Integrated geological and geophysical interpretation case study, and Lamé rock parameter extractions using AVO analysis on the Blackfoot 3C‐3D seismic data, southern Alberta, Canada

Geophysics ◽  
2002 ◽  
Vol 67 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Jocelyn Dufour ◽  
Jason Squires ◽  
William N. Goodway ◽  
Andy Edmunds ◽  
Ian Shook
Keyword(s):  
Cross Sections ◽  
Seismic Data ◽  
Oil And Gas ◽  
Well Log ◽  
Amplitude Variation With Offset ◽  
Incised Valley ◽  
Geophysical Interpretation ◽  
Porous Sandstone ◽  
Incised Valleys ◽  
Geological Facies

Blackfoot field, southeast of Calgary, Alberta, Canada, has produced oil and gas from a Glauconitic compound incised‐valley system. The Glauconitic compound incised valley has three cycles of incision and valley fill: lower, lithic, and upper incised valleys. The upper and lower incised valleys are the main reservoirs. The geophysical interpretation of compressional PP‐seismic data resulted in the definition of the compound‐valley extent, and in the mapping of the upper and lower incised valleys. A stratigraphic well‐log template was built using the most significant lithological information and well logs. To integrate both geological and geophysical interpretations, the well log cross‐sections and corresponding depth‐converted seismic were superimposed. Furthermore, a detailed geological facies interpretation of the upper and lower incised valleys was undertaken and incorporated. A good correlation was found between the interpreted geological facies and the seismic data response. Information about the nature of the fill within the compound valley was gained from the integration of the PP‐ and PS‐wave interpretations. However, this is limited to Vp/Vs analyses on given intervals. Amplitude‐variation‐with‐offset analysis of the PP‐data was run to discriminate lithology and pore‐fluid saturates. The products of the Lamé rock parameters, incompressibility (λ) and rigidity (μ), with density (ρ) were extracted from seismic inversions for P‐ and S‐impedances. The extraction of λ ρ and μρ showed the presence of gas‐bearing porous sandstone within the Glauconitic incised‐valley system.

Brittleness index calculation based on amplitude-variation-with-offset inversion for coal-bed methane reservoir: A case study of the Qinshui Basin, China

2020 ◽  
Vol 8 (1) ◽  
pp. SA63-SA72
Author(s):  
Wu Haibo ◽  
Cheng Yan ◽  
Zhang Pingsong ◽  
Dong Shouhua ◽  
Huang Yaping
Keyword(s):  
Seismic Data ◽  
Brittleness Index ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Well Log ◽  
Amplitude Variation ◽  
Frequency Model ◽  
Log Data ◽  
Amplitude Variation With Offset ◽  
Avo Inversion

The brittleness index (BI) is an important parameter for coal-bed methane (CBM) reservoir fracturing characterization. Most published studies have relied on petrophysical and well-log data to estimate the geomechanical properties of reservoir rocks. The major drawback of such methods is the lack of control away from well locations. Therefore, we have developed a method of combining BI calculation from well logs with that inverted from 3D seismic data to overcome the limitation. A real example is given here to indicate the workflow. A traditional amplitude-variation-with-offset (AVO) inversion was conducted first. BI for the CBM reservoir was then calculated from the Lamé constants inverted from prestack seismic data through a traditional AVO inversion method. We build an initial low-frequency model based on the well-log data. Comparison of the seismic inverted BI at the target reservoir and BI extracted from the well-log data showed satisfactory results. This method has been proved to be efficient and effective enough at identifying BI sweet spots in CBM reservoirs.

Quaternary compound incised valleys of the Roussillon coast (SE France): correlation of seismic data with core data

2010 ◽  
Vol 181 (2) ◽  
pp. 183-196 ◽  
Author(s):  
Michel Tesson ◽  
Caroline Labaune ◽  
Bernard Gensous ◽  
Vincent Delhaye-Prat
Keyword(s):  
Seismic Data ◽  
Coastal Lagoons ◽  
Atlantic Coast ◽  
Shelf Area ◽  
Quaternary Compound ◽  
Seismic Unit ◽  
Data Set ◽  
Barrier Beach ◽  
Incised Valley ◽  
Incised Valleys

