Pub Date : 2018-06-11DOI: 10.3997/2214-4609.201800726
A. Garg, S. Sharma, D. J. Verschuur
Summary Any target-oriented localised inversion scheme for reservoir elastic parameters is as good as the input dataset. Thus, the accuracy of the input dataset i.e. local reflection response or impulse response (virtual source-receiver response) is of utmost importance, especially when the target area is below a complex overburden. In these subsurface settings, the overburden internal multiples and associated transmission imprint obscure the local response, which in turn affects the estimated elastic parameters resolution. Here, we demonstrate a novel process called JMI-res, based on Joint Migration Inversion (JMI), to estimate the reservoir elastic parameters from the surface seismic elastic data for a complex subsurface scenario. In JMI-res, we first obtain the accurate local impulse responses at the target depth level, while correctly accounting for overburden internal multiples and then we apply a localized inversion scheme on the estimated impulse responses to get the reservoir elastic parameters. Moreover, the propagation velocity estimation is an integral part of JMI-res. In this paper, we show that JMI-res provides much more reliable local target impulse responses, thus yielding high-resolution elastic parameters, compared to standard redatuming based on time reversal of recorded data, courtesy of proper handling of internal multiples in the redatuming step.
{"title":"Reservoir Elastic Parameters Estimation from Surface Seismic Data Using JMI-res: A Full-Wavefield Approach","authors":"A. Garg, S. Sharma, D. J. Verschuur","doi":"10.3997/2214-4609.201800726","DOIUrl":"https://doi.org/10.3997/2214-4609.201800726","url":null,"abstract":"Summary Any target-oriented localised inversion scheme for reservoir elastic parameters is as good as the input dataset. Thus, the accuracy of the input dataset i.e. local reflection response or impulse response (virtual source-receiver response) is of utmost importance, especially when the target area is below a complex overburden. In these subsurface settings, the overburden internal multiples and associated transmission imprint obscure the local response, which in turn affects the estimated elastic parameters resolution. Here, we demonstrate a novel process called JMI-res, based on Joint Migration Inversion (JMI), to estimate the reservoir elastic parameters from the surface seismic elastic data for a complex subsurface scenario. In JMI-res, we first obtain the accurate local impulse responses at the target depth level, while correctly accounting for overburden internal multiples and then we apply a localized inversion scheme on the estimated impulse responses to get the reservoir elastic parameters. Moreover, the propagation velocity estimation is an integral part of JMI-res. In this paper, we show that JMI-res provides much more reliable local target impulse responses, thus yielding high-resolution elastic parameters, compared to standard redatuming based on time reversal of recorded data, courtesy of proper handling of internal multiples in the redatuming step.","PeriodicalId":325587,"journal":{"name":"80th EAGE Conference and Exhibition 2018","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123569020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-11DOI: 10.3997/2214-4609.201800652
C. Willacy, M. Kryvohuz
Steep salt boundaries can be poorly illuminated or completely absent in the migrated image. To provide a solution to this problem, we apply two reverse time migration imaging methods which use transmitted (refracted) wavefields. In the first technique, down-going waves, typically recorded in walkaway VSP surveys, are used to image the salt flank via the generation of aplanatic isochrones. It is demonstrated that this image can be generated in the absence of an explicit interpretation of the salt flank. In the second technique, we extend the basic theory to include imaging of up-going source wave fields which then refract at the base salt, as acquired by a surface acquisition geometry. This technique has similarities to the prism-imaging method, yet it uses transmitted instead of reflected waves at the salt boundary. We demonstrate that this is not only a viable technique for imaging of the salt boundary, but also to determine the correct salt velocity when used in conjunction with conventional reflection imaging. A combination of synthetic and field datasets is used to demonstrate the transmission imaging methodologies for imaging salt flanks with reverse time migration.
