A Study On Fine Reservoir Description Of The Da208 Area Of The Da'an Oil Field

Region 208 of Da'an Oilfield, an oil-gas accumulation zone squeezed by terrace structures, lies in the second tectonic zone of Da'an-Honggang terrace at the central depressed area of Songliao Basin. It belongs to a transition belt between two first grade structural units with relatively up-and-down movement as the central depressed area and the western slope area. The low permeable targets of Fu and Yang, which are developed as the main pay zones, have poor physical properties and are difficult to exploit. In this paper the fine reservoir geology were studied at the Region 208 of Da'an Oilfield by comprehensive analyses of the 3-D seismic method, core data and the dynamic information to determine the features of the oil layers development, the relations between 4 reservoir properties and the distribution laws of oil formation, then to build the 3-D model of Fu-Yang targets. This study would be meaningful to guide the studies and development of the residual oil inside this area, and to provide further foundation for the development methods and the adjustment program. There are fruits as following:Firstly cores from holes were surveyed to determine the types of sedimental microfacies and their development laws and features of the rocks within this area. For each substratum or sand group, the sedimental microfacies were interpreted manually to determine the standard of the relation between rock and electricity and to construct the model of the vertical sedimental microfacies of every well.On the combined bases of core survey and logging information, the substratum was divided and compared again to the substratum system under the control of high-resolution strata sequence. Based on the stratigraphy of the rock and the high-resolution strata sequence, in usage of the integrated method system of points, lines and fancies, the fine substratum model was built by closely division and comparison for the 25 substrata in the 67 wells of Fu-Yang reservoir.According to the results of oil testing and production, the relationship of the 4 properties were studied to build the electricity recognition limit of the pay zone. The well logging information was treated secondly digitally to interpret the oil-water layers comprehensively and to divide the effective thickness.With the results of the fine substratum contrast, by the fine interpretation with 3-D seismic data, a 3-D fine structural reservoir model was built to provide important bases for the fine reservoir model.In sum of the above studies, the statistical model about the space distribution of reservoir sand body was then fixed to provide parameters for the predictive model of the sand body skeleton. And in combination with the treatment of the logging data the effect of sedimental microfacies on reservoir physical properties was analyzed for the target area.In accordance with results of both substratum comparison and studies on sedimental microfacies, the two modeling methods of both trend and target were used to simulate the sedimental microfacies of substrata or sandstone groups.The reservoir model construction software, Petrel, is used to build the 3-D phased model of the Matrix and its properties such as the physical parameters and their random distribution.