3D Subsurface Imaging Research Articles

3D electrical resistivity investigation and subsurface imaging of the Kasane warm spring area, northwest Botswana

3D electrical resistivity investigation and subsurface imaging of the Kasane warm spring area, northwest Botswana

Integrating 3D subsurface imaging, seismic attributes, and wireline logging analyses: Implications for a high resolution detection of deep-rooted gas escape features, eastern offshore Nile Delta, Egypt

The eastern part of the offshore Nile Delta is one of Egypt's most productive gas provinces. This study utilizes well logs dataset and 2D seismic from Port Fouad marine (PFM) Field to investigate reservoir lithofacies, rock-types as well as the associated gas chimneys, pockmarks, bright anomalies of escaping fluids in the seafloor, and high-faulted zones caused by the chimney's developments. First, structural smoothing and median filters are used to improve the continuity of the stratigraphic horizons while preserving various geological structures, in order to pick all formation tops and structural faults. Afterwards, variance and energy attributes were computed and extracted for amplitude enhancement of various geobodies such as faults, gas chimneys, and bright reflectors. After that, petrophysical analyses revealed that the Upper Miocene Wakar Formation hosts scattered, thin gas pay zones (<10m) with low hydrocarbon saturation values (average Shc = 27.9%), high water saturation (average Sw > 70%), and high shale volume (average Vsh > 30%). These poor reservoir characteristics prevented accumulation of thick gas zones, thereby several gas escape features (e. vertical chimneys) are observed in the region. Finally, the estimated petrophysical parameter logs and the structure maps derived from seismic data are crucial components of the built 3D structural model. This model reveals the presence of four major normal faults (F1, F2, F3, and F4) oriented NW-SE and WNW-ESE, creating grabens and half grabens. These major faults (F1, F2, F3, and F4) are directly related to the inverted tectonics during the Cretaceous-Paleogene compression (Syrian Arc phase). A link between these structural patterns and gas escape zones is proposed, and the absence of good reservoir facies likely promoted an active phase of gas seepage in the study region. In addition, such gas escape chimneys can create catastrophic events on the seafloor and are considered direct evidence for the presence of gas generation and failure in accumulation.

Estimation of Geotechnical Parameters for Coal Exploration from Quasi-3D Electrical Resistivity Measurements

Geotechnical parameters are crucial for mine planning and operation at different stages of development. However, estimating these parameters requires a large number of boreholes and subsequent detailed analysis of the samples, making it a cumbersome exercise. Moreover, even after conducting these studies, it is not possible to cover the entire operational area. To address this issue, this study presents an indirect method of estimating geotechnical parameters through mathematical relations using resistivity data. The present study incorporated 2D and 3D subsurface imaging techniques for exploring coal reserves and analyzing geotechnical parameters that define subsurface soil properties. Electrical resistivity tomography (ERT) was utilized for data acquisition, employing a Dipole–dipole array with a multielectrode ABEM Terrameter LS instrument. Six parallel profiles were conducted, each 400 m in length, with an inter-electrode spacing of 10 m and a spacing of 50 m between profiles. These profiles were combined into a 3D dataset referred to as quasi-3D ERT. The inversion process for both 2D and 3D data was performed using the Res2dinv and Res3dinv programs, respectively. This study overcame the challenges of 2D resistivity sections by evaluating horizontal depth slices in the x-z plane from layers 1 to 10, reaching a depth of 81.2 m. The geotechnical parameters, including cohesion, friction angle, moisture content, and plastic index, were derived from the resistivity data. The ERT method proved to be cost-effective and efficient in determining soil properties over a large area compared with traditional laboratory analysis of borehole samples. Additionally, the variation of geotechnical parameters with resistivity values exhibited unique characteristics. The results from both the 2D and quasi-3D ERT were well correlated with the borehole data. Such studies are valuable for resource exploration and mine planning purposes.

