In contrast to marine deposits, continental deposits in China are characterized by diverse sedimentary types, rapid changes in sedimentary facies, complex lithology, and thin, small sand bodies. In seismic sedimentolo...In contrast to marine deposits, continental deposits in China are characterized by diverse sedimentary types, rapid changes in sedimentary facies, complex lithology, and thin, small sand bodies. In seismic sedimentology studies on continental lacustrine basins, new thinking and more detailed and effective technical means are needed to generate lithological data cubes and conduct seismic geo- morphologic analyses. Based on a series of tests and studies, this paper presents the concepts of time-equivalent seismic attributes and seismic sedimentary bodies and a "four-step approach" for the seismic sedimentologic study of conti- nental basins: Step 1, build a time-equivalent stratigraphic framework based on vertical analysis and horizontal corre- lation of lithofacies, electrofacies, seismic facies, and pale- ontological combinations; Step 2, further build a sedimentary facies model based on the analysis of single- well facies with outcrop, coring, and lab test data; Step 3, convert the seismic data into a lithological data cube reflecting different lithologies by means of seismic tech- niques; and Step 4, perform a time-equivalent attribute analysis and convert the planar attribute into a sedimentary facies map under the guidance of the sedimentary facies model. The whole process, highlighting the verification and calibration of geological data, is an iteration and feedback procedure of geoseismic data. The key technologies include the following: (1) a seismic data-lithology conversion technique applicable to complex lithology, which can convert the seismic reflection from interface types to rock layers; and (2) time-equivalent seismic unit analysis and a time- equivalent seismic attribute extraction technique. Finally, this paper demonstrates the validity of the approach with an example from the Qikou Sag in the Bohai Bay Basin and subsequent drilling results.展开更多
Seismic sedimentology is the study of sedimentary rocks and facies using seismic data. However, often the sedimentary body features can't be described quantitatively due to the limit of seismic resolution. High resol...Seismic sedimentology is the study of sedimentary rocks and facies using seismic data. However, often the sedimentary body features can't be described quantitatively due to the limit of seismic resolution. High resolution inversion offsets this limitation and is applied to seismic sedimentology to identify subtle traps under complex geologic conditions, thereby widening the applicable range of seismic sedimentology. In this paper, based on seismic sedimentology, seismic phase-controlled nonlinear random inversion is used to predict the sandy conglomerate reservoir of Es3 in the Chezhen depression in Shengli Oilfield. Thickness and sedimentary microfacies maps of sandy conglomerate bodies in several stages are presented and several subtle traps were predicted and verified by drilling.展开更多
The fluvial-deltaic reservoirs of the Oligocene Huagang Formation in the Xihu sag of the East China Sea shelf basin reflect rapid lateral change in sedimentary facies and poor morphology of conventional slice attribut...The fluvial-deltaic reservoirs of the Oligocene Huagang Formation in the Xihu sag of the East China Sea shelf basin reflect rapid lateral change in sedimentary facies and poor morphology of conventional slice attributes,which bring difficulties to the reservoir prediction for subsequent exploration and development of lithologic reservoirs.The traditional seismic sedimentology technology is optimized by applying the characteristic technologies such as frequency-boosting interpretation,inversion-conventional–90°phase shift joint construction of seismic lithologic bodies,nonlinear slices,paleogeomorphology restoration,and multi-attribute fusion,to obtain typical slice attributes,which are conducive to geological form description and sedimentary interpretation.The Huagang Formation developed three types of sedimentary bodies:braided river,meandering river and shallow water delta,and the vertical sedimentary evolution was controlled by the mid-term base-level cycle and paleogeomorphology.In the early–middle stage of the mid-term base-level ascending cycle,braided channel deposits were dominant,and vertical superimposed sand bodies were developed.In the late stage of the ascending half-cycle and the early stage of the descending half-cycle,meandering river deposits were dominant,and isolated sand bodies were developed.In the middle–late stage of the descending half-cycle,shallow-water delta deposits were dominant,and migratory medium–thick sand bodies were developed.Restricted paleogeomorphology controlled the sand body distribution,while non-restricted paleogeomorphology had little effect on the sand body distribution.Based on reservoir characterization,the fault sealing type and reservoir updip pinch-out type structural lithological traps are proposed as the main directions for future exploration and development in the Xihu sag.展开更多
