The Study On Logging Interpretation Method Of Pyroclastic Rocks Reservoir In Wuerxun Group

The complexity of pyroclastic rocks reservoir diverse, complex pore structure. Therefore, the evaluation of pyroclastic rocks more difficult than general sandshale reservoirs. However, with the increasing size of the oil and gas exploration and the depth of exploration, more and more attention to pyroclastic rocks. A large number of exploration confirmed that many parts of the world there are complex reservoir lithology. So there are great potential for development. For example, Wuerxun depression of the Hailar Basin region, there are large-scale volcanic clastic sedimentary rocks in the complex as the main reservoir lithology. Therefore, the establishment of methods of log interpretation for complex reservoirs lithology have great significance to the exploitation .This paper analyzed the geological characteristics and log response characteristics of pyroclastic rocks, and combined with log data of complex reservoir lithology in Wuerxun, such as the Physical Properties, the test oil, water-borne, mercury. According to the mechanism of reservoir lithology and basic geological features, this paper comes to the conclusion that because of its source and the complexity of the structure result in changing the characteristics of the reservoir in response to logging.On the basis of the study of formation characteristics and log response characteristics, this paper study the method of pyroclastic rocks identification and the calculation method of reservoir parameters with reservoir lithology logging data of Wuerxun depression.The accurate method of Lithology identification is an important task of reservoir evaluation logging. It can provide lithologic information on geological research, as well as the correct interpretation of log interpretation methods and explanation of parameters. Therefore, how to identify accurately reservoir lithology become a serious problem. At present, there are a lot of methods to identify lithology. For the actual situation of complex reservoir lithology, this article will choose the method of fuzzy pattern recognition to identify lithology of the reservoir.By studying the description data of core and the analysis data of flakes, we can find that the reservoir lithology is very complex and have a wide range of more than 20 kinds, and most of sedimentary rocks belonging to the transition of pyroclastic rock lithology and the mineral composition is similar, have the similar performance characteristics of the logging. To the principle of Similar response characteristics, Similar geological significance and Log response can be identified, this paper established the statistical model through dividing reservoir lithology into seven model and extracting the parameters of the each of model. Through the principal component analysis of all Logging, wo can Optimized 10 high sensitivity identification logging as logging parameters, such as GR, LLD, RMLL, KTH, DEN, CNC, DT, U, TH, PE. Then, according to the principle of fuzzy pattern recognition, this paper identified the reservoir lithology and correct rate over 83 percent.Log interpretation is to clear the Characteristics of the reservoir physical properties for the actual production to provide reliable information of the reservoir. So the calculation of reservoir parameters is an important part of log interpretation. In the basis of analyzing the reservoir lithology, physical properties, oil and electrical properties and combining with research results, this paper calculated reservoir parameters. In view of the complexity of reservoir lithology, This paper divided the study horizon into a number of reservoirs in order to achieve its purpose to explain the Reservoir parameters and Conducted a study on the each Layer.Parameters of the rock skeleton is a prerequisite for the work of evaluating reservoir quantitative using logging data, which is directly related to the reliability of a variety of reservoir parameters by logging evaluation. So, the reasonable parameters of a regional interpretation is very important for the logging evaluation. Different methods used to achieve the neutron, acoustic and density parameter of framework respectively, determined the optimal parameter values and the optimal method by comparing the accuracy.In log interpretation, the reservoir is composed of the rock, mud and pore. The presence of argillaceous rocks have a significant impact on reservoir physical properties. Therefore, to determine the clay content of rocks is an important task in log interpretation. This paper calculated the clay content of rocks with neutron and density by comparing the various methods of calculating clay content of reservoir. The clay content by calculating and the core analysis's result agree well.This paper effective porosity parameters of reservoir by the multiple regression method. The effective porosity calculated by the density logging, sonic logging, neutron logging with the effective porosity by core analysis return to the regression coefficient of each. So we determined the relationship calculating effective porosity for applying to the entire study area block.The ultimate goal of log interpretation is to evaluate the reservoir oil-bearing. In this paper, we calculated Wuerxun's oil saturation by Archie formula and compared with the conclusions of test oil, the correct rate over 83 percent. Compared to the previous explanation, the correct rate has been markedly improved.