Logging Secondary Interpretation Of Lacustrine Carbonate In The Forth Member, Shahejie Fm.,Zhan-che Area

The lacustrine carbonate rocks within the Jiyang depression are viewed as a special kind of reservoir type, showing great exploration potential. The lacustrine carbonate rocks within the depression develop in the first member and the upper fourth member of Shahejie Formation. In Zhanhua sag, carbonate rocks mainly develop in the Yidong and Luojia areas, on the southern gentle slope of Chezhen sag. High-productivity wells have been drilled; therefore it is of great significance to enhance the understanding of the law of deposition of carbonate rocks and the development of reservoir rocks, which have very essential and practical use in guiding exploration and development in the area.Because the upper fourth member of Shahejie Formation is very thin in the area, it is very difficult to study the distribution of carbonate rocks merely on the basis of seismic data, and drilling, logging data are essential data for studying the causes and types of carbonate rocks and their distribution. However, the logging data has great span of time, therefore in order to make full use of logging data for studying the distribution of carbonate facies, genetic types, and the law of reservoir development, it is necessary to take full advantage of core, logging and production data and so on to carry out the secondary interpretation.The research thoughts in this dissertation are as follows: based on regional geology, the author observed and studied the cores, and also digitalized and studied core logging data, and at the same time observed and described many thin sections, then the classification scheme of carbonate rocks in this area was gained. Furthermore, rock-electricity template was established on the basis of curve standardization, subsequently the author carried out lithologic interpretation based on the integrated use of cross plot and cluster analysis methods in combination with the analysis genetic types and test data and so on, at last the interpretation was elaborated based on the existing rock-electric template.Through this research some achievements are accomplished: the author summarized the method of carbonate rocks observation, and classified the carbonate rocks based on integrated use of cores, thin sections, and therefore had a better understanding the lithology of lacustrine carbonate rocks and facies; chose suitable logging series, including gamma ray and acoustic slowness data and so on, and standardized them, and then a process of log curve standardized was formed, and after a comprehensive analysis of core and logging data, established rock-electricity template suitable for this area; then carried out lithology interpretation based on integrated use of production and depositional facies data, in the interpretation of the lithology, the author first summarized the lithology and divided the lacustrine carbonate rocks into limestone, argillaceous limestone, mudstone, and then elaborated the interpretation integratedly using rock-electricity template, got a relatively finer interpretation for key wells in these areas, and also laid a good foundation for the study of the distribution of sedimentary facies study and the prediction of reservoir rocks.