Interference of thin-interbedded layers in seismic reflections has great negative impact on thin-interbedded reservoirs prediction.To deal with this,two novel methods are proposed that can predict the thin-interbedded...Interference of thin-interbedded layers in seismic reflections has great negative impact on thin-interbedded reservoirs prediction.To deal with this,two novel methods are proposed that can predict the thin-interbedded reservoirs distribution through strata slices by suppressing the interference of adjacent layer with the help of seismic sedimentology.The plane distribution of single sand bodies in thin-interbedded reservoirs can be clarified.(1)The minimum interference frequency slicing method,uses the amplitude-frequency attribute estimated by wavelet transform to find a constant seismic frequency with the minimum influence on the stratal slice of target layer,and then an optimal slice corresponding the constant frequency mentioned above can be obtained.(2)The superimposed slicing method can calculate multiple interference coefficients of reservoir and adjacent layers of target geological body,and obtain superimposed slice by weighted stacking the multiple stratal slices of neighboring layers and target layer.The two proposed methods were used to predict the distribution of the target oil layers of 6 m thick in three sets of thin-interbedded reservoirs of Triassic Kelamayi Formation in the Fengnan area of Junggar Basin,Northwestern China.A comparison with drilling data and conventional stratal slices shows that the two methods can predict the distribution of single sand bodies in thin-interbedded reservoirs more accurately.展开更多
To solve the problems in restoring sedimentary facies and predicting reservoirs in loose gas-bearing sediment,based on seismic sedimentologic analysis of the first 9-component S-wave 3D seismic dataset of China,a four...To solve the problems in restoring sedimentary facies and predicting reservoirs in loose gas-bearing sediment,based on seismic sedimentologic analysis of the first 9-component S-wave 3D seismic dataset of China,a fourth-order isochronous stratigraphic framework was set up and then sedimentary facies and reservoirs in the Pleistocene Qigequan Formation in Taidong area of Qaidam Basin were studied by seismic geomorphology and seismic lithology.The study method and thought are as following.Firstly,techniques of phase rotation,frequency decomposition and fusion,and stratal slicing were applied to the 9-component S-wave seismic data to restore sedimentary facies of major marker beds based on sedimentary models reflected by satellite images.Then,techniques of seismic attribute extraction,principal component analysis,and random fitting were applied to calculate the reservoir thickness and physical parameters of a key sandbody,and the results are satisfactory and confirmed by blind testing wells.Study results reveal that the dominant sedimentary facies in the Qigequan Formation within the study area are delta front and shallow lake.The RGB fused slices indicate that there are two cycles with three sets of underwater distributary channel systems in one period.Among them,sandstones in the distributary channels of middle-low Qigequan Formation are thick and broad with superior physical properties,which are favorable reservoirs.The reservoir permeability is also affected by diagenesis.Distributary channel sandstone reservoirs extend further to the west of Sebei-1 gas field,which provides a basis to expand exploration to the western peripheral area.展开更多
Low-frequency components of seismic data tend to characterize thicker litho-stratigraphic units, while high-frequency components tend to characterize thinner isochronous-stratigraphic units. Thus, frequency dependent ...Low-frequency components of seismic data tend to characterize thicker litho-stratigraphic units, while high-frequency components tend to characterize thinner isochronous-stratigraphic units. Thus, frequency dependent interpretation can help to achieve fine sedimentary sequence analysis. However, in current seismic sedimentology method, a certain frequency profile generated by frequency filtering, loses some stratum reflection information, which is out of the limited frequency band. To achieve real frequency dependent stratum reflection profiles with whole stratum information, a time-varying sparse-spiking deconvolution based method is proposed in this paper. A synthetic example and a real delta progradation example show the accuracy and effectiveness of proposed method.展开更多
