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Collaborating Authors
Cross-well tomography
ABSTRACT Magnetotelluric (MT) data naturally manifests itself as noise in marine controlled-source electromagnetic (CSEM) data. It follows that MT data can be extracted from measured CSEM data for the relatively negligible cost of additional data processing. With availability of both data sets, we present a new approach to 3D joint inversion of both CSEM and MT data. Our method is based on the 3D integral equation method for modeling, and focusing regularized inversion. Our examples show that joint CSEM and MT inversion has better model resolution compared to CSEM or MT inversion alone.
- Europe > Russia > Barents Sea > East Barents Sea Basin > Shtokmanovskoye Field (0.99)
- Europe > Norway > North Sea > Central North Sea > Utsira High > PL 338C > Block 16/1 > Gemini Prospect > Hugin Formation (0.99)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Cross-well tomography (0.56)
ABSTRACT We present a “structure”-based approach for the joint inversion of marine Controlled-Source Electromagnetic (mCSEM, ) and Magnetotelluric (MT, ) data which uses a priori, information on the geometry to reduce the number of unknown parameters and to improve the resolution of the reconstructed resistivity image. This “structure”-based approach can also be used to refine the resistivity image obtained using an image-based approach. The “structure”-based inversion adopts the multiplicative regularized Gauss-Newton method. In this approach the shape of the various regions expressed as 2D “structures” defined by their vertices (nodes) are reconstructed along with their locations and resistivities. We illustrate the advantages and drawbacks of this inversion using synthetic data.
- Reservoir Description and Dynamics > Formation Evaluation & Management > Cross-well tomography (0.70)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (0.52)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (0.48)
ABSTRACT A 3D inversion approach is presented for marine controlled-source electromagnetic (CSEM) and magnetotelluric (MT) data influenced by formation anisotropy. The algorithm is based on the Gauss-Newton approach and finite-difference modeling, and assumes traverse isotropy in the vertical direction (TIV). The synthetic example shows that inline CSEM data are essential to detect the resistive reservoirs, while addition of broadside data is needed to recover anisotropic structures. Although MT data alone are not suited for defining anisotropy, joint inversion CSEM and MT data can improve the resolution of anisotropic resistivity images that is attained by CSEM data, particularly when CSEM data are acquired with only the inline configuration.
- Reservoir Description and Dynamics > Formation Evaluation & Management > Cross-well tomography (0.54)
- Reservoir Description and Dynamics > Reservoir Characterization > Geologic modeling (0.34)
ABSTRACT We present an algorithm of joint inversion of seismic traveltimes and magnetotelluric impedances. To link velocity and resistivity we introduce structural constraint similar to well-known cross-gradients constraint, but more rigid one. Suggested constraint incorporates into inversion a priori information about sign of correlation between velocity and resistivity. Algorithm is tested on synthetic data.
- Geophysics > Electromagnetic Surveying (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling > Seismic Inversion (0.71)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Cross-well tomography (0.63)
ABSTRACT In conventional marine CSEM methods, we need a survey vessel that tows a long cable to which both an EM transmitter and receivers are attached. Therefore, it is difficult to survey shallow sub-seafloor structure below the seafloor of complex topography around submarine massive sulphides (SMS) because of the risk of cable-tangling. In this research, we propose a new marine CSEM method to solve this problem using two autonomous underwater vehicles (AUV). Using this method, it is possible to keep a low height of diving AUVs from the seafloor, so we can carry out the exploration of SMS effectively. We discussed the possibility of new CSEM method employing the 2.5-D FEM program. From numerical results, it is possible to detect the rough existent area of SMS and the rough thickness of SMS.
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Cross-well tomography (0.41)
Time-lapse Down-hole Seismic Surveys For Deep EOR Target Monitoring In South Oman
Kiyashchenko, Denis (Shell International Exploration and Production) | Mehta, Kurang (Shell International Exploration and Production) | Lopez, Jorge (Shell International Exploration and Production) | Maamari, Abdullah (Petroleum Development of Oman) | Adawi, Rashid (Petroleum Development of Oman) | Busaidi, Said (Petroleum Development of Oman) | Maskari, Yahya (Petroleum Development of Oman) | Rocco, Guillermo (Petroleum Development of Oman)
ABSTRACT A time-lapse borehole seismic monitoring program was executed in a pilot steam injection pattern in field ‘X’ in South Oman. The program involved baseline and repeat acquisition of 3DVSP and multi-profile cross-well seismic. The down-hole surveys allowed us to see time-lapse changes in 3DVSP reflection images, cross-well tomography and cross-well reflection images. It was important to develop time-lapse processing workflows for these three techniques. Cross-well processing required reliable data selection, and 3DVSP required noise removal and data matching. The cross-well and 3DVSP data indicate a preferential direction for time-lapse anomaly development which is broadly consistent with temperature surveys and top reservoir relief. However, the details of the anomaly visible on 3DVSP, cross-well tomography and cross-well imaging are different and integration of these results is required to understand the anomaly better. 3DVSP should be considered as an option for targeted onshore monitoring, as the images are very repeatable after careful time-lapse processing. Cross-well surveys are sensitive to small velocity changes and impedance changes over thin zones, as they occur in the early stages of field production.
- Asia > Middle East > Oman (0.86)
- North America > United States > Texas > Dawson County (0.36)
- Asia > Middle East > Saudi Arabia > Eastern Province > Al-Ahsa Governorate > Arabian Basin > Widyan Basin > Ghawar Field > Haradh Field > Lower Fadhili Formation (0.98)
- Asia > Middle East > Saudi Arabia > Eastern Province > Al-Ahsa Governorate > Arabian Basin > Widyan Basin > Ghawar Field > Haradh Field > Khuff D Formation (0.98)
- Asia > Middle East > Saudi Arabia > Eastern Province > Al-Ahsa Governorate > Arabian Basin > Widyan Basin > Ghawar Field > Haradh Field > Khuff C Formation (0.98)
- (4 more...)