The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theor...The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theoretical and practical significance for guiding oil and gas exploration.The sedimentary facies and sedimentary evolution of the high-resolution sequence framework of the Carboniferous Taiyuan Formation in the Hangjinqi area have been systematically analyzed for the first time by drilling,logging and seismic data.The results show that four types of sequence interfaces can be identified in the Taiyuan Formation:regional unconformity surfaces,scour surfaces,lithologic-lithofacies transformation surfaces and flooding surfaces.According to the sedimentary response caused by the upward and downward movements of the base level at different levels,the Taiyuan Formation can be divided into 2 long-term cycles(LSC_(1)-LSC_(2)),4 mid-term cycles(MSC_(1)-MSC4)and 7 short-term cycles(SSC_(1)-SSC7).The long-and mid-term cycles correspond to members T_(1)and T_(2)and layers T_(1)-1,T_(1-2),T_(2-1),and T_(2)-2,respectively.Long-term cycles are dominated by C_(1);mid-term cycles are dominated by C_(1)and C_(2),followed by A2;and short-term cycles are dominated by C_(1),C_(2),A1 and A2.Under the high-resolution sequence stratigraphic framework,the Hangjinqi area underwent a transformation of fan delta and tidal flat depositional systems during the Taiyuan Formation sedimentary period.In the MSC_(1)-MSC_(2)stage,owing to a large-scale paleocontinent,the fan delta sedimentary body,which was limited in scale and scope,developed only in the southeastern corner and gradually transitioned basinward to tidal flat facies.In the MSC3-MSC4 stage,as the paleocontinent continuously decreased and the sedimentary range expanded,fan-delta plain sedimentation began in the study area.Several braided distributary channels with poor connectivity developed on the fan-delta plain,and between them were floodplains and peat swamps.展开更多
The sedimentary characteristics and their combination succession of the Permian in the Shandong nd Huainan-Huaibei coalfields are analyzed. The mid-and short-term stratigraphic base-level cycles are identified. High-r...The sedimentary characteristics and their combination succession of the Permian in the Shandong nd Huainan-Huaibei coalfields are analyzed. The mid-and short-term stratigraphic base-level cycles are identified. High-resolution sequences are divided based on the above results. The study shows that the stratigraphic base-level cyclic method is an efficient way in the determination of the high-resolution sequences, especially in the classification of tbe terrestrial and transitional depositional succession.展开更多
Shallow lacustrine delta front （SLDF） comprises mainly sheetlike subaqueous distributary channels （SDC） formed in shallow, gentle, and tectonically steady slope （Cai and Zhu, 2011）. SDC proves an important hydro...Shallow lacustrine delta front （SLDF） comprises mainly sheetlike subaqueous distributary channels （SDC） formed in shallow, gentle, and tectonically steady slope （Cai and Zhu, 2011）. SDC proves an important hydrocarbon reservoir type in the Daqing oilfield, Changqing oilfield, and the newly discovered Moxizhuang oilfield in Central Junggar Basin. However, SDC tends to prograde quickly and move laterally frequently,展开更多
The phase change of lacustrine gravity flow deposition is fast and complex. In its reservoir division and correlation, the isochronous problem is very important. Taking the oil formation I of Es3 in Wuhaozhuang oilfie...The phase change of lacustrine gravity flow deposition is fast and complex. In its reservoir division and correlation, the isochronous problem is very important. Taking the oil formation I of Es3 in Wuhaozhuang oilfield as an example, through the analysis of stratigraphic drilling and logging data in the study area, according to the genetic types of different levels of base level cycle interfaces and the characteristics of high-resolution sequence stratigraphy, this paper subdivides the lacustrine gravity flow oil layer of lower Es3 in Wuhaozhuang Oilfield, divides it into four short-term base level cycle sequences, and establishes the high-resolution isochronous stratigraphic framework of this interval. It is found that the mid-term, short-term and ultra short-term base level cycles correspond to the oil formation, sand layer group and single layer in the oil layer correlation unit of the oilfield respectively. Based on this, the oil layer correlation unit of the interval is divided, and the sublayer correlation model is established according to the identification characteristics of the short-term base level cycle.展开更多
