| With the increasingly demand of natural gas & decreasingly supply of natural gas reserve in the world, the tight sandstone gas reservoir has been taken as the important reserve resource by many countries, most of which have explored and developed in large scale and achieved economic & social benefits. From the results of the second round resource evaluation, our national onshore natural gas is 30.23 × 1012 m3, some of which are from abnormal tight natural gas with about 40% of total ( about12×1012 m3 ). At present, nearly 1/3 natural gas production is produced from abnormal tight classic reservoir. Our current reserve analysis shows that the normal natural gas peak point will be dropped down by 2010, it must have new takeover resource for supplement. So, abnormal tight natural gas resource shall be an important takeover energy. Upper Triassic tight classic natural gas in western Sichuan basin is an important natural gas energy production base with 18000 - 25000×108m3 in Sichuan basin. But it still has potential exploration & development future due to 2300×108 m3 proved & probe reserve with only 10.7% of total energy. Through the research of reservoir forming mechanism, rules of enrichment, prediction technology for tight low permeability and development technologies, this article achieves the following innovative results.1. The conditions and whole process of main gas-bearing areas in the world are generally completed in an important tectonic event. But for the multi cycle superimposed basin, it is still a problem to be solved for the theoretical study of reservoir forming with several important tectonic events. The several tectonic events of western Sichuan depression since late Triassic leads to the changes of physical property, structure characteristics, fluid characters and stress field of upper Triassic Xujiahe formation, and the migration & accumulation of oil & gas formed after going through many times. Based on the research of reservoir forming mechanism, rules of enrichment, it is considered that the early palaeostructure is the basis of gas accumulation in early period, abnormal overpressure compartment is condition of natural gas preservation in middle period, fracture activation is the key point of natural gas enrichment in late period, so it is put forward the progressive dynamic geologic theory of tight classic rock in western Sichuan, that is "early accumulation, middle compartment and late activation", and solves the oil & gas reservoir theoretic problem of undergoing several important tectonic events and deep—super deep formation in western Sichuan depression, meanwhile, it riches and expands the geologic theory of reservoir forming.2. Through the research for hydrocarbon generating & expulsion peak point, reservoir tightening, fracture forming & trap forming period and its time—space disposition, it solves the chronology problem of upper Triassic super deep & over pressure and makes it clear that the fill peak of 2nd section of Xujiahe formation is at late Xu4—late middle Jurassic, the filling peak of Xu4 is at late Jurassic -late Cretaceous.3. On the basis of exploration & development experiences and further research of reservoir forming mechanism, it is pointed the enrichment rules of upper Triassic natural gas is that natural gas regional mineralizing belt located at large scale paleohigh & slope, the types of accumulation is mostly structural, stratigraphic and lithologic traps, high production place is at clear natural fracture systems stacked at effective traps, all which point out the direction of exploration4. The comprehensive prediction technology for natural gas enrichment belt of super tight reservoir in deep formation, the recognition technology for fractural reservoir and gas prediction geophysical method & technology have been developed and formed.5. Some key technologies of productivity evaluation, well net optimization, water controlling & discharge and reservoir modification, drilling, completion and reservoir protection have been improved & perfected.
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