Tight Sand Reservoir Prediction Of Terrestrial Formation In Northeast Sichuan

In the 21st century, the lithology reservoir is becoming a significant spot in the energy exploration field. Many researches have revealed that China has abundant lithology formation oil and gas reserves. There is great potential developing possibility in this field. Gas-bearing tight sandstone reservoir owns the most hydrocarbon reserves than any other type of lithology reservoirs. The terrestrial formation clastic rock reservoir in northeastern Sichuan is a typical tight sand reservoir. Because the marine carbonate formations which are the main pay formation are interesting formations, the study extent of terrestrial formations is comparatively low and has finite understanding. The well logging of the terrestrial formations displayed abundant oil-gas in northeastern Sichuan Basin. There could be enormous exploration discovery in this region. Needless to say, predicting and delineation of Northeastern Sichuan gas-bearing tight sand reservoir will assist natural gas exploration.The thesis summarized the current main ideas of research and development of tight sand reservoir prospection. Based on the geologic structures, seismic data and well logs, we processed reservoir prediction on northeastern Sichuan continental formation of gas-bearing tight sandstone formations. The interesting formations have the same features of tight sand reservoir such as the thin thickness of layers, low porosity, low permeability, heterogeneity and great differences in the abundance of gas and so on. In order to find the interesting areas, certain geophysical methods are applied in the research.According to the fine geologic interpretation, the features of geologic structure style are cleared. The solid formation data has built a firm foundation for the future work. Because of the compact sandstone and too many thin layers laid on each other, the normal acoustic log curves are not sensitive to the response of sandstone and mudstone. This kind of curves may not well distinguish lithology or determine formations. In order to acquire high resolution, the author applied GR curves to setup pseudo-acoustic which are sensitive to lithology. Take these curves as controlling points to establish primary model. Appling model based seismic inversion method to figure out he plane and spatial distribution of the sand reservoir in the target area.Meanwhile, we learnt theories of a series of seismic attributes. Under the high efficient seismic attributes analysis idea, the attenuation gradient attribute which gain the ability to distinguish gas-bearing sand and other rocks has been extracted and used to detect the fluid response in the region. This method was used for predicting the possibility of the existence of oil-gas in target area. Finally, numerical simulation of stress field is selected to detect fracture reservoir in the northeastern Sichuan area. The result shows that fracture reservoirs exist along those NW faults, same direction with the geologic structure background.In conclusion, the thesis processed reservoir prediction by means of rough-to-fine steps and applied the results of these methods to reduce the uncertainty of reservoir prediction. Meanwhile the author studied the spatial distribution and characteristics of the gas-bearing tight sand reservoir in northeast Sichuan. The results of prospection are well matched with known drilling data. All of the work could be regard as experience accumulation for the further exploration and study in this region. The paper also provides preliminary basic reasons and efficient reference ideas for the follow engineers.