Three third-order sequences and about one hundred high-frequency cycles or Milankovitchcycles within the Late Permian Changxingian to Early Triassic Griesbachian are identified in theMeishan Section of Changxing, Zhej...Three third-order sequences and about one hundred high-frequency cycles or Milankovitchcycles within the Late Permian Changxingian to Early Triassic Griesbachian are identified in theMeishan Section of Changxing, Zhejiang Province, southern China, the candidate stratotype sec-tion of the global Permo-Triassic boundary, based on a detailed study of the biological,ecological and high-resolution allochthonous cyclic events, microfacies and depositional systems.Furthermore, the stacking pattern of the depositional systems across various Changxingian andGriesbachian sedimentary facies of the Lower Yangtze and the sequence stratigraphic frameworkare outlined with the Meishan section as the principal section. In this paper the habitat types offossil biota are applied to semiquantitative palaeobathymetry and the study of relative sea levelchanges.展开更多
In view of the high accuracy and predictability, high-resolution sequence stratigraphy had been extensively applied to oil exploration and gotten prominent practicable results. This article takes the first layer, uppe...In view of the high accuracy and predictability, high-resolution sequence stratigraphy had been extensively applied to oil exploration and gotten prominent practicable results. This article takes the first layer, upper second submember, Shahejie （沙河街） Formation from Pucheng （濮城） oilfield as an example to analyze the application of high-resolution sequence stratigraphy in reservoir study on the basis of a comprehensive study of core log data. Firstly, facies analysis of this area reveals the corresponding terminal fan system occurring where sediment-laden streams decrease in size and vanish as a result of evaporation and transmission losses. The model includes a tripartite zonation of terminal fan into feeder, distributary, and basinal zones. Secondly, electrofacies were made by well-log analysis and then matched with sedimentary facies defined by core analysis. Four electrofacies characterizing the main sedimentary facies association and depositional environments within target area are defined （channel, lag deposit, lake or flood-plain, and overflow deposits）. Thirdly, related correlations based on high-resolution sequence stratigraphy were established. By observing the stacking arrangement of genetic sequences, different scales of stratigraphic cycle can be identified. Within scale and duration, the stratigraphic cycles are termed as genetic sequences, genetic sequence sets, and minor cycles.展开更多
Wavelet transformation is a widely used method in high-frequency sequence stratigraphic analysis.However, the application is problematic since different wavelets always return the same sequence analysis results. To ad...Wavelet transformation is a widely used method in high-frequency sequence stratigraphic analysis.However, the application is problematic since different wavelets always return the same sequence analysis results. To address this issue, we applied five commonly used wavelets to theoretical sequence models to document some application criteria. Five gradual scale-change sequence models were simplified from the glutenite succession deposition by gravity flows to form the fining-upwards cycle sequences(FUCS) and coarsening-upwards cycle sequences(CUCS). After conducting theoretical sequence model tests, the optimal wavelet(sym4) was selected and successfully used with actual data to identify the sequence boundaries. We also proposed a new method to optimize the scale of continuous wavelet transformation(CWT) for sequence boundary determination. We found that the balloon-like marks in scalograms of db4, sym4, and coif4 wavelet determine, respectively, the fourth-order sequence boundary, the thick succession sequence boundaries in FUCS, and the thick succession sequence in FUCS and CUCS. Comparing the sequence identification results shows that the asymmetric wavelets had an advantage in high-frequency sequence boundary determination and sedimentary cycle discrimination through the amplitude trend of the coefficient, in which the sym4 wavelet is the most effective. In conclusion, the asymmetry of wavelets is the first selection principle, of which asymmetric wavelets are more sensitive to sediment deposition by flood flows. The match of the wavelet between the sequence is the second selection principle, in which the correlation of time-frequency impacts the accuracy of sequence surface localization. However, the waveform of the wavelet is a visual and abstract parameter for sequence boundary detection. The appropriate wavelet for lacustrine sequence analysis is the asymmetric wavelet with a weak number of side lobes. The depositional flows, depositional process,and autogenic are three sedimentary factors that influence the sequence analysis results.展开更多
