Application Of Wave Impedance Inversion To Predict The Sandstone Reservoir

This paper is focused on comprehensive study of seismic reservoir prediction on a prospective oilfield. The research area is located in the east of D in Chad B basin. The basin experienced multiple period tectogenesis and a great number of small faults spread, which cause laterally varied and discontinuous reservoirs to difficultly value resources. The integrated technology of three-dimensional seismic interpretation, attributive analysis, inversion and prediction are applied to obtain detailed reservoir information in this project. Combined seismic data with the known geological information, I conduct careful seismic interpretation, including horizon tracking interpretation, well-seismic calibration and coherent data volume slice attribute, to find out the small faults. The characteristic of seismic wave reflection from object horizon layer is summarized and the structural map is drawn. Based on this results, the low amplitude structure traps is identified. According to the characteristic of this area, the geostatistical inversion method, not limited by seismic wave frequency band, is employed to predict reservoir information. According to geostatistical relationship of seismic and well data, stochastic simulation inversion and seismic inverse iteration method are used to inverse wave impedance and elastic parameters. Statmod of Jason software is used and some variables are tested and optimized to make sure the high accuracy. The object reservoirs inversion results show sand body distribution and reservoir properties. Compare on logging data, the wave impedance match the seismic reflectivity very well and the thickness error between the predicted and the actual measurement sand body is small. Especially, The result shows the lateral variation and distribution of sand body spread clearly and its trend coincides well with that of logging profile. In the gas and oil production stage, the geostatistical inversion method can effectively predict reservoir information, especially for thinner reservoirs.In this study, three-dimensional seismic interpretation technology and reservoir prediction method are summarized and a reasonable workflow is integrated. For the geostatistical inversion used on the study area, some variables are important for better inversion result. They are tested and optimized. Through this study, The structural map of D east in B basin are drawn. And the reservoirs information with high resolution is achieved in research area. The results are compared with logging data and they coincide well. At the same time, the study workflow and method can provide reference and help for reservoir prediction on the similar oilfield.