Seismic sedimentology is a new frontier inter-discipline subject, and shows good prospect and potentiality in reservoir deposition research with seismic data and geophysics technologies. We made seismic sedimentology ...Seismic sedimentology is a new frontier inter-discipline subject, and shows good prospect and potentiality in reservoir deposition research with seismic data and geophysics technologies. We made seismic sedimentology research of shallow sea area, gentle slope belt of Chengning (埕宁) uplift, Bohalwan (渤海湾) basin. In shallow sea area with sparse well coverage, it was difficult to characterize the reservoir architecture with the traditional method based on wells. A new method to resolve the above problems is built: (1) information on plane and in section is inter-ealibrated with each other; (2) recognize the isochronic surfaces by frequency decomposition and interpret the depositional character with technology of stratal slicing; (3) make a comprehensive research with the stratal slice interpreta- tion and the dissection of well group. The depositional model of this area is built and used in the architecture analysis of area without wells. The architecture description reveals that the sedimentary character of pan-connection sand bodies in braided rivers is the reason for high water cut of the new horizontal wells. .展开更多
The Yuanba (元坝) area is considered another potential large-scale reef-bank gas field following the Puguang (普光) field. However, there are lots of difficulties on the spatial and temporal distribution of reef-b...The Yuanba (元坝) area is considered another potential large-scale reef-bank gas field following the Puguang (普光) field. However, there are lots of difficulties on the spatial and temporal distribution of reef-beach and the detailed prediction of the effective reservoir in the sequence stratigraphic framework. In this paper, based on the seismic data, well, log and core, we conduct a high-resolution sequence division and build an isochronal sequence stratigraphic framework for the Changxing (长兴) Formation by the methods of wavelet transformation, FMI, etc.. Then, the corresponding relationship among the lithologic facies, logging facies, seismic facies, seismic attribute facies and reservoir of Changxing Formation were established through well-seismic calibration and geological-geophysical modeling. Furthermore, detailed study on the spatial and temporal distribution of microfacies of the reef-beach was carried out by means of seismic attribute extraction. Meanwhile,combined with impedance inversion, the spatial distribution of porosity of reef-beach reservoir was predicted. The results show that the revolution of the reef-beach system contains three stages which are initial bioclastic bank establishment stage, reef development stage and exposure stage. Also, porosity inversion shows that the region with high value of porosity is located in the reef cap, fore reef and back reef.Seismic Sedimentology Study in the High-Resolution Sequence Framework展开更多
Reservoir architecture of meandering river deposition is complex and traditional seismic facies interpretation method cannot characterize it when layer thickness is under seismic vertical reso- lution. In this study, ...Reservoir architecture of meandering river deposition is complex and traditional seismic facies interpretation method cannot characterize it when layer thickness is under seismic vertical reso- lution. In this study, a seismic sedimentology interpretation method and workflow for point bar char- acterization is built. Firstly, the influences of seismic frequency and sandstone thickness on seismic re- flection are analyzed by outcrop detection with ground penetrating radar (GPR) and seismic forward modeling. It is found that (1) sandstone thickness can influence seismic reflection of point bar architecture. With the increasing of sandstone thickness from 1/4 wavelength (λ) to λ/2, seismic reflection geometries various from ambiguous reflection, "V" type reflection to "X" type reflection; (2) seismic frequency can influence reservoirs' seismic reflection geometry. Seismic events follow inclined lateral aggradation surfaces, which is isochronic depositional boundaries, in high frequency seismic data while the events extend along lithologic surfaces, which are level, in low frequency data. Secondly, strata slice interpretation method for thin layer depositional characterization is discussed with seismic forward modeling. Lastly, a method and workflow based on the above study is built which includes seismic frequency analysis, 90° phasing, stratal slicing and integrated interpretation of slice and seismic profile. This method is used in real data study in Tiger shoal, the Gulf of Mexico. Two episodes of meandering fluvial deposition is recognized in the study layer. Sandstone of the lower unit, which is formed in low base level stage, distributes limited. Sandstone distribution dimension and channel sinuosity become larger in the upper layer, which is high base level deposition.展开更多
