Research On Logging Evaluation Methods For Sub-salt Carbonate Reservoirs In L Oilfield Abroad

Carbonate rocks are widely distributed throughout the world,and its exploitation of oil and gas production accounts for more than half of world output,The logging interpretation of carbonate reservoirs has gradually become one of the key points in logging evaluation.Carbonate reservoir has a very strong heterogeneity,and the reservoir space is complex and diverse.Therefore,the evaluation of carbonate rocks is one of the difficult problems in logging interpretation evaluation.In this paper,the carbonate rocks under salt of L oilfield are studied,on the basis of conventional logging evaluation,comprehensive imaging logging and nuclear magnetic resonance(NMR)logging and elemental capture logging method,established a set of suitable for the area accurately explain the evaluation method.Based on the comprehensive analysis of geological data,core analysis data and logging data,the four relations of reservoirs were studied,and the relationship between lithology,physical properties,electrical properties and oiliness were discussed in detail.Secondly,the reservoir characteristics are studied,the logging characteristics of various lithologies are summarized and the reservoir is classified.After using P1/2 method,porosity-saturation crossplot discriminant method and nuclear magnetic resonance(NMR)method are used to identify the fluid,using neutron density envelope method and poisson's ratio and volume coefficient of compression method in gas reservoir recognition are discussed in this paper.Then the mud content model is established by the conventional formula,using crossplot method,double mineral model method and nuclear magnetic resonance(NMR)method,porosity interpretation model is established,using crossplot,flow stratified index method and nuclear magnetic resonance(NMR)method to establish the permeability interpretation model of saturation interpretation model is established according to archie formula.On the basis of the model,the property,resistivity and saturation limit are determined and the interface of oil-water layer is divided.Finally,the above interpretation method is summed up,and a set of well logging interpretation method is set up in this area,and the comprehensive interpretation and processing of 6 wells in L oilfield are carried out.