The accumulation characteristics and exploration potential of oil and gas in the back-arc basin of Japan under the background of high heat flow

The Sea of Japan is located in the southeast margin of Eurasia, in the triangle area of the western Pacific Ocean. Due to the interaction of the Pacific plate, Eurasian plate and Philippine plate, its tectonic environment is complex, forming a typical trench-arc-basin system. At present, 148 oil and gas fields have been discovered in Japan, with an oil and gas resource of 255.78×10^(6) t, showing a good prospect for oil and gas exploration. Based on the previous research and the recently collected geological and geophysical data, the characteristics of tectonic-sedimentary evolution and geothermal field in the basins around the Sea of Japan are analyzed. The results show that the tectonic evolution of the basin is mainly controlled by plate subduction and back-arc oceanic crust expansion, and it mainly undergone four tectonic-sedimentary evolution stages: Subduction period, basin development period, subsidence period and compression deformation period. The overall heat flow value of Japan Sea is high, and it is distributed annularly along Yamato Ridge. The geothermal heat flow value is about 50–130 MW/m^(2), and the average heat flow is75.9±19.8 MW/m^(2), which has a typical “hot basin ”. The high heat flow background provides unique thermal evolution conditions for hydrocarbon generation, which leads to the high temperature and rapid evolution. The authors summarized as “early hydrocarbon generation, rapid maturity and shallow and narrow hydrocarbon generation window”. The type of oil and gas is mainly natural gas, and it mainly distributed in Neogene oil and gas reservoirs. The trap types are mainly structural traps, lithologic traps and composite traps. In addition, the pre-Neogene bedrock oil and gas reservoirs also show a good exploration prospect. The resource prospecting indicates that Niigata Basin, Ulleung Basin and kitakami Basin are the main target areas for future exploration and development.

Organic geochemical characteristics and significance of Permian Gufeng formation siliceous shale in well CSDP-2 of South Yellow Sea central uplift

In order to understand the hydrocarbon generation potential of the siliceous shale in the Permian Gufeng Formation of the South Yellow Sea,the organic geochemistry and organic petrology of the siliceous shale in the Gufeng Formation of the CSDP-2 well were studied and analyzed.It is found that the TOC of the samples is mainly between 9%and 12%,and Tmaxis mainly distributed between 510 and 540℃.The value of the organic microscopic type index(TI)is between 25.71 and 31.00,which is a set of II_(2)high-quality source rocks with high organic matter abundance in the over mature stage of largescale gas generation.According to the distribution characteristics of Molecular fossils in siliceous shale of Gufeng Formation of well CSDP-2,bacterial organic matter is the main hydrocarbon generating parent material,and aquatic animal organic matter is an important hydrocarbon generating parent material.The siliceous shale in Gufeng Formation of CSDP-2 well is in the stage of large-scale gas generation;Therefore,the Gufeng Formation in the central uplift of the South Yellow Sea has the material basis for the formation of large-scale shale gas reservoirs.At the same time,the siliceous metasomatism of the siliceous shale reservoir of Gufeng Formation is not conducive to the primary migration of oil,and there is much oil and gas remaining in the reservoir.

Low glucose metabolism in hepatocellular carcinoma with GPC3 expression

AIM To investigate the relationship between glucose metabolism and glypican-3(GPc3)expression in hepatocellular carcinoma(Hcc).METHODSImmunohistochemical staining of pathological samples for GPc3 and glucose transporter 1(GLUT1),and whole-body ^(18)F-FDG PET/c T for measuring tumour glucose uptake were performed in 55 newly diagnosed Hcc patients.The maximum standard uptake value(s UVmax)and tumour-to-non-tumourous liver uptake(T/NT)ratio were used to quantify ^(18)F-FDG uptake.In vitro ^(18)F-FDG uptake assay of GPc3-expressing Hep G2 and non-GPc3-expressing RH7777 cel ls was used to examine the effect of GPc3 in cellular glucose metabolism.The relationships between GPc3 expression and ^(18)F-FDG uptake,GLUT1 expression,tumour differentiation,and other clinical indicators were analysed using spearman rank correlation,univariateand multiple logistic regression analyses.RESULTSPositive GPc3 expression was observed in 67.3%of Hcc patients,including 75.0%of those with well or moderately differentiated Hcc and 36.4%of those with poorly differentiated Hcc.There was an inverse relationship between GPc3 expression and s UVmax(Spearman correlation coefficient=-0.281,P=0.038)and a positive relationship between GLUT1 expression and sU Vmax(Spearman correlation coefficient=0.681,P<0.001)in patients with Hcc.Univariate analysis showed that two glucose metabolic parameters(sU Vmax and T/NT ratio),tumour differentiation,lymph node metastasis,and TNM stage were all significantly associated with GPc3 expression(P<0.05),whereas GLUT1 expression,sex,age,tumour size,intrahepatic lesion number,and distant metastasis showed no statistical association(P>0.05).Further multivariate analysis revealed that only the T/N ratio was significantly correlated with GPC3 expression in patients with Hcc(P<0.05).In vitro assay revealed that the uptake of ^(18)F-FDG in GPc3-expressing HepG2 cells was significantly lower than that of non-GPc3-expressing RH7777 cells(t=-20.352,P<0.001).CONCLUSIONThe present study demonstrated that GPc3 expression is inversely associated with glucose metabolism,suggesting that GPc3 may play a role in regulating glucose metabolism in Hcc.

Discussion on "sandwich"structures and preservation conditions of shale gas in the South Yellow Sea Basin

In order to make a breakthrough in Mesozoic-Paleozoic shale gas exploration in the South Yellow Sea Basin,a comparison of the preservation conditions was made within the Barnett shale gas reservoirs in the Fortworth Basin,the Jiaoshiba shale gas reservoirs in Sichuan Basin and potential shale gas reservoirs in Guizhou Province.The results show that the "Sandwich"structure is of great importance for shale gas accumulation.Therein to,the "Sandwich"structure is a kind of special reservoir-cap rock assemblage which consist of limestone or dolomite on the top,mudstone or shale layer in the middle and limestone or dolomite at the bottom.In consideration of the Mesozoic-Paleozoie in the Lower Yangtze,and Laoshan Uplift with weak Paleozoic deformation and thrust fault sealing On both flanks of the Laoshan Uplift,a conclusion can be drawn that the preservation conditions of shale gas probably developed "Sandwich" structures in the Lower Cambrian and Permian,which are key layers for the breakthrough of shale gas in the South Yellow Sea.Moreover,the preferred targets for shale gas drilling probably locate at both flanks of the Laoshan Uplift.

Discovery of Late Cretaceous-Paleocene faulted basins developed on the Yandang Low Uplift, East China Sea Shelf Basin

1.Objective The East China Sea Shelf Basin (ECSSB) is a typical Meso-Cenozoic superimposed basin which consists several tectonic units including the Changjiang Sag, Oujiang Sag, Hupijiao Uplift, Haijiao Uplift, Yandang Low Uplift (YDLU), Minjiang Sag, Taipei Low Uplift, Xihu Sag, Jilong Sag and so on.