基金supported by the Key Scientific and Technological Project‘‘Seismic-Sedimentology Software System Investigation and Application’’of Petro China Company Limited(2012B-3709)
文摘In contrast to marine deposits, continental deposits in China are characterized by diverse sedimentary types, rapid changes in sedimentary facies, complex lithology, and thin, small sand bodies. In seismic sedimentology studies on continental lacustrine basins, new thinking and more detailed and effective technical means are needed to generate lithological data cubes and conduct seismic geo- morphologic analyses. Based on a series of tests and studies, this paper presents the concepts of time-equivalent seismic attributes and seismic sedimentary bodies and a "four-step approach" for the seismic sedimentologic study of conti- nental basins: Step 1, build a time-equivalent stratigraphic framework based on vertical analysis and horizontal corre- lation of lithofacies, electrofacies, seismic facies, and pale- ontological combinations; Step 2, further build a sedimentary facies model based on the analysis of single- well facies with outcrop, coring, and lab test data; Step 3, convert the seismic data into a lithological data cube reflecting different lithologies by means of seismic tech- niques; and Step 4, perform a time-equivalent attribute analysis and convert the planar attribute into a sedimentary facies map under the guidance of the sedimentary facies model. The whole process, highlighting the verification and calibration of geological data, is an iteration and feedback procedure of geoseismic data. The key technologies include the following: (1) a seismic data-lithology conversion technique applicable to complex lithology, which can convert the seismic reflection from interface types to rock layers; and (2) time-equivalent seismic unit analysis and a time- equivalent seismic attribute extraction technique. Finally, this paper demonstrates the validity of the approach with an example from the Qikou Sag in the Bohai Bay Basin and subsequent drilling results.
基金sponsored by the 973 Program(Grant No.2006CB202306)Open Fund of the State Key Laboratory of Petroleum Resource and Prospecting(Grant No.PRPDX2008-07)
文摘Seismic sedimentology is the study of sedimentary rocks and facies using seismic data. However, often the sedimentary body features can't be described quantitatively due to the limit of seismic resolution. High resolution inversion offsets this limitation and is applied to seismic sedimentology to identify subtle traps under complex geologic conditions, thereby widening the applicable range of seismic sedimentology. In this paper, based on seismic sedimentology, seismic phase-controlled nonlinear random inversion is used to predict the sandy conglomerate reservoir of Es3 in the Chezhen depression in Shengli Oilfield. Thickness and sedimentary microfacies maps of sandy conglomerate bodies in several stages are presented and several subtle traps were predicted and verified by drilling.
基金Supported by the China National Science and Technology Major Project(2016ZX05027-004)CNOOC(China)Science and Technology Projects(CNOOC-KJ 135,ZDXM 39 SH03).
文摘The fluvial-deltaic reservoirs of the Oligocene Huagang Formation in the Xihu sag of the East China Sea shelf basin reflect rapid lateral change in sedimentary facies and poor morphology of conventional slice attributes,which bring difficulties to the reservoir prediction for subsequent exploration and development of lithologic reservoirs.The traditional seismic sedimentology technology is optimized by applying the characteristic technologies such as frequency-boosting interpretation,inversion-conventional–90°phase shift joint construction of seismic lithologic bodies,nonlinear slices,paleogeomorphology restoration,and multi-attribute fusion,to obtain typical slice attributes,which are conducive to geological form description and sedimentary interpretation.The Huagang Formation developed three types of sedimentary bodies:braided river,meandering river and shallow water delta,and the vertical sedimentary evolution was controlled by the mid-term base-level cycle and paleogeomorphology.In the early–middle stage of the mid-term base-level ascending cycle,braided channel deposits were dominant,and vertical superimposed sand bodies were developed.In the late stage of the ascending half-cycle and the early stage of the descending half-cycle,meandering river deposits were dominant,and isolated sand bodies were developed.In the middle–late stage of the descending half-cycle,shallow-water delta deposits were dominant,and migratory medium–thick sand bodies were developed.Restricted paleogeomorphology controlled the sand body distribution,while non-restricted paleogeomorphology had little effect on the sand body distribution.Based on reservoir characterization,the fault sealing type and reservoir updip pinch-out type structural lithological traps are proposed as the main directions for future exploration and development in the Xihu sag.
