scholarly journals Advanced seismic processing/imaging techniques and their potential for geothermal exploration

2016 ◽  
Vol 4 (4) ◽  
pp. SR1-SR18 ◽  
Author(s):  
Cédric Schmelzbach ◽  
Stewart Greenhalgh ◽  
Fabienne Reiser ◽  
Jean-François Girard ◽  
François Bretaudeau ◽  
...  
Keyword(s):  
Seismic Imaging ◽  
Imaging Techniques ◽  
Waveform Inversion ◽  
Seismic Exploration ◽  
S Wave ◽  
Converted Wave ◽  
Seismic Attribute ◽  
Geothermal Reservoirs ◽  
Hydrocarbon Reservoir ◽  
Attribute Analysis

Seismic reflection imaging is a geophysical method that provides greater resolution at depth than other methods and is, therefore, the method of choice for hydrocarbon-reservoir exploration. However, seismic imaging has only sparingly been used to explore and monitor geothermal reservoirs. Yet, detailed images of reservoirs are an essential prerequisite to assess the feasibility of geothermal projects and to reduce the risk associated with expensive drilling programs. The vast experience of hydrocarbon seismic imaging has much to offer in illuminating the route toward improved seismic exploration of geothermal reservoirs — but adaptations to the geothermal problem are required. Specialized seismic acquisition and processing techniques with significant potential for the geothermal case are the use of 3D arrays and multicomponent sensors, coupled with sophisticated processing, including seismic attribute analysis, polarization filtering/migration, converted-wave processing, and the analysis of the diffracted wavefield. Furthermore, full-waveform inversion and S-wave splitting investigations potentially provide quantitative estimates of elastic parameters, from which it may be possible to infer critical geothermal properties, such as porosity and temperature.

The evolution of FWI and its perceived benefits

2019 ◽  
Vol 59 (1) ◽  
pp. 432
Author(s):  
Tony Martin ◽  
Andrew Long
Keyword(s):  
High Resolution ◽  
Seismic Imaging ◽  
Waveform Inversion ◽  
Low Frequencies ◽  
Near Surface ◽  
Surface Features ◽  
Case Examples ◽  
Velocity Models ◽  
Attribute Analysis ◽  
Seismic Volumes

Despite the mathematics behind full waveform inversion (FWI) being published in the early 1980s, it was 30 years before the method could be efficiently implemented on the scale of conventional 3D marine seismic volumes. FWI has evolved from using only transmitted waves and being constrained because towed streamer data lacked the very long offsets and ultra-low frequencies necessary to derive stable velocity updates beyond shallow depths. FWI now uses the full seismic wavefield (both transmitted and scattered wavefields), recovers deep velocity updates for standard offsets and frequencies and increasingly uses a wider range of frequencies that contribute to seismic imaging. We use several case examples to consider the benefits and caveats for robust FWI application: for resolving near-surface features and reducing seismic imaging uncertainty in areas with complex overburden heterogeneities; for resolving near-surface features and improving volumetric estimates; for using an enlarged bandwidth to resolve small model features; for updating the velocity in high contrast regimes; and for the creation of survey-wide, high-resolution models to reduce imaging uncertainty, complement attribute analysis, estimate elastic properties and prospect derisking. Collectively, we demonstrate how to produce high-resolution velocity models when conventional methods cannot and how to generate earth models in an accelerated fashion to reduce project turnaround. We describe pragmatic limits to what maximum FWI frequencies are reasonable and suggest ways that may soon by-pass signal processing and obtain direct earth attributes.

Minibasin mobility and obstruction on salt-detached slopes: implications for canopy dynamics and sediment routing

2020 ◽  
Author(s):  
Naiara Fernandez ◽  
Oliver Duffy ◽  
Frank Peel ◽  
Michael Hudec ◽  
Gillian Apps ◽  
...  
Keyword(s):  
Large Scale ◽  
Early Stage ◽  
Regional Scale ◽  
Local Strain ◽  
Seismic Attribute ◽  
Structural Domains ◽  
Hydrocarbon Reservoir ◽  
Sediment Routing ◽  
Attribute Analysis ◽  
The Individual

