Research On Data Processing And Interpretation Of Through-Casing Resistivity Logging

With the deepening of the oilfield exploitation,most of the oilfields in our country enter the phase of high water cut one after another.After waterlogging,formation properties and logging response will change,which brings difficulties to the evaluation of waterlogging.Through casing resistivity logging has unique advantages in remaining oil monitoring,old well excavation,determination of reservoir waterlogging rule,dynamic monitoring of reservoir production,etc.However,through casing resistivity values have some problems,such as discretization,non-equal interval,and multiple values at equal depth,which need to be processed in advance.Therefore,this paper constructs a set of waterlogged layer interpretation method suitable for this block on the basis of the pre-processing of the resistivity data through the casing,so as to provide technical support for the development and adjustment of this block.In this paper,the through casing resistivity logging interpretation process is studied,which can be roughly divided into four stages,namely,through casing resistivity RLAC data processing,flooding characteristics analysis,reservoir parameter model construction,and qualitative and quantitative interpretation of waterlogged layer.According to the characteristics of the casing resistivity data,Boxplot test,Grubbs test,nearest interpolation,linear interpolation,quadratic interpolation,cubic interpolation and other methods were used to obtain the casing resistivity values at equal depth intervals.Then,based on the change of formation characteristics before and after flooding,the logging response characteristics corresponding to different flooding degrees are analyzed.On this basis,the previous water-flooded reservoir interpretation model is studied and some open-hole well parameter interpretation models are used to complete the calculation of water-flooded reservoir parameters in this block.Then,the waterlogged layer was qualitatively identified by curve overlap method,cross plot,Fisher discriminant method and resistivity reconstruction method.The waterlogged layer was quantitatively characterized by the relative variation of resistivity RTR,hydrocarbon depletion index η and water production rate Fw.The accuracy of interpretation results was 85.7%,which can provide data support for oil field adjustment and development scheme.It has certain guiding significance for further exploration of oil production potential.