New dimensions in land seismic technology

Oilfield Review

Volumn 17, Issue 3, 2005, Pages 42-53

  Ait Messaoud, Malik ^a   Boulegroun, Mohamed Zerrouk ^a   Gribi, Aziza ^a   Kasmi, Rachid ^a   Touami, Mahieddine ^a   Anderson, Boff ^b   Van Baaren, Peter ^b   El Emam, Adel ^c   Rached, Ghassan ^c   Laake, Andreas ^d   Pickering, Stephen ^d   Moldoveanu, Nick ^b   Özbek, Ali ^e  

^a SONATRACH   (Algeria)

^b WESTERNGECO   (United States)

^c KUWAIT OIL COMPANY   (Kuwait)

^d WESTERNGECO   (United Kingdom)

^e NONE

Author keywords

[No Author keywords available]

Indexed keywords

ATTENUATION; BANDWIDTH; NATURAL FREQUENCIES; OPTICAL RESOLVING POWER; SENSORS; SIGNAL TO NOISE RATIO;

FREQUENCY BANDWIDTH; SEISMIC INTERPRETERS; SEISMIC TECHNOLOGY; SOURCE ARRAYS;

SEISMOLOGY;

EID: 29844443476     PISSN: 09231730     EISSN: None     Source Type: Journal    
DOI: None     Document Type: Review

References (22)

