Study On The Reservoir Architecture And Main Controlling Factors Of The Delta Front Of Slope-shifting Sandbody

This paper studies the slope-shifting fan sand body of the mid Es₃ member of Shahejie formation in the South of Niuzhuang Sag,through centimeter core observation of the key coring wells,particle size analysis,log response,seismic interpretation and other methods,comparing the deposition characteristics of the slope-shifting fan with the delta front sand body and turbidite sand in multi-angle,establishing the identification of slope-shifting fan and the longitudinal sequential pattern.On the basis of this study,the main controlling factors and distribution range of the deposition are discussed.In depth anatomy of the superposition styles and connectivity of the reservoir structure of the slope-shifting fan.In the end,the characteristics of oil content and the main control factors of slope–shifting fan are discussed.The study area is located in the southeast slope of Niuzhuang Sag and the tectonic pattern is southeast high,northwest low.The sedimentary center migrated from east to West.The slope-shifting fan mainly developed in Es₃⁶-Es₃³.The slope-shifting fan sand body are different from the delta front sand body and turbidite sand in lithologic character,particle size analysis,fluid type,sedimentary structure,structural feature,log response,seismic interpretation and other methods.The reverse cycle is shown in the sedimentary cycle.Petrological characteristics show that the dual features of this type of sand body with gravity flow and traction flow.The well logging facies show the combination of the box type and funnel shape of the features.In seismic facies,foreset reflection axis near the root is disconnected,showing the moderate,strong amplitude properties and good continuity.The ancient geomorphological features,sedimentary slope,growth faults are the main factors of the development of the slope-shifting fan.The most developed region of the slope-shifting fan is in the front of Wang 23 fault.The slope angle range which is conducive to the development of the slope-shifting fan is in the range of 3.86 degrees to 8.01 degrees.The favorable development zone of the slope-shifting fan range from Guan7 fault to the north margin of the Niuzhuang Sag to Chenguanzhuang area.Through fine calibration and analysis of seismic reflection characteristics,Identificat 47lithologic trap,?28 kinds of sand body of slope-shifting fan among them?,in destination layer.Through the fine dissection of vertical connectivity and lateral continuity between the single sand bodies in the sand bodies of the the slope-shifting fan of the mid Es₃ member of Shahejie formation.The vertical direction is mainly divided into two types,which are separate type and sand-shale alternating type,and the horizontal direction are divided into four types,such as pinch out in transverse,false connection,stable type and two-way pointed out.The oil content of the sand body is effected by the layered structure of the inner layer of the slope-shifting fan.The early deposition of drilled reservoir is in above the oil layer and below the water type in Es₃⁶ sedimentary period,when in medium deposition period,the reservoir is in above the water and below the oil layer type,and the oil reservoir is drilled in oil-water inversion only in some wells.The slope-shifting fan sand body is 200-300 meters away from the hydrocarbon source rock.The main factors which controlling the reservoir formation are pressure and fault.The pressure coefficient of this area is between 1.0-1.2.The sand body oil filling degree is low,generally between 30%-50%,but when the sand body of the oil source connected with fault,the oil filling degree can be 60%-70%.The slope-shifting fan is buried depth shallow?<3000m?,reservoir physical properties?porosity 16-24%?.Once the reservoir is into accumulation,the conventional oil test can get a higher production capacity.