Logging Evaluation Of Tight-gas-sandstone Reservoirs

Tight-sandstone-gas has become China's most realistic unconventional natural gas resource.In this paper,the Cretaceous Bashijiqike Formation in the study area is a low porosity and low permeability tight-gas-sandstone reservoir.There are features which are complex lithology and poor physical properties of the reservoir.It is difficult to evaluate the fluid properties accurately,the distribution of gas and water is unclear,which will affect the development of a reasonable development program.The paper will fully combine the coring analysis data,logging data to establish a sound reservoir evaluation and fluid evaluation system.Experimental analysis shows that the reservoir permeability is difficult to calculate,because of that the reservoir has a variety of storage space.The presence of muddy and carbonate rocks seriously affects the accuracy of reservoir modeling in the study area.According to the lithological characteristics of the study area,the rock volume model is established,and the reservoir is modeled by stratification.Based on the interpretation of stratified reservoir logs,a number of data were used to identify the reservoir fluid properties.Then the water saturation of single well reservoir was explained.Five kinds of calculation methods are used to calculate the effective thickness lower limit of reservoir,finally the lower limit of effective thickness of reservoir is determined by comprehensive analysis.The effectiveness of the reservoir is evaluated.Establish the logging phase-rock facies database and set up the discriminant functions.The automatic classification of reservoir types has been achieved.The completion of this paper has established a complete reservoir evaluation and fluid evaluation system for the study area.It also provides a practical solution for evaluating the effectiveness of the reservoir accurately.