The Application Of Reservoir Geophysics In Thin Sand-shale Inter-bedded Layer

Reservoir geophysics technique, also called exploration geophysics technique, has been widely applied by petroleum explorers. Presently, reservoir geophysics, as an important technique in production, has extended to the oilfield exploration, and improved in application. With the development and application in Shengli Oilfield, reservoir geophysics has formed a series of techniques, aiming at the exploration of the continental deposition, which could identify low level faults, interpret thin inter-bedded layer, providing 3-D information of fluid and model fine deterministic reservoir. It includes integration of single geophysical technique, joint inversion from multi scale geophysical data and deterministic reservoir modeling.Thin inter-bedded layer is geological phenomena of different litho logical thin layer appearing alternately. The important feature is the different litho logical characters between two adjacent layers, which repeatedly appear in the vertical formation, such as sand-shale inter-bedded layers and salt rock-shale inter-bedded layers. With the deepening of the exploration, the research of inter-bedded layer has become more and more important orientation. The thickness of inter-bedded layer is generally smaller than the tuning thickness, which is hardly identified on the seismic profiles, leading to the result that the core problem in the exploration is the prediction of the thickness of inter-bedded layers.This paper begins with the collection of different scale geophysical data, including drilling data, well-logging data, rock physical data, cross hole seismic data, 3-D VSP data, high precision seismic data and multi-wave and multi-component seismic data. Then the paper analyses the characters and advantages of different data in the prediction of sand-shale inter-bedded layers. Based on the analysis about the features of thin inter-bedded layer, the technological procedure is set up, including series of techniques, such as improving resolution processing with well constraint, formation frame modeling based on the coherence of well and seismic data, multi cube structure interpretation, joint inversion by multi data and identify advantageous facieses. Next, further study about the key techniques carries out by reservoir modeling interpretation and practice in real model. At the same time, the procedure is improved and the resolution is increased. Finally, this paper introduces the application of the series of geophysical techniques above.Based on the study of the geophysical techniques and prediction methods to the sand-shale inter-bedded layers, using the abundant well logging data and production information, taking the advantages of the high resolution of cross hole seismic data and 3DVSP seismic data, the paper predict the thin inter- bedded layers and improve the horizontal and vertical interpreting resolution, and meet the need of reservoir production in the eastern continental oilfield. At present, the prediction methods has been practiced in the area of thin inter-bedded layer. It solved the problem of low resolution. Meanwhile, this prediction method is very significant for the resolution and researchers efficiency improving.