1. Beckett C, Brooks T, Parker G, Bjoroy R, Pajot D, Taylor P, Deitz D, Flaten T, Jaarvik LJ, Jack I, Nunn K, Strudley A and Walker R: "Reducing 3D Seismic Turnaround," Oilfield Review 7, no. 1 (January 1995): 23-37.
2. Aronsen HA, Osdal B, Dahl T, Eiken O, Goto R, Khazanehdari J, Pickering S and Smith P: "Time Will Tell: New Insights from Time-Lapse Seismic Data," Oilfield Review 16, no. 2 (Summer 2004): 6-15.
3. Barkved O, Bartman B, Compani B, Gaiser J, Van Dok R, Johns T, Kristiansen P, Probert T and Thompson M: "The Many Facets of Multicomponent Seismic Data," Oilfield Review 16, no. 2 (Summer 2004): 42-56.
4. Coherent noise is unwanted seismic energy that shows consistent phase from one seismic trace to another. This may consist of waves that travel through the air at very low velocities such as airwaves or air blast, and ground roll that travels through the top of the surface layer, also known as the weathering layer. The energy trapped within a layer, also known as multiples, is another form of coherent energy. Noncoherent energy is typically nonseismic-generated noise, such as noise from wind, moving vehicles, overhead power line or high-voltage pickup, gas flares and water injection plants.
5. A vibrator source sends a controlled-frequency sweep into the Earth. The recorded data are then convolved with the original sweep to produce a usable signal.
6. Each trace consists of one recording corresponding to a single source-receiver pair. In practice, traces from one source are simultaneously recorded at several receivers. Then, sources and receivers are moved along the survey line and another set of recordings is made. When a seismic wave travels from a source to a reflector and then back to the receiver, the elapsed time is the twoway traveltime. The common depth point (CDP) is the halfway point of the path; it is situated vertically below the common midpoint. Sorting of traces by collecting traces that have the same subsurface midpoint is called a common-midpoint (CMP) gather. The number of traces summed or stacked is called a fold. For instance, in 24-fold data, every stacked trace represents the average of 24 traces. In the case of dipping beds, there is no common depth point shared by multiple sources and receivers, so dip-moveout (DMO) processing becomes necessary to reduce smearing or inappropriate mixing of data. For more on seismic recording: Farmer P, Gray S, Whitmore D, Hodgkiss G, Pieprzak A, Ratcliff D and Whitcombe D: "Structural Imaging: Toward a Sharper Subsurface View," Oilfield Reviews, no. 1 (January 19931:28-41.
7. Ashton CP, Bacon B, Mann A, Moldoveanu N, Déplanté C, Ireson D, Sinclair T and Redekop G: "3D Seismic Survey Design," Oilfield Reviews, no. 2 (April 1994): 19-32.
8. Ongkiehong L and Askin HJ: "Towards the Universal Seismic Acquisition Technique," First Breaks, no. 2 (1988): 46-63.
9. Newman P and Mahoney JT: "Patterns - With a Pinch of Salt" Geophysical Prospecting 21, no. 2 (1973): 197-219.
10. Aliasing is the ambiguity that arises because of insufficient sampling. It occurs when the signal is sampled less than twice the cycle. The highest frequency defined by a sampling interval is termed the Nyquist frequency and is equal to inverse of 2Δt, where At is the sampling interval. Frequencies higher than the Nyquist frequency will be "folded back" or "wrapped back." This condition can be observed in video or motion pictures: the spoke wheels on horse-drawn wagons sometimes appear to be turning backward instead of forward. Aliasing can be avoided by a finer spatial sampling that is at least twice the Nyquist frequency of the waveform.
11. El-Emam A, Moore I and Shabrawi A: "Interbed Multiple Prediction and Attenuation: Case History from Kuwait," presented at the 2005 SEG International Exposition and 75th Annual Meeting, Houston, (November 6-11, 2005).
12. Roden R and Latimer R: "An Introduction - Rock Geophysics/AVO," The Leading Edge 22, no. 10 (October 2003): 987.
13. Ongkiehong and Askin, reference 7.
14. Christie P, Nichols D, Özbek A, Curtis T, Larsen L, Strudley A, Davis R and Svendsen M: "Raising the Standards of Seismic Data Quality," Oilfield Review 13, no. 2 (Summer 2001): 16-31.
15. y, on the other two. Wavenumber is the inverse of wavelength and represents the frequency of the wave in space. For more on APOCS: Özbek A, Hoteit L and Dumitru G: "3-D Filter Design on a Hexagonal Grid for Point-Receiver Land Acquisition," EAGE Research Workshop, Advances in Seismic Acquisition Technology, Rhodes, Greece, September 20-23, 2004.
16. Quigley J: "An Integrated 3D Acquisition and Processing Technique Using Point Sources and Point Receivers," Expanded Abstracts, 2004 SEG International Exposition and 74th Annual Meeting, Denver, (October 10-15, 2004): 17-20.
17. Shabrawi A, Smart A, Anderson B, Rached G and El-Emam A: "How Single-Sensor Seismic Improved Image of Kuwait's Minagish Field," first Break 23, no. 2 (February 2005): 63-69.
18. The Q-Borehole system optimizes all aspects of borehole seismic services, from job planning through data acquisition, processing and interpretation. Well logs, VSP and surface-seismic data are combined to build a property model of vertical velocities, frequency attenuation factors, anisotropy related to vertical variations in interval velocities and the multiples wavefield. The model is then used for enhanced surface-seismic processing and calibration in the Well-Driven Seismic process.
19. A zero-offset VSP is acquired when a seismic source is placed on the surface close to the wellhead and receivers are positioned at different depths in a borehole. In a walkaway VSP, an array of receivers collects data for multiple source positions located along a line that extends from the wellhead. For more on VSP and walkaway VSPs: Arroyo JL, Breton P, Dijkerman H, Dingwall S, Guerra R, Hope R, Hornby B, Williams M, Jimenez RR, Lastennet T, Tulett J, Leaney S, Lim T, Menkiti H, Puech J-C, Tcnerkashnev S, Burg TT and Verliac M: "Superior Seismic Data from the Borehole," Oilfield Review 15, no. 1 (Spring 2003): 2-23.
20. The Well-Driven Seismic process uses borehole seismic data for true amplitude and phase recovery, velocity analysis, multiple attenuation, anisotropic migration and angle-based muting. For more on the Well-Driven Seismic technique: Morice SP, Andersen J, Boulegroun M and Decombes O: "Integrated Borehole and Surface Seismic: New Technologies for Acquisition, Processing and Reservoir Characterization; Hassi Messaoud Field," presented at the 13th SPE Middle East Oil and Gas Show and Conference (MEOS). Bahrain, June 9-12, 2003.
21. El-Emam et al, reference 10.
22. The ant-tracking algorithm delineates discontinuities in a seismic cube and maps faults and fractures. The algorithm tracks discontinuities built upon previous knowledge, mimicking the behavior of ants when they find the shortest path between their nest and their food source. The ants communicate using pheromones, a chemical substance that attracts other ants. Therefore, the shortest path to the food source will be marked with more pheromones than the longest path, so the next ant is more likely to choose the shortest route, and so on. The idea is to distribute a large number of these electronic "ants" in a seismic volume. Ants deployed along a fault should be able to trace the fault surface for some distance before being terminated. The algorithm then automatically extracts the result as a set of fault-patches, a highly detailed mapping of discontinuities. Fault discrimination is based on the size of the fault, its orientation, and on the amplitude of vertical displacement For more on ant tracking: Pedersen SI, Randen T, Senneland L and Steen Ø: "Automatic Fault Extraction Using Artificial Ants," Expanded Abstracts, 2002 SEG International Exposition and 72nd Annual Meeting, Salt Lake City, Utah, USA (October 6-11, 2002): 512-515.