Understanding the quantitative responses of anisotropic dynamic properties in organic-rich shale with different kerogen content(KC)is of great significance in hydrocarbon exploration and development.Conducting control...Understanding the quantitative responses of anisotropic dynamic properties in organic-rich shale with different kerogen content(KC)is of great significance in hydrocarbon exploration and development.Conducting controlled experiments with a single variable is challenging for natural shales due to their high variations in components,diagenesis conditions,or pore fluid.We employed the hot-pressing technique to construct 11 well-controlled artificial shale with varying KC.These artificial shale samples were successive machined into prismatic shape for ultrasonic measurements along different directions.Observations revealed bedding perpendicular P-wave velocities are more sensitive to the increasing KC than bedding paralleling velocities due to the preferential alignments of kerogen.All elastic stiffnesses except C_(13)are generally decreasing with the increasing KC,the variation of C_(1) and C_(33)on kerogen content are more sensitive than those of C_(44)and C_(66).Apparent dynamic mechanical parameters(v and E)were found to have linear correlation with the true ones from complete anisotropic equations independent of KC,which hold value towards the interpretation of well logs consistently across formations,Anisotropic mechanical parameters(ΔE and brittlenessΔB)tend to decrease with the reducing KC,withΔB showing great sensitivity to KC variations.In the range of low KC(<10%),the V_(P)/V_(S) ratio demonstrated a linearly negative correlation with KC,and the V_(P)/V_(S) ratio magnitude of less than 1.75may serve as a significant characterization for highly organic-rich(>10%)shale,compilation of data from natural organic rich-shales globally verified the similar systematic relationships that can be empirically used to predict the fraction of KC in shales.展开更多
Simultaneous source technology,which reduces seismic survey time and improves the quality of seismic data by firing more than one source with a narrow time interval,is compromised by the massive blended interference.T...Simultaneous source technology,which reduces seismic survey time and improves the quality of seismic data by firing more than one source with a narrow time interval,is compromised by the massive blended interference.Therefore,deblending algorithms have been developed to separate this interference.Recently,deep learning(DL)has been proved its great potential in suppressing the interference.The most popular DL method employs neural network as a filter to attenuate the blended noise in an iterative estimation and subtraction framework(IESF).However,there are still amplitude distortion and blended noise residual problems,especially when dealing with weak signal submerged in strong interference.To address these problems,we propose a hybrid WUDT-NAFnet,which contains two sub-networks.The first network is a wavelet based U-shape deblending transformer network(WUDTnet),incorporated into IESF as a robust regularization term to iteratively separate the blended interference.The second network is a nonlinear activate free network(NAFnet)designed to recover the event amplitude and further suppress the weak noise residual in IESF.With the hybrid network,the blended noise can be separated purposefully and accurately.Examples using synthetic and field seismic data demonstrate that the WUDTNAFnet outperforms traditional curvelet transform(CT)based method and the deblending transformer(DT)model in terms of deblending.Additionally,for field applications,the data augmentation method of bicubic interpolation is applied to mitigate the feature difference between synthetic and field data.Consequently,the trained network exhibits strong signal preservation ability in numerical field example without requiring additional training.展开更多
Microcosmic details of pore structure are the essential factors affecting the elastic properties of tight sandstone reservoirs,while the relationships in between are still incompletely clear due to the fact that quant...Microcosmic details of pore structure are the essential factors affecting the elastic properties of tight sandstone reservoirs,while the relationships in between are still incompletely clear due to the fact that quantitative or semi-quantitative experiments are hard to achieve.Here,three sets of tight sandstone samples from the Junggar Basin are selected elaborately based on casting thin sections,XRD detection,and petro-physical measurement,and each set is characterized by a single varied microcosmic factor(pore connectedness,pore type,and grain size)of the pore structure.An ultrasonic pulse transmission technique is conducted to study the response of elastic properties to the varied microcosmic details of pore structure in the situation of different pore fluid(gas,brine,and oil)saturation and confining pressure.Observations show samples with less connectedness,inter-granular dominant pores,and smaller grain size showed greater velocities in normal conditions.Vpis more sensitive to the variations of pore type,while Vsis more sensitive to the variations of grain size.Samples with better connectedness at fluid saturation(oil or brine)show greater sensitivity to the confining pressure than those with gas saturation with a growth rate of 6.9%-11.9%,and the sensitivity is more likely controlled by connectedness.The pore types(inter-granular or intra-granular)can be distinguished by the sensitivity of velocities to the variation of pore fluid at high confining pressure(>60 MPa).The samples with small grain sizes tend to be more sensitive to the variations of confining pressure.With this knowledge,we can semi-quantitatively distinguish the complex pore structures with different fluids by the variation of elastic properties,which can help improve the precision of seismic reservoir prediction for tight sandstone reservoirs.展开更多