Common‐midpoint cross‐correlation stacking tomography: A 3D approach for frequency‐dependent mapping of Rayleigh waves, group and phase velocity throughout an active seismic network

AbstractShear‐wave velocity constitutes an important characterization parameter in terms of engineering properties. Several techniques of surface wave analysis have been widely adopted for building near‐surface 1D, or even 2D, S‐wave velocity models, but comparable 3D approaches, such as the surface wave tomography (SWT) method, are usually limited to global or regional seismological studies. Moreover, a reliable 3D subsurface imaging in a complex and noisy near‐surface environment becomes difficult when using the fully automated processing techniques that are commonly suggested for the SWT method. Here, a new strategy that is well adapted to geotechnical investigations is proposed to accomplish automatically the frequency‐dependent mapping of Rayleigh waves, both for group and phase velocity, throughout an active seismic network. The specific methodology can be implemented in both 2D and 3D active seismic data acquisition schemes involving both uniform and non‐uniform layouts of receivers. It combines the advantages of a newly created common‐midpoint (CMP) cross‐correlation (CC) analysis technique, with the precision of the travel‐time tomography method that is usually used in regional seismological studies. The main analysis is based on partitioning the different wave propagation directions, weighting the CC frequency–velocity analysis around one‐wavelength and stacking the CMP dispersion images. The tomographic inversion is applied to frequency‐dependent virtual travel‐times, produced from the azimuth‐dependent results of the specific analysis, in order to generate, as output, the local dispersion curves. The output of the proposed processing method can be interpreted with any preferred inversion algorithm for group and phase velocity, either individually or jointly. Simple synthetic tests together with a 3D seismic experiment in well‐known conditions, using standard refraction and multichannel analysis of surface waves (MASW) equipment, confirmed the effectiveness of the proposed methodology in detecting both lateral and vertical S‐wave velocity variations. A ‘construction site’ case study finally highlighted the potential of the new tool in a very difficult and noisy environment.

3D interpretation of helicopter-borne frequency-domain electromagnetic (HEM) data from Rams\xe5 Basin and adjacent areas at And\xf8ya, Norway

The Ramså Basin is situated on the strandflat on the northeastern side of Andøya between Ramså and Skarstein. It is the only known Mesozoic sedimentary basin onshore Norway and therefore represents an easily accessible analogue to study the setting and development of the offshore Mesozoic basins along the Norwegian continental shelf. Basement rocks (100–10,000 Ωm) and sedimentary rocks (5–1000 Ωm) have distinct ranges of the electrical resistivity. Resistivity of the subsurface can be investigated by electric and electromagnetic (EM) methods to delineate the extent of the sedimentary basin. This paper presents the interpretation of helicopter-borne frequency-domain electromagnetic (HEM) data and their correlation with data obtained from borehole logging and two-dimensional (2D) electrical resistivity tomography (ERT). Resistivity data obtained from these methods show a good agreement. Spatially constrained inversion (SCI) of HEM presents a three-dimensional (3D) subsurface resistivity image of a larger area in comparison to what could have been drawn from few ERT lines and borehole logging. HEM interpretation together with other ERT and borehole resistivity data indicates the extent of Ramså Basin beyond the presently mapped boundary. This extension is also supported by interpretation of earlier collected gravity, magnetic and seismic data. The Ramså sedimentary basin shows a wide range of electrical resistivity between ca. 10 and 600 Ωm at different depths. Two highly conductive areas are newly identified by HEM data interpretation. In one of these areas, outcropping graphite and sulfide minerals were found by field observations.

Characterizing soil piping networks in loess‐derived soils using ground‐penetrating radar

AbstractSoil piping remains a relatively unexplored phenomenon despite its substantial impacts on water and sediment transfer at the watershed scale at numerous locations around the world. One of the main limitations regarding the study of this singular process is the characterization of the pipe networks (in terms of number, position, dimensions, and connectivity of pipes). In this context, noninvasive subsurface imaging using ground‐penetrating radar (GPR) has proven to be a promising technique. This study used two three‐dimensional (3D), high‐resolution GPR surveys performed in loess‐derived soils to characterize small pipe networks with little prior information about their location. The adopted methodology relies on high spatial resolution scanning, 3D subsurface imaging, and automated detection of reflection hyperbolas using a 200‐MHz center‐frequency antenna. Two small watersheds affected by piping were investigated at Sippenaeken and Kluisbergen (Belgium). Over the two scanned zones, results revealed significant subsurface continuous patterns. Even though the most obvious patterns corresponded to recent or past anthropic activities (e.g., artificial drainage pipes), validation tests confirmed that the chosen methodology can be used for pipe network characterization because some important continuity patterns were related to soil piping: for instance, a fairly small pipe (approximately 10–15 cm in diameter) was detected and validated for more than 100 m. Nevertheless, the high variability in size, depth, and orientation of the pipes imply that GPR may only be truly efficient when using very high spatial resolution scanning, which limits its application to specific conditions not always met in piped areas.