In this study,we developed a high-resolution stratigraphic framework for the Yanchang Formation in the Huachi Block of the Qingyang Oilfield,located in the Ordos Basin,northwest China.Using well log and seismic data,w...In this study,we developed a high-resolution stratigraphic framework for the Yanchang Formation in the Huachi Block of the Qingyang Oilfield,located in the Ordos Basin,northwest China.Using well log and seismic data,we traced and correlated sweet-spot sand bodies in tight oil reservoirs.Three long-term base-level cycles were identified in the Yanchang Formation,and five medium-term base-level cycles were delineated from the Chang 72 sub-Member to the Chang 4+5 Members,corresponding to five distinct oil groups.The primary production layer,Oil Group 3,was further divided into short-term and very short-term base-level cycles to facilitate the prediction of hydrocarbon target zones.Sweet-spot sand bodies were traced and correlated within very short-term cycles.The sweet-spot sand bodies are mainly sublacustrine channel deposits in the delta front,which were mainly developed in the five single layers(3-1-2,3-1-3,3-1-4,3-2-2,3-2-3 and 3-2-5)of the small layers 3-1 and 3-2 during the regression periods of base-level cycles.The sweet spot sand bodies within the small layer 3-2 are derived from three sets of sources in the northeast,northwest,and south of the basin.The Class I sweet spot is distributed within the single layer 3-2-5,with an average thickness of about 6 m,covering about 25%of the study area.The Class II sweet spot is developed in all five single layers,with the thickest and largest sweet-spot sand body in the Single layer 3-2-3,covering about 90%of the study area.This study highlights the critical importance of establishing a high-resolution sequence stratigraphic framework for the refined delineation of sweet-spot sand bodies within a deltaic-lacustrine depositional system.Additionally,sublacustrine fan deposits formed during the regressive semi-cycle were identified as key sweet spots in the study area.展开更多
This comprehensive study establishes a novel high-resolution sequence stratigraphic framework for a shallow,warm,land-tied carbonate-rimmed shelf represented by the Ponta do Mel Formation.Integration of cores and cutt...This comprehensive study establishes a novel high-resolution sequence stratigraphic framework for a shallow,warm,land-tied carbonate-rimmed shelf represented by the Ponta do Mel Formation.Integration of cores and cuttings with seismic and well-log data provides the detailed subsurface stratigraphic framework encompassing two fourth-order genetic sequences.The high-resolution approach unveiled the step-by-step depositional and diagenetic evolution of the Ponta do Mel Formation at the fourth-order systems tracts scale and established the reservoir zonation.In each zone,the lateral contact between high-energy outer shelf and shelf rim potential reservoirs and low-energy inner shelf deposits constitutes critical reservoir heterogeneities that may affect production planning and development projects.Moreover,the reservoir scale enabled discussion on the controls on deposition,high-resolution sequence architecture,diagenesis,and insight into the zonation and characterisation of similar oil and gas reservoirs worldwide.展开更多
Due to the low sound propagation speed, the tradeoff between high azimuth resolution and wide imaging swath has severely limited the application of sonar underwater target imaging. However, based on compressed sensing...Due to the low sound propagation speed, the tradeoff between high azimuth resolution and wide imaging swath has severely limited the application of sonar underwater target imaging. However, based on compressed sensing(CS) technique, it is feasible to image targets with merely one pulse and thus avoid the above tradeoff. To investigate the possible waveforms for CS-based underwater imaging, the deterministic M sequences widely used in sonar applications are introduced in this paper. By analyzing the compressive matrix constructed from M sequences, the coherence parameter and the restricted isometry property(RIP) of the matrix are derived. Also, the feasibility and advances of M sequence are demonstrated by being compared with the existing Alltop sequence in underwater CS imaging framework. Finally, the results of numerical simulations and a real experiment are provided to reveal the effectiveness of the proposed signal.展开更多
基金supported by the Fundamental Research Funds for the Liaoning Universities(Grant No.LJ202410166012).
