Sandbody Genesis And Distribution Research Of Carboniferous Kalashayi Formation In Sangtamu Area

Sangtamu area is the main producing area of the clastic rock in Tahe oilfield.There are some high-productivity wells,such as S70,TK303,TK310,etc.The sandstone-mudstone member of Carboniferous Kalashayi formation is the main development segment.The Kalashayi formation is a favorable reservoir for the increase of oil and gas in Tahe oilfield and has great development respect.Current exploration and development indicate that the thickness of sand body,the fast transverse change,the deep buried depth and the poor seismic quality lead to great difficulty to predict fine reservoir.Therefore,it is very important to study the genetic types of sand body and the distribution regularity.The study is conducted in Sangtamu area with good three-dimensional seismic data and high exploration and development degree.Through core observation,rock thin slices observation,physical data,logging characteristics,seismic response and other geological and geophysical data,the formation of sand body is determined and the characteristics of various genetic sand bodies are clarified.Through the analysis of single well and connecting well,it is clear that the sand body overlay styles are different;On the basis of the third-order sequence of predecessors and the characteristic of single well rock and logging,the high quality stratigraphic framework is divided by synthetic recording,time-frequency analysis and well seismic calibration.Based on the theory of seismic sedimentology,the seismic waveform instruction is performed to identify and describe sand body subtly under the constraint of high precision grid.By the use of stratigraphic section technique and seleeting sensitive properties of sand body,the plane and spatial distribution of sand body is described.Finally,the quality reservoir is forecasted and the favorable sand trap is implemented.The study showed that the topography slope was gentle when the Carboniferous Kalashayi formation was deposited.Under the control of delta-tidal sedimentary system,the main types of sand bodies include water diversion channel,underwater distributary channel,tidal diversion channel,sand flat aid tidal channel,etc.The favorable genetic sand body are water and underwater distributary channel sand bodies.The sand body overlay styles include vertical overlay and lateral distribution.On the vertical section,it is divided into scour overlay,interlayer and interbed overlay.On the lateral section,it is divided into serial,oblique,butt and isolated.Dififefent genetic sand body overlay styles me differait.Based on the inversion mid slxatigraphie section,the surface distribution and qharacteristies of the sand body are delineated,and the sedimentary model of Kalashayi formation in the research area is established,and two Favorable sand body targets,S1072 and S1071 well areas,are optimized in target area.