3D Dental Subsurface Imaging Using Enhanced Truncated Correlation-Photothermal Coherence Tomography

Development of accurate and sensitive dental imaging technologies is a top priority in the pursuit of high-quality dental care. However, while early dental caries detection and routine monitoring of treatment progress are crucial for effective long-term results, current radiographic technologies fall short of this objective due to low sensitivity for small lesions and use of ionizing radiation which is unsuitable for frequent monitoring. Here we demonstrate the first application of enhanced Truncated Correlation-Photothermal Coherence Tomography (eTC-PCT) to dental imaging. eTC-PCT is non-invasive and non-ionizing, operates well below the maximum permissible exposure (MPE) limit, and features 3D subsurface imaging capability with operator controlled axial resolution. We explore the potential of this method for dental applications and demonstrate its capability for depth-resolved tomographic 3D reconstructions of the details and subsurface extent of a variety of dental defects. To this end, in this proof-of-concept study, dental eTC-PCT imaging results, and its sensitivity to dental caries, are discussed in comparison with visual examination, x-rays and micro-CT imaging.

Voxel solution and 3D sub-surface imaging in the Douala sedimentary sub-basin (Cameroon)

Gravity data consisting of a total of 128 data points located between latitudes 3° 21′N and 4° 9′ N and longitudes 8° 27′ E and 9° 16′ E have been computed for Bouguer and residual anomaly maps in this study. From the plots of these maps which are characterized by very high positive ring shaped contours towards the centre, which are suggestive of a subsurface intrusive body, three anomaly zones as well as two minor peaks were identified. The maps were also characterized by W-E alignment of contours to the N and S as well as approximately NNW-SSE alignments to the E and to some extent, the W of the study area. A layered earth model which constitutes a depth model built using the geosoft montaj extension, GM-SYS 3D, was used to provide a surface-oriented model for this intrusive body. Using constant layers added to a 3D model at depths of 5 km, 10 km, 15 km, 20 km, 25 km, 30 km, 33 km, 35 km and 39 km; each in the absence of the others, forward calculations were employed to calculate the density contrast of each layer while their densities were recalculated using constant density inversion. Structural inversion of each of these layers then generated their surface-oriented models. The optimum inverse model for the intrusive body was obtained at a depth of about 33 km. The model has a surface and surroundings with a density of about 2.5 g/cm3 which corresponds to that of sedimentary basins. It also presents an intrusive body with density of about 2.77 g/cm3 located at a depth of about 6.1 km with its bottom located at about 33 km giving an average vertical height of about 26.9 km. This 3D relief sub-surface model was used to define the geometry of the starting model for 3D data voxels to generate the block structure of the intrusive body. Applying the basic statistical kriging algorithm, the 3D voxel solution of the intrusive body underneath this study area as well as its corresponding calculated maps were generated. This solution is similar in features to that of the surface-oriented solution and presents a block structure of the intrusive body with a major peak at a depth of about 6.2 km and having a relatively sharp sloping boundary towards its NE edge and gradual sloping edges towards its NW, W and E limits. Its density of 2.77 g/cm3 is further confirmation to the fact that this body is of igneous origin. This model however shows evidence that this block extends further south beyond this study area and consequently requires more data in this direction to image it fully. These results from the 3D surface-oriented solution and the 3D voxel solution are in good agreement with previous results from 2.5D studies in this very area of study.

Toward Creating a Subsurface Camera.

In this article, the framework and architecture of a Subsurface Camera (SAMERA) are envisioned and described for the first time. A SAMERA is a geophysical sensor network that senses and processes geophysical sensor signals and computes a 3D subsurface image in situ in real time. The basic mechanism is geophysical waves propagating/reflected/refracted through subsurface enter a network of geophysical sensors, where a 2D or 3D image is computed and recorded; control software may be connected to this network to allow view of the 2D/3D image and adjustment of settings such as resolution, filter, regularization, and other algorithm parameters. System prototypes based on seismic imaging have been designed. SAMERA technology is envisioned as a game changer to transform many subsurface survey and monitoring applications, including oil/gas exploration and production, subsurface infrastructures and homeland security, wastewater and CO2 sequestration, and earthquake and volcano hazard monitoring. System prototypes for seismic imaging have been built. Creating SAMERA requires interdisciplinary collaboration and the transformation of sensor networks, signal processing, distributed computing, and geophysical imaging.

