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EAGE Research Workshop - Advances in Seismic Acquisition Technology
- Conference date: 20 Sep 2004 - 23 Sep 2004
- Location: Rhodes, Greece
- Published: 20 September 2004
21 - 32 of 32 results
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Principles Behind Vector Acquisition
Authors P.W. Maxwell, D.N. Burch and C.J. CrissA25 PRINCIPLES BEHIND VECTOR ACQUISITION Summary 1 The subject of vector acquisition is a new but developing topic initiated through the advances in seismic sensor technology with the introduction of digital MEMS based accelerometers that make multi-component measurement economically viable. The term vector acquisition can also be expressed as full wave-field recording. Traditionally seismic acquisition has employed pwave geophones sensing in a single axis nominally vertical. However the true earth motion is only fully described in a three dimensional space. The multiplicity of wave trains arriving at the receiver can make the local ground move in any direction. If the
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Recent Advances in Point Receiver Technology – Are Field Arrays a Requirement Any Longer?
Authors D.J. Tessman, M. Bahorich and D. MonkA26 RECENT ADVANCES IN POINT RECEIVER TECHNOLOGY – ARE FIELD ARRAYS A REQUIREMENT ANY LONGER? Summary: 1 The recent introduction of full wavefield (i.e. multicomponent) point receiver technology has rekindled an ongoing debate amongst geophysicists as to the suitability of point receivers for use in the acquisition of standard compressional (P-wave) seismic data. Conventional wisdom tells most geophysicists that for a variety of reasons P-wave data should be acquired using arrays of receivers (and sources). While the spatial dimensions and number of elements deployed varies greatly throughout the world it is nonetheless common practice to employ some form of array.
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OBC Signal Fidelity
Authors M. Johnson, M. Norris and M. WalshA27 OBC SIGNAL FIDELITY Abstract 1 A simple definition of signal fidelity is “the accuracy of the reproduction of the true ground motion by the complete recording system”. This definition while simple is also quite restrictive and moves beyond the concept of “vector fidelity”. OBC signal fidelity can be compromised in many ways. A few of the more common ways are: temporal and spatial sampling recording filters spiking due to cable leakage or telemetry errors geophone resonances and noise due to gimbal mechanisms geophone noise due to cable interactions geophone coupling with the sea bottom and environmental noise (bottom currents
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Vector-Fidelity Benefits of Buried OBC Detectors at Teal South
By J.E. GaiserA28 VECTOR-FIDELITY BENEFITS OF BURIED OBC DETECTORS AT TEAL SOUTH Summary 1 Coupling of detectors on the seafloor is well understood and has been characterized by damped oscillatory systems that vary in amplitude and phase as a function of frequency. Furthermore this response is very different than the response on land due to inertial effects of water. When seafloor motion is out of phase with water motion larger resonances and phase distortions can result. However this phenomenon should be alleviated for permanently installed detectors that are buried below the seafloor and provide near-perfect coupling for time-lapse observations. At Teal South
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Field Trial of a 4C Fiber Optic Seabed System
Authors S. Maas, J. Bunn, B. Bunn, R. Metzbower, J. Bowlus and J. BielinskiA29 FIELD TRIAL OF A 4C FIBER OPTIC SEABED SYSTEM SUMMARY 1 A fiber optic 4C seabed cable has been successfully demonstrated in the North Sea. The cable design and performance is reviewed. A 2400 m array length with 4C sensor stations located every 25 m was tested in a water depth of 300 m. The cable was tested in shallow water and is relatively short in seismic acquisition terms. However we have demonstrated in the lab the optical systems capabilities beyond 3000 m depth and 12 km array lengths with channel counts in excess of 2000. In the field
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Design and Implementation of Wide-Azimuth 4C OBC Seismic in the Arabian Gulf
Authors S. Slawson, S. Burns, M. Fenton and D. PainterA30 DESIGN AND IMPLEMENTATION OF WIDE- AZIMUTH 4C OBC SEISMIC IN THE ARABIAN GULF Abstract 1 We describe the design and implementation of a ~147 km 2 full fold (~250 km 2 surface area) wideazimuth multi-component (“4C”) 3D seismic survey over the Idd El Shargi North and South Domes offshore Qatar. This survey is being used to delineate fracture orientation and fracture density in producing carbonate Shuaiba reservoirs and is one of the few wide-azimuth marine 4C surveys over carbonate reservoirs. Challenges of seismic operations in these actively producing oil fields are presented along with methods to mitigate the impact
