scholarly journals Direct and indirect inversion and a new and comprehensive perspective on the role of primaries and multiples in seismic data processing for structure determination and amplitude analysis

2018 ◽  
Vol 8 (2) ◽  
Author(s):  
Arthur B. Weglein

The removal and use of multiples have a single shared goal and objective: the imaging and inversion of primaries. There are two kinds of primaries: recorded primaries and unrecorded primaries. For imaging recorded primaries using an industry standard practice smooth velocity model, recorded multiples must be removed, to avoid false and misleading images due to the multiples. Similarly, to find an approximate image of an unrecorded