Oil Reservoir Characterization Of Sheng554Fault Block In Daqing Oilifeld

Sheng554fault block of Daqing oil field is located in south pitching end ofShengping nose structure in the Central Depression in Songliao basin. The tectonicstyles which develop successively from buttom to top are mainly normal faults withhigh-angle.The stratigraphic framework of the targets of Fuyu oil layers which belong toQuantou-3and Quantou-4Formation of Lower Cretaceous strata is firstly established.The targets can be divided into four sandstone groups including FⅠ、FⅡ、FⅢ andYⅠ, among which FⅠsandstone groups are subdivided into seven layers and sixteensedimentary time units furtherly and the FⅡ are into five layers and nine sedimentarytime units and the FⅢ is into five layers and ten sedimentary time units and the YⅠis into seven layers and sixteen sedimentary time units. According to the thickness anddrilling rate of effective sands, the FⅠ51、FⅠ61、FⅠ71and FⅠ72sedimentary timeunits are comfirmed as the main oil layers in the study area.On the basis of logging and core data analysis, three sedimentary faciesdistinguished are meandering facies and meandering-delta facies and lacustrine faciesof which can be subdivided into six subfacies and eighteen microfacies. Thesedimentary evolution sequence of bottom–top is meandering�'delta pain�'deltafront�'lacustrine�'delta front�'delta pain�'meandering�'delta front. According tothe analysis of reservoir physical properties of sedimentary facies, the low porosityand the extre-low permeability reservoirs are dominated in the study area, amongwhich only channel sands is of better physical properties.In the study area, the seepage barriers of reservoir flow units are mainlyargillaceous barriers which are shown as interlayers of sands in section and as pelyteof interchannel and distributary channel in plane. Based on the value of flow zoneindex (FZI)，can reservoir flow units be classified to three types with the FZIboundary value of0.5μm and1.0μm. From Type one to Type three, the seepage capability and storage capability of reservoirs is declined gradually. Among the threetypes, Type one flow units develop poorly, yet the other two develop well. Type oneflow units is mainly located in the axis of channel or (underwater) distributarychannel, and the other two which adjoin Type one always border the channel or（underwater）distributary channel and some appear in the overbank sand or levee.Based on the analysis of sedimentary facies and reservoir flow units,three-dimension geological modeling and remaining oil study of main oil layers areconduct next. The geological modeling involves strata modeling and tectonicmodeling and property modeling. The main controlling factors of remaining oilenrichment are tectonic and sedimentary characteristics and distribution of sands andtypes of reservoir flow units and so on so forth. In the both sides of the main faultzone and the transition area of channel and interchannel and the boundary of effectivesands are the mainly position of remaining oil enrichment. In addition, the remainingoil also distributes in the reservoir flow units of Type two and also enriches in theinterwell area which is not affected by water injection.