文摘The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theoretical and practical significance for guiding oil and gas exploration.The sedimentary facies and sedimentary evolution of the high-resolution sequence framework of the Carboniferous Taiyuan Formation in the Hangjinqi area have been systematically analyzed for the first time by drilling,logging and seismic data.The results show that four types of sequence interfaces can be identified in the Taiyuan Formation:regional unconformity surfaces,scour surfaces,lithologic-lithofacies transformation surfaces and flooding surfaces.According to the sedimentary response caused by the upward and downward movements of the base level at different levels,the Taiyuan Formation can be divided into 2 long-term cycles(LSC_(1)-LSC_(2)),4 mid-term cycles(MSC_(1)-MSC4)and 7 short-term cycles(SSC_(1)-SSC7).The long-and mid-term cycles correspond to members T_(1)and T_(2)and layers T_(1)-1,T_(1-2),T_(2-1),and T_(2)-2,respectively.Long-term cycles are dominated by C_(1);mid-term cycles are dominated by C_(1)and C_(2),followed by A2;and short-term cycles are dominated by C_(1),C_(2),A1 and A2.Under the high-resolution sequence stratigraphic framework,the Hangjinqi area underwent a transformation of fan delta and tidal flat depositional systems during the Taiyuan Formation sedimentary period.In the MSC_(1)-MSC_(2)stage,owing to a large-scale paleocontinent,the fan delta sedimentary body,which was limited in scale and scope,developed only in the southeastern corner and gradually transitioned basinward to tidal flat facies.In the MSC3-MSC4 stage,as the paleocontinent continuously decreased and the sedimentary range expanded,fan-delta plain sedimentation began in the study area.Several braided distributary channels with poor connectivity developed on the fan-delta plain,and between them were floodplains and peat swamps.
文摘The sedimentary characteristics and their combination succession of the Permian in the Shandong nd Huainan-Huaibei coalfields are analyzed. The mid-and short-term stratigraphic base-level cycles are identified. High-resolution sequences are divided based on the above results. The study shows that the stratigraphic base-level cyclic method is an efficient way in the determination of the high-resolution sequences, especially in the classification of tbe terrestrial and transitional depositional succession.
基金financially supported by National Natural Science Foundation of China(Grant No.41272159 and 41372123)
文摘Shallow lacustrine delta front （SLDF） comprises mainly sheetlike subaqueous distributary channels （SDC） formed in shallow, gentle, and tectonically steady slope （Cai and Zhu, 2011）. SDC proves an important hydrocarbon reservoir type in the Daqing oilfield, Changqing oilfield, and the newly discovered Moxizhuang oilfield in Central Junggar Basin. However, SDC tends to prograde quickly and move laterally frequently,
文摘The phase change of lacustrine gravity flow deposition is fast and complex. In its reservoir division and correlation, the isochronous problem is very important. Taking the oil formation I of Es3 in Wuhaozhuang oilfield as an example, through the analysis of stratigraphic drilling and logging data in the study area, according to the genetic types of different levels of base level cycle interfaces and the characteristics of high-resolution sequence stratigraphy, this paper subdivides the lacustrine gravity flow oil layer of lower Es3 in Wuhaozhuang Oilfield, divides it into four short-term base level cycle sequences, and establishes the high-resolution isochronous stratigraphic framework of this interval. It is found that the mid-term, short-term and ultra short-term base level cycles correspond to the oil formation, sand layer group and single layer in the oil layer correlation unit of the oilfield respectively. Based on this, the oil layer correlation unit of the interval is divided, and the sublayer correlation model is established according to the identification characteristics of the short-term base level cycle.
