Research On Fine Logging Interpretation Method For Complex Reservoir In PY Oil Field

The PY oil field has complex lithology and strong longitudinal inhomogeneity of the reservoir,which makes log interpretation and evaluation difficult,and there are thin reservoirs and low-resistance reservoirs in the oilfield that are not interpreted or missed.In this study,a set of high-precision reservoir parameter evaluation model is established by carrying out research on fine interpretation methods of logging data.It also conducts research on the methods for improving the resolution of thin-layer logging curves,and on the causes and identification of low-resistance oil reservoirs.The aim is to enrich the technical means for reservoir containing oil and gas evaluation and concealed reservoir interpretation in oil fields,which is of great significance for reserve evaluation and remaining oil tapping.In view of the data and development status of the study area,this study carried out logging curve standardization,core depth homing,porosity and permeability pressure correction,saturation correction,multi-mineral evaluation,permeability modeling,saturation evaluation,effective thickness lower limit and other logging fine interpretation research.In which,after analysing the factors influencing the saturation of the confined core,the mathematical statistical method and the phase permeability partitioning method were selected for confined core saturation correction.Using the information from the core homing and overburden correction,the parameters in the multi-mineral optimum logging interpretation model were optimised and used to evaluate the mud content and porosity.Application of the stratigraphic flow zone index to delineate flow units and evaluate permeability.Analysis of the influencing factors of rock-electric parameters in the study area,classification of rock-electric parameters based on wettability,and using the Indonesian formula to evaluate water saturation.Using the empirical statistical method,the Hingle plot method and the log interpretation plot method to study the porosity,saturation and lower limit of mud content of the formation.On the basis of fine interpretation and evaluation,research has been carried out on methods to improve the resolution of logging curves,and on the causes and identification of low resistance.In which,after using the rate of change of the logging curve at the layer interface to determine the integrated longitudinal response function,a combined longitudinal response discretization method and wavelet analysis method are proposed for improving the resolution of the logging curve.Based on the investigation of low-resistance types in the Pearl River Mouth basin and the logging and recording data in the study area,it was determined that the macroscopic causes of low-resistance in the study area are low-amplitude tectonics and weak hydrodynamic depositional environment,and the microscopic causes are high bound water saturation due to fine rock particles and high mud content,and a natural gamma relative value-visual formation water resistivity rendezvous combined with logging fluorescence was established to identify low-resistance oil formations.The method was applied to the log interpretation of four coring wells in the study area,and the statistical results showed that the average relative error of porosity was 3.72%,the average magnitude error of permeability was 16.98%and the average absolute error of saturation was 1.79%,indicating that the established model has high accuracy and can meet the oilfield interpretation requirements.The fine interpretation of the remaining 178 wells in the study area uncovered one thin potential layer and two low resistance oil potential layers,which achieved good results in tapping the potential and also provided guidance for the subsequent production,development,well layout and adjustment of the oil field.