Acoustic impedance inversion and seismic reflection continuity analysis for delineating gas hydrate resources near the Mallik research sites, Mackenzie Delta, Northwest Territories, Canada

Geophysics ◽  
2009 ◽  
Vol 74 (5) ◽  
pp. B125-B137 ◽  
Author(s):  
Michael Riedel ◽  
Gilles Bellefleur ◽  
Stephanie Mair ◽  
Thomas A. Brent ◽  
Scott R. Dallimore
Keyword(s):  
Northwest Territories ◽  
Gas Hydrate ◽  
Seismic Data ◽  
Acoustic Impedance ◽  
Depth Range ◽  
3D Seismic ◽  
Mackenzie Delta ◽  
Seismic Attribute ◽  
Impedance Inversion ◽  
Acoustic Impedance Inversion

We combine acoustic impedance inversion of 3D seismic data, log-to-seismic correlation, and seismic attribute analyses to delineate gas-hydrate zones at the Mallik site, Mackenzie Delta, Northwest Territories, Canada. Well-log data define three distinct hydrate zones over a depth range of 890–1100 m. Synthetic seismic modeling indicates the base of the two deeper hydrate zones are prominent reflectors. The uppermost gas-hydrate zone correlates to seismic data with a lower degree of confidence. The extent and geometry of the two lower hydrate zones suggest that local geology plays a significant role in the lateral and vertical distribution of gas hydrate at Mallik. The reliability of the hydrate concentrations calculated from the inverted impedances isqualified by the match between original and synthetic seismic data to produce confidence maps for the two lower gas-hydrate-bearing intervals. A total in-place volume estimate of solid gas hydrate for an area of [Formula: see text] around well 5L-38 yields a value of approximately [Formula: see text] (equivalently, [Formula: see text] of gas). We further qualify our mapping of gas hydrates by some amount of continuous resource, defined as lateral continuity measured by seismic attribute similarity and sand-dominated rock. Using these attributes, the continuous amount of hydrate at Mallik is about half the in-place volume (i.e., [Formula: see text]). Elsewhere within the 3D seismic cube, the seismic impedance inversion yields evidence of potential gas-hydrate deposits near wells A-06 and P-59 at levels near the predicted base of the hydrate stability zone.

Amplitude and frequency anomalies in regional 3D seismic data surrounding the Mallik 5L-38 research site, Mackenzie Delta, Northwest Territories, Canada

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. B183-B191 ◽  
Author(s):  
M. Riedel ◽  
G. Bellefleur ◽  
S. R. Dallimore ◽  
A. Taylor ◽  
J. F. Wright
Keyword(s):  
Northwest Territories ◽  
Gas Hydrate ◽  
Seismic Data ◽  
Ratio Method ◽  
Unfrozen Water ◽  
3D Seismic ◽  
Mackenzie Delta ◽  
Data Set ◽  
Seismic Amplitude ◽  
3D Seismic Data

Amplitude and frequency anomalies associated with lakes and drainage systems were observed in a 3D seismic data set acquired in the Mallik area, Mackenzie Delta, Northwest Territories, Canada. The site is characterized by large gas hydrate deposits inferred from well-log analyses and coring. Regional interpretation of the gas hydrate occurrences is mainly based on seismic amplitude anomalies, such as brightening or blanking of seismic energy. Thus, the scope of this research is to understand the nature of the amplitude behavior in the seismic data. We have therefore analyzed the 3D seismic data to define areas with amplitude reduction due to contamination from lakes and channels and to distinguish them from areas where amplitude blanking may be a geologic signal. We have used the spectral ratio method to define attenuation (Q) over different areas in the 3D volume and subsequently applied Q-compensation to attenuate lateral variations ofdispersive absorption. Underneath larger lakes, seismic amplitude is reduced and the frequency content is reduced to [Formula: see text], which is half the original bandwidth. Traces with source-receiver pairs located inside of lakes show an attenuation factor Q of [Formula: see text], approximately half of that obtained for source-receiver pairs situated on deep, continuous permafrost outside of lakes. Deeper reflections occasionally identified underneath lakes show low-velocity-related pull-down. The vertical extent of the washout zones is enhanced by acquisition with limited offsets and from processing parameters such as harsh mute functions to reduce noise from surface waves. The strong attenuation and seismic pull-down may indicate the presence of unfrozen water in deeper lakes and unfrozen pore water within the sediments underlying the lakes. Thus, the blanking underneath lakes is not necessarily related to gas migration or other in situ changes in physical properties potentially associated with the presence of gas hydrate.