文摘Three third-order sequences and about one hundred high-frequency cycles or Milankovitchcycles within the Late Permian Changxingian to Early Triassic Griesbachian are identified in theMeishan Section of Changxing, Zhejiang Province, southern China, the candidate stratotype sec-tion of the global Permo-Triassic boundary, based on a detailed study of the biological,ecological and high-resolution allochthonous cyclic events, microfacies and depositional systems.Furthermore, the stacking pattern of the depositional systems across various Changxingian andGriesbachian sedimentary facies of the Lower Yangtze and the sequence stratigraphic frameworkare outlined with the Meishan section as the principal section. In this paper the habitat types offossil biota are applied to semiquantitative palaeobathymetry and the study of relative sea levelchanges.
基金supported by the National Key Technology R&D Program (No. 2006BAC18B05)
文摘In view of the high accuracy and predictability, high-resolution sequence stratigraphy had been extensively applied to oil exploration and gotten prominent practicable results. This article takes the first layer, upper second submember, Shahejie （沙河街） Formation from Pucheng （濮城） oilfield as an example to analyze the application of high-resolution sequence stratigraphy in reservoir study on the basis of a comprehensive study of core log data. Firstly, facies analysis of this area reveals the corresponding terminal fan system occurring where sediment-laden streams decrease in size and vanish as a result of evaporation and transmission losses. The model includes a tripartite zonation of terminal fan into feeder, distributary, and basinal zones. Secondly, electrofacies were made by well-log analysis and then matched with sedimentary facies defined by core analysis. Four electrofacies characterizing the main sedimentary facies association and depositional environments within target area are defined （channel, lag deposit, lake or flood-plain, and overflow deposits）. Thirdly, related correlations based on high-resolution sequence stratigraphy were established. By observing the stacking arrangement of genetic sequences, different scales of stratigraphic cycle can be identified. Within scale and duration, the stratigraphic cycles are termed as genetic sequences, genetic sequence sets, and minor cycles.
文摘Wavelet transformation is a widely used method in high-frequency sequence stratigraphic analysis.However, the application is problematic since different wavelets always return the same sequence analysis results. To address this issue, we applied five commonly used wavelets to theoretical sequence models to document some application criteria. Five gradual scale-change sequence models were simplified from the glutenite succession deposition by gravity flows to form the fining-upwards cycle sequences(FUCS) and coarsening-upwards cycle sequences(CUCS). After conducting theoretical sequence model tests, the optimal wavelet(sym4) was selected and successfully used with actual data to identify the sequence boundaries. We also proposed a new method to optimize the scale of continuous wavelet transformation(CWT) for sequence boundary determination. We found that the balloon-like marks in scalograms of db4, sym4, and coif4 wavelet determine, respectively, the fourth-order sequence boundary, the thick succession sequence boundaries in FUCS, and the thick succession sequence in FUCS and CUCS. Comparing the sequence identification results shows that the asymmetric wavelets had an advantage in high-frequency sequence boundary determination and sedimentary cycle discrimination through the amplitude trend of the coefficient, in which the sym4 wavelet is the most effective. In conclusion, the asymmetry of wavelets is the first selection principle, of which asymmetric wavelets are more sensitive to sediment deposition by flood flows. The match of the wavelet between the sequence is the second selection principle, in which the correlation of time-frequency impacts the accuracy of sequence surface localization. However, the waveform of the wavelet is a visual and abstract parameter for sequence boundary detection. The appropriate wavelet for lacustrine sequence analysis is the asymmetric wavelet with a weak number of side lobes. The depositional flows, depositional process,and autogenic are three sedimentary factors that influence the sequence analysis results.
基金supported by the National Key Research and DevelopmentProgram of China(Grant No.2023YFF0804300 and 2023YFF0804303).
