scholarly journals Comparison study between the elevation and datum statics in NC 210, western Libya

2021 ◽  
Author(s):  
Riyadh Alhajni
Keyword(s):  
Conventional Method ◽  
Seismic Data ◽  
Seismic Velocity ◽  
Sand Dunes ◽  
Angle Of Repose ◽  
Amplitude Analysis ◽  
Reflected Waves ◽  
Geometric Spreading ◽  
Amplitude Compensation ◽  
Seismic Lines

Abstract This research compares the results of each method to solve problems caused by sand dunes, In the southwestern region of Libya, the Murzuq basin is covered with sand dunes, which are a significant source of noise in land seismic data, which caused issues in seismic processing, also sand dunes cause increases of travel time of reflected events in seismic data, procuring false structures this problem caused by residual static errors. The presence of extensive sand dunes causes logistic and technical difficulties for seismic reflection prospecting, Due to the steep angle of repose of the sand dunes faces and the low seismic velocity within them, which causes significant time delay to the reflected waves. In this research, three seismic lines (202, 207, 209), of total length 12 km, have been completely reprocessed at Western Geco processing center (Tripoli) using omega software. the methods of gain corrections: time function gain and geometric spreading. Spreading amplitude compensation, has been proceed the results will be compared to another method of gain corrections called residual amplitude analysis compensation (RAAC) which is has better results for static problems the conventional method of computing field statics has been implemented and the result is compared with elevation static. It is obtained by using uphole method (conventional method) yielded a significant improvement over the elevation method.

Technique for reflection prospecting in the Rub’ Al‐Khali

Geophysics ◽  
1982 ◽  
Vol 47 (8) ◽  
pp. 1135-1152 ◽  
Author(s):  
Don K. Robinson ◽  
Moujahed I. Al‐Husseini
Keyword(s):  
Average Velocity ◽  
Sand Dune ◽  
Sand Dunes ◽  
Angle Of Repose ◽  
Low Velocity ◽  
High Quality ◽  
Reflected Waves ◽  
Common Depth Point ◽  
Receiver Arrays

The Rub’ Al‐Khali desert with its extensive and massive sand dunes presents difficult technical and logistic problems for reflection prospecting. The steep angle of repose of the sand dune faces and the low velocity of the air‐filled sand cause significant delays to the reflected waves. In the dunes, in order to maintain the fidelity of both the downgoing and upcoming waves, small dynamite source and receiver arrays are each contoured to a single elevation. In the flat sabkhas, larger arrays are maintained. After application of dune statics (which are derived initially from an average velocity for the sand and then refined with residual refraction statics), the small arrays are summed so as to simulate the larger arrays used on the flat sabkhas. When the terrain is dominated by dunes, increased use of small arrays reduces the maximum spread length to the detriment of the deeper reflections. Where this occurs, a second set of dynamite patterns is fired so as to increase the effective receiver arrays from 120 to 240. In this manner the simulated spread length is maintained at a minimum of 12,000 ft. The traces resulting from the array simulation on the dunes are then gathered, along with the sabkha traces, into mixed fold common‐depth‐point (CDP) gathers and processed conventionally. This technique results in the recording of high‐quality, broadband reflection profiles with improved continuity beneath the dunes.

scholarly journals Application of Velocity Analysis Picking for 2D Seismic Data Processing in West An-Najaf Are

2021 ◽  
pp. 555-564
Author(s):  
Kamal K. Ali ◽  
Ahmed Wanas ◽  
Mohanad E. Mahdi
Keyword(s):  
Seismic Data ◽  
Seismic Velocity ◽  
Velocity Analysis ◽  
Seismic Data Processing ◽  
Root Mean Square Velocity ◽  
Seismic Section ◽  
Sorting Data ◽  
Omega System ◽  
Analysis Application ◽  
Amplitude Compensation

     In the current study, 2D seismic data in west An-Najaf (WN-36 line) were received after many steps of processing by Oil Exploration Company in 2018. Surface Consistent Amplitude Compensation (SCAC) was applied on the seismic data. The processing sequence in our study started by sorting data in a common mid-point (CMP) gather, in order to apply the velocity analysis using Interactive Velocity Analysis Application (INVA) with Omega system. Semblance of velocity was prepared to preform normal move-out (NMO) vs. Time. Accurate root mean square velocity (VRMS) was selected, which was controlled by flatness of the primary events. The resultant seismic velocity section for the study area shows that the velocity analysis became smother and provided an accurate seismic section.