Delta reservoir characterization using complex trace seismic attribute method and acoustic impedance inversion method case study in KX field

2021 ◽  
Author(s):  
Rahadian Anggit Wirawan ◽  
Supriyanto Supriyanto ◽  
Yayan Sofyan ◽  
Dede Djuhana ◽  
Waluyo Waluyo ◽  
...  
Keyword(s):  
Acoustic Impedance ◽  
Reservoir Characterization ◽  
Inversion Method ◽  
Seismic Attribute ◽  
Impedance Inversion ◽  
Acoustic Impedance Inversion

scholarly journals Reservoir Characterizarion Using Acoustic Impedance Inversion and Multi-Attribute Analysis in Nias Waters, North Sumatra

2019 ◽  
Vol 34 (1) ◽  
Author(s):  
Fathkhurozak Yunanda Rifai ◽  
Tumpal Bernhard Nainggolan ◽  
Henry Munandar Manik
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Source Rocks ◽  
Time Migration ◽  
Attribute Analysis ◽  
Impedance Inversion ◽  
Acoustic Impedance Inversion ◽  
Well Data ◽  
North Sumatra ◽  
Rock Lithology

Seismic method is one of the most frequently applied geophysical methods in the process of oil and gas exploration. This research is conducted in Nias Waters, North Sumatra using one line 2D post-stack time migration seismic section and two wells data. Reservoir characterization is carried out to obtain physical parameters of rocks affected by fluid and rock lithology. Seismic inversion is used as a technique to create acoustic impedance distribution using seismic data as input and well data as control. As final product, multi-attribute analysis is applied to integrate of inversion results with seismic data to determine the lateral distribution of other parameters contained in well data. In this research, multi-attribute analysis is used to determine the distribution of NPHI as a validation of hydrocarbon source rocks. In that area, there is a gas hydrocarbon prospect in limestone lithology in depth around 1450 ms. Based on the results of sensitivity analysis, cross-plot between acoustic impedance and NPHI are sensitive in separating rock lithology, the target rock in the form of limestone has physical characteristics in the form of acoustic impedance values in the range of 20,000-49,000 ((ft/s)*(g/cc)) and NPHI values in the range of 5-35 %. While the results of the cross-plot between the acoustic impedance and resistivity are able to separate fluid-containing rocks with resistivity values in the range about 18-30 ohmm. The result of acoustic impedance inversion using the model based method shows the potential for hydrocarbons in the well FYR-1 with acoustic impedance in the range 21,469-22,881 ((ft/s)*(gr/cc)).

scholarly journals Stochastic Gabor reflectivity and acoustic impedance inversion

2018 ◽  
Vol 15 (1) ◽  
pp. 179-191
Author(s):  
Diako Hariri Naghadeh ◽  
Christopher Keith Morley ◽  
Angus John Ferguson
Keyword(s):  
Acoustic Impedance ◽  
Impedance Inversion ◽  
Acoustic Impedance Inversion

scholarly journals Characterization of reservoir sands using 3D seismic attributes in the coastal swamp area of Niger Delta Basin

2021 ◽  
Author(s):  
Oluwatoyin Khadijat Olaleye ◽  
Pius Adekunle Enikanselu ◽  
Michael Ayuk Ayuk
Keyword(s):  
Seismic Data ◽  
Niger Delta ◽  
Seismic Attributes ◽  
Effective Porosity ◽  
High Porosity ◽  
Hydrocarbon Accumulation ◽  
3D Seismic ◽  
Seismic Attribute ◽  
Niger Delta Basin

AbstractHydrocarbon accumulation and production within the Niger Delta Basin are controlled by varieties of geologic features guided by the depositional environment and tectonic history across the basin. In this study, multiple seismic attribute transforms were applied to three-dimensional (3D) seismic data obtained from “Reigh” Field, Onshore Niger Delta to delineate and characterize geologic features capable of harboring hydrocarbon and identifying hydrocarbon productivity areas within the field. Two (2) sand units were delineated from borehole log data and their corresponding horizons were mapped on seismic data, using appropriate check-shot data of the boreholes. Petrophysical summary of the sand units revealed that the area is characterized by high sand/shale ratio, effective porosity ranged from 16 to 36% and hydrocarbon saturation between 72 and 92%. By extracting attribute maps of coherence, instantaneous frequency, instantaneous amplitude and RMS amplitude, characterization of the sand units in terms of reservoir geomorphological features, facies distribution and hydrocarbon potential was achieved. Seismic attribute results revealed (1) characteristic patterns of varying frequency and amplitude areas, (2) major control of hydrocarbon accumulation being structural, in terms of fault, (3) prospective stratigraphic pinch-out, lenticular thick hydrocarbon sand, mounded sand deposit and barrier bar deposit. Seismic Attributes analysis together with seismic structural interpretation revealed prospective structurally high zones with high sand percentage, moderate thickness and high porosity anomaly at the center of the field. The integration of different seismic attribute transforms and results from the study has improved our understanding of mapped sand units and enhanced the delineation of drillable locations which are not recognized on conventional seismic interpretations.

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