Abstract A detailed study of a Pliocene to Quaternary incised-valley system located under the Roussillon coastal area (Gulf of Lion) is carried out by means of a high-resolution seismic data set (coastal lagoons and adjacent shelf area), drill reports and analysis of a cored drill (Leucate SC1) performed in 2007 on the barrier beach in the North of Leucate lagoon. The lowermost surface (S100/S200), correlated with a pebbles level on the Leucate core SC1 (R0), erosionnally overlies pliocene deposits. It is incised by a thalweg 15 m depth and deepens progressively from the coastal plain to the outer shelf and dips under the Quaternary forced regressive wedges. Above this basal surface, the infilling of the incised valley corresponds to the seismic unit U1. The lower part of U1 shows continuous sub-horizontal reflectors and is correlated (Leucate SC1) to marine muds with levels of mud-supported gravels (body B). The upper part of unit U1 comprises seismic erosional reflectors that are almost amalgamated under the barrier beach. It is correlated on the Leucate well to body C comprising coarse levels (gravels and pebbles) alternating with marine muds (lower part) and marine coarse sands (upper part). The upper part of the unit is dated 12900 cal yr B.P. This unit is interpreted as resulting of successive phases of incision and infilling due to base-level changes during Pleistocene glacial and interglacial periods. Coarse levels of sand and gravel corresponding to river stages and sands and muds shelly levels representing marine stages. The overlying units represent post-glacial late transgressive (S650) and highstand (U660, U661, U662) deposits. This system is a rare example of well preserved compound incised valleys correlated offshore with Quaternary lowstand wedges. By comparison, the incised valleys along the Atlantic coast of France are “simple” incised valleys where only the last episode of incision/infilling is observable. The Quaternary “compound” incised valleys cited in the literature represent examples of the fluvial part of incised systems, whereas the Languedoc-Roussillon incised valleys probably correspond to estuary or embayment, successively reoccupied during the various Quaternary eustatic cycles. Tectonics is the main factor controlling the depositional stratigraphic architecture. The studied area is located at the hinge point between continental uplift and marine subsidence and favoured the preservation of successive phases of erosion/infilling. The geometry of the Pliocene deposits has also an impact on the shape and orientation of the buried paleovalleys.

Seismic reservoir characterization of a class-1 amplitude variation with offset turbiditic system located offshore Cote d’Ivoire, West Africa

2018 ◽  
Vol 6 (2) ◽  
pp. SD115-SD128
Author(s):  
Pedro Alvarez ◽  
William Marin ◽  
Juan Berrizbeitia ◽  
Paola Newton ◽  
Michael Barrett ◽  
...  
Keyword(s):  
West Africa ◽  
Seismic Data ◽  
Reservoir Characterization ◽  
Rock Physics ◽  
Rock Properties ◽  
Well Log ◽  
Amplitude Variation ◽  
Amplitude Variation With Offset ◽  
Fluid Content ◽  
Class 1

We have evaluated a case study, in which a class-1 amplitude variation with offset (AVO) turbiditic system located offshore Cote d’Ivoire, West Africa, is characterized in terms of rock properties (lithology, porosity, and fluid content) and stratigraphic elements using well-log and prestack seismic data. The methodology applied involves (1) the conditioning and modeling of well-log data to several plausible geologic scenarios at the prospect location, (2) the conditioning and inversion of prestack seismic data for P- and S-wave impedance estimation, and (3) the quantitative estimation of rock property volumes and their geologic interpretation. The approaches used for the quantitative interpretation of these rock properties were the multiattribute rotation scheme for lithology and porosity characterization and a Bayesian lithofluid facies classification (statistical rock physics) for a probabilistic evaluation of fluid content. The result indicates how the application and integration of these different AVO- and rock-physics-based reservoir characterization workflows help us to understand key geologic stratigraphic elements of the architecture of the turbidite system and its static petrophysical characteristics (e.g., lithology, porosity, and net sand thickness). Furthermore, we found out how to quantify and interpret the risk related to the probability of finding hydrocarbon in a class-1 AVO setting using seismically derived elastic attributes, which are characterized by having a small level of sensitivity to changes in fluid saturation.

