps within the layer. Based on the parameters like the lengths of the core of the seismites and the particle-sizes we have find a way as to how to measure the intensive levels of the effect of the seisms through IDS index. The results show that the IDS index in Es2 are higher than Es3 as a whole,and the high value areas of the IDS index isogram in Es2 mainly lie in the principal part of the centralupliftbelt. This confirms from the sedimentology point that the tectonic activities in Es2 period were fiercer than in the Es3 period,and the centralupliftbelt was formed mainly from the early stage of Es2 to the last stage of Dongying group.The variation laws of sandbody permeability are in accordance with the distributions of the IDS index isogram,whicn proves that seisms did something good for the permeability of reservoirs which can improve the reservoir physical property.Based on the analysing of the features of the depositional microfacies,the types of the rocks,the storage space and the pore configurations in the study area,we have made a comprehensive evaluation of the reservoirs in this area and divided the reservoirs into three types.Typeâ… ,the distribution space of the reservoir is small,and is mainly developed in the mouth bar. Typeâ…¡,the reservoir is mainly distributed in the river channel and the mouth bar. Typeâ…¢,the reservoir is mainly spreaded in the edge of distributary channel,sheet sandstone. Besides, tectonic activities in this area are fierce and lots of cracks have been formed due to this. In some local regions,the effects of the cracks play a key role in the development of the reservoir,and favorable reservoirs may be formed because of this.