<p>In salt-detached gravity-gliding/spreading systems the detachment geometry is a key control on the downslope mobility of the supra-canopy (supra-salt) sequence. As supra-canopy minibasins translate downslope, they also subside into salt. If the base of salt has high relief, minibasins may weld and stop from further free translation downslope. The degree of minibasin obstruction controls both the kinematics of the individual basins, and the more regional pattern of supra-canopy strain. Here, we use regional 3D seismic data to examine a salt-stock canopy in the northern Gulf of Mexico slope, in an area where supra-canopy minibasins subsided vertically and translated downslope above a complex base-of-salt with high relief.</p><p>At a regional scale, we distinguish two structural domains in the study area: a highly obstructed or locked domain and a highly mobile domain. Large-scale translation of the supra-canopy sequence is recorded in the mobile domain by two different structures (a far-travelled minibasin and a ramp syncline basin). Although identifying the deformation area between the two regional domains is challenging due to its diffusive nature, characterizing domains according to base-of-salt geometry and supra-canopy minibasin configuration is helpful in identifying structural domains that may share similar subsidence and downslope translation histories.</p><p>At minibasin scale, minibasins that become obstructed modify the local strain field, typically developing a zone of shortening immediately updip of it and an extensional breakaway zone immediately downdip. Seismic attribute analysis performed in a cluster of minibasins in the study area illustrates a long-lived sediment transport system affected by the complex strain patterns associated with minibasin obstruction. At an early stage, a submarine channel system is captured and subsequently rerouted in response to the updip shortening associated with minibasin obstruction. At a later stage, a mass-transport complex (MTC) is steered by the topographic barrier created by the downdip extensional breakaway associated with minibasin obstruction.</p><p>Our work illustrates how salt-tectonic processes related to minibasin obstruction can affect the canopy dynamics at both regional and minibasin scale. Furthermore, we show that minibasin obstruction processes can modify the seafloor and subsequently control deepwater sediment dispersal, which, ultimately can affect hydrocarbon reservoir distribution on salt-influenced slopes</p>

Integrating 3-D seismic imaging and seismic attribute analysis with genetic stratigraphy: Implications for infield reserve growth and field extension, Budare Field, Venezuela

Geophysics ◽  
1997 ◽  
Vol 62 (5) ◽  
pp. 1510-1523 ◽  
Author(s):  
Sandra K. Raeuchle ◽  
Douglas S. Hamilton ◽  
M. Uzcátegui
Keyword(s):  
Seismic Data ◽  
Seismic Imaging ◽  
Field Extension ◽  
Growth Potential ◽  
Well Log ◽  
Seismic Attribute ◽  
Attribute Analysis ◽  
Reserve Growth ◽  
Mouth Bar ◽  
Seismic Amplitudes

Despite being a mature oil producer, the Budare Field in the Eastern Venezuela Basin offers considerable reserve growth potential because of stratigraphic and structural complexity. Our ability to resolve these complexities was enhanced following acquisition in 1995 of a 3-D seismic data set over a large part of the field. The seismic data were tied by synthetic to well‐log data by several wells having sonic and density information and then integrated with the high‐resolution genetic stratigraphic framework established from well‐log correlations. Two key surfaces identified on the seismic data correlated directly to two stratigraphically defined sequence boundaries, maximum flooding surfaces (MFS) 80 and 100. A third seismic surface correlated approximately with the stratigraphically defined MFS 62. Collectively, these surfaces form fundamental control surfaces from which seismic attribute analysis and imaging from inverse modeling were undertaken. Four depositional trends detected by the seismic imaging and attribute analysis have important implications for reserve growth potential, guiding future field development. An incised valley, filled primarily with thick fluvial sandstones, was detected by mapping average seismic amplitudes between the MFS 62 and 80 markers, and several step‐out drilling locations were identified where the sandstones intersect structurally high positions. The distribution of thick distributary‐mouth‐bar facies, and moreover, the boundary with adjacent thin‐bedded strandplain facies, were similarly detected by mapping average seismic amplitudes in a 35-ms time window below MFS 80. The mouth‐bar facies coincide with the crestal position of a potentially large, structurally defined field extension supporting multiple potential infill wells. Several high‐negative‐amplitude anomalies coinciding with thick fluvial sandstones overlying MFS 62 display faulted boundaries and are interpreted as direct hydrocarbon indicators, providing obvious infill drilling locations, and finally, a marine ravinement surface separating the key oil‐producing reservoirs below MFS 80 was identified by seismic inversion.

