Sequence Constrained Seismic Prediction Of Fluvial Reservoir In The Middle Of Zhunga'er Basin

According to the third round of Petroleum Resources Evaluation, the lithological and stratigraphic reservoirs take 42% of the residual petroleum resources offshore China. In a very long period, the lithological and stratigraphic reservoirs would be the most potential and realistic on-shore exploration frontiers in China. In the last several years, lithological and stratigraphic reservoirs take more than 50% of the proven reserves of PetroChina. Giant oil fields with 50 million to several hundred million reserves from lithological and stratigraphic reservoirs have been found in Sonliao, Bohai Bay, Ordos and Erlian Basin. Lithological and stratigraphic reservoirs have been an important type of reservoirs contributing large percent of proven reserves in China.After discovered the Jurassic Toutunhe reservoir in the Middle of the Zhungar'er Basin, the subsequent drilling result by appraisal wells couldn't support the seismic prediction result. How to improve the reservoir seismic prediction? What will be a good way for future exploration of lithological reservoirs? How to evaluate seismic prediction errors in this area were challenging questions that explorationists were trying to answer. Finding solutions could be a very good reference for exploration of lithological reservoirs in other areas.Based on large amount of reading and investigating, the research focused on the study of the basis of reasonable reservoir prediction - high resolution sequence stratigraphy, and of the method of improving the vertical resolution. The following research principals to improve the sand reservoir prediction:The main achievements of the dissertation are as followings:1)Forward Modeling analysis helped to understand the seismic response characterization of the target reservoir. This is a very important basis for developing the effective method of seismic prediction.2)A high resolution sequence frame was first built up based on the analysis of fifth order sequence of Toutunhe Formation of Shinan21 well block, the sedimentary facies of the reservoir was then analyzed .3)Geological and geophysical elements affecting the velocity field were analyzed, and selected the most applicable field inversion method to calculate the average velocity field constrained by the sequence frame.4)Built up a sequence constrained reservoir prediction technology set, including: sequence constrained velocity field inversion, sedimentary facies analysis, lithology prediction, physical property prediction technology. The technology set can be a preliminary one for other area in the middle of Zhuangar'er Basin.5)For the first time, the thesis systematically conducted the error analysis of the prediction comparing with the real drilling data. Stimulating the exploration and appraisal history of the Shinan21 Block, the thesis finished the structure mapping, seismic inversion before and after every run of appraisal wells drilling, the result showed that sequence constraining is an effective way to improve the reservoir seismic prediction.6)The thesis developed tunning energy enhancement method mainly for identifying thin beds on poststack data. By modeling test, synthetic seismogram and section comparison, it is showed that the method could effectively improve the apparent resolution.