A possible new hydrocarbon play, offshore central West Greenland

1998 ◽  
pp. 28-30
Author(s):  
Nina Skaarup ◽  
James A. Chalmers
Keyword(s):  
Seismic Data ◽  
Mineral Resources ◽  
Source Rocks ◽  
Bright Spot ◽  
Offshore Area ◽  
West Greenland ◽  
The Government ◽  
Structural Closure ◽  
Multichannel Seismic Data ◽  
Seismic Lines

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Skaarup, N., & Chalmers, J. A. (1998). A possible new hydrocarbon play, offshore central West Greenland. Geology of Greenland Survey Bulletin, 180, 28-30. https://doi.org/10.34194/ggub.v180.5082 _______________ The discovery of extensive seeps of crude oil onshore central West Greenland (Christiansen et al. 1992, 1994, 1995, 1996, 1997, 1998, this volume; Christiansen 1993) means that the central West Greenland area is now prospective for hydrocarbons in its own right. Analysis of the oils (Bojesen-Koefoed et al. in press) shows that their source rocks are probably nearby and, because the oils are found within the Lower Tertiary basalts, the source rocks must be below the basalts. It is therefore possible that in the offshore area oil could have migrated through the basalts and be trapped in overlying sediments. In the offshore area to the west of Disko and Nuussuaq (Fig. 1), Whittaker (1995, 1996) interpreted a few multichannel seismic lines acquired in 1990, together with some seismic data acquired by industry in the 1970s. He described a number of large rotated fault-blocks containing structural closures at top basalt level that could indicate leads capable of trapping hydrocarbons. In order to investigate Whittaker’s (1995, 1996) interpretation, in 1995 the Geological Survey of Greenland acquired 1960 km new multichannel seismic data (Fig. 1) using funds provided by the Government of Greenland, Minerals Office (now Bureau of Minerals and Petroleum) and the Danish State through the Mineral Resources Administration for Greenland. The data were acquired using the Danish Naval vessel Thetis which had been adapted to accommodate seismic equipment. The data acquired in 1995 have been integrated with the older data and an interpretation has been carried out of the structure of the top basalt reflection. This work shows a fault pattern in general agreement with that of Whittaker (1995, 1996), although there are differences in detail. In particular the largest structural closure reported by Whittaker (1995) has not been confirmed. Furthermore, one of Whittaker’s (1995) smaller leads seems to be larger than he had interpreted and may be associated with a DHI (direct hydrocarbon indicator) in the form of a ‘bright spot’.

Super-Resolution of Seismic Velocity Model Guided by Seismic Data

2021 ◽  
pp. 1-12
Author(s):  
Yinshuo Li ◽  
Jianyong Song ◽  
Wenkai Lu ◽  
Patrice Monkam ◽  
Yile Ao
Keyword(s):  
Seismic Data ◽  
Seismic Velocity ◽  
Super Resolution ◽  
Velocity Model

Late Miocene to present-day tectonostratigraphy of the northern central Algerian Basin: Evidence of a contractional salt system from reprocessed seismic data

2021 ◽  
Author(s):  
Simon Blondel ◽  
Angelo Camerlenghi ◽  
Anna Del Ben ◽  
Massimo Bellucci
Keyword(s):  
Seismic Data ◽  
Driving Forces ◽  
Salt System ◽  
Good Resolution ◽  
Deep Basin ◽  
The North ◽  
Depth Processing ◽  
Deformation Intensity ◽  
First Time ◽  
Seismic Lines