The Research on the Depositional Systems Types and Characteristics of Sublacustrine Fan Deposits in the Second Member of Dongying Formation, Liaodong Bay

2013 ◽  
Vol 868 ◽  
pp. 46-50
Author(s):  
Zhen Hu ◽  
Jing Yan Liu ◽  
Shi Qiang Xia ◽  
Yan Yan Chang
Keyword(s):  
Three Dimensional ◽  
Seismic Attribute ◽  
Geological Evidence ◽  
Fan Identification ◽  
Sedimentary Characteristics ◽  
Hydrocarbon Reservoir ◽  
Integrated Employment ◽  
Attribute Analysis ◽  
Plane Distribution ◽  
Stacking Patterns

Integrated employment of wireline logging and seismic data, turbidite fan types and distribution characteristics were analyzed in the Paleogene strata of the second Member of Dongying Formaiton. The results showed that: the study area developed many types of turbidite fan, including the slump turbidite fans, deepwater turbidite fan, steep nearshore turbidite fan, far shore slope turbidite fan, etc. There are significant differences in the developmental environment, sedimentary characteristics, the main factors and so on. The differences in delta size, provenance, ancient terrain and triggering mechanism affect the development of different turbidite fan deposits. By identifying wireline logs stacking patterns, the external geometry and internal reflection structure of seismic events, the types of lacustrine fan identification modes were determined. And also with three-dimensional seismic attribute analysis techniques for predicting sublacustrine fan and determining the plane distribution, it provide basic geological evidence for lacustrine fan hydrocarbon reservoir exploration.

scholarly journals Integration of Well Logs and Seismic Attribute Analysis in Reservoir Identification on PGS Field Onshore Niger Delta, Nigeria

2020 ◽  
Vol 4 (1) ◽  
pp. 12-22
Author(s):  
C. C. Okpoli ◽  
D. I Arogunyo
Keyword(s):  
Niger Delta ◽  
Gamma Ray ◽  
Hole Drilling ◽  
High Porosity ◽  
Seismic Attribute ◽  
Oil Companies ◽  
Hydrocarbon Reservoir ◽  
Attribute Analysis ◽  
Reservoir Identification ◽  
Seismic Scale

AbstractIntegrated well dataset and seismics delineated the PGS field onshore Niger Delta for reservoir identification. Gamma ray, resistivity, Neutron and density Logs identified four lithologies: sandstone, shaly sandstone, shaly sand and shale. They consist of sand-shale intercalation with the traces of shale sometimes found within the sand Formation. Petrophysical parameters of the reservoirs showed varying degree of lower density, low gamma ray, high porosity and resistivity response with prolific hydrocarbon reservoir G due to its shale volume and the clean sand mapped as a probable hydrocarbon reservoir. 3D seismic data located both seismic scale and sub-seismic scale structural and stratigraphic elements. Risk reduction in dry hole drilling due fault missing in conventional seismic attribute analysis and interpretation, have to be integrated into the Oil companies standard practice.

Fluid-solid coupled full-waveform inversion in the curvilinear coordinates for ocean-bottom cable data

Geophysics ◽  
2020 ◽  
Vol 85 (3) ◽  
pp. R113-R133 ◽  
Author(s):  
Yingming Qu ◽  
Zhe Guan ◽  
Jinli Li ◽  
Zhenchun Li
Keyword(s):  
Waveform Inversion ◽  
Curvilinear Coordinates ◽  
Seismic Exploration ◽  
Full Waveform Inversion ◽  
Ocean Bottom ◽  
S Wave ◽  
Full Waveform ◽  
Curvilinear Grid ◽  
Irregular Interface ◽  
Simulation Scheme

Marine seismic exploration with ocean-bottom cable technology is able to record P- and S-wave information simultaneously. Elastic full-waveform inversion (EFWI) uses P- and S-waves to invert multiple parameters with adequate amplitude information and complete illumination of the subsurface. To calculate the wavefield within EFWI, we use different formats of wave equations in fluid and solid mediums and an appropriate boundary condition to convert waves on the interface. This partitioned simulation scheme is more stable and efficient than the traditional integrated simulation scheme. However, if the fluid-solid coupled medium has an extremely irregular interface, the conventional finite-difference method with rectangular grids cannot obtain accurate source and receiver wavefields. We use the curvilinear coordinates to overcome this limitation. In the curvilinear coordinates, the irregular interface can be transformed into a horizontal interface. To reduce the crosstalk of inverted P- ([Formula: see text]) and S-velocities ([Formula: see text]), we derive the gradient formulas of [Formula: see text] and [Formula: see text] based on P- and S-wave mode separation in the curvilinear coordinates, and, finally, we develop a 2D curvilinear-grid-based fluid-solid separated-wavefield EFWI (CFS-SEFWI) method. Numerical examples that include an anomaly model and a modified Marmousi II model demonstrate that CFS-SEFWI overcomes the influence of the irregular fluid-solid interface and efficiently reduces crosstalk effects between [Formula: see text] and [Formula: see text]. Our results also demonstrate that this method is less sensitive to noise compared to the conventional CFS FWI method without separating wave modes.