基金supported by the National Natural Science Foundation of China(42004112,42274175,42030812,41974160)Natural Science Foundation of Sichuan Province(2023NSFSC0764)。
文摘Understanding the quantitative responses of anisotropic dynamic properties in organic-rich shale with different kerogen content(KC)is of great significance in hydrocarbon exploration and development.Conducting controlled experiments with a single variable is challenging for natural shales due to their high variations in components,diagenesis conditions,or pore fluid.We employed the hot-pressing technique to construct 11 well-controlled artificial shale with varying KC.These artificial shale samples were successive machined into prismatic shape for ultrasonic measurements along different directions.Observations revealed bedding perpendicular P-wave velocities are more sensitive to the increasing KC than bedding paralleling velocities due to the preferential alignments of kerogen.All elastic stiffnesses except C_(13)are generally decreasing with the increasing KC,the variation of C_(1) and C_(33)on kerogen content are more sensitive than those of C_(44)and C_(66).Apparent dynamic mechanical parameters(v and E)were found to have linear correlation with the true ones from complete anisotropic equations independent of KC,which hold value towards the interpretation of well logs consistently across formations,Anisotropic mechanical parameters(ΔE and brittlenessΔB)tend to decrease with the reducing KC,withΔB showing great sensitivity to KC variations.In the range of low KC(<10%),the V_(P)/V_(S) ratio demonstrated a linearly negative correlation with KC,and the V_(P)/V_(S) ratio magnitude of less than 1.75may serve as a significant characterization for highly organic-rich(>10%)shale,compilation of data from natural organic rich-shales globally verified the similar systematic relationships that can be empirically used to predict the fraction of KC in shales.
基金partly supported by the National Natural Science Foundation of China(grant Nos.42004104,42030812,42204136)。
文摘Simultaneous source technology,which reduces seismic survey time and improves the quality of seismic data by firing more than one source with a narrow time interval,is compromised by the massive blended interference.Therefore,deblending algorithms have been developed to separate this interference.Recently,deep learning(DL)has been proved its great potential in suppressing the interference.The most popular DL method employs neural network as a filter to attenuate the blended noise in an iterative estimation and subtraction framework(IESF).However,there are still amplitude distortion and blended noise residual problems,especially when dealing with weak signal submerged in strong interference.To address these problems,we propose a hybrid WUDT-NAFnet,which contains two sub-networks.The first network is a wavelet based U-shape deblending transformer network(WUDTnet),incorporated into IESF as a robust regularization term to iteratively separate the blended interference.The second network is a nonlinear activate free network(NAFnet)designed to recover the event amplitude and further suppress the weak noise residual in IESF.With the hybrid network,the blended noise can be separated purposefully and accurately.Examples using synthetic and field seismic data demonstrate that the WUDTNAFnet outperforms traditional curvelet transform(CT)based method and the deblending transformer(DT)model in terms of deblending.Additionally,for field applications,the data augmentation method of bicubic interpolation is applied to mitigate the feature difference between synthetic and field data.Consequently,the trained network exhibits strong signal preservation ability in numerical field example without requiring additional training.
基金supported by the Open Fund(PLC2020002,PLC20190507)of the State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Chengdu University of Technology)National Natural Science Foundation of China(42004112,42274175,42030812,41974160)+1 种基金sponsored by Special projects of local science and technology development guided by the central government in Sichuan(2021ZYD0030)Natural Science Foundation of Sichuan Province(23NSFSC5311)
文摘Microcosmic details of pore structure are the essential factors affecting the elastic properties of tight sandstone reservoirs,while the relationships in between are still incompletely clear due to the fact that quantitative or semi-quantitative experiments are hard to achieve.Here,three sets of tight sandstone samples from the Junggar Basin are selected elaborately based on casting thin sections,XRD detection,and petro-physical measurement,and each set is characterized by a single varied microcosmic factor(pore connectedness,pore type,and grain size)of the pore structure.An ultrasonic pulse transmission technique is conducted to study the response of elastic properties to the varied microcosmic details of pore structure in the situation of different pore fluid(gas,brine,and oil)saturation and confining pressure.Observations show samples with less connectedness,inter-granular dominant pores,and smaller grain size showed greater velocities in normal conditions.Vpis more sensitive to the variations of pore type,while Vsis more sensitive to the variations of grain size.Samples with better connectedness at fluid saturation(oil or brine)show greater sensitivity to the confining pressure than those with gas saturation with a growth rate of 6.9%-11.9%,and the sensitivity is more likely controlled by connectedness.The pore types(inter-granular or intra-granular)can be distinguished by the sensitivity of velocities to the variation of pore fluid at high confining pressure(>60 MPa).The samples with small grain sizes tend to be more sensitive to the variations of confining pressure.With this knowledge,we can semi-quantitatively distinguish the complex pore structures with different fluids by the variation of elastic properties,which can help improve the precision of seismic reservoir prediction for tight sandstone reservoirs.