<p>This study presents the interpretation of reprocessed seismic data covering the southwestern Balearic promontory and the central Algerian basin. The new depth processing of 2D seismic lines dataset allows for the first time a good resolution on salt structures in the deep basin. Most of the salt structures result from active diapirism. In the deep basin, sedimentary loads and regional shortening are proposed to be the dominant driving forces, showing an overall contractional salt system. The north Algerian margin tectonic reactivation could have provoked a regional shortening of the salt structures and overburden. Identified unconformities suggest that this process probably started shortly after salt deposition and is still active nowadays. It is expressed by salt sheets, pinched diapirs and a décollement level. The African convergence and the narrowness of the western Algerian basin could be the explanation of an overall greater salt deformation intensity compared to the eastern Algerian basin. This demonstrates how in tectonic and sedimentary components appear to be dominant in salt deformation in the central Algerian basin compared to gravitational gliding, only localized in the proximal parts of the margin.</p>

Deepwater reservoir prediction using broadband seismic-driven impedance inversion and seismic sedimentology in the South China Sea

2018 ◽  
Vol 6 (4) ◽  
pp. SO17-SO29 ◽  
Author(s):  
Yaneng Luo ◽  
Handong Huang ◽  
Yadi Yang ◽  
Qixin Li ◽  
Sheng Zhang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Seismic Data ◽  
Seismic Velocity ◽  
The South China Sea ◽  
Hydrocarbon Exploration ◽  
The South ◽  
Low Frequencies ◽  
China Sea ◽  
Impedance Inversion

In recent years, many important discoveries have been made in the marine deepwater hydrocarbon exploration in the South China Sea, which indicates the huge exploration potential of this area. However, the seismic prediction of deepwater reservoirs is very challenging because of the complex sedimentation, the ghost problem, and the low exploration level with sparse wells in deepwater areas. Conventional impedance inversion methods interpolate the low frequencies from well-log data with the constraints of interpreted horizons to fill in the frequency gap between the seismic velocity and seismic data and thereby recover the absolute impedance values that may be inaccurate and cause biased inversion results if wells are sparse and geology is complex. The variable-depth streamer seismic data contain the missing low frequencies and provide a new opportunity to remove the need to estimate the low-frequency components from well-log data. Therefore, we first developed a broadband seismic-driven impedance inversion approach using the seismic velocity as initial low-frequency model based on the Bayesian framework. The synthetic data example demonstrates that our broadband impedance inversion approach is of high resolution and it can automatically balance between the inversion resolution and stability. Then, we perform seismic sedimentology stratal slices on the broadband seismic data to analyze the depositional evolution history of the deepwater reservoirs. Finally, we combine the broadband amplitude stratal slices with the impedance inversion results to comprehensively predict the distribution of deepwater reservoirs. Real data application results in the South China Sea verify the feasibility and effectiveness of our method, which can provide a guidance for the future deepwater hydrocarbon exploration in this area.

3D constraints and finite-difference modeling of massive sulfide deposits: The Kristineberg seismic lines revisited, northern Sweden

Geophysics ◽  
2012 ◽  
Vol 77 (5) ◽  
pp. WC69-WC79 ◽  
Author(s):  
Mahdieh Dehghannejad ◽  
Alireza Malehmir ◽  
Christopher Juhlin ◽  
Pietari Skyttä
Keyword(s):  
Finite Difference ◽  
Seismic Data ◽  
Massive Sulfide ◽  
Northern Sweden ◽  
Seismic Reflection Data ◽  
Sulfide Deposits ◽  
Time Migration ◽  
Massive Sulfide Deposits ◽  
Prestack Time Migration ◽  
Seismic Lines