Subsurface fault detection using seismic data for hazardous‐waste‐injection well permitting: An example from St. John the Baptist Parish, Louisiana

Geophysics ◽  
1995 ◽  
Vol 60 (2) ◽  
pp. 468-475 ◽  
Author(s):  
Edward V. Zinni
Keyword(s):  
Drinking Water ◽  
Hazardous Waste ◽  
Cross Sections ◽  
Vertical Migration ◽  
Seismic Data ◽  
Normal Faults ◽  
Well Log ◽  
John The Baptist ◽  
Freshwater Aquifers

The Covington aquifer is used as a major source of drinking water for east St. John the Baptist Parish, Louisiana. A recent subsurface geologic study in Herbert and Hanson (1991) suggested that the Covington aquifer might communicate hydrologically with two hazardous‐waste‐injection reservoirs, thus putting the fresh‐water Covington aquifer in danger of contamination. A case history shows how seismic‐reflection and electric well‐log data were used to determine the possibility of hydrologic communication between the Covington aquifer and the hazardous‐waste‐injection reservoirs. Cross‐sections, net‐sand isopachs, and structure maps are constructed for three hazardous‐waste‐injection reservoirs and the Covington aquifer. Four previously undetected normal faults bisect the three injection reservoirs and the Covington aquifer. The presence of these faults significantly increases the possibility of communication by acting as conduits and allowing vertical migration of fluids along the fault planes, or by causing juxtaposition of sand against sand and allowing leakage to occur across the fault planes. In addition, the upper injection reservoir is part of a fluvial system that occasionally scours down into the Covington aquifer, depositing sand from the injection reservoir interval directly on the Covington aquifer sand. Because of this stratigraphic contact, the injection reservoir is possibly in hydrologic communication with the Covington aquifer. The injection of liquid‐hazardous‐waste into these reservoirs could jeopardize not only the water quality of the Covington aquifer, but possibly the quality of other shallow freshwater aquifers, should vertical migration occur along the fault planes. Without the use of seismic data, the risk of contaminating underground sources of drinking water would not have been properly assessed.

Find the rocks and the fluids will follow — AVO as a tool for lithology classification

2014 ◽  
Vol 2 (2) ◽  
pp. SC77-SC91 ◽  
Author(s):  
Kester D. Waters ◽  
Michael A. C. Kemper
Keyword(s):  
Case Studies ◽  
Seismic Data ◽  
Oil And Gas ◽  
Rock Physics ◽  
Amplitude Variation With Offset ◽  
Primary Means ◽  
Interpretation Process ◽  
Close Cooperation ◽  
Key Steps

Full-stack seismic interpretation continues to be the primary means of subsurface interpretation. However, the underlying impact of amplitude variation with offset (AVO) is effectively ignored or overlooked during the full-stack interpretation process. Recent advances in well-logging and rock physics techniques highlight the fact that AVO is a useful tool not only for detection of fluid anomalies, but also for the detection and characterization of lithology. We evaluated an overview of some of the key steps in the rock physics assessment of well logs and seismic data, and highlight the potential to move toward a new convention of interpretation on so-called lithology stacks. Lithology stacks may come in a variety of forms but should form the focus of interpretation efforts in the early part of the exploration and appraisal cycle. Several case studies were used to highlight that subtle fluid effects can only be extracted from the seismic data after careful assessment of the lithology response. These case studies cover a wide geography and variable geology and demonstrate that the techniques we tested are transferable and applicable across many different oil and gas provinces. The use of lithology stacks has many benefits. It allows interpretation on a single stack rather than many different offset or angle stacks. A lithology stack provides a robust, objective framework for lithostratigraphic interpretation and can be calibrated to offset wells when available. They are conceptually simple, repeatable, and transferable, allowing close cooperation across the different subsurface disciplines.

scholarly journals Forced Fold Amplitude and Sill Thickness Constrained by Wireline and 3-D Seismic Data Suggest an Elastic Magma-Induced Deformation in Tarim Basin, NW China

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 293
Author(s):  
Wei Tian ◽  
Xiaomin Li ◽  
Lei Wang
Keyword(s):  
Tarim Basin ◽  
Seismic Data ◽  
Inelastic Deformation ◽  
Northwest China ◽  
Well Log ◽  
Total Thickness ◽  
Nw China ◽  
Seismic Method ◽  
Two Parameters ◽  
Outer Area

