Fine Geological Research Of PI Reservoir Group In ZP50-88 Well Block, Songliao Basin

The ZP50-88 well area is located in the Southeastern part of the 401 block of the central depression area in the northern part of the Songliao Basin,China.It is located at a lower structural part with a working area of 4 km~2.With the development,the well bock exploitation has been entering the middle and late stage,the imbalance of production conditions is prominent,and it is concentrated as“injection without production or production without injection”.In order to achieve efficient development and meet the needs of subsequent stable and increasing production,the thesis mainly focuses on the problems of the distribution of single sand bodies and insufficient understanding of connectivity between sand bodies and makes full use of geology,geophysics and test data to clarify the single sand body distribution and the connectivity between sand bodies on the basis of fine stratigraphic division and contrast and the identification of sedimentary microfacies.Besides,the distribution of geological remaining oil is also predicted,which provides reliable geological results for future potential development.Using drilling and logging data,based on the results of the second interpretation,the stratigraphic division and comparison are carried out.In the order of"oil layer group-sand layer group-small layer-single sand layer",and the PI reservoir Group is divided into six single sand layers,including PI52,PI51,PI32,PI31,PI22 and PI21,and a single sand level isochronous stratigraphic framework is established.Making full use of the coring data and logging data,and referring to the previous research results,based on the analysis of the core facies,the logging facies and the multi-well facies,the sedimentary facies of working area is the delta front subfacies,mainly developing four microfacies which are underwater distributary channel,mat sand,leading edge mud and estuarine sand dam.According to sandstone thickness distribution and sand-ground ratio distribution,the evolution characteristics of sedimentary microfacies of each single sand layer are clarified.According to the morphologic characteristics of logging,the differences between sand surface elevation,channel deposition and thickness difference of river sand bodies,four kinds of constraint conditions are used to analyze the spatial contact relationship of single channel.The contact relationship between single sand bodies was analyzed in detail according to the vertical superposition characteristics and plane composite characteristics.Focusing on the main layer PI52,PI51,PI22,PI21 to relate and analyze,25 single sand bodies are identified in 4 single sand layers combined with the distribution of faults within the block.Based on the fine characterization of single sand body,the single sand body connectivity of the four main sand layers is analyzed.In the vertical direction,two types of interlayers which are muddy and physical are identified in the working area.By distributing the thickness of interlayers on the plane,the communication between single sand layers in each well was displayed on the plane.Laterally,combined with the results of sedimentary microfacies and single sand body distribution,four types of inter-well sand body connectivity were established.Finally,based on the production dynamic data,the research results of sand body distribution and connectivity are verified.