The Study Of High-resolution Stratigraphic Framework And Sandbody Characteristics Of Dalinghe Oil Layer In Shuerarea

Taking high-resolution sequence stratigraphy theories and fine sedimentology theories asguidance, this study comprehensively used full and accurate well core, well logging and the3-D seismic data, etc in higher exploration degree area. Through the identification of thedepositional stage division sign, a set of division and correlation method of sublacustrine fansand body (single gravity channel) is put forward. Applied the contrast method (The regionalframework closed profile as plane control, combination sign controlled by standard layer withstandard profile as reference, guidance of depositional model-syngenetic fault model,gradual approximation, gradually partition closed and push away, finally genesis movingboundary), the problem of contrast of sublacustrine fan sand body is solved. The method wasapplied to establish the high resolution sequence stratigraphic framework by monosandbodyrank of the Dalinghe reservoir (4sand sets,12layers and19depositional units).Under the control of fine isochronous stratigraphic frame, the distribution characteristicsof sedimentary system, facies and provenance is analysed.The distribution and sedimentarymodel of gentle slope type of sublacustrine fan sand body based on the analysis of singlegravity channel is put forward. The zonal main channel and braided channel along the sourceas the skeleton sand body of sublacustrine fan controlled the distribution and sedimentarymodel of sublacustrine fan sandbody. The main channel extended forward gradually to largerscale of the braided channel and both sides are the braided channel side edge as a strip–shaped distribution. Into the center of the basin the main channel gradually evolved into anumber of small ends of braided channel deposition. Into the front and sides of the mainchannel gradually transition to the main channel levee and lake mud or the braided channel,braided channel side edge body,(a class) braided channel side edge, terminals and lake mud.Between banded sediment bodies controlled by each small braided channel are obviouslydeep lake and semi deep lake mudstones segmentation. As zonal-tongue shaped sedimentarybody extends toward the center of the basin far.Sublacustrine fan of Dalinghe oil layer developed in the Basin expansion period andBasin shrinking period. Its characteristics is obviously advanced progradation and afterretrogradation. In the vertical direction, it shows on sedimentary sequence from top tobottom,which is deep lake�'outer fan�'middle fan�'inner fan�'middle fan�'outer fan�'deeplake. It is thicker upward and coarsens, and then it is thinner and tapering. The formation ismainly controlled by three main factors of changes in sediment supply, lake level fluctuation and ancient landform change. When sediment supply increases, sublacustrine fan depositdevelops, the distribution area is the most widely, extending to the center of the basin is thefarthest; the obvious progradational stacking is presented. On the contrary, a smaller scaleretrogradational sublacustrine fan deposit is formed. The influence of sublacustrine fandevelopment by the change of lake level is similar to source. During the fall of lake level, thesource area promoted to the center of basin, sediment supply increases. The scope ofsublacustrine fan advancing and the distance is large.It is easy to form the sublacustrine fan inthe deep lake. Sublacustrine fan deposit affected by ancient landform is more significantly.That is of two aspects. Firstly, distribution patterns of sublacustrine fan sand body iscontrolled by ancient landform and Geomorphology that is the development of trench is moreeasily to form a sand belt. Secondly, facies differentiation is controlled by synsedimentaryfault boundary and the distribution boundary of main channel is roughly corresponding withthe distribution of fault.Based on the study of the isochronous stratigraphic framework and sandbody distribution,a set of sublacustrine fan sandody "flow units and heterogeneity controlled by phase” researchideas and methods that the single period gravity channel is as the object of study are putforward. Using the high resolution sequence stratigraphy and reservoir architecture theory,flow unit of sublacustrine fan sandbody is graded (level) and classified (types). Under thecontrol of sedimentary microfacies of monosandbody, flow units and reservoir heterogeneityare studied. The distribution of flow unit and heterogeneity in sublacustrine fan sandbody iscontrolled by the microfacies and energy unit. The spatial distribution difference of porosity,permeability and storage capacity is big and heterogeneity is strong in sublacustrine fansandbody.