One of the main challenges in deep-water drilling is gas-hydrate plugs,which make the drilling unsafe.Some oil-based drilling fluids（OBDF） that would be used for deep-water drilling in the South China Sea were teste...One of the main challenges in deep-water drilling is gas-hydrate plugs,which make the drilling unsafe.Some oil-based drilling fluids（OBDF） that would be used for deep-water drilling in the South China Sea were tested to investigate the characteristics of gas-hydrate formation,agglomeration and inhibition by an experimental system under the temperature of 4 ？C and pressure of 20 MPa,which would be similar to the case of 2000 m water depth.The results validate the hydrate shell formation model and show that the water cut can greatly influence hydrate formation and agglomeration behaviors in the OBDF.The oleophobic effect enhanced by hydrate shell formation which weakens or destroys the interfacial films effect and the hydrophilic effect are the dominant agglomeration mechanism of hydrate particles.The formation of gas hydrates in OBDF is easier and quicker than in water-based drilling fluids in deep-water conditions of low temperature and high pressure because the former is a W/O dispersive emulsion which means much more gas-water interfaces and nucleation sites than the later.Higher ethylene glycol concentrations can inhibit the formation of gas hydrates and to some extent also act as an anti-agglomerant to inhibit hydrates agglomeration in the OBDF.展开更多
A preliminary survey of estrogenic activity of the contaminant in part of waters (Ziya River and the estu- ary of Haihe River) in Haihe River, Tianjin has been per- formed with the plasma vitellogenin (Vtg) in feral f...A preliminary survey of estrogenic activity of the contaminant in part of waters (Ziya River and the estu- ary of Haihe River) in Haihe River, Tianjin has been per- formed with the plasma vitellogenin (Vtg) in feral fish as a biomarker for estrogenic activity. The concentrations of bisphenol A (BPA), 4-tert-octylphenol (OP) and 4-nonyl- phenol (NP) in surface water were also determined. The presence of Vtg in male fish plasma as well as that in female can be detected at different sites and different seasons. The results indicate that the water in the sampling sites was con- taminated by some estrogenic compounds. Although BPA, OP and NP can be detected in all of the water samples, their concentrations were much lower than the effective concen- trations for those chemicals to induce Vtg production in male fish.展开更多
基金supported by Project 863 (No. 2006AA09Z316)NSFC (No. 50704028 and 40974071)
文摘One of the main challenges in deep-water drilling is gas-hydrate plugs,which make the drilling unsafe.Some oil-based drilling fluids（OBDF） that would be used for deep-water drilling in the South China Sea were tested to investigate the characteristics of gas-hydrate formation,agglomeration and inhibition by an experimental system under the temperature of 4 ？C and pressure of 20 MPa,which would be similar to the case of 2000 m water depth.The results validate the hydrate shell formation model and show that the water cut can greatly influence hydrate formation and agglomeration behaviors in the OBDF.The oleophobic effect enhanced by hydrate shell formation which weakens or destroys the interfacial films effect and the hydrophilic effect are the dominant agglomeration mechanism of hydrate particles.The formation of gas hydrates in OBDF is easier and quicker than in water-based drilling fluids in deep-water conditions of low temperature and high pressure because the former is a W/O dispersive emulsion which means much more gas-water interfaces and nucleation sites than the later.Higher ethylene glycol concentrations can inhibit the formation of gas hydrates and to some extent also act as an anti-agglomerant to inhibit hydrates agglomeration in the OBDF.
基金This work was supported by the High Tech Re-search and Development Progran of China (“863” Plan) (Grant No.2003AA640610) the National Natural Science Foundation of China (Grant No. 20137010) and the Chinese Academy of Sciences (Grant No.KZCX2-4 14).
文摘A preliminary survey of estrogenic activity of the contaminant in part of waters (Ziya River and the estu- ary of Haihe River) in Haihe River, Tianjin has been per- formed with the plasma vitellogenin (Vtg) in feral fish as a biomarker for estrogenic activity. The concentrations of bisphenol A (BPA), 4-tert-octylphenol (OP) and 4-nonyl- phenol (NP) in surface water were also determined. The presence of Vtg in male fish plasma as well as that in female can be detected at different sites and different seasons. The results indicate that the water in the sampling sites was con- taminated by some estrogenic compounds. Although BPA, OP and NP can be detected in all of the water samples, their concentrations were much lower than the effective concen- trations for those chemicals to induce Vtg production in male fish.