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Solid Streamers and Single Hydrophones
Authors M. Brink and J. SpackmanA31 SOLID STREAMERS AND SINGLE HYDROPHONES Summary 1 Solid streamers are less sensitive to weather-related noise than liquid streamers. Hence with the solid streamers the operational weather window can be extended. In addition solid streamers can be towed shallower without a prohibitive increase in noise. The application of noise filters on single hydrophones in a solid streamer only yields marginal improvements over application of the same filters on hydrophone groups. These improvements do not justify the introduction of single hydrophone recording. For reduction of weather noise a hydrophone spacing of 3 m may be adequate for solid streamers. However the
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A New Look and an Old Source
Authors J. Ross, W.J. Mooney and D. MonkA33 A NEW LOOK AND AN OLD SOURCE Introduction 1 In this paper we examine the performance and operation of a controllable surface referenced weight drop system which has the capability of generating very high amplitude but manageable impacts. The source is compared to conventional dynamite and the potential benefits are demonstrated. Background Seismic surveys conducted using weight drop sources have been used for many years but have fallen out of favor recently. Two years ago we examined the potential for high impact energy sources where a weight was dropped from a high altitude. While it was possible to generate
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Optimization of Swell Noise Specifications as Part of Survey Design
Authors J.M. Mougenot, O. Zdraveva and K. KravikA34 OPTIMIZATION OF SWELL NOISE SPECIFICATIONS AS PART OF SURVEY DESIGN Abstract 1 A swell noise simulation was carried out during the survey design of a 3D acquisition planned by Total in the Norwegian Sea. The motivation for this study was that reprocessing of previous 2D data in the area had shown great sensitivity to swell noise of some programs of the forecasted 3D processing sequence (especially shot interpolation and pre-stack migration in time or in depth). Swell noise contaminated records were simulated by adding real noise records to shot points recorded in quiet conditions. The full processing sequences (Pre-Stack
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Acquisition Design Loop and Predictions of Seismic Qualities
Authors P. Meldahl, A. Jakobsen and C. StrandA35 ACQUISITION DESIGN LOOP AND PREDICTIONS OF SEISMIC QUALITIES Introduction 1 Fundamental issues in the acquisition design loop are acquisition specifications seismic qualities seismic cost and seismic payback. In this paper we discuss the design loop from a user perspective and present a method for predictions of seismic qualities based on seismic modeling. This method is efficient because it is automated simplified and separated in two loops. We define “notional seismic qualities”. These qualities can be convolved with the target response and quickly display the image quality of any target shape. By splitting the prediction of seismic qualities in two
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Rich Azimuth Marine Acquisition
By M.S. HowardA36 RICH AZIMUTH MARINE ACQUISITION 1 M.S. HOWARD 1 BHP Billiton 1360 Post Oak Blvd. Suite 500 Houston Texas 77056 USA There are many areas of complex velocity structure such as sub-salt areas in the Gulf of Mexico where improvements in depth imaging and noise removal have given better images. However there are many areas some known to contain large accumulations of hydrocarbons where the images are inadequate for cost effective appraisal and development and other areas where better images could open new exploration opportunities. Throughout the history of seismic processing computer power has been a limiting factor leading to
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Mitigating Noise in Seismic Surveys with an "Acoustic Blanket
Authors W.S. Ross, P.J. Lee, S.E. Heiney, E.N. Drake, R. Tenghamn and A. StenzelA37 MITIGATING NOISE IN SEISMIC SURVEYS WITH AN "ACOUSTIC BLANKET" Summary 1 For several years we have been conducting research on the use of bubble curtains (and more generally physical masking devices) to suppress marine noises. The research initially focussed on suppressing multiples in marine seismic acquisition by placing a bubble curtain at the bounce point of the multiple on the air-water interface. ExxonMobil conducted successful small-scale field tests of the method at its seismic test facility in Houston. ExxonMobil and Petroleum Geo-Services (PGS) conducted an offshore field test in early 2002 to establish the fundamentals of the bubble curtain
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