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Reports that the Lunnan area in the Tarim Basin has become an important onshore oil production base in China. Statement that the formation of the oil and gas pools in the low uplift of Lunnan has experienced a comparatively complex process of dynamics; Reference to the fact that, based on the hydrocarbon generation period of source rocks, the formation period of cap rocks and traps, the analysis of organic inclusion and the analysis of bitumen in the reservoir, this paper draws the conclusion that the low uplift area of Lunnan has experienced three pool formation periods: the Permian period, the Cretaceous-Early Tertiary period and the Late Tertiary-Quaternary period and two oil and gas reservoir adjustment periods: the Late Permian period and the Late Tertiary-Quaternary period; Indication of the comprehensive study that the large-scale Ordovician buried hill, formed in Early Hercynian, became the reservoir during the Permian period, because the Cambrian-Lower Ordovician oil was discharged laterally into the reservoir along the top of the Ordovician weathering crust from south to north; Claim that the reservoir experienced a complicated process—reconstruction in the end of Permian, adjustment in Cretaceous-Early Tertiary and re-discharging process in Late Tertiary-Quaternary, leading to the early original heavy oil reservoir of marine facies and the late original light oil reservoir and gas pool; Statement that carboniferous, Triassic and Jurassic oil and gas reservoirs result from upward adjustment and re-distribution of Ordovician oil and gas reservoirs; Reference to the fact that, of those results, the formation of Triassic-Jurassic oil and gas pools came under the influence of the northward-tilting structure; Vertical migration of the oil and gas sourcing from the different hydrocarbon source rock intervals into the base unconformity of Triassic system; Migration of the the oil and gas laterally from north to south and accumulated into th

Hetianhe is a big carbonate gas field which is found and demonstrated in the period of "Chinese National Ninth 5-Year Plan". The proved reserve of Hetianhe gas field is over 600x10&sup8; m³. Its main producing layers are Carboniferous bioclastic limestone and Ordovician carbonate composed of buried hill. The former is stratified gas pool with water around its side, and the latter is massive gas pool with water in its bottom. The gases in the gas pools belong to dry gases with normal temperature and pressure systems. Based on the correlation of gas and source rock, the gases are mainly generated from Cambrian source rocks. According to the researches on source rock and structure evolution, and the observations on the thin section to reservoir bitumen and the studies on homogenization temperature of fluid inclusions, the gas pool has been identified and divided into three formation periods. The first is Late Caledonian when the oil generated from the Cambrian source rocks and migrated along faults, as a form of liquid facies into Ordovician carbonate reservoir and accumulated there. After that, the crust uplifted, the oil reservoir had been destroyed. The second is Late Hercynian when condensate gases generated from the Cambrian source rocks and migrated into Ordovician reservoir, as a form of liquid facies. Since the fractures had reached P strata, so the trap might have a real poor preservation condition, and the large-scale gas pool formation had not happened. The third gas reservoir formation period occurred in Himalaya. The fractures on both sides of Hetianhe gas field developed violently under the forces of compression, and thus the present fault horst formed. The dry gases generated from Cambrian source rocks and migrated upwards as the form of gas facies into Ordovician and Carboniferous reservoirs, and the large gas pool as discovered at present was formed finally.

Reports that the Kela-2 gas field is located in the center of Kelasu structural belt in Kuqa Depression. Fact that this trap is one of a series of traps in the folded belts which are distributed in a string of pearls in the dual structure; Statement that the primary gasbearing layers are sandstone of Lower Cretaceous K&sub1;bs while the secondary layers are dolomite member and glutenite member of Lower Tertiary E&sub1-2;km and sandstone of Lower Cretaceous K&sub1;b; Reference to the fact that the main component of natural gas is methane whose content is higher than 97%; Characterization by dry gas whose source rock is Jurassic coal measure; Formation of the Kela-2 structural trap during the Xiyu period, becoming a reservoir in the late time; Formation of late and the thick seal rock of Lower Tertiary gipsmantle in the reservoir as the avail reason why the giant Kela-2 gas field has been well kept; Conclusion that the abnormal high pressure of the Kela-2 gas field results from the strong structural compression in the northern part during the Xiyu period.

Reports that the Kuqa depression is a foreland basin developed with Mesozoic-Triassic-Jurassic coal-bearing formation. Indication of the research results of the coal-derived hydrocarbon foreland basins in Kuqa depression that the coal-bearing formation can be the rich sources for generating gas because of their thickness and rich source rocks with gas-generating predominant kerogen; Statement that although the foreland thrust belt mainly acting in compression is very complicated, integral large structural traps can be formed; Claim that the thrust belt can act as the passage for communication with deep source rocks; Development of the high quality gypsolish and gypseous mudstone cap rock in the upper formation as the key for the formation of the large gas field; Dependence of the late formation of reservoirs in the large gas fields on the hydrocarbon-generating history controlled by the foreland basin and the developing process of foreland thrust belt.