Research and Development of a Permanent OBC System for Time-lapse Seismic Survey and Microseismic Monitoring at the Offshore CO2 Storage Sites

Over the past 30 years, towed streamer has evolved into a mature and highly effective technology for 3D subsurface imaging. Time-lapse 3D seismic monitoring at Sleipner in the North Sea has clearly demonstrated the practical usefulness in monitoring CO2 injected into the deep saline aquifers. Although sometimes it is unsafe to towed streamers when acquiring data in areas of shallow water or surface infrastructures associated with production platforms and fishing gears. That is why seabed seismic worth considering in some situations. In addition, the quality of time-lapse 3D seismic acquisition depends strongly upon the positioning of seismic sources and receivers. Improving the resolution of seismic data has been selected as the most important factor in increasing the value of seismic data. A permanent OBC (Ocean Bottom Cable) system offers a number of potential benefits for obtaining increased resolution by permanently deployed seismic sensors on the seabed or under the seabed. Compared to the towed streamer the permanent OBC also offers the opportunity to record shear waves, not only the P-waves. We are developing a permanent OBC system to meet requirements of Japanese offshore CO2 sequestration in coastal areas.

Constraining a 3D anisotropic tomography inversion with 800 wells – A Canadian oil sands case history

This Canadian oil-sands case history is a very shallow play with a complex geology that includes Quaternary thrusting at surface, sinkholes, and highly karsted Devonian carbonates at the base of the notoriously complex McMurray reservoir. Despite this challenging environment, we were able to demonstrate that Depth Imaging brought significant improvements as compared to the routinely used time imaging. Recent developments in Anisotropic Pre-Stack Depth Imaging technologies provided a better focused and better positioned 3D subsurface image that accurately tied several hundreds of wells. These results were achieved using steering filters, solver bounds and simultaneous multi-parameter tomography inversion while constraining the tomography updates with the well top picks from over 800 wells. Surveys of different vintages, geometries, orientations and shooting directions were regularized using 5D interpolation and merged together. Besides a better imaging of the subsurface, one of main objective of the project was the characterization of the McMurray reservoir. To that aim, the Anisotropic Pre-Stack Depth Migration (APSDM) generated better conditioned Offset Vector Tile gathers for subsequent pre-stack inversion work. The Alberta oil sands are one of the largest bituminous hydrocarbon reserves in the world (Alberta Energy Regulator, 2015). At reservoir temperature, the bitumen is so viscous that it can almost be considered as a solid. In situ thermal recovery processes such as steam-assisted gravity drainage (SAGD) that lower viscosity and increase mobility are required to extract the bitumen from the reservoir. SAGD operations consist of horizontal well pairs that are drilled into the base of the reservoir. In each pair, one well is drilled about 5 m directly above the other well. The top well is injected with steam to melt the bitumen. The bitumen seeps down towards the bottom producing well, which pumps the bitumen to the surface. The well pairs are generally configured to about ten parallel horizontal well pairs that are around 100 m apart horizontally and are 1000 m long, which constitute a 1-km2 pad.