The Kristineberg mining area in the western part of the Skellefte ore district is the largest base metal producer in northern Sweden and currently the subject of extensive geophysical and geologic studies aimed at constructing 3D geologic models. Seismic reflection data form the backbone of the geologic modeling in the study area. A geologic cross section close to the Kristineberg mine was used to generate synthetic seismic data using acoustic and elastic finite-difference algorithms to provide further insight about the nature of reflections and processing challenges when attempting to image the steeply dipping structures within the study area. Synthetic data suggest processing artifacts manifested themselves in the final 2D images as steeply dipping events that could be confused with reflections. Fewer artifacts are observed when the data are processed using prestack time migration. Prestack time migration also was performed on high-resolution seismic data recently collected near the Kristineberg mine and helped to image a high-amplitude, gently dipping reflection occurring stratigraphically above the extension of the deepest Kristineberg deposit. Swath 3D processing was applied to two crossing seismic lines, west of the Kristineberg mine, to provide information on the 3D geometry of an apparently flat-lying reflection observed in both of the profiles. The processing indicated that the reflection dips about 30° to the southwest and is generated at the contact between metasedimentary and metavolcanic rocks, the upper part of the latter unit being the most typical stratigraphic level for the massive sulfide deposits in the Skellefte district.

Traveltime information-based wave-equation inversion

Geophysics ◽  
2009 ◽  
Vol 74 (6) ◽  
pp. WCC27-WCC36 ◽  
Author(s):  
Yu Zhang ◽  
Daoliu Wang
Keyword(s):  
Wave Equation ◽  
Conventional Method ◽  
Seismic Data ◽  
Waveform Inversion ◽  
Back Propagation ◽  
Velocity Model ◽  
Data Fitting ◽  
Inversion Method ◽  
New Wave ◽  
Seismic Record

We propose a new wave-equation inversion method that mainly depends on the traveltime information of the recorded seismic data. Unlike the conventional method, we first apply a [Formula: see text] transform to the seismic data to form the delayed-shot seismic record, back propagate the transformed data, and then invert the velocity model by maximizing the wavefield energy around the shooting time at the source locations. Data fitting is not enforced during the inversion, so the optimized velocity model is obtained by best focusing the source energy after a back propagation. Therefore, inversion accuracy depends only on the traveltime information embedded in the seismic data. This method may overcome some practical issues of waveform inversion; in particular, it relaxes the dependency of the seismic data amplitudes and the source wavelet.

An integrated broadband preprocessing method for towed-streamer seismic data

Geophysics ◽  
2020 ◽  
Vol 85 (2) ◽  
pp. V201-V221 ◽  
Author(s):  
Mehdi Aharchaou ◽  
Erik Neumann
Keyword(s):  
Seismic Data ◽  
High Frequency ◽  
Pressure Data ◽  
Amplitude Variation ◽  
Field Source ◽  
Amplitude Variation With Offset ◽  
Ringing Artifacts ◽  
Joint Application ◽  
Amplitude Compensation ◽  
Unified Method

Broadband preprocessing has become widely used for marine towed-streamer seismic data. In the standard workflow, far-field source designature, receiver and source-side deghosting, and redatuming to mean sea level are applied in sequence, with amplitude compensation for background [Formula: see text] delayed until the imaging or postmigration stages. Thus, each step is likely to generate its own artifacts, quality checking can be time-consuming, and broadband data are only obtained late in this chained workflow. We have developed a unified method for broadband preprocessing — called integrated broadband preprocessing (IBP) — which enables the joint application of all the above listed steps early in the processing sequence. The amplitude, phase, and amplitude-variation-with-offset fidelity of IBP are demonstrated on pressure data from the shallow, deep, and slanted streamers. The integration allows greater sparsity to emerge in the representation of seismic data, conferring clear benefits over the sequential application. Moreover, time sparsity, full dimensionality, and early amplitude [Formula: see text] compensation all have an impact on broadband data quality, in terms of reduced ringing artifacts, improved wavelet integrity at large crossline angles, and fewer residual high-frequency multiples.

Multivariate Classification for the Integration of Core, Log and Seismic Data on Intersecting Pre-Stack Inverted 2D Seismic Lines, Lublin Basin, Poland

2015 ◽  
Author(s):  
D.A. Handwerger ◽  
R. Castañeda-Aguilar ◽  
G.V. Dahl ◽  
H. Borgos ◽  
J. Zacharski ◽  
...  
Keyword(s):  
Seismic Data ◽  
Multivariate Classification ◽  
Seismic Lines
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