Reports that there is a gas-rich and well-charged petroleum system in the Kuqa Depression where Triassic and Jurassic source rocks play important roles. Distribution in an area of more than 10000 km² and with a thickness of up to 1000 m; Composition of dark mudstones, carbonaceous mudstones and coal seams containing 6%, 40% and 90% of TOC, respectively, mainly of humic organic matter; Statement that, as high-quality regional cap rocks, the Neogene and Eogene gypsum rocks and gypseous mudstones matched well with the underlying Neogene and Cretaceous-Eogene sandstones; Formation of the most favorable reservoir-seal assemblages in the Kuqa Depression; Formation of the Jurassic sandstones and mudstones into another favorable reservoir-seal assemblage; Shaping of the traps late in the fold-thrust belt, mainly fixed in the Tertiary-Quaternary, where ten structure styles have been distinguished; Reference to tge fact that these traps spread as a zone in N-S, are scattered like a segmental line in W-E and show tier-styled vertically; Statement that the best traps are gypsum-salt covered fault-bend anticlines related to the passive roof duplex; Characterization of this petroleum system by late accumulation; Distribution in the early Himalayan Movement of an accumulation of mainly gas condensate and oil in the outer circular region of the kitchen; Claim that in the middle and late Himalayan the gas accumulations mainly formed and were distributed in the inner circular region near the kitchen; Statement that the overpressure of gas pools is common and is formed by seal capacity of thick gypsum layers, extensive tectonic compression and large uplift; Suggestion that the well-preserved anticline traps underlying the high-quality regional cap rocks of the Tertiary gypsum rocks and gypseous mudstones are the main targets for the discovery of giant and medium-sized gas fields; Importance of the above conclusions for the petroleum geology theory and the exploratio

Reports that, based on the theory of plate tectonics, combining with the isotopic dating of ophiolite, igneous and volcanics, geochemical tests rare earth element analyze and seismic interpretation, this paper studies the pre-Carboniferous tectonics and sedimentary formation of the south edge of the Tarim Basin and proves that there exists the Kunlun Ocean under tensional tectonics during the Sinian and Cambrian in the south edge of the Tarim Plate. Statement that, due to the collision orogenesis, there formed the peripheral foreland basin in the south edge of Tarim; Reference to the fact that Upper Silurian and Devonian molasses sedimentary system superposed on the Sinian and Middle Silurian passive margin flysch sedimentary system and formed the bivariate structure of the foreland basin; Identification, based on the field geology and seismic interpretation, that the formation of the Silurian and Devonian have the character of half deposit which shows thick in the south area and thin in the north, and the pre-Carboniferous thrust compression tectonics remained in the foreland thrust belt, which further demonstrates that there existed the Silurian and Devonian peripheral foreland basin on the south edge of the Tarim Basin.

Reports that, analyzing the characteristics of the Tethyan tectonic field, the authors think that the Tethyan tectonic field underwent three evolutional stages: closing of Paleo-Tethys and rifting of Neo-Tethys from early Permian to late Triassic, subduetion of Neo-Tethys and collision between the Indian plate and the Eurasia plate from Jurassic to early of low Tertiary, and collision between the Arab plate and the Eurasia plate and the A-type subduction of Indian plate from late of low Tertiary to the present. Suggestion that, combining the evolution of the Tethyan orogenic belt with the characteristics of the Northern Margin basin, the sedimentary and tectonic characteristics and types of the Northern Margin basin are controlled by the formation and evolution of the Tethyan orogenic belt and the ingression of Tethys; Statement that the evolution of Northern Margin basin can be divided into three development stages: back-arc foreland basin from late Permian to Triassic, the back-arc fault subsidence and depression from Jurassic to the early of low Tertiary, and the reactive foreland basin from the late of low Tertiary to the present; Conclusion that the Northern Margin basin in the Tethyan tectonic field is an important region for natural gas accumulation, and the Tarim Basin is a part of this region.

Reports that using the modern tectonic geology theories and methods such as the plate tectonic analysis, the paleo-structure analysis, the structural-lithofacies analysis, and the fault related fold and petroleum system, and combining with the seismic data, well drilling data and the circumferential field geology, study on the structural characteristics and petroleum prospect in the Tarim Basin has been carried out. Results showing that the Tarim Basin is a large superimposition and combination basin with continental crustal basement, composed of a Paleozoic craton and Meso-Cenozoic foreland basins; Characteristics of the basin, including that the kernel part of the basin is the marine facies Paleozoic craton, superimposed 4 continental facies foreland basins; Statement that though the scale of the paleozoic craton of the Tarim Basin is relatively small, the structure is steady; Reference to the petroleum prospect of the Paleozoic craton: multiphase pool-generation and accumulation controlled by ancient uplift; Report that the Meso-Cenozoic foreland basins in the Tarim Basin, which are distributed on the cratonic circumference and are a long-term subsidence, turned into rejuvenated foreland basins after the Meso-Cenozoic period; Petroleum prospects, including coal-bed generating hydrocarbon, abundant natural gas, pool-generation in later and recent periods, the oil and gas distribution controlled by the foreland thrust belt; Statement that the structural characteristics of Tarim provide it with a superimposition and combination petroleum system of multiple resources, multiple reservoirs and multiphase pool-generation; Report that the oil and gas exploration prospect covers two large fields: the Paleozoic craton and the Meso-Cenozoic foreland thrust belt.