A new three-dimensional laterolog array sonde（3D-LS） is presented. The 3DLS is based on existing high-resolution laterolog array and azimuthal resistivity imaging sondes with radial, longitudinal, and circumferentia...A new three-dimensional laterolog array sonde（3D-LS） is presented. The 3DLS is based on existing high-resolution laterolog array and azimuthal resistivity imaging sondes with radial, longitudinal, and circumferential detection abilities. Six investigation modes are designed using the 3D finite-element method and different investigation depths are simulated based on the pseudo-geometrical factor of the six modes. The invasion profile is described using multi-array radial logs. From the analysis of the pseudo-geometrical factor, the investigation depth of the 3D-LS is about 1.5 m for conductive invasion, which is close to that of the dual laterolog tool but greater than that of the highly integrated azimuthal laterolog sonde. The vertical and azimuthal resolution is also analyzed with the same method. The 3DLS can detect low-resistivity anomalies of 0.5 m thickness and 15？ around the borehole for infinitely thick formations. This study lays the foundation for more work on 3D laterolog array sonde for evaluating low-resistivity anomalies.展开更多
OBJECTIVE:To evaluates the antioxidant and hepatoprotective potentials of Dicoma anomala Sond.(Asteraceae) on body weight,feed and water intake,biochemical parameters and organ histology.METHODS:Various concentrations...OBJECTIVE:To evaluates the antioxidant and hepatoprotective potentials of Dicoma anomala Sond.(Asteraceae) on body weight,feed and water intake,biochemical parameters and organ histology.METHODS:Various concentrations(1.56-25 μg/m L)were used in the in vitro assays 1,1-diphenyl-2-picryl hydrazyl(DPPH,superoxide anion,hydroxyl radicals,etc.).The effects of treatment with 125,250 and 250 mg/m L Dicoma anomala aqueous roots extract(DARE) was investigated in vivo in the CCl4-induced hepatotoxic rats during the 15 days study.RESULTS:Water extract exhibited the best activity(IC50:15.20 ± 0.03,11.70 ± 0.10,and 0.84 ± 0.05 μg/m L) in vitro in DPPH,hydroxyl and superoxide anion radicals,respectively,when compared with standards.Pre-treatment and treatment with different concentrations of DARE significantly(P < 0.05)attenuated the elevated serum activities of aspartate transaminase,alanine transaminase levels while increasing the activities of superoxide dismutase,catalase and glutathione peroxidase.The histopathological evaluations revealed extensive liver damage characterized by severe vacuolar and cytoplasmic degeneration,hepatic necrosis,and cellular infilteration in pre-treated groups while in the treated groups;such liver damages were not observed most especially at 500 mg/kg dose.CONCLUSION:The results proved the hepatoprotective potential of DARE against CCl4-induced oxidative stress.Moreover,histopathological examinations revealed better therapeutic advantage of DARE than prophylactic use.展开更多
When entering an anisotropic formation, a shear wave splits into a fast wave and a slow wave. Based on the principle of four-component cross-dipole acoustic wave measurement, the anisotropy of HTI （Horizontal Transve...When entering an anisotropic formation, a shear wave splits into a fast wave and a slow wave. Based on the principle of four-component cross-dipole acoustic wave measurement, the anisotropy of HTI （Horizontal Transverse Isotropy） formation can be determined. The method of calculating the fast and slow wave data when a shear wave propagates along the borehole axis in anisotropic formation was analyzed, and the implementation of a cross-dipole acoustic logging tool was demonstrated. The tool was composed of transmitter electronics, transmitter mandrel, acoustic isolator, receiver mandrel and main control electronics. Sonde, transmitter circuit, signal receiving and processing circuit, data acquisition system, system control circuit and telemetry interface circuit were presented and analyzed. The test model was used in production wells and standard wells in various areas and the four-component cross-dipole waves were acquired and processed. The waves had good signal-to-noise ratio and clear characteristics, and the fast and slow waveforms, processed slowness curves, anisotropy and fast shear wave azimuth well matched with each other.展开更多
The response characteristics of the dual-induction logging tool while drilling in a half-spaceare computed and analyzed when the instrument slots opening direction, instrument height, ground conductivity is changed re...The response characteristics of the dual-induction logging tool while drilling in a half-spaceare computed and analyzed when the instrument slots opening direction, instrument height, ground conductivity is changed respectively. The results show that the haJ^-space response of the different opening direction of instrument slots has a nonlinear change with the increase of the ground conductivity. The effect of half-space response on the instrument slots downward opening direction is greatest and the upward is minimal The half-space response of the deep induction reaches the maximum near the 0.4m height when tool is above ground. The peak position does not change with the ground conductivity changes.These results have a practical significance to determine accurately the sonde error of the dual-induction logging tool while drilling.展开更多
基金sponsored by the National Oil and Gas Major Projects(No.2011ZX05020-009)
文摘A new three-dimensional laterolog array sonde（3D-LS） is presented. The 3DLS is based on existing high-resolution laterolog array and azimuthal resistivity imaging sondes with radial, longitudinal, and circumferential detection abilities. Six investigation modes are designed using the 3D finite-element method and different investigation depths are simulated based on the pseudo-geometrical factor of the six modes. The invasion profile is described using multi-array radial logs. From the analysis of the pseudo-geometrical factor, the investigation depth of the 3D-LS is about 1.5 m for conductive invasion, which is close to that of the dual laterolog tool but greater than that of the highly integrated azimuthal laterolog sonde. The vertical and azimuthal resolution is also analyzed with the same method. The 3DLS can detect low-resistivity anomalies of 0.5 m thickness and 15？ around the borehole for infinitely thick formations. This study lays the foundation for more work on 3D laterolog array sonde for evaluating low-resistivity anomalies.
