After research the total nature gas resources in Sichuan Basin, we can see that the ratio of proved reserves is only seven point seven five percent, and the exploration potential is large. There are six exploration areas of major gas fields in Sichuan Basin. First is the Precambrian weathered residuum on the leshan-longnushi uplift in the middle of Sichuan Basin, second is the Alexandria xiaoheba sand in the east southern of Sichuan, third is the caboniferous structural slope traps, fourth is the ochoan continental shelf marginreef around kaijing-liangping trough in the east of Sichuan, fifth is the Scythian feixianguan Oolite beach in east Sichuan, sixth is the Jurassic and the Rhactic exploration areas in the west of sichuan. There are much natrue gas resource in these six exploration areas, but the major gas exploration traps in no enough and exploration technology need to be improved for the next five to ten years, so the author draws out three exploration strategies how to keep the development ratio of nature gas industry in sichuan basin.
This paper is by the synthesis analysis to a large number of geochemical data, and has systematically research to the source rock features of the different age of the south of the Dabashan and Micangshan, points out major source rock are C1S1 and P1. Similar to the Sichuan Basin, in this area, the precentage of organic carbon of I’s grade of source rock is higher, the kerogen type is good, the maturity reach over mature, and the horizon distribution is stable. The heat evolution history research of source rock indicates, the heat evolution level of its is lower in the period of the Paleozoic, and the oil-gas fromation phase by control of Jurassic stratum deposit thickness. The oil windows of C1 is upper Triassic-lower Jurassic, and natrual gas windows is lower Jurassic-upper Jurassic; The oil windows of S1 is lower Jurassic-middle Jurassic, and natural gas windows is middle Jurassic-Cretaceous; The oil windows of P1 is middle Jurassic-upper Jurassic, and natural gas windows is upper Jurassic-Cretaceous. This possesses important referennce to the research of source rock of high evolution area, and for oil-gas correlating, magrating and gathering of this area has established on the foundtaion.
Based on the studies of molecular and carbon isotope of the nature gases that are from over 40 drillings and gas-seeps of the surface. The systematic studies relate to types and thermal evolution stages and collected conditions of nature gases. Combined with thermal simulation experiments of hydrocarbon source rocks of lower evolution stages from Jurassic coal-measure in the Junggar Basin. The nature gases in the Basin are divided to four types from lower evolution stage to high evolution stage, they are coal-related gas for mature to over mature, oil-related gas for mature, and oil-related gas for over mature. The coal-related gases for over-mature distributed in mainly the Lunan Uplift of the center of the Basin. The nature gases of Qigu gas field belongs to over-mature or lower mature coal-related nature gases, while the gas from Dushanzioil-gas field are mainly the lower mature in the southern of the Basin. Lower-mature oil-related gas is distributed mainly over oil-gas regions in the eastern of basin.
Test resultes of downhole hydrocarbon geo-chemical exploration from five wells in the south of Songliao Basin show that the identification ratio of light hydrocarbon of top air in gas wells and oil-gas indication wells is higher than that in dry wells. The role of acidolysisabsorption hydrocarbon of rock cutting is only auxiliary in hydrocarbon evaluation. The ratio of light hydrocarbon to alkane of the top air in abnormal well sections suggests that the gas wells of the study area possess the characteristics of dry gas
On the basis of analyzing the geological characteristics of east section South slope Chenbei Sag, Es3-Ng (!) is decided and described as main petroleum system through comparing hydrocarbon-property of three oil fields, so the exploration direction in this area is found and obvious economic result is gained.
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