he use of an absorption trap off-line two-dimensional gas chromatography (2-DGC) in conjunction with a mass spectrometer greatly improved the separation andidefitification of minor constituents of a complex mixture su...he use of an absorption trap off-line two-dimensional gas chromatography (2-DGC) in conjunction with a mass spectrometer greatly improved the separation andidefitification of minor constituents of a complex mixture such as a natural essentialoil. The absorption trap device used as an interface of 2-DGC offered the advantageof convenient manipulation.展开更多
Almost all the oil and gas reservoirs developed in marine sedimentary strata of China have undergone processes of multi-phase reservoir formation and later modification. The irregular reservoirs are classified into th...Almost all the oil and gas reservoirs developed in marine sedimentary strata of China have undergone processes of multi-phase reservoir formation and later modification. The irregular reservoirs are classified into three types as the Naxi, Tahe and Renqiu ones, increasing successively in the development degree of karstificated pores and fissures and the connection degree of independent reservoirs. In these reservoirs, the unity in the fluid feature, pressure and oil-gas-water interface also increases successively from the Naxi to the Renqiu type. The main body of Ordovician reservoirs of the Tahe Oilfield in the Tarim Basin is a network pool rather than a stratified, massive, stratigraphically-unconformed or weathering-crust one. The fluid nature of oil, gas and water, the interface positions and the pressures, as well as the dynamic conditions of fluids within the reservoirs during the production are all different from those in stratified or massive oil and gas reservoirs. Carbonates in the Akekule uplift and the Tahe Oilfield are assemblages of various types of reservoirs, which have an overall oil-bearing potential and obvious uneven distribution. Testing and producing tests are the major means to evaluate this type of reservoirs and acid fracturing improvement is a key link in petroleum exploration and development.展开更多
The penetration of water during water flooding has been observed over many years using several methods. A microfocused X-ray computed tomography scanner can be used to directly observe 3D water flooding in a nondestru...The penetration of water during water flooding has been observed over many years using several methods. A microfocused X-ray computed tomography scanner can be used to directly observe 3D water flooding in a nondestructive manner. To eliminate the possibility of false images being produced because of X-ray broadening effects, we developed a visualization method by arranging the brightness distribution of all phases involved. Water flooding experiments were conducted using oil-wet and water-wet porous media. The water phase was injected upward into packed glass beads containing an oil phase, and the process was scanned every minute until steady state was reached. Using this scheme, real-time, the water invasion pattern and oil trapping process in clusters of pores and individual pores can be observed clearly. By eliminating false images, the boundary of each phase could be identified with high precision, even in a single pore. Porelevel phenomena, including snap off (which has never before been captured in a real 3D porous medium), piston-like displacement, and the curvature of the interface, were also observed. Direct measurement of the pore throat radius and the contact angle between the wetting and nonwetting phases gave an approximation of the capillary pressure during the piston-like displacement and snap-off processes.展开更多
TiO2 semiconductive nanoparticles are added into mineral and ester based transformer oil to form semiconductive nanofluids (SNFs) with the aim of enhancing the oil’s insulating performance. Charge accumulation and de...TiO2 semiconductive nanoparticles are added into mineral and ester based transformer oil to form semiconductive nanofluids (SNFs) with the aim of enhancing the oil’s insulating performance. Charge accumulation and decay characteristics of both pure oils and SNFs are measured by pulse electroacoustic (PEA) technique. The result reveals that compared with pure oil, SNFs have more uniform in- ternal electric fields with voltage applied and higher charge decay rate after removing the applied voltage. This is caused by the increase of shallow trap density in SNFs, due to the test results of thermally stimulated current (TSC). It is proposed that the electron trapping and de-trapping processes in shallow traps could be the main charge transport processes in the nanofluid transformer oil.展开更多
文摘he use of an absorption trap off-line two-dimensional gas chromatography (2-DGC) in conjunction with a mass spectrometer greatly improved the separation andidefitification of minor constituents of a complex mixture such as a natural essentialoil. The absorption trap device used as an interface of 2-DGC offered the advantageof convenient manipulation.
文摘Almost all the oil and gas reservoirs developed in marine sedimentary strata of China have undergone processes of multi-phase reservoir formation and later modification. The irregular reservoirs are classified into three types as the Naxi, Tahe and Renqiu ones, increasing successively in the development degree of karstificated pores and fissures and the connection degree of independent reservoirs. In these reservoirs, the unity in the fluid feature, pressure and oil-gas-water interface also increases successively from the Naxi to the Renqiu type. The main body of Ordovician reservoirs of the Tahe Oilfield in the Tarim Basin is a network pool rather than a stratified, massive, stratigraphically-unconformed or weathering-crust one. The fluid nature of oil, gas and water, the interface positions and the pressures, as well as the dynamic conditions of fluids within the reservoirs during the production are all different from those in stratified or massive oil and gas reservoirs. Carbonates in the Akekule uplift and the Tahe Oilfield are assemblages of various types of reservoirs, which have an overall oil-bearing potential and obvious uneven distribution. Testing and producing tests are the major means to evaluate this type of reservoirs and acid fracturing improvement is a key link in petroleum exploration and development.
文摘The penetration of water during water flooding has been observed over many years using several methods. A microfocused X-ray computed tomography scanner can be used to directly observe 3D water flooding in a nondestructive manner. To eliminate the possibility of false images being produced because of X-ray broadening effects, we developed a visualization method by arranging the brightness distribution of all phases involved. Water flooding experiments were conducted using oil-wet and water-wet porous media. The water phase was injected upward into packed glass beads containing an oil phase, and the process was scanned every minute until steady state was reached. Using this scheme, real-time, the water invasion pattern and oil trapping process in clusters of pores and individual pores can be observed clearly. By eliminating false images, the boundary of each phase could be identified with high precision, even in a single pore. Porelevel phenomena, including snap off (which has never before been captured in a real 3D porous medium), piston-like displacement, and the curvature of the interface, were also observed. Direct measurement of the pore throat radius and the contact angle between the wetting and nonwetting phases gave an approximation of the capillary pressure during the piston-like displacement and snap-off processes.
基金Project supported by National Natural Science Foundation of China （51077050）, Chinese Universities Scientific Fund.
文摘TiO2 semiconductive nanoparticles are added into mineral and ester based transformer oil to form semiconductive nanofluids (SNFs) with the aim of enhancing the oil’s insulating performance. Charge accumulation and decay characteristics of both pure oils and SNFs are measured by pulse electroacoustic (PEA) technique. The result reveals that compared with pure oil, SNFs have more uniform in- ternal electric fields with voltage applied and higher charge decay rate after removing the applied voltage. This is caused by the increase of shallow trap density in SNFs, due to the test results of thermally stimulated current (TSC). It is proposed that the electron trapping and de-trapping processes in shallow traps could be the main charge transport processes in the nanofluid transformer oil.