文摘In this study,we developed a high-resolution stratigraphic framework for the Yanchang Formation in the Huachi Block of the Qingyang Oilfield,located in the Ordos Basin,northwest China.Using well log and seismic data,we traced and correlated sweet-spot sand bodies in tight oil reservoirs.Three long-term base-level cycles were identified in the Yanchang Formation,and five medium-term base-level cycles were delineated from the Chang 72 sub-Member to the Chang 4+5 Members,corresponding to five distinct oil groups.The primary production layer,Oil Group 3,was further divided into short-term and very short-term base-level cycles to facilitate the prediction of hydrocarbon target zones.Sweet-spot sand bodies were traced and correlated within very short-term cycles.The sweet-spot sand bodies are mainly sublacustrine channel deposits in the delta front,which were mainly developed in the five single layers(3-1-2,3-1-3,3-1-4,3-2-2,3-2-3 and 3-2-5)of the small layers 3-1 and 3-2 during the regression periods of base-level cycles.The sweet spot sand bodies within the small layer 3-2 are derived from three sets of sources in the northeast,northwest,and south of the basin.The Class I sweet spot is distributed within the single layer 3-2-5,with an average thickness of about 6 m,covering about 25%of the study area.The Class II sweet spot is developed in all five single layers,with the thickest and largest sweet-spot sand body in the Single layer 3-2-3,covering about 90%of the study area.This study highlights the critical importance of establishing a high-resolution sequence stratigraphic framework for the refined delineation of sweet-spot sand bodies within a deltaic-lacustrine depositional system.Additionally,sublacustrine fan deposits formed during the regressive semi-cycle were identified as key sweet spots in the study area.
基金support from Petrobras and the Programa de Pos-Graduacao em Geologia e Geofisica da Universidade Federal do Rio Grande do NorteWe are grateful to Gustavo Barros for his drafting skills.
文摘This comprehensive study establishes a novel high-resolution sequence stratigraphic framework for a shallow,warm,land-tied carbonate-rimmed shelf represented by the Ponta do Mel Formation.Integration of cores and cuttings with seismic and well-log data provides the detailed subsurface stratigraphic framework encompassing two fourth-order genetic sequences.The high-resolution approach unveiled the step-by-step depositional and diagenetic evolution of the Ponta do Mel Formation at the fourth-order systems tracts scale and established the reservoir zonation.In each zone,the lateral contact between high-energy outer shelf and shelf rim potential reservoirs and low-energy inner shelf deposits constitutes critical reservoir heterogeneities that may affect production planning and development projects.Moreover,the reservoir scale enabled discussion on the controls on deposition,high-resolution sequence architecture,diagenesis,and insight into the zonation and characterisation of similar oil and gas reservoirs worldwide.
基金supported in part by National Natural Science Foundation of China (Grant No. 61271391)111 Project of China Ministry of Education (MOE) (Grant No. B14010)+2 种基金New Century Excellent Talents Supporting Plan of China MOE (Grant No. NCET-13-0049)Ministry Research Foundation (Grant No. 9140A21050114HT05338)Outstanding Youth Teacher Training Plan of BIT (Grant No. BIT-JC-201205)
文摘Due to the low sound propagation speed, the tradeoff between high azimuth resolution and wide imaging swath has severely limited the application of sonar underwater target imaging. However, based on compressed sensing(CS) technique, it is feasible to image targets with merely one pulse and thus avoid the above tradeoff. To investigate the possible waveforms for CS-based underwater imaging, the deterministic M sequences widely used in sonar applications are introduced in this paper. By analyzing the compressive matrix constructed from M sequences, the coherence parameter and the restricted isometry property(RIP) of the matrix are derived. Also, the feasibility and advances of M sequence are demonstrated by being compared with the existing Alltop sequence in underwater CS imaging framework. Finally, the results of numerical simulations and a real experiment are provided to reveal the effectiveness of the proposed signal.