基金Supported by the National Science and Technology Major Project(2017ZX05001-003)PetroChina Science and Technology Major Project(2021DJ0403).
文摘Interference of thin-interbedded layers in seismic reflections has great negative impact on thin-interbedded reservoirs prediction.To deal with this,two novel methods are proposed that can predict the thin-interbedded reservoirs distribution through strata slices by suppressing the interference of adjacent layer with the help of seismic sedimentology.The plane distribution of single sand bodies in thin-interbedded reservoirs can be clarified.(1)The minimum interference frequency slicing method,uses the amplitude-frequency attribute estimated by wavelet transform to find a constant seismic frequency with the minimum influence on the stratal slice of target layer,and then an optimal slice corresponding the constant frequency mentioned above can be obtained.(2)The superimposed slicing method can calculate multiple interference coefficients of reservoir and adjacent layers of target geological body,and obtain superimposed slice by weighted stacking the multiple stratal slices of neighboring layers and target layer.The two proposed methods were used to predict the distribution of the target oil layers of 6 m thick in three sets of thin-interbedded reservoirs of Triassic Kelamayi Formation in the Fengnan area of Junggar Basin,Northwestern China.A comparison with drilling data and conventional stratal slices shows that the two methods can predict the distribution of single sand bodies in thin-interbedded reservoirs more accurately.
基金Supported by the CNPC Science and Technology Projects(2022-N/G-47808,2023-N/G-67014)RIPED International Cooperation Project(19HTY5000008).
文摘To solve the problems in restoring sedimentary facies and predicting reservoirs in loose gas-bearing sediment,based on seismic sedimentologic analysis of the first 9-component S-wave 3D seismic dataset of China,a fourth-order isochronous stratigraphic framework was set up and then sedimentary facies and reservoirs in the Pleistocene Qigequan Formation in Taidong area of Qaidam Basin were studied by seismic geomorphology and seismic lithology.The study method and thought are as following.Firstly,techniques of phase rotation,frequency decomposition and fusion,and stratal slicing were applied to the 9-component S-wave seismic data to restore sedimentary facies of major marker beds based on sedimentary models reflected by satellite images.Then,techniques of seismic attribute extraction,principal component analysis,and random fitting were applied to calculate the reservoir thickness and physical parameters of a key sandbody,and the results are satisfactory and confirmed by blind testing wells.Study results reveal that the dominant sedimentary facies in the Qigequan Formation within the study area are delta front and shallow lake.The RGB fused slices indicate that there are two cycles with three sets of underwater distributary channel systems in one period.Among them,sandstones in the distributary channels of middle-low Qigequan Formation are thick and broad with superior physical properties,which are favorable reservoirs.The reservoir permeability is also affected by diagenesis.Distributary channel sandstone reservoirs extend further to the west of Sebei-1 gas field,which provides a basis to expand exploration to the western peripheral area.
文摘Low-frequency components of seismic data tend to characterize thicker litho-stratigraphic units, while high-frequency components tend to characterize thinner isochronous-stratigraphic units. Thus, frequency dependent interpretation can help to achieve fine sedimentary sequence analysis. However, in current seismic sedimentology method, a certain frequency profile generated by frequency filtering, loses some stratum reflection information, which is out of the limited frequency band. To achieve real frequency dependent stratum reflection profiles with whole stratum information, a time-varying sparse-spiking deconvolution based method is proposed in this paper. A synthetic example and a real delta progradation example show the accuracy and effectiveness of proposed method.
