Putaohua Oil Layer In Block 254,Sanzhao Sag,Songliao Basin Study On Sedimentary Microfacies In Horizontal Wells

The subfacies sand bodies in the delta front of the Putaohua oil layer in the Sanzhao Sag were formed in the large-scale river-delta sedimentary system in the north,and the physical properties of the reservoir gradually deteriorated from north to south.The thickness of single-layer sand bodies in Zhouzhou 254 block is relatively thin and thin interlayers are developed.The lateral phase of sand bodies changes rapidly and the reservoir heterogeneity is strong.In order to economically and effectively develop low permeability thin marginal oil layers,25 horizontal wells are distributed in the study area.Compared with purely applying vertical well information to describe facies,horizontal wells participate in facies combination,which is equivalent to increasing the density of the well pattern,which can reflect the situation of underground geological bodies more finely,reasonably and accurately,making the contact relationship between sand bodies and the reservoir plane non-uniform.The description of homogeneity is clearer.However,due to the stratification of horizontal wells,the geological body structure around the wellbore,logging environment,wellbore geological body manifestation,sedimentary sequence characteristics along the well,logging characteristics,etc.have changed,or even changed greatly,plus the limitations of the borehole,Which brings difficulties to the study of facies and reservoir.In this paper,on the basis of fully absorbing and summarizing the previous research results,the core data,vertical well logging data and horizontal well logging data in the study area are used to guide the theory of sequence stratigraphy,sedimentology and applied geophysics.The logging,logging data and logging response mechanism of horizontal and vertical wells in the study area were analyzed.Through the corresponding analysis of horizontal well core and log response,various quantitative response characteristics of horizontal wells with different lithology are established,and the quantitative distribution characteristics of various log responses are counted through a large number of non-coring horizontal wells;similarly,different Quantitative distribution characteristics of various logging responses of lithologic vertical wells;thus,the quantitative difference characteristics of the same logging responses of the same lithological horizontal wells and vertical wells are established.In order to analyze the quantitative differences of various logging responses of various lithological horizontal wells and vertical wells.Through the analysis of the relative inclination of the horizontal shaft and the formation,the lithology combination and thickness,the formation anisotropy,the wellbore environment,the instrument detection range and otherinfluencing factors,the correction method of the horizontal well resistivity logging curve was established,Correction of horizontal well resistivity logging curve,construction and perfection of horizontal well logging sedimentary microfacies discrimination,and establishment of horizontal well logging facies model,can accurately identify horizontal well sedimentary microfacies types.The combined vertical and horizontal well leveling phase correction can accurately identify the boundary of microfacies,clarify the contact relationship between microfacies,and more accurately draw the sedimentary microfacies map.The horizontal continuous advantage of horizontal wells can make the identification of river channels more accurate and continuous.Some horizontal wells can accurately determine the channel boundary position and channel scale.The fine description method of horizontal well reservoirs formed during the research has the potential for efficient development of horizontal wells in the future.The important guiding significance is to further the goal of precise geological research.