Study On Fahliyan Reservoir Characteristics Of Yadavaran Oilfield In Iran

Iran's Yadavaran Oilfield,an important area of Sinopec Group's overseas' science and technology research,is vital to support Sinopec's domestic market's oil supply.Therefore,it's of great necessity to carry out a comprehensive research in its oil reservoir and geological conditions.Aiming at solving Yadavaran Oilfield's three main problems of reservoir exploitation,this paper provides effective technology support combining with all kinds of geologic and reservior material.Especially in log data preprocessing,researching of reservoir's four characters,modeling finely of log interpretation,study of reservior distributive regularity and overpressure formation's mechanism,some new research results has been obtained.The main research production displays as the following aspects.Firstly,based on Fermat principle and rock bulk physical model,environmental correction methods of porosity log data(acoustic,density,neutron)are established to eliminate influences of log data and mud invasion.Those methods are proved to be very effective in pratical data processing.Secondly,the key well,HOS2,was selected as the standard well,meanwhile,a pure limestone formation with distributional stability in the research region was chosed as the standard stratum to normalize all log data such as GR,RT,DEN,CNL and AC in this region.The standardization has eliminated log data's system errors of different series,and provided accurate data foundation for researching of reservior's four characters and modeling finely of log interpretation.Thirdly,a law in Fahliyan oil layer has been found that when the property of pore fluid varies slightly,that is to say,when formation water saturation is limited to a fixed range,the formation's resistivity declines as reservoir physical property becomes better,while when reservior physical property varies slightly,the formation's resistivity increases as the property of oilness becomes better.Fourthly,Fahliyan oil layer is divided into two groups.Due to combined action of structural feature and oil-water system,in vertical,oil layer lies mainly at the top part of lower Fahliyan layer,while,the water layer lies at the bottom.It is clear for oil-water interface.Horizontally,by the influence of region structural feature,the oil layer mainly strenches at higher position of structure in the research region especially in KSK1,KOS2 and HOS1 well area.Fifthly,region structural feature is the main controlling facter of Fahliyan oil reservior,and Fahliyan oil reservior is a typical structural reservior,which is controlled by an anticlinal structure.Under the control of region structural feature,Fahliyan oil reservior's transverse distribution is largely influenced by crack's growth situation.The reservior's percolation feature,development,and oil-bearing characteristic show well in those areas which has good crack development and large porosity.Sixthly,Fahliyan reservoir's reservoir types can be divided into three classes based on quality index.The first type is the best and is the main development formation,this type reservoir mainly distributed in the structural high place and its matrix porosity,fracture porosity and reservoir seepage ability are all the best in three reservoir types.The second type is the second and it mainly distributed in transition place which from structural high place to low place.The third type is the worst and it mainly distributed in structural side,its reservoir porosity and seepage ability are all poor,not the main exploration and development area.