Architecture And Remaining Oil Distribution Discipline Of Sand Bodies Of Gaotaizi Oil Layer In Qian'an Oilfield

Shallow water delta reservoir is one of the most significant development targets in south of Songliao Basin.The complex spatial superposition relationships of sand bodies lead to the complex remaining oil distribution in this type of reservoir,deepening the understanding of the internal structure of the reservoir,which is an urgent problem in this type of reservoir.Currently,the research achievements in reservoir architecture of continental deposition are mainly focused on the meandering river sand bodies and mouth bar sand bodies of delta front,understanding of the reservoir of subaqueous distributary channel is concentrated in the composite river channel level,the internal architecture in these sand bodies is unclear,further development of this type of reservoir and potential tapping of remaining oil is greatly restricted.In this thesis,take Gaotaizi oil layer in the upper Cretaceous in Qian'an area,south of Songliao Basin as an example,integrated with coring data,seismic profile,well-logging and dynamic data,on the establishment of high-resolution sequence stragraphic framework and determination of sedimentary microfacies,composite subaqueous distributary river channel sand bodies are represented on the basis of seismic sedimentology.Furthermore,the identification and classification methods of single subaqueous distributary channel sand bodies in the non-dense well zone is presented based on seismic forward simulation,finally the internal architecture mode of subaqueous distributary channel sand bodies is established.Based on the theories of high-resolution sequence stratigraphy,identification marker of multi-level sequence boundaries are summarized systematically on the comprehensive application of seismic,well-logging and coring data.The characteristics of stratigraphic superposition in the multi-level sequences are discussed.Then the high-resolution sequence stratigraphic framework in the study area is established.Furthermore,the division and comparison of the Gaotaizi oil layer is finished finally.The sedimentary background during the deposition period of Gaotaizi oil layer of the research region is analyzed based on the analysis of heavy mineral combination characteristics,the source supply during this period is mainly from the baokang river system in the southwest of Songliao Basin.Integrated with detail coring data observation and well-logging response characteristics,all kinds of sedimentary facies markers are recognized.Furthermore,single well sedimentary faices and profile sedimentary facies are researched.The sedimentary microfacies types of Gaotaizi oil layer in the upper Cretaceous in research region is dicussed in detail finally.The relationship between seismic events and lithofacies has been established after the phase adjustment of seismic data.From the typical strata slice extracted,three main types of sand bodies have been recognized,each type has unique seismic facies.The spatial superposition relationships of single channel sand bodies within the composite subaqueous channels can be divided into three classes,which refers to six well-logging and geological identification marker respectively,based on the unique seismic responses at the connection positions of various single channel combinations,six forward simulation models were developed for single channel combinations using forward simulation.A width/thickness ratio empirical formula for estimating single subaqueous distributary channel sand bodies scales was obtained by fitting the classification of single channel sand bodies in dense well zones.Using this formula and cross-well seismic responses according to the developed forward simulation model characteristics,single channel sand bodies within composite subaqueous distributary channels in sparse well zones were identified.Using pair well data,accretionary structures in the single subaqueous distributary channel sand bodies is characterized.Two types of accretionary structures including lateral and vertical are mainly developed in the research region.The lateral accretionary surface occurrence is 6° to 10°,the vertical accretionary surface occurrence is 0° to 4°.Level ? to ? architecture model of subaqueous distributary channel sand bodies in the research region has been built finally.From the influence and controlling factors of macro remaining oil distribution,combined with the occurence reserve status of remaining oil distribution,discipline and characteristics of remaining oil distribution under the control of multi-level architecture elements within the subaqueous distributary channel sand bodies are discussed.