Study Of Log Interpretation Methods And Its Application Based On Reservoir Flow Units

Carrying out the research on logging identification of carbonate reservoir types and flow unit research of reservoir,exploring the distribution law of fracture-cave system,and deepening cognition to expansion feature of reservoir,is very important for understandinggeological properties and productivity construction,and provide more accurate physical parameter for oilfield development.The Ordovician carbonate reservoir in the Tenth Block of Tahe Oilfield is featured with strong heterogeneity,various space.In this paper,based on core data,mud logging data,seismic data and development data analysis,reservoir types identification and flow unit research were developed using both dynamic and static methods.Static data mainly includes wireline logging and analysis assay data.Dynamic methods include pressure trend analysis,inter-well production interference analysis.Based on laws of karstification and identification consequences of single well,vertical vadose and horizontal phreatic zones were classified below T74 unconformity interface.In shallow part,vertical vadose zone was widely developed.In deep part,horizontal phreatic zone was widely developed,and faults and fractures provided flow channel for fluid,leading to large karst cave developed along fault zones.On basis of flow units research,logging interpretation based on flow units was developed.Properties of five types of flow units were summarized about lithofacies,physical properties,electronic properties and oiliness.In aspects of logging interpretation model for parameters.Firstly,porosity was calculated respectively by density,neutron and interval transit time.Secondly,through regression analysis,five different porosity interpretation models were erected according to five flow units.Thirdly,flow unit identification was based on permeability-porosity relationship,so five different permeability interpretation models were erected according to five flow units.Compared with regular methods,the interpretation accuracy of parameters was improved significantly and more reliable data was provided.According to cave reservoir,fracture reservoir,and matrix porous reservoir,corresponding oil-water discrimination cross-plot was worked out.And three types of oil layer were recognized.Finally,the distributive law of reserve parameters in vertical vadose zone and horizontal phreatic zone with statistics proved a good correlation between distribution of parameters and flow units.