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Origin and characteristics of under pressure systems in Dongying depression

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... Abnormal pressure is a common geological phenomenon in the petroliferous basins worldwide. In recent years, consistent with the discovery of the coexistence of abnormal underpressure, normal pressure and overpressure in numerous basins in China and other countries (Belitz and Bredehoeft, 1988;Corbet and Bethke, 1992;Bachu and Underschultz, 1995;Karsten and Stefan, 2001;Liu and Xie, 2002;Dai et al., 2003;Raymond, 2005;Wang and Chen, 2007), the distribution and controlling factors of these different pressure regimes has generated interest among petroleum geologists and engineers (Luo and Vasseur, 1992;Parks and Toth, 1995;Xie et al., 2003;Jeirani and Mohebbi, 2006;Kabir and Izgec, 2009). Previous investigation has been carried out on the genetic mechanism of low pressure and high pressure systems (Powley, 1980;Law and Dickinson, 1985;Hunt, 1990;Hao et al., 1995;Warbrick and Osborne, 1998;Neuzil, 2000;Hao, 2005;Xu et al., 2009). ...
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Three types of natural gases, including coal-derived gas, oil-derived gas and biogenic gas have been found in the Liaodong Bay. All of the natural gases in the main gas fields of the Liaodong Bay are wet gas except those in JZ31-6 which are dry biogenic gas. The natural gas mainly distributes in the northern part of the Liaodong Bay with only a small part in the southern part. In the deep, it mainly distributes in the Shahejie Formation with little in the lower Dongying Formation and the Neogene. The distribution characteristics of the natural gas is controlled by the types and thermal maturity of the organic matters, the thickness of the cap rocks and the formation mechanisms of the overpressure. The organic matter in the northern part are type II2-prone which mainly generates natural gas with a higher maturity while those in the northern part are type II1-prone which mainly generates oil with a lower maturity. The thickness of the cap rocks in the 3rd member of the Dongying Formation(E3d3) decreases from the north to the south. The overpressure which evolves in the 3rd member of the Dongying Formation(E3d3) is caused by the uncompaction, providing a good condition for the gas preservation in cooperation with the huge-thick cap rocks, while the overpressure which evolves in the 3rd member of the Shahejie Formation(E3s3) is caused by the expansion of the hydrocarbon, providing a strong power for the natural gas which migrates from the sag to the Liaoxi Salient.
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A series of 18 novel 1-indolyl acetate-5-nitroimidazole 3a-3r were designed, synthesized, and evaluated for their in vitro biological activities as potential tubulin polymerization inhibitors. Among these compounds, 3p displayed strong antitumor activity with IC50 of 2.00, 1.05, 0.87 μM against A549, Hela and U251 respectively, and also showed the most potent PLK1 inhibitory activity with IC50 of 2.4 μM. Molecular docking studies within the colchicine binding site of tubulin were in good agreement with the tubulin polymerization inhibitory data and confirmed the importance of the configuration of the synthesized 1-indolyl acetate-5-nitroimidazolefor potential tubulin polymerization inhibitors.
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On the basis of measuring the pressure distribution and analyzing its origin in the Carboniferous and Permian of Shenmu-Yulin area, the evolution history of ancient pressure is restored mainly by means of the basin numerical simulation technique, in which the paleo-pressure has been constrained by the compaction restoration and the examination of fluid inclusion temperature and pressure. Then the development and evolution history of abnormal pressure and its effect on gas migration and accumulation are investigated. Studies show that the pressure in southeastern and northwestern parts of studied area is near to hydrostatic pressure, whereas in the remainder vast area the pressure is lower than the hydrostatic pressure, which is caused by difficulty to measure pressure accurately in tight reservoir bed, the calculating error caused by in-coordinate between topography relief and surface of water potential, pressure lessening due to formation arising and erosion. There are geological factors beneficial to forming abnormal high pressure in the Upper Palaeozoic. On the distraction of measured pressure, paleo-pressure data from compaction restoration and fluid inclusion temperature and pressure examining, the evolution history of ancient pressure is restored by the basin numerical simulation technique. It is pointed out that there are at least two high peaks of overpressure in which the highest value of excess pressure could be 5 to 25 MPa. Major gas accumulated in main producing bed of Shanxi Fm (P1s) and lower Shihezi Fm (P2x), because of two-fold control from capillary barrier and overpressure seal in upper Shihezi Fm (P2s). In the middle and southern districts, the two periods of Later Jurassic to the middle of Early Cretaceous, and middle of Later Cretaceous to Palaeocene are main periods of gas migration and accumulation, while they belong to readjustment period of gas reservoirs after middle of Neocene.
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