Dark mudstones and shales of the Carboniferous Jiusi Formation are widely developed in northern Guizhou and Yunnan provinces, SW China. However, the distribution, reservoir characterization, and exploration potential ...Dark mudstones and shales of the Carboniferous Jiusi Formation are widely developed in northern Guizhou and Yunnan provinces, SW China. However, the distribution, reservoir characterization, and exploration potential of organic-rich shales in this area are yet to be quantified, thus limiting the prospect of shale gas in this area. This study investigates the basic geological conditions of Jiusi shale gas, using core data, well-logs, and some other test data, obtaining the following results. The organic-rich shales are mainly composed of deltaic-to-shallow-shelf deposits, with thickness ranging from 0 to 450 m, and above 350 m around the subsidence center. The organic matter is mainly type Ⅱ kerogen with TOC content of mostly 1%–2%, indicating a moderate maturity. The argillaceous shale reservoirs are indicative of strong heterogeneity, high clay minerals content, low porosity, low permeability, high specific surface area, and relatively developed secondary porosity. The gas-log anomaly intervals obtained from the survey wells have a cumulative thickness that is apparently greater than 200 m, and a few shale intervals showing high desorbed and adsorbed gas contents. Due to complex structures in the study area, conditions responsible for shale gas occurrence and trapping are generally moderate. However, areas having wide and gentle folds with moderate depth of burial reveals relatively favorable conditions of hydrocarbon traps. In contrast with typical marine-continental transitional shales, the Jiusi shale have better geological conditions for shale gas preservation. The analysis of the geological framework and hydrocarbon potential of Carboniferous Jiusi Formation provide more insight for the exploration of Carboniferous shale gas in southern China.展开更多
In order to imitate biological addesion performance nd skin properties,phase transitions on dielectric elastomers(D E)with high voltages are studied.The states of flat,rinkled and bulging on the circular active area w...In order to imitate biological addesion performance nd skin properties,phase transitions on dielectric elastomers(D E)with high voltages are studied.The states of flat,rinkled and bulging on the circular active area which is coated w th electrodes verify the theoretical prediction of phase transitions and failure phenomena.When the DE membrane is subjected to a radial force and increasing voltage,four experimental phenomena are discovered before electric breakdown:The active region expands,and the thin membrane is still flat till breakdown;bulging forms instead of a fa t area on the membrane;wrinkes and bulging coexist;and the active aea is completely wrinlded there are two types of phase transitions between the fa t andwrinded regions in a membrane:Wrinkles form in small regions,and te n propagate at the expense of t e flat area until he entire active part becomes wrinded;b o t the wrinded a d flat regions move interchangeably on a membrane with ramping voltage till breakdown.It is found that when Aere is no prestretch of a DE membrane,bulging w ill occur with te increasing voltage.Wrinkles commonly appear at large prestretch and,terefore,the prestetched ratio significantly affects electomechanical phase tansitions.展开更多
基金supported by National Science and Technology Major Project entitled Test and Application Promotion of Shale Gas Exploration and Evaluation Techniques(No.2016ZX05034)a project organized by the China Geological Survey entitled Shale Gas Geological Survey in Northeastern Yunnan(No.DD20190080).
文摘Dark mudstones and shales of the Carboniferous Jiusi Formation are widely developed in northern Guizhou and Yunnan provinces, SW China. However, the distribution, reservoir characterization, and exploration potential of organic-rich shales in this area are yet to be quantified, thus limiting the prospect of shale gas in this area. This study investigates the basic geological conditions of Jiusi shale gas, using core data, well-logs, and some other test data, obtaining the following results. The organic-rich shales are mainly composed of deltaic-to-shallow-shelf deposits, with thickness ranging from 0 to 450 m, and above 350 m around the subsidence center. The organic matter is mainly type Ⅱ kerogen with TOC content of mostly 1%–2%, indicating a moderate maturity. The argillaceous shale reservoirs are indicative of strong heterogeneity, high clay minerals content, low porosity, low permeability, high specific surface area, and relatively developed secondary porosity. The gas-log anomaly intervals obtained from the survey wells have a cumulative thickness that is apparently greater than 200 m, and a few shale intervals showing high desorbed and adsorbed gas contents. Due to complex structures in the study area, conditions responsible for shale gas occurrence and trapping are generally moderate. However, areas having wide and gentle folds with moderate depth of burial reveals relatively favorable conditions of hydrocarbon traps. In contrast with typical marine-continental transitional shales, the Jiusi shale have better geological conditions for shale gas preservation. The analysis of the geological framework and hydrocarbon potential of Carboniferous Jiusi Formation provide more insight for the exploration of Carboniferous shale gas in southern China.
基金The National Natural Science Foundation of China No.51775108)
文摘In order to imitate biological addesion performance nd skin properties,phase transitions on dielectric elastomers(D E)with high voltages are studied.The states of flat,rinkled and bulging on the circular active area which is coated w th electrodes verify the theoretical prediction of phase transitions and failure phenomena.When the DE membrane is subjected to a radial force and increasing voltage,four experimental phenomena are discovered before electric breakdown:The active region expands,and the thin membrane is still flat till breakdown;bulging forms instead of a fa t area on the membrane;wrinkes and bulging coexist;and the active aea is completely wrinlded there are two types of phase transitions between the fa t andwrinded regions in a membrane:Wrinkles form in small regions,and te n propagate at the expense of t e flat area until he entire active part becomes wrinded;b o t the wrinded a d flat regions move interchangeably on a membrane with ramping voltage till breakdown.It is found that when Aere is no prestretch of a DE membrane,bulging w ill occur with te increasing voltage.Wrinkles commonly appear at large prestretch and,terefore,the prestetched ratio significantly affects electomechanical phase tansitions.