空中磁気データによる地熱地域の3次元地下イメージング解析

秋田焼山は仙岩地熱地域北西端に位置する第四紀火山であり，周辺の山麓部で地熱開発が行われ現在複数の地熱発電所が稼働中である。当該地域では新エネルギー・産業技術総合開発機構 (NEDO) や地質調査所（現産業技術総合研究所）等によって地熱調査に係わる諸調査が行われ，空中磁気データの解析も行われた。例えば，かつて著者等は付近で行われたボーリング調査に伴う岩石磁気測定結果や地質断面図を拘束条件として，フォワードモデリングにより秋田焼山の磁気構造を推定した。この結果，北麓に伏在する貫入花崗岩体に加え南山腹には逆帯磁の古玉川溶結凝灰岩の伏在をモデリングできた。しかしながら，この作業には先験情報と相当量の時間と労力が必要であった。一方，その後電子技術の発展に伴いコンピュータ環境が向上し，磁気異常の3次元インバージョンも実用化された。そこで，今回国内外の火山での磁気異常の解析に用いた3次元イメージング法を秋田焼山にも適用し，先のフォワードモデリングの解析結果との比較検討を行った。その結果は，北麓の伏在貫入花崗岩体の分布など概ね既往の解析結果と整合的であった。さらに，3次元イメージングによって，既往の解析結果以外にも新たな磁気構造の推定が可能となった。例えば秋田焼山南方の倉沢山付近の地下深部を中心として顕著な負の磁化強度域が分布し，付近に露出する逆帯磁の玉川溶結凝灰岩と下位の古玉川溶結凝灰岩の推定分布域に対応するものと考えられる。また，秋田焼山北麓の貫入花崗岩体伏在域のさらに東方でも高磁化強度域が分布し，その北方に位置する大沼地熱発電所の熱源に係わる可能性もある貫入岩体の伏在も示唆された。このように，磁気異常の3次元イメージング解析により地熱地域の地下構造を推定することが以前に比べ格段に容易に行えるようになった。今後は，高分解能空中磁気探査を実施して新たな磁気異常データを取得し，これに3次元イメージング法を適用することによって，地熱地域の詳細な地下構造の推定の進展が期待される。

Electromagnetic 3D subsurface imaging with source sparsity for a synthetic object

This paper concerns electromagnetic 3D subsurface imaging in connection with sparsity of signal sources. We explored an imaging approach that can be implemented in situations that allow one to obtain a large amount of data over a surface or a set of orbits but at the same time require sparsity of the signal sources. Characteristic to such a tomography scenario is that it necessitates the inversion technique to be genuinely three-dimensional: for example, slicing is not possible due to the low number of sources. Here, we primarily focused on astrophysical subsurface exploration purposes. As an example target of our numerical experiments we used a synthetic small planetary object containing three inclusions, e.g. voids, of the size of the wavelength. A tetrahedral arrangement of source positions was used, it being the simplest symmetric point configuration in 3D. Our results suggest that somewhat reliable inversion results can be produced within the present a priori assumptions, if the data can be recorded at a specific resolution. This is valuable early-stage knowledge especially for the design of future planetary missions in which the payload needs to be minimized, and potentially also for the development of other lightweight subsurface inspection systems.

An improved dual sensor summation method with application to four-component (4-C) seafloor seismic data from the Niger Delta

Conventional towed streamer seismic acquisition has proven highlyeffective over the years for 3D subsurface imaging. However, in areas wherewater depths are too shallow or where there are too many obstacles for streameroperations, seabed seismic sensors have, in some cases, been employed as analternative to image the subsurface. Apart from seabed seismic acquisitionbeing extremely expensive compared to surface streamer, seabed seismic data areseverely affected by receiver ghosts generated by water column reverberation.We present an improved method of summing the pressure (hydrophone data) and verticalgeophone (geophone data) data to reduce the deleterious effects of ghosts andwater column reverberations in a seabed seismic data acquired at water depthsranging from 21.1m to 40.0m in the Niger Delta. The method is based on the separationof up and down-going wavefields from the geophone and hydrophone data, andprovides an efficient noise rejection and amplitude preservation in the summeddata.

An entropy method for 3D subsurface imaging of a nucleated cell based on orthogonal phase images

Aiming at the difficulty of nucleated cells 3D subsurface imaging, this paper presents a tomography entropy method of 3D imaging based on orthogonal phase images. According to the average refractive index of the cytoplasmic axial direction and orthogonal interferometric phase images, the method can be applied to the tomographic imaging combined with the maximum entropy method. Through 3D tomographic image reconstruction, not only the morphology of the extracellular cell but also the subsurface morphology of the cell as well as its physical location can be determined. This method has been proved to be effective in imaging a monocyte. The results show that subsurface imaging of nucleated cell can be quickly achieved based on the tomography entropy method using only limited phase images obtained from two orthogonal directions. It can be regarded as a new idea for the study of real cellular substructure imaging.

Aeromagnetic 3D subsurface imaging with effective source volume minimisation and its application to data from the Otoge cauldron, Shitara, Central Japan

Three-dimensional (3D) imaging techniques using the conjugate gradient solution are discussed for magnetic anomaly source reconstruction, especially for areas of rugged terrain, such as those of volcanoes. The analysis model configuration permits surface undulation and variable depth slicing. First, primitive source model data are put into the analysis to confirm the characteristic behaviour of the regularisation methods and parameter scaling. The compact regularisation method is then applied to synthetic geologic models to understand the resolving power of the method given the problem of the inherent weakness of a non-unique solution. Finally, the field data of a helicopter-borne magnetic survey of the Otoge cauldron are put into the 3D imaging analysis with the method. The analysis reveals a quite reasonable subsurface image of the magma reservoir and the Otoge cone sheets and Otoge stocks of post-cauldron activity, as inferred from geological studies.