The application of seismic attribute analysis technique in coal field exploration

2016 ◽  
Vol 4 (1) ◽  
pp. SB13-SB21 ◽  
Author(s):  
Cui Jingbin ◽  
Wan Zhonghong ◽  
Chen Ping ◽  
Li Quanhu ◽  
Xu Chen
Keyword(s):  
Coal Mining ◽  
Eastern China ◽  
Seismic Exploration ◽  
Burial Depth ◽  
Seismic Attribute ◽  
Accurate Identification ◽  
Perfect Agreement ◽  
Mining Areas ◽  
Attribute Analysis ◽  
Tunnel Design

Seismic exploration technologies developed in coal mines and oil fields are basically the same but with certain differences. Safety is one of the key issues in coal mining in China due to unexpected fatal accidents of underground work. Most of these accidents were derived from a geologic anomaly, such as minor faults, subsidence columns, gobs (old coal mining areas), and caving zones (collapse areas), which are of fundamental importance to prevent mining losses from coal mining risk caused by flooding accidents, broken coal beds, added fissures, and accumulated gas. In addition, minor faults also have significant influences on tunnel design in mechanical mining. Above all, accurate identification of these factors is critical in coal mining. We have focused on a coal mine located in eastern China with a burial depth from 500 to 1000 m and a smaller area of less than [Formula: see text]. Using high-precision 3D seismic data and seismic attribute analysis techniques, such as variance, curvature, ant tracking, etc., satisfactory results have been achieved in identifying minor faults, subsidence columns, coal tunnels, and gobs. Verified with actual coal mining, up to 85% of the predicted minor faults with a fault throw within 2–3-m match actual minor faults, and the predicted subsidence columns, coal tunnel, and gob were in perfect agreement with the real-world situation.

Converted‐wave seismic exploration: Methods

Geophysics ◽  
2002 ◽  
Vol 67 (5) ◽  
pp. 1348-1363 ◽  
Author(s):  
Robert R. Stewart ◽  
James E. Gaiser ◽  
R. James Brown ◽  
Don C. Lawton
Keyword(s):  
Survey Design ◽  
Data Interpretation ◽  
P Wave ◽  
Seismic Exploration ◽  
Single Element ◽  
S Wave ◽  
Converted Wave ◽  
P Waves ◽  
Prestack Migration ◽  
Recording Channels

Multicomponent seismic recording (measurement with vertical‐ and horizontal‐component geophones and possibly a hydrophone or microphone) captures the seismic wavefield more completely than conventional single‐element techniques. In the last several years, multicomponent surveying has developed rapidly, allowing creation of converted‐wave or P‐S images. These make use of downgoing P‐waves that convert on reflection at their deepest point of penetration to upcoming S‐waves. Survey design for acquiring P‐S data is similar to that for P‐waves, but must take into account subsurface VP/VS values and the asymmetric P‐S ray path. P‐S surveys use conventional sources, but require several times more recording channels per receiving location. Some special processes for P‐S analysis include anisotropic rotations, S‐wave receiver statics, asymmetric and anisotropic binning, nonhyperbolic velocity analysis and NMO correction, P‐S to P‐P time transformation, P‐S dip moveout, prestack migration with two velocities and wavefields, and stacking velocity and reflectivity inversion for S‐wave velocities. Current P‐S sections are approaching (and in some cases exceeding) the quality of conventional P‐P seismic data. Interpretation of P‐S sections uses full elastic ray tracing, synthetic seismograms, correlation with P‐wave sections, and depth migration. Development of the P‐S method has taken about 20 years, but has now become commercially viable.

Seismic Attribute Analysis - An Aid in Fracture Play Mapping

2007 ◽  
Author(s):  
Srinivasa Rao Narhari ◽  
Nikhil Banik ◽  
Sunil Kumar Singh ◽  
Talal Fahad Al-Adwani
Keyword(s):  
Seismic Attribute ◽  
Attribute Analysis
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