Feasibility modeling and a VSP repeatability test demonstrate that timelapse reservoir monitoring of thin layers during gas and wag injection is possible in Middle East carbonates with both landvibrator and marine-air gun sources

2008 ◽  
Author(s):  
William Soroka ◽  
Suaad Khouri ◽  
Samer Marmash ◽  
Ahmed Dawoud ◽  
Saleh Barakat ◽  
...  
Keyword(s):  
Middle East ◽  
Thin Layers ◽  
Air Gun ◽  
Reservoir Monitoring ◽  
Marine Air ◽  
Repeatability Test ◽  
Wag Injection

Time‐lapse VSP test results demonstrate good repeatability for both land‐vibrator and marine air‐gun VSP surveys in Middle East carbonates

2007 ◽  
Author(s):  
William L. Soroka ◽  
Samer F. Marmash ◽  
Suaad Khouri ◽  
Ahmed Dawoud ◽  
Saleh Barakat ◽  
...  
Keyword(s):  
Middle East ◽  
Time Lapse ◽  
Test Results ◽  
Air Gun ◽  
Good Repeatability ◽  
Marine Air

scholarly journals A long-offset seismic reflection and refraction study of the Gippsland and Bass Basins from onshore recording of a marine air-gun source

1989 ◽  
Vol 20 (2) ◽  
pp. 293
Author(s):  
C.D.N. Collins ◽  
J.P. Cull ◽  
J.B. Willcox ◽  
J.B. Colwell
Keyword(s):  
Deep Structure ◽  
Seismic Refraction ◽  
Reflection And Refraction ◽  
Air Gun ◽  
Long Offset ◽  
Deep Crustal Structure ◽  
Basin Formation ◽  
Seismic Refraction Data ◽  
Marine Air ◽  
Refraction Data

Seismic refraction data were obtained for the Bass and Gippsland Basins during the 1988 cruise of the BMR research vessell "Rig Seismic". Seismic recorders were deployed on land by BMR and Monash University to record long-offset wide-angle reflection and refraction data using the ship's air-guns as the energy source. Preliminary results have now been obtained from these data providing information on deep crustal structure related to the basin formation. Two crustal layers have been detected with velocities of 4.5 km/s increasing to 7.4 km/s (unreversed) at depths exceeding 20 km. Additional data have now been obtained over a traverse length of 170 km to provide constraints on the deep structure of Bass Strait and the Lachlan Fold Belt in Victoria and Tasmania.

On the theory of air‐gun bubble interactions

Geophysics ◽  
1988 ◽  
Vol 53 (2) ◽  
pp. 192-200 ◽  
Author(s):  
R. C. Bailey ◽  
P. B. Garces
Keyword(s):  
Ambient Pressure ◽  
Bubble Radius ◽  
Dynamical Equations ◽  
Local Pressure ◽  
Know How ◽  
R And D ◽  
Bubble Interactions ◽  
Interaction Terms ◽  
Air Gun ◽  
Marine Air

Calculation of the seismic signatures of marine air‐gun arrays often requires that the interactions among the bubbles from air guns be taken into account. The standard method of doing this is to use the Giles‐Johnston approximation in which a time‐dependent effective ambient pressure is calculated for each bubble as the sum of the true ambient pressure and the local pressure signals of all the other bubbles in the array. These effects of interaction have a relative importance in the dynamics proportional to (R/D), where R and D are the typical bubble radius and interbubble separation, respectively. To ensure that current methods of calculating signatures are accurate, it is necessary to know how good this approximation is. This paper shows that there are no interaction terms in the full dynamical equations proportional to [Formula: see text] or [Formula: see text], and that the errors of the Giles‐Johnston approximation are only of order [Formula: see text]. The Giles‐Johnston approximation is therefore justified even for fairly accurate signature calculations for noncoalescing bubbles. The analysis here also shows how to incorporate bubble motions and deformations into the dynamical equations, so that the errors can be reduced to order [Formula: see text] if desired.

scholarly journals Comparing the broadband acoustic frequency response of single, clustered, and arrays of marine air guns

