Logging Evaluation Study Of Fractured Gas Reservoir Parameters

Reservoir parameter is an important indicator of reservoir productivity evaluation. Cracks have an important impact on the reservoir parameters, especially on permeability. Cracks give a large contribution on the productivity for the fracture area, so its quantitative evaluation is very important. But on the reservoir where cracks are not developed or less developed, matrix perform a dominant action to reservoir properties, so reservoir evaluation makes matrix part as the center. The study area reservoir has a small amount of cracks and their properties are very poor. Therefore, matrix part is dominated and evaluation of matrix parameters is key work.Influenced by many environmental factors such as geological, reservoir physical properties in the study area have great difference in the vertical and plane. In the vertical, physical properties in different geological layers are also different. In the horizontal, the study area shows a trend feature that properties are good in the southeast and poor in the northwest. Besides, the large span history of logging data in this area, many types of logging equipments, messy raw data, all give difficult to the detailed evaluation of reservoir parameters in this region.Focusing on data characteristics, The thesis starts from logging data preprocessing. At first, the original logging data is spliced and edited. Then two different methods of standardization distinguished with histogram and trend surface are applied and compared using actual data. Based on this, the article presents a standardized method combining histogram and geology trend analysis technologies using standard reservoir. Practical application shows that this method can eliminate the system and artificial error and take good effect in multiwell evaluation. The paper classifies reservoir according to lithology and researches each logging response characteristics. According to the vertical difference of facies and log phase,the paper divides reservoir into several sections referencing to geologic and distribution of data points. Based on this, matrix property parameters interpretation models can established for each segment using core data and logging data. Then the clay content and porosity and permeability parameters are fine explained, and evaluation of results is consistent with the regional geological. The paper counts the distribution of reservoir properties and analysis that there are better internal relations between geological origin and physical evaluation results.This paper calculates gas saturation using Archie formula and Kukal equation respectively. By comparison, the latter has better results because of less affection of porosity. This paper also calculates physical parameters of fracture using empirical formulas and the results are close to the core data. Then the thesis studies the crack affection to reservoir properties.Finally, on the basis of above studies, the complete data processing is raised and an effective fractured gas reservoir evaluation method of logging is formed.