Research On Sandbodies Characteristics And Distribution Law Of Slope Fans In Dongying Delta Front

The lithologic reservoir in Dongying sag is highly developed,It is the main type of oilfield exploration and development.Such traditional subtle reservoir as river sand,turbidite rock and glutenite is highly developed,but the study on the new type of reservoir as slope fan is still in the initial stage.After initial exploration,it is found that there is very good exploration potential with the slope fan.On the basis of previous studies,according to core analysis and testing,well logging,seismic data and field outcrop pictures,the sedimentary features was completed.Combined with physical deposition simulation experiment,the development pattern and distribution law of slope fan are discussed.On the basis of this,the definition of slope fan is defined.Slope fan is a kind of event sedimentary body formed by the sand body of delta or fan delta front slope with sliding or debris flow in the slope belt.According to analysis and test data,the lithology of slope fan sand body is mainly light gray fine,silty sandstone and dark gray,brick red mudstone,mainly consisting of debris feldspar sandstone and feldspar lithic sandstone,compositional maturity and structural maturity were low.Grain size probability map can be divided into four types.C-M maps shows the sedimentary characteristics of gravity flow.Such grain size parameters as average value M_Z???,standard deviation?₁???all indicate a sediment and retransport delta front slope environment.Sedimentary structure is mainly physical genetic structure such as flow genetic structure,contemporaneous deformed structure and biogenic structure such as bioturbation structure,biological heritage structure.Log curves of slope fan sand body were divided into 5 types:box type,funnel type,etc.In profile,slope fan sand body located in the anterior layer,developed horizon is Es3,the continuity of sand body was good.The single sand body is mostly a lens or a wedge shape,the thickness is also different.Seismic facies is moundy or sphenoid and amplitude characteristic is moderate to strong.Based on the field investigation of deposition,outcrop characteristics of delta front shallow water deposition was analyzed,which was an important reference to the slope fan research.According to the similarity principle,physical sedimentary simulation experiments were done.Three kinds of development patterns of slope fan were summarized,such as longitudinal backward extension,lateral expansion and random expansion.Five types of slope fan sand body on the slope were identified and exhibit a regular zonation.The controlling factors of the formation of slope fan are triggered mechanism and its duration,the volume fraction of the sediment and the composition of the sediment,the bottom of the sediment and so on.According to the geology condition of Niuzhuang Sag,combined with relevant data and experimental analysis,6 slope fan sand bodies are identified,frontal sand body,slope fan and turbidity fan were divided into zones and the distribution of slope fan were forecasted and two favorable prospecting target area of slope fan:sliding collapse type slope fan distribution area and debris flow type slope fan distribution area were divided.