Study On The Formation, Distribution And Effectiveness Of Reservoir Fractures With Oil And Gas

The objects of this study are the crop and the underground igneous rock. On the basis of classification, origin, controlling factor and distribution characters of the fractures, the identification of fractures in reservoirs was studied by utilizing the log data, and a kind of log computing method was established. Many kinds of new methods,which were used to forecast the distribution of the fractures in reservoirs by many single factors and compound factors, were proposed. The characters of fractures in reservoirs were quantitatively evaluated by many factors, and the validity of the fractures was analyzed by utilizing the crop, drill core, thin section and logging method of fractured reservoir. The main conclusions and results in this thesis were as follows:On the basis of the geologic research about the extinct volcano group in the Changle area, Shandong province and Shang741 well area, Shanghe oilfield, the geologic model of fractures about the extinct volcano and underground igneous rock were established. And the main influential factor of the fractures was analyzed, which includes lithofacies, tectonic stress, lithology, stratum thickness, sectonic position and so on.According to the result of rock mechanical test, rock acoustic emission test, and the analysis of the fracture log response, the log computing method of rock mechanics factor was established, which can be used to provide variable rock mechanics factor for ground stress field simulation.The fault-stratum ratio was first raised in this thesis, which refers to a ratio between the plane of the fault and the coverage of the gridded research area. The fault-stratum ratio parameter is a basic parameter which is used to describe the faulted gradation of fault and fault system in specific region. It can be used to forecast the developmental gradation of fracture in reservoir, and the theory of the fault-stratum ratio was completed. A kind of modified method was established to forecast the developmental gradation of fracture in reservoir by using the microtectonics curvature. Using the variation microtectonics curvatureâ–³K, a new kind of method was proposed to forecast the developmental gradation of irruptive rock fractures in reservoir, and this method overcomes the disadvantages of the method, which forecast the developmental gradation of fracture by utilizing the curvature of the stratum.On the basis of the result of the rock mechanics parameter logging computation, the stress field simulation of Shang 741 well area was completed. The high figure of the stress in Shang 741 well area was distributed in densely faulted section, and the distribution of the stress appeared in two longitudinal high figure areas.The conception of fracture discriminate parameter was put forward. Based on the study of the influential factors of fractures in reservoir, the fracture discriminate parameter was raised to forecast developmental gradation of fractures in reservoir. This method overcomes the limitation of the fracture forecasting method by utilizing single factors.Using the multi-parametric to estimate fractures of reservoir, the quantitative estimation method was completed, which overcomes the limitation of the quantitative fractures estimation by utilizing single factors. And we do some research about the validity of the fractures by using the crops, cores, thin slice observation and the logging method and so on, especially the method of dual lateral logging.