Planar array 3D electrical capacitance tomography

Electrical capacitance tomography (ECT) is a promising non-invasive imaging technique that is capable of mapping the dielectric permittivity of an object. ECT has great potential to be used as a new non-destructive evaluation (NDE) method. In the majority of NDE applications for ECT there is only limited access to the targeted objects, making conventional circular array ECT impractical. In this paper, a planar array ECT system is developed and proposed for 3D subsurface imaging as a form of limited access tomography. The sensor development, practical implications, capabilities and limitations of the proposed planar array ECT system are discussed. The experimental results are used to evaluate the system performance. A depth of up to 53% of the length of the sensor array can be achieved using experimental data using an array of 4 × 3 electrodes.

Investigation of the subsurface geometry of fissure-ridge travertine with GPR, Pamukkale, western Turkey

Cracks in the upper crust are the result of either local or regional tectonic stress. Such structural elements are conduits for fluids in the crust. In Pamukkale, hot water which is rich in calcium carbonate emerges from fissures. The hot water issuing from the fissures precipitates travertine both in the fissures and on the surface. As a result, a ridge, which is called fissure-ridge travertine, forms along the central fissure. Fissure-ridge travertines are lens-shaped at the surface. Since fissure-ridge travertines are of great tectonic significance, their surface characteristics have been studied in detail. However, the subsurface geometry of travertine ridges is not well known. GPR was used to examine the subsurface geometry of fissure-ridge travertine and the central fissure. GPR profiles were combined across the ridge to produce a three-dimensional (3D) subsurface image of the travertine mass. The 3D image showed that the thickness and width of the travertine mass are at a maximum near the centre of the ridge and they both decrease asymmetrically towards the ends. Perpendicular GPR slices across the central fissure showed that the thickness of the vertically banded fissure-travertine increases with depth. 3D modelling suggests that the lateral propagation of the central fissure is asymmetric.

PLANAR MAGNETIC INDUCTION TOMOGRAPHY FOR 3D NEAR SUBSURFACE IMAGING

Magnetic induction tomography (MIT) is a tomographic technique utilising inductive coils and eddy currents to map the passive electromagnetic properties of an object. Eddy current methods are widely used for non-destructive testing (NDT) in inspection of metallic structures. Eddy current based NDT uses a single coil or a pair of coils to scan the samples. As an emerging NDT technique, MIT scans the sample with a coil array through an eddy current based tomographic approach. In this paper, a planar array MIT system (PMIT) is proposed for 3D near subsurface imaging. This is of great importance as there are large numbers of potential applications for MIT that allow limited access to the materials under testing. The system development, practical implication, capability and limitations of PMIT are discussed. The fundamental principles are demonstrated through simulations. Experimental data are used to evaluate the capability and detectability this system has as a potential 3D subsurface imaging tool.

To CSEM or not to CSEM? Feasibility of 3D marine CSEM for detecting small targets

The marine controlled-source electromagnetic (CSEM) method is an important tool for offshore exploration. It allows recovery of subsurface resistivity, a key hydrocarbon (HC) indicator, using modeling- and inversion-based interpretation of the EM data acquired on the seafloor. Application of CSEM can reduce risk and optimize drilling operations, as well as improve estimates of HC reserves. The CSEM workflow consists of the following main steps: feasibility study, survey design, data acquisition, processing, and interpretation. Feasibility study and data interpretation rely heavily on 3D EM modeling to properly select and plan surveys and recover the 3D subsurface resistivity image. Detection of deep small targets immersed in anisotropic environments is a challenging task for the current CSEM technology, making it essential to employ the best practices in performing reliable feasibility studies. To manage this task, a skilled modeler needs to take into account all available geological and geophysical data to build a 3D Earth model and utilize accurate 3D EM modeling software. The fast and reliable 3D EM modeling that can accurately handle arbitrary anisotropic resistive media with complex structural interfaces and HC reservoirs would make a crucial contribution to the success of CSEM technology.