Study On Single Sand Body Of Neogene ?-? Oil Layer Group In Footpanbei Area Of ??No. 2 Fault In Gasikule Oilfield

This thesis is based on sedimentology,petroleum geology,reservoir geology,oilfield subsurface geology,reservoir characterization and modeling.The division and correlation of sedimentary time unit have been accomplished by using "Half amplitude point" and multiple stratigraphic correlation method.Single sand body has been identified and divided according to sedimentary genetic analysis.The sedimentary microfacies of single sand body has been interpreted by using geological and well logging data.Miall's reservoir architecture theory of fluvial facies is used to study the reservoir architecture in the study area.Using the deterministic model and stochastic modeling method to establish three-dimensional geological model of single sand body.Achieved the following results:Using principle of stratigraphic correlation of "Half amplitude point" and stratigraphic correlation analysis of mark layer,isoaltitude stratigraphic correlation and slicing,the 38 small layers of ?-? oil layer group is subdivided into 108 sedimentary time units(barrier-layer,baffle and reservoir time unit).The single sand body in this thesis refers to the sandstone body in a reservoir sedimentary time unit whose upper,lower and lateral are all enclosed by the seal layer(mudstone layer and fault).the 1-level single body is controlled longitudinally by barrier-layer time unit and laterally by interdistributary mudstone or lacustrine mudstone,the 2-level single sand body is controlled by the baffle time unit or fault vertically and horizontally.The single sand body of the target strata in the study area is divided by the sedimentary type and the shape of sandstone lens.The target strata in the study area mainly developed braided river delta plain and braided river delta front subfacies.The sedimentary microfacies included distributary channel,braided bar,interdistributary,underwater distributary channel,distributary mouth bar,sheet sand and underwater interdistributary.? oil layer group in the study area are mainly braided river delta front facies,II oil layer group of braided river delta front and the relative to braided river delta plain subfacies transition,I oil layer group in the study area are mainly braided river delta plain facies.In the longitudinal direction,the facies sequence of the progressive product cycle is shown.According to coring and logging data,the architeture interface grading scheme of the study area is established,the lithofacies combination types of five sedimentary micro facies and the contact relations of architecture units are expounded,and the reservoir architecture patterns of braided river delta plain facies and front facies are summarized.Based on the results of geological-seismic comprehensive interpretation,the structural model of the study area is established by well interpolation under the constraint of key layers.Using sedimentary microfacies artificially interpreted by geological facies and logging facies,the sedimentary microfacies model of single sand body and barrier-layer time unit model in the study area are established by deterministic modeling method.The baffle time unit in the study area is virtually treated as a regional interlayer,while the local interlayer adopts random modeling method to establish a geological model of second-level single sand body.The reservoir properties(porosity,permeability,oil saturation)are modeled by sequential gaussian simulation under the constraints of the facies model and the barrier-layer time unit model.