{"title":"Wavefield Transmission Imaging with Reverse Time Migration","authors":"C. Willacy, M. Kryvohuz","doi":"10.3997/2214-4609.201800652","DOIUrl":"https://doi.org/10.3997/2214-4609.201800652","url":null,"abstract":"Steep salt boundaries can be poorly illuminated or completely absent in the migrated image. To provide a solution to this problem, we apply two reverse time migration imaging methods which use transmitted (refracted) wavefields. In the first technique, down-going waves, typically recorded in walkaway VSP surveys, are used to image the salt flank via the generation of aplanatic isochrones. It is demonstrated that this image can be generated in the absence of an explicit interpretation of the salt flank. In the second technique, we extend the basic theory to include imaging of up-going source wave fields which then refract at the base salt, as acquired by a surface acquisition geometry. This technique has similarities to the prism-imaging method, yet it uses transmitted instead of reflected waves at the salt boundary. We demonstrate that this is not only a viable technique for imaging of the salt boundary, but also to determine the correct salt velocity when used in conjunction with conventional reflection imaging. A combination of synthetic and field datasets is used to demonstrate the transmission imaging methodologies for imaging salt flanks with reverse time migration.","PeriodicalId":325587,"journal":{"name":"80th EAGE Conference and Exhibition 2018","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125305025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-11DOI: 10.3997/2214-4609.201801715
L. Sehoole, M. Manzi, S. Zhang
{"title":"Application of 3D seismic to Enhance Mapping of Potholes in the Western Bushveld Complex, South Africa","authors":"L. Sehoole, M. Manzi, S. Zhang","doi":"10.3997/2214-4609.201801715","DOIUrl":"https://doi.org/10.3997/2214-4609.201801715","url":null,"abstract":"","PeriodicalId":325587,"journal":{"name":"80th EAGE Conference and Exhibition 2018","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125375529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-11DOI: 10.3997/2214-4609.201801063
D. Curia, P. Veeken, D. Justo, Martín Alayón
{"title":"Anisotropic Wide Azimuth 3D Seismic Data for an Unconventional Shale Oil Project, Aguada Federal Block, Argentina","authors":"D. Curia, P. Veeken, D. Justo, Martín Alayón","doi":"10.3997/2214-4609.201801063","DOIUrl":"https://doi.org/10.3997/2214-4609.201801063","url":null,"abstract":"","PeriodicalId":325587,"journal":{"name":"80th EAGE Conference and Exhibition 2018","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125528042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-11DOI: 10.3997/2214-4609.201800962
X. Zeng, J. Sun, H. Dong, L. Cui
{"title":"Simulating the Influence of Micro-Pore Structure on Mud Invasion Using the Digital Rock Technology","authors":"X. Zeng, J. Sun, H. Dong, L. Cui","doi":"10.3997/2214-4609.201800962","DOIUrl":"https://doi.org/10.3997/2214-4609.201800962","url":null,"abstract":"","PeriodicalId":325587,"journal":{"name":"80th EAGE Conference and Exhibition 2018","volume":"28 4 Pt 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125687721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-11DOI: 10.3997/2214-4609.201800950
Hemin Yuan, M. Montazeri, M. Looms, J. Kammann, L. Nielsen
{"title":"Enhanced Resolution of Reflection GPR Data by Diffraction Imaging","authors":"Hemin Yuan, M. Montazeri, M. Looms, J. Kammann, L. Nielsen","doi":"10.3997/2214-4609.201800950","DOIUrl":"https://doi.org/10.3997/2214-4609.201800950","url":null,"abstract":"","PeriodicalId":325587,"journal":{"name":"80th EAGE Conference and Exhibition 2018","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126859036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-11DOI: 10.3997/2214-4609.201800934
S. Chen, Y. Li, J. Cheng
Summary The main characteristics of ground roll are dispersion, low frequency, low velocity and high amplitude. It significantly affects the quality of the seismic data as a kind of noise and is necessary to be subtracted from the original data. Common ground roll attenuation methods include band-pass filtering, f-k filtering and so on, but the effective signal is inevitably harmed in the denoising process. In this paper, ground roll noise is extracted by using matching pursuit (MP) algorithm. Low frequency as the feature of ground roll can be identified as atom, and the time shift parameter is also employed to preserve the effective signal. Synthetic example shows that the ground roll is attenuated and the effective signal is preserved in the events that are polluted seriously by the ground roll noise. Application of field data proves the efficiency and superiority of matching pursuit algorithm compared with band-pass filtering and f-k filtering.
{"title":"Ground Roll Attenuation Applying Matching Pursuit Algorithm","authors":"S. Chen, Y. Li, J. Cheng","doi":"10.3997/2214-4609.201800934","DOIUrl":"https://doi.org/10.3997/2214-4609.201800934","url":null,"abstract":"Summary The main characteristics of ground roll are dispersion, low frequency, low velocity and high amplitude. It significantly affects the quality of the seismic data as a kind of noise and is necessary to be subtracted from the original data. Common ground roll attenuation methods include band-pass filtering, f-k filtering and so on, but the effective signal is inevitably harmed in the denoising process. In this paper, ground roll noise is extracted by using matching pursuit (MP) algorithm. Low frequency as the feature of ground roll can be identified as atom, and the time shift parameter is also employed to preserve the effective signal. Synthetic example shows that the ground roll is attenuated and the effective signal is preserved in the events that are polluted seriously by the ground roll noise. Application of field data proves the efficiency and superiority of matching pursuit algorithm compared with band-pass filtering and f-k filtering.","PeriodicalId":325587,"journal":{"name":"80th EAGE Conference and Exhibition 2018","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126936195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-11DOI: 10.3997/2214-4609.201801081
L. Uspenskaya
{"title":"The Strong Effect of Compaction on Elastic Properties of Rocks, (An Example of a Poorly Consolidated Formation from Russ","authors":"L. Uspenskaya","doi":"10.3997/2214-4609.201801081","DOIUrl":"https://doi.org/10.3997/2214-4609.201801081","url":null,"abstract":"","PeriodicalId":325587,"journal":{"name":"80th EAGE Conference and Exhibition 2018","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126971247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-11DOI: 10.3997/2214-4609.201801446
L. Zühlsdorff, A. Atkinson, H. Gjøystdal, T. Kaschwich, A.J.S. Wilson
Summary Sharp velocity contrasts in the overburden may cause problems for seismic imaging of deeper targets. Pre-stack depth migration in combination with traveltime tomography to build the velocity model is generally considered as a solution to the problem. However, building the velocity model with sufficient lateral and vertical resolution near discontinuities is difficult and imperfect velocity models will result in imperfect seismic images. Forward modelling seismic data followed by PSDM is a way to investigate and quantify sensitivity to imperfections in the velocity model. Kirchhoff modelling offers an efficient alternative to full-wavefield modelling; it is based on advanced ray tracing and can model diffractions, but is still computationally quick. In this study Kirchhoff pre-stack modelling provides a means for testing the impact of velocity errors on the final seismic image: Kirchoff modelling is followed by Kirchhoff target migration with the model velocity field and with degraded velocity fields. Results reveal the scale of potential imaging errors under a shallow velocity discontinuity at the Golden Eagle field in the North Sea. Results show that the danger of creating false structure due to image distortion is low, but that vertical positioning due to inaccurate velocity models carries a higher risk.
