Using well logs data only, the evaluation of shale gas hydrocarbon potential of Talhar Shale Member of Lower Goru Formation has been a challenge in Southern Lower Indus Basin in Pakistan. Well logs data analysis is he...Using well logs data only, the evaluation of shale gas hydrocarbon potential of Talhar Shale Member of Lower Goru Formation has been a challenge in Southern Lower Indus Basin in Pakistan. Well logs data analysis is helpful to evaluate the gas potential of source shale rocks. We introduced and applied empirical and graphical method to fulfil this task and derived geochemical parameters from well logs data. The method mentioned is cheap and fast. Talhar Shale has kerogen type Ⅲ and type Ⅱ which are montmorillonite clay and have potential to produce oil and gas. Talhar Shale has better sorption property. Empirical formulas are used to derive parameters, using well logs of porosity, density and uranium. Porosity and volume of kerogen, calculated from density log, give average values of 11.8% and 11.4%. Average value of level of maturity index （LMI） derived from log is 0.54, which indicates that it is at the early stage of maturity. Vitrinite reflectance is between 0.5%-0.55% as calculated by graphical method and empirical formula. Talhar Shale is at onset of oil generation, with main products of oil and gas. It is a good potential source in the study area.展开更多
This paper presents an algorithm for analysis of the dielectric radomes. In this method, the radome is discretized by a regular grid with rooftop basic functions. The Volume Integral Equation (VIE) for 3D dielectric o...This paper presents an algorithm for analysis of the dielectric radomes. In this method, the radome is discretized by a regular grid with rooftop basic functions. The Volume Integral Equation (VIE) for 3D dielectric object is transformed to linear system by Galerkin’s testing formulation. Furthermore, the linear system is presented by Toeplitz matrix which can be solved by the Conjugate Gradient algorithm combined with Fast Fourier Transform (CG-FFT) iteratively. Also, the algorithm requires less computational complexity and memory. This paper simulates the mono-static Radar Cross Section of dielectric radome by the CG-FFT, which was validated against commercial software FEKO.展开更多
In recent years, significant advancements have been made in deep-sea broadband seismic acquisition and its support data processing technologies. Compared with traditional constant-depth flat-cable acquisition, variabl...In recent years, significant advancements have been made in deep-sea broadband seismic acquisition and its support data processing technologies. Compared with traditional constant-depth flat-cable acquisition, variable-depth cable acquisition significantly differentiates frequency notches and enhances information complementarity between traces, effectively broadening the frequency band of acquired seismic data. Based on the international slanted cable technology, China has independently developed a plow-type cable seismic acquisition and imaging system: a combination of slanted and deep-deployed flat cables,along with a deghosting processing technique. This innovation optimizes the segmented depth variation of cables, further improving low-frequency response and broadening the high-frequency range. This paper extends the 2D technology into three dimensions, establishing an integrated technology system for deep-sea broadband, wide-azimuth seismic acquisition and imaging, consisting of three-ship and six-source acquisition equipments, 3D plow-type cable mat, blended acquisition design with rolling dual-random sources, and wavenumber-domain 3D deghosting techniques. Applications to two tectonic zones in the South China Sea demonstrate that the frequency band of seismic data is expanded from three octaves(8–85 Hz) by conventional acquisition and imaging methods to five octaves(2–130 Hz), significantly improving the data quality and imaging precision of deep structures. This advancement effectively supports the researches of fundamental geology, hydrocarbon accumulation,reservoir prediction, and fluid identification in deep-water basins. The successful deployment of these technologies has advanced China's deep-sea oil and gas exploration and has been generalized to more than ten international deep-sea oilfields.展开更多
文摘Using well logs data only, the evaluation of shale gas hydrocarbon potential of Talhar Shale Member of Lower Goru Formation has been a challenge in Southern Lower Indus Basin in Pakistan. Well logs data analysis is helpful to evaluate the gas potential of source shale rocks. We introduced and applied empirical and graphical method to fulfil this task and derived geochemical parameters from well logs data. The method mentioned is cheap and fast. Talhar Shale has kerogen type Ⅲ and type Ⅱ which are montmorillonite clay and have potential to produce oil and gas. Talhar Shale has better sorption property. Empirical formulas are used to derive parameters, using well logs of porosity, density and uranium. Porosity and volume of kerogen, calculated from density log, give average values of 11.8% and 11.4%. Average value of level of maturity index （LMI） derived from log is 0.54, which indicates that it is at the early stage of maturity. Vitrinite reflectance is between 0.5%-0.55% as calculated by graphical method and empirical formula. Talhar Shale is at onset of oil generation, with main products of oil and gas. It is a good potential source in the study area.
文摘This paper presents an algorithm for analysis of the dielectric radomes. In this method, the radome is discretized by a regular grid with rooftop basic functions. The Volume Integral Equation (VIE) for 3D dielectric object is transformed to linear system by Galerkin’s testing formulation. Furthermore, the linear system is presented by Toeplitz matrix which can be solved by the Conjugate Gradient algorithm combined with Fast Fourier Transform (CG-FFT) iteratively. Also, the algorithm requires less computational complexity and memory. This paper simulates the mono-static Radar Cross Section of dielectric radome by the CG-FFT, which was validated against commercial software FEKO.
基金supported jointly by National Major Science and Technology Project of China (Grant No. 2016ZX05026001)Major Projects for the 14th Five-Year Plan of National Laboratory for Marine Science and Technology (Qingdao) (Grant No. 2021QNLM020001)。
文摘In recent years, significant advancements have been made in deep-sea broadband seismic acquisition and its support data processing technologies. Compared with traditional constant-depth flat-cable acquisition, variable-depth cable acquisition significantly differentiates frequency notches and enhances information complementarity between traces, effectively broadening the frequency band of acquired seismic data. Based on the international slanted cable technology, China has independently developed a plow-type cable seismic acquisition and imaging system: a combination of slanted and deep-deployed flat cables,along with a deghosting processing technique. This innovation optimizes the segmented depth variation of cables, further improving low-frequency response and broadening the high-frequency range. This paper extends the 2D technology into three dimensions, establishing an integrated technology system for deep-sea broadband, wide-azimuth seismic acquisition and imaging, consisting of three-ship and six-source acquisition equipments, 3D plow-type cable mat, blended acquisition design with rolling dual-random sources, and wavenumber-domain 3D deghosting techniques. Applications to two tectonic zones in the South China Sea demonstrate that the frequency band of seismic data is expanded from three octaves(8–85 Hz) by conventional acquisition and imaging methods to five octaves(2–130 Hz), significantly improving the data quality and imaging precision of deep structures. This advancement effectively supports the researches of fundamental geology, hydrocarbon accumulation,reservoir prediction, and fluid identification in deep-water basins. The successful deployment of these technologies has advanced China's deep-sea oil and gas exploration and has been generalized to more than ten international deep-sea oilfields.