Geophysics ◽  
2020 ◽  
Vol 85 (3) ◽  
pp. P27-P36
Author(s):  
Martin Landrø ◽  
Jan Langhammer
Keyword(s):  
Acoustic Signal ◽  
High Frequency ◽  
High Speed ◽  
Acoustic Stimulation ◽  
Main Peak ◽  
Water Tank ◽  
High Frequency Signal ◽  
Acoustic Frequency ◽  
Air Gun ◽  
Marine Air

Field data acquired from a seismic vessel by a seabed hydrophone is used to analyze the broadband response (10 Hz to 62.5 kHz) for various source configurations: single air guns, clustered air guns, and a full array consisting of 30 air guns. The various parts of the acoustic signal are analyzed in detail, and it is found that a high-frequency signal arriving prior to the main peak of a single air-gun signal most likely is caused by small vapor cavities collapsing at or close to the surface of the gun. This is confirmed by high-speed photographs taken when a small air gun is fired in a water tank. When the full array is used, a second type of cavitation signal is observed: ghost cavitation caused by acoustic stimulation by the negative pressure that is backscattered from the free surface. As this ghost signal from 30 different guns arrives at a specific location in the water, cavities might be formed, and they create a high-frequency acoustic signal.

Optimizing spatial distribution to minimize the inline directivity for a marine air-gun source

Geophysics ◽  
2020 ◽  
Vol 85 (3) ◽  
pp. P37-P44
Author(s):  
Honglei Shen ◽  
Chunhui Tao ◽  
Thomas Elboth ◽  
Hanchuang Wang ◽  
Jianping Zhou ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
High Resolution ◽  
Directional Pattern ◽  
Stimulation Mode ◽  
Air Gun ◽  
Air Water Interface ◽  
Seismic Acquisition ◽  
Highly Correlated ◽  
Marine Air ◽  
Mathematical Derivation

The spatial distribution of an air-gun array and the ghost reflection from the air-water interface cause a directional pattern of the source signature and introduce notches at certain frequencies. This significantly limits the bandwidth of the seismic data and the ability to obtain high-resolution subsurface imaging. With mathematical derivation and numerical simulation, we have determined that the inline directivity relies on the number of air guns and their spacing. Furthermore, the effective width of the take-off angles for an air-gun array is highly correlated with the reciprocal of the distance variance along the inline direction, which is subsequently used for optimizing the source design. For a normal horizontal source, one could adjust the distance between two consecutive air guns to improve the source signature. We optimize the spatial distribution for air guns along the inline and depth directions, that is, by using the synchronized multidepth stimulation mode, to minimize the inline directivity. Simulated results show that a six-gun composed multidepth source could be designed to achieve nearly identical energy distribution with up to ±30° take-off angle for the high-frequency end up to 250 Hz. This represents a significant improvement compared to a normal horizontal source and is more suitable for high-resolution seismic acquisition.

Source signature determination by inversion

Geophysics ◽  
1992 ◽  
Vol 57 (12) ◽  
pp. 1633-1640 ◽  
Author(s):  
M. Landrø ◽  
R. Sollie
Keyword(s):  
Reflection Coefficient ◽  
Forward Modeling ◽  
Sea Surface ◽  
Inversion Algorithm ◽  
Air Bubble ◽  
Damping Coefficients ◽  
Air Gun ◽  
Marine Air ◽  
Source Array ◽  
Effective Source

A new method for estimating the pressure wavefield generated by a marine air‐gun array is presented. It is assumed that data is acquired at a ministreamer located below the source array. Effective source signatures for each air gun are estimated by an inversion algorithm. The forward modeling scheme used in the inversion algorithm is based upon a physical modeling of the air bubble generated by each air gun. This means that typical inversion parameters are: gun depths, empirical damping coefficients, and reflection coefficient of the sea surface. Variations in streamer depth are also taken into account by the inversion scheme. The algorithm has been successfully tested on examples with unknown streamer positions, gun parameters, reflection coefficient of sea surface, and ministreamer data contaminated with white noise.

Fracture orientation from marine air‐gun OSS data

1990 ◽  
Author(s):  
Subhashis Mallick ◽  
L. Neil Frazer
Keyword(s):  
Fracture Orientation ◽  
Air Gun ◽  
Marine Air
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