基金Supported by Research committee,University of the Free State,Qwaqwa campus,(entity No.211427604)Free State,SA
文摘OBJECTIVE:To evaluates the antioxidant and hepatoprotective potentials of Dicoma anomala Sond.(Asteraceae) on body weight,feed and water intake,biochemical parameters and organ histology.METHODS:Various concentrations(1.56-25 μg/m L)were used in the in vitro assays 1,1-diphenyl-2-picryl hydrazyl(DPPH,superoxide anion,hydroxyl radicals,etc.).The effects of treatment with 125,250 and 250 mg/m L Dicoma anomala aqueous roots extract(DARE) was investigated in vivo in the CCl4-induced hepatotoxic rats during the 15 days study.RESULTS:Water extract exhibited the best activity(IC50:15.20 ± 0.03,11.70 ± 0.10,and 0.84 ± 0.05 μg/m L) in vitro in DPPH,hydroxyl and superoxide anion radicals,respectively,when compared with standards.Pre-treatment and treatment with different concentrations of DARE significantly(P < 0.05)attenuated the elevated serum activities of aspartate transaminase,alanine transaminase levels while increasing the activities of superoxide dismutase,catalase and glutathione peroxidase.The histopathological evaluations revealed extensive liver damage characterized by severe vacuolar and cytoplasmic degeneration,hepatic necrosis,and cellular infilteration in pre-treated groups while in the treated groups;such liver damages were not observed most especially at 500 mg/kg dose.CONCLUSION:The results proved the hepatoprotective potential of DARE against CCl4-induced oxidative stress.Moreover,histopathological examinations revealed better therapeutic advantage of DARE than prophylactic use.
文摘When entering an anisotropic formation, a shear wave splits into a fast wave and a slow wave. Based on the principle of four-component cross-dipole acoustic wave measurement, the anisotropy of HTI （Horizontal Transverse Isotropy） formation can be determined. The method of calculating the fast and slow wave data when a shear wave propagates along the borehole axis in anisotropic formation was analyzed, and the implementation of a cross-dipole acoustic logging tool was demonstrated. The tool was composed of transmitter electronics, transmitter mandrel, acoustic isolator, receiver mandrel and main control electronics. Sonde, transmitter circuit, signal receiving and processing circuit, data acquisition system, system control circuit and telemetry interface circuit were presented and analyzed. The test model was used in production wells and standard wells in various areas and the four-component cross-dipole waves were acquired and processed. The waves had good signal-to-noise ratio and clear characteristics, and the fast and slow waveforms, processed slowness curves, anisotropy and fast shear wave azimuth well matched with each other.
文摘The response characteristics of the dual-induction logging tool while drilling in a half-spaceare computed and analyzed when the instrument slots opening direction, instrument height, ground conductivity is changed respectively. The results show that the haJ^-space response of the different opening direction of instrument slots has a nonlinear change with the increase of the ground conductivity. The effect of half-space response on the instrument slots downward opening direction is greatest and the upward is minimal The half-space response of the deep induction reaches the maximum near the 0.4m height when tool is above ground. The peak position does not change with the ground conductivity changes.These results have a practical significance to determine accurately the sonde error of the dual-induction logging tool while drilling.
