Seismic Sedimentology Application Of MPE-3 Block In Venezuela Oil Field

Quantification of the braided river delta sandbody in horizontal wells region is a difficult problem in seismic sedimentary facies study.The study takes braided river delta reservoir of the Oficina group in MPE-3 block of Venezuela oil field as an example.Under the guidance of sedimentary model,the study combined with the vertical wells,horizontal wells,3-D seismic data and quantificates braided river delta sandbody based on the method and technology of seismic sedimentology in order to solve the difficult problem of strong reservoir heterogeneity,sedimentary microfacies and sandbody distribution are difficult to characterize and difficult to meet the needs of fine development of horizontal wells.Based on classical sequence stratigraphy and seismic stratigraphy,on the basis of the isochronous sedimentary interface logging and seismic response characteristics analysis,the study area consists of a complete three-level sequence and six internal four-level sequences.Isochronous stratigraphic framework.In the isochronous unit,10 types of lithofacies are identified by coring analysis,the shallow-soil braided river delta front and plain sedimentary subfacies under the sea-land transitional environment of the study area are defined.The channel and the braided channel are Main reservoir deposition type.Seismic sedimentary characterization of strong heterogeneous thick sand bodies in braided river delta is carried out.The good correlation between sandstone and seismic peaks is achieved by 90 o phase transformation of seismic data.Strata suitable for different four-level sequence sedimentary filling characteristics is established.The slicing method adopts a parallel top-section slicing method on the unconformity surface at the initial stage of deposition,and uses equal-scale stratigraphic slicing in the middle transgression sequence,and a slice method parallel to the maximum sea surface in the upper stratum to ensure different deposition.The isochronism of the slice under the feature enables accurate characterization of the sedimentary microfacies.The study found that the lower part of the target layer developed the deposition of the braided river delta plain.The provenance of the study area is sufficient,and the river belt is large in scale,showing the characteristics of “full basin sand”.During the deposition period of MSC5 and MSC6,the study area develops braided river delta.The leading edge deposits,the diverging channel is large,and the river branches are developed on the plane;the combination of well and earthquake has established the core-river sedimentary combination model of the study area,revealing the vertical overlap and lateral migration of the heart and river sand bodies in the study area."law.On the sub-scale,the combined anatomical area of vertical well and horizontal well is selected,and the horizontal well-field seismic sedimentary interpretation method for horizontally high-resolution calibration of horizontal wells is proposed to realize the single sand body of the beach and the braided channel.The characterization of its internal structure;Based on finely characterized geometric parameters of channel bar and braided channel,summarizes the quantitative relationship between length and width of channel bar,relationship between width of channel bar and width of braided channel,relationship between width of channel bar and width of gully.Based on the study of sedimentary microfacies and sand bodies,the next development and adjustment proposals for the study area are proposed,which provides a geological basis for the development of horizontal wells in super heavy oil reservoirs.