Disparities between fold amplitude (A) and intrusion thickness (Hsill) are critical in identifying elastic or inelastic deformation in a forced fold. However, accurate measurements of these two parameters are challenging because of the limit in separability and detectability of the seismic data. We combined wireline data and 3-D seismic data from the TZ-47 exploring area in the Tarim Basin, Northwest China, to accurately constrain the fold amplitude and total thickness of sills that induced roof uplift in the terrain. Results from the measurement show that the forced fold amplitude is 155.0 m. After decompaction, the original forced fold amplitude in the area penetrated by the well T47 ranged from 159.9 to 225.8 m, which overlaps the total thickness of the stack of sills recovered by seismic method (171.4 m) and well log method (181.0 m). Therefore, the fold amplitude at T47 area is likely to be elastic. In contrast, the outer area of the TZ-47 forced fold is characterized by shear-style deformation, indicating inelastic deformation at the marginal area. It is suggested that interbedded limestone layers would play an important role in strengthening the roof layers, preventing inelastic deformation during the emplacement of intrusive magma.

Fracture mapping using seismic amplitude variation with offset and azimuth analysis at the Weyburn CO2 storage site

Geophysics ◽  
2012 ◽  
Vol 77 (6) ◽  
pp. B295-B306 ◽  
Author(s):  
Alexander Duxbury ◽  
Don White ◽  
Claire Samson ◽  
Stephen A. Hall ◽  
James Wookey ◽  
...  
Keyword(s):  
Cross Sections ◽  
Co2 Storage ◽  
Horizontal Stress ◽  
Storage Site ◽  
Fracture Zones ◽  
Amplitude Variation ◽  
Amplitude Variation With Offset ◽  
Seal Integrity ◽  
Cap Rock ◽  
Weyburn Field

Cap rock integrity is an essential characteristic of any reservoir to be used for long-term [Formula: see text] storage. Seismic AVOA (amplitude variation with offset and azimuth) techniques have been applied to map HTI anisotropy near the cap rock of the Weyburn field in southeast Saskatchewan, Canada, with the purpose of identifying potential fracture zones that may compromise seal integrity. This analysis, supported by modeling, observes the top of the regional seal (Watrous Formation) to have low levels of HTI anisotropy, whereas the reservoir cap rock (composite Midale Evaporite and Ratcliffe Beds) contains isolated areas of high intensity anisotropy, which may be fracture-related. Properties of the fracture fill and hydraulic conductivity within the inferred fracture zones are not constrained using this technique. The predominant orientations of the observed anisotropy are parallel and normal to the direction of maximum horizontal stress (northeast–southwest) and agree closely with previous fracture studies on core samples from the reservoir. Anisotropy anomalies are observed to correlate spatially with salt dissolution structures in the cap rock and overlying horizons as interpreted from 3D seismic cross sections.

Stochastic discrete fracture network modeling in shale reservoirs via integration of seismic attributes and petrophysical data

2021 ◽  
pp. 1-50
Author(s):  
Yongchae Cho
Keyword(s):  
Seismic Data ◽  
Stochastic Approach ◽  
Fracture Network ◽  
Natural Fracture ◽  
Well Logs ◽  
Fracture Model ◽  
Well Log ◽  
Discrete Fracture ◽  
Discrete Fracture Network Modeling ◽  
Fracture Network Modeling

The prediction of natural fracture networks and their geomechanical properties remains a challenge for unconventional reservoir characterization. Since natural fractures are highly heterogeneous and sub-seismic scale, integrating petrophysical data (i.e., cores, well logs) with seismic data is important for building a reliable natural fracture model. Therefore, I introduce an integrated and stochastic approach for discrete fracture network modeling with field data demonstration. In the proposed method, I first perform a seismic attribute analysis to highlight the discontinuity in the seismic data. Then, I extrapolate the well log data which includes localized but high-confidence information. By using the fracture intensity model including both seismic and well logs, I build the final natural fracture model which can be used as a background model for the subsequent geomechanical analysis such as simulation of hydraulic fractures propagation. As a result, the proposed workflow combining multiscale data in a stochastic approach constructs a reliable natural fracture model. I validate the constructed fracture distribution by its good agreement with the well log data.

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