{"title":"Forward Kirchhoff Modelling to Evaluate Potential Interpretation Pitfalls beneath Sub-vertical Velocity Discontinuities","authors":"L. Zühlsdorff, A. Atkinson, H. Gjøystdal, T. Kaschwich, A.J.S. Wilson","doi":"10.3997/2214-4609.201801446","DOIUrl":"https://doi.org/10.3997/2214-4609.201801446","url":null,"abstract":"Summary Sharp velocity contrasts in the overburden may cause problems for seismic imaging of deeper targets. Pre-stack depth migration in combination with traveltime tomography to build the velocity model is generally considered as a solution to the problem. However, building the velocity model with sufficient lateral and vertical resolution near discontinuities is difficult and imperfect velocity models will result in imperfect seismic images. Forward modelling seismic data followed by PSDM is a way to investigate and quantify sensitivity to imperfections in the velocity model. Kirchhoff modelling offers an efficient alternative to full-wavefield modelling; it is based on advanced ray tracing and can model diffractions, but is still computationally quick. In this study Kirchhoff pre-stack modelling provides a means for testing the impact of velocity errors on the final seismic image: Kirchoff modelling is followed by Kirchhoff target migration with the model velocity field and with degraded velocity fields. Results reveal the scale of potential imaging errors under a shallow velocity discontinuity at the Golden Eagle field in the North Sea. Results show that the danger of creating false structure due to image distortion is low, but that vertical positioning due to inaccurate velocity models carries a higher risk.","PeriodicalId":325587,"journal":{"name":"80th EAGE Conference and Exhibition 2018","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114927979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-06-11DOI: 10.3997/2214-4609.201801231
O. Ovcharenko, V. Kazei, D. Peter, X. Zhang, T. Alkhalifah
Full-waveform inversion (FWI) benefits in many ways from having low-frequency data. However, those are rarely available due to acquisition limitations. Here, we explore the feasibility of frequency-bandwidth extrapolation using an Artificial Neural Network (ANN) approach. The ANN is trained to be a non-linear operator that maps high-frequency data for a single source and multiple receivers to low-frequency data. Assuming that the source is a point (delta function) in both time and space, we train the network on synthetic data generated using random velocity models. Extending our previous work, we apply the ANN to multiple collocated source-receiver acquisitions to predict 0.5~Hz data for a crop from the acoustic BP 2004 benchmark model. Prediction results, in general, resemble the reference ones but the prediction accuracy is barely sufficient to directly use extrapolated data in FWI. To demonstrate, we show regularized mono-frequency FWI on extrapolated data.
{"title":"Low-Frequency Data Extrapolation Using a Feed-Forward ANN","authors":"O. Ovcharenko, V. Kazei, D. Peter, X. Zhang, T. Alkhalifah","doi":"10.3997/2214-4609.201801231","DOIUrl":"https://doi.org/10.3997/2214-4609.201801231","url":null,"abstract":"Full-waveform inversion (FWI) benefits in many ways from having low-frequency data. However, those are rarely available due to acquisition limitations. Here, we explore the feasibility of frequency-bandwidth extrapolation using an Artificial Neural Network (ANN) approach. The ANN is trained to be a non-linear operator that maps high-frequency data for a single source and multiple receivers to low-frequency data. Assuming that the source is a point (delta function) in both time and space, we train the network on synthetic data generated using random velocity models. Extending our previous work, we apply the ANN to multiple collocated source-receiver acquisitions to predict 0.5~Hz data for a crop from the acoustic BP 2004 benchmark model. Prediction results, in general, resemble the reference ones but the prediction accuracy is barely sufficient to directly use extrapolated data in FWI. To demonstrate, we show regularized mono-frequency FWI on extrapolated data.","PeriodicalId":325587,"journal":{"name":"80th EAGE Conference and Exhibition 2018","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115177520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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