Reservoir Geological Model And Its Dynamically Real-time Tracking Method

Nowadays, the reservoir geological model has earned widespread respect from the oil companies and research institutions both at home and abroad, which have carried out lots of studies for the purpose of reducing the uncertainty and improving the accuracy of the geological model. The method mainly includes facies-controlled reservoir modeling, isochronous modeling, four-dimensional reservoir modeling, the combination of deterministic and stochastic modeling, multi-point geostatistics and so on. Based on the previous study, tracking methods is presented in this article to improve the accurate predictions of geological model.The geological constraints are widely used now in order to further improve the accuracy of the reservoir geological model. However, periods of reservoir geological models are always set up seperately without systemic tracking research, causing numerous new feedback information not being used to improve the model's accuracy. The feedback information is different in different development stages, which makes the model tracking methods and characteristics vary at the same time. The paper proposed targeted geological modeling tracking methods for each field stage, including the geological model dynamically real-time tracking method on the basis of logging while drilling, the geological model tracking method on the early development stage, and geological model integrated method on the middle and late development stage. In a narrow sense, the method based on logging while drilling is real-time tracking, while the others are not. For implementing dynamically real-time tracking, a new software--GMUS (Geological Model Updating System) is designed by using the Matlab software, which can realize the well data loading, data acquisition while drilling, drilling curve view, stochastic simulation, automatic update, etc.The dynamically real-time method based on logging while drilling is applied on the block one of Chenghai field and carried on the Zh8Es-h3, Zh8Es-h4, and Zh8Es-h5 well. Drilling practice showed that the drilling catching rate was obviously improved due to the accurate model. It took four years to track the Chenghai oilfield block two after applying the tracking methods on the early development stage and got the conclusion that the main factors on influencing the model accuracy were structure, variation function, grid size, etc. The sand thickness prediction in the restructured model had a decreased relative error 12.3 %. A more reliable integrated model was set up with the tracking methods on the middle and late development stage used in the 79-53 well group in Pubeiâ…£block and the EnKF method in the dynamic modeling. Dynamic geologic model and integrated geologic model recreated the permeability change of the subsurface reservoir, which had important significance on in-depth analysis and understanding on the channeling path existed in the Puâ… oil group.The geological model dynamically real-time track has been applied in the oilfield and made the best results now. Reservoir geological model dynamic tracking method can be applied to various stages of field development to increase the precision and reliability, and get the most represent of the real situation underground. This research is of great significance not only in the peripheral oilfields in Dagang and Daqing, but also in the similar oilfields in the other areas.