LOGGING INTERPRETATION MODEL FOR RESERVOIR PHYSICAL PARAMETER IN THE QUATERNARY NATURAL GAS RESERVOIR

Taking Quaternary unconsolidated biogas reservoir of Tainan area in Eastern Qaidam basin as an example, the building methods of logging interpretation model for physical parameters of this kind of reservoir were studied. The JD 581 conventional log data were used to establish the porosity logging interpretation model by making compaction, correction of shale content and gas bearing influence on acoustic logging and quantitative calculation. A quantitative correction method for gas influence on acoustic logging was developed. According to the capillary theory, the capillary pressure curve and log data were applied to establish the permeability logging interpretation model. The interpretation accuracy was improved much more than that of the conventional method. It is a feasible method to make a quantitative correction of natural gas effect on the acoustic log by the use of the resistivity log. It can improve the accuracy of acoustic logging interpretation model for gas reservoir porosity and implement the evaluation research on the reservoir porosity parameters by applying the JD 581 conventional log data. The rock specific surface and porosity primarily influence the mean radius of pore throat. This kind of parameters for the reservoir micro pore structures can be calculated accurately by the integration of porosity and lithologic log. This model can provide a solid foundation for evaluating the reservoir permeability parameters.