基金supported by the National Natural Science Foundation of China (No. 40872094)the Natural Science Foundation of Shandong Province (No. Z2008E01)
文摘Seismic sedimentology is a new frontier inter-discipline subject, and shows good prospect and potentiality in reservoir deposition research with seismic data and geophysics technologies. We made seismic sedimentology research of shallow sea area, gentle slope belt of Chengning (埕宁) uplift, Bohalwan (渤海湾) basin. In shallow sea area with sparse well coverage, it was difficult to characterize the reservoir architecture with the traditional method based on wells. A new method to resolve the above problems is built: (1) information on plane and in section is inter-ealibrated with each other; (2) recognize the isochronic surfaces by frequency decomposition and interpret the depositional character with technology of stratal slicing; (3) make a comprehensive research with the stratal slice interpreta- tion and the dissection of well group. The depositional model of this area is built and used in the architecture analysis of area without wells. The architecture description reveals that the sedimentary character of pan-connection sand bodies in braided rivers is the reason for high water cut of the new horizontal wells. .
基金supported by the SINOPEC Group Project (No. 2009026324)
文摘The Yuanba (元坝) area is considered another potential large-scale reef-bank gas field following the Puguang (普光) field. However, there are lots of difficulties on the spatial and temporal distribution of reef-beach and the detailed prediction of the effective reservoir in the sequence stratigraphic framework. In this paper, based on the seismic data, well, log and core, we conduct a high-resolution sequence division and build an isochronal sequence stratigraphic framework for the Changxing (长兴) Formation by the methods of wavelet transformation, FMI, etc.. Then, the corresponding relationship among the lithologic facies, logging facies, seismic facies, seismic attribute facies and reservoir of Changxing Formation were established through well-seismic calibration and geological-geophysical modeling. Furthermore, detailed study on the spatial and temporal distribution of microfacies of the reef-beach was carried out by means of seismic attribute extraction. Meanwhile,combined with impedance inversion, the spatial distribution of porosity of reef-beach reservoir was predicted. The results show that the revolution of the reef-beach system contains three stages which are initial bioclastic bank establishment stage, reef development stage and exposure stage. Also, porosity inversion shows that the region with high value of porosity is located in the reef cap, fore reef and back reef.Seismic Sedimentology Study in the High-Resolution Sequence Framework
基金supported by the China Postdoctoral Science Foundation (No.2012M521366)the Shandong University of Science and Technology Scientific Research Startup Fund for Introduction of Talent (No.2013RCJJ009)the National Natural Science Foundation of China (No.41202092)
文摘Reservoir architecture of meandering river deposition is complex and traditional seismic facies interpretation method cannot characterize it when layer thickness is under seismic vertical reso- lution. In this study, a seismic sedimentology interpretation method and workflow for point bar char- acterization is built. Firstly, the influences of seismic frequency and sandstone thickness on seismic re- flection are analyzed by outcrop detection with ground penetrating radar (GPR) and seismic forward modeling. It is found that (1) sandstone thickness can influence seismic reflection of point bar architecture. With the increasing of sandstone thickness from 1/4 wavelength (λ) to λ/2, seismic reflection geometries various from ambiguous reflection, "V" type reflection to "X" type reflection; (2) seismic frequency can influence reservoirs' seismic reflection geometry. Seismic events follow inclined lateral aggradation surfaces, which is isochronic depositional boundaries, in high frequency seismic data while the events extend along lithologic surfaces, which are level, in low frequency data. Secondly, strata slice interpretation method for thin layer depositional characterization is discussed with seismic forward modeling. Lastly, a method and workflow based on the above study is built which includes seismic frequency analysis, 90° phasing, stratal slicing and integrated interpretation of slice and seismic profile. This method is used in real data study in Tiger shoal, the Gulf of Mexico. Two episodes of meandering fluvial deposition is recognized in the study layer. Sandstone of the lower unit, which is formed in low base level stage, distributes limited. Sandstone distribution dimension and channel sinuosity become larger in the upper layer, which is high base level deposition.