Logging Evaluation Of Tight Sandstone Reservoir Effectiveness

During the exploration and development process of the Daning-Jixian area,we founded that tight sandstone gas reservoir has some characteristics such as low porosity and permeability,complex pore structure,poor transverse continuity and strong heterogeneity,and unidentify of fluid properties,etc.Lacking of accurate evaluation criteria for reservoir effectiveness restricts the exploration of tight gas in this area.It is urgent to carry out research on fluid property identification and logging evaluation of reservoir effectiveness to guide the exploration and development plan in the research area.Based on core analysis,well logging,gas logging and regional geological data,this dissertation achieved the following successes: using the four-relation analysis of reservoir to identified fluid properties;established logging interpretation model of reservoir parameters;determined the evaluation criteria for reservoir effectiveness,and then screened the favorable areas for development.Specifically:(1)The characteristics of four relationships of reservoir in the research area are proved.Reservoir physical property and gas-bearing property are controlled by lithology.Compared with siltstone,medium and fine sandstone have better physical and gas-bearing properties.Resistivity,especially array induced resistivity,can reflect the gas-bearing characteristics of reservoir well.(2)Using multi-information fusion technology,we established the fluid property identification chart.It is found that compensated acoustic and compensated neutron logging crossplot method can effectively identify the gas-water layer,and the dipole shear wave logging method also has high accuracy.(3)A fine logging interpretation model for reservoir parameters was established by using the idea of core calibration logging.Logging data processing and interpretation of 55 Wells in the research area were carried out by logging interpretation program.(4)The characteristics of pore-throat structure in the research area are systematically analyzed,and the comprehensive reservoir parameters are calculated.Therefore,the logging evaluation standards of reservoir effectiveness are determined,and the reservoir is further divided into three types of development favorable areas.