Study On The Identification And Reservoir Characteristics Of Silty Laminae/Beds In The Shale Strata In Qingshankou Formation Of The Southern Songliao Basin

A large organic semi-deep lake-deep lake facies deposited with high organic matter abundance of shale in the southern section of the Songliao Basin.The good oil and gas display of the shale well in the Fuxin uplift proves that the area has huge shale oil exploration potential.Therefore,this paper takes the section of Qingshankou Formation in the southern part of Songliao Basin as the research object,and uses various test methods to study the type of reservoir space,pore size distribution and connectivity for silty laminae / beds in shale.The difference in the storage properties of silty laminae / beds and shale was compared.The laminae / beds in the shale strata is predicted at different scales by fractal and logging methods.It is found that the intragranular pores and intergranular pores are mainly developed in the silt laminae,and the fragile mineral edge pores and intergranular dissolution pores in the intergranular pores are most developed.In addition,shale develops more organic pores.Shale is mainly dominated by intragranular pores,generally greater than 50%.The silty laminae /beds is mainly composed of intergranular pores,generally more than 50%.The silty laminae layer is mainly composed of mesopores and macropores,and the layered joints are developed.The joint pore diameter curve type is front and rear bimodal.The main pore size distribution of the silty interlayer is well sorted,mainly based on macropores,and the combined pore diameter curve type is medium peak type.The shale is mainly mesoporous,and the specific surface area is the largest.The joint pore diameter curve type is the front peak and the low type.The silty laminae are concentrated along the bedding plane and interconnected to form a pore throat network.The pore network and sample connectivity of pure mud shale are poorly developed,and the pore morphology is mostly spherical,small in size,and isolated and disconnected.On the prediction of the silty laminae / beds,based on the fine description of the silty laminae / beds in the shale strata,and established a fractal model(NS)to predict the silty laminae / beds of a single well.The calculation of the HEI 60 well The number of layers is 136,which is 115 layers,and the error is 18%.Calculate the total cumulative thickness of38.43 cm,the measured total cumulative thickness of 35.3cm,the error of 8.8%.The HONG68 well counts the number of layers 93,the measured layer number is 90,and the error is3.33%.The total cumulative thickness of the silty layer is calculated to be 50.68 cm,and the total accumulated thickness is 43.4cm,with an error of 15%.At the same time,using AC,CNL,DEN,GR,RLLD logging data,and MRGC clustering analysis method,divided into 12 kinds of logging phases,through the combination of excessive types to identify silty grain laminae,silty beds and shale,The last have achieved full-area prediction of silty layer thickness.Comprehensive comparison of the microscopic characteristics of silty laminae,silty beds and shale reservoir,oiliness,brittleness,physical properties,etc.It is believed that the siltylaminae mesopores-macropores and bedding seams are developed in large quantities,and pores It is connected along the level,has good oil content and high anisotropy and brittleness,so it can be used as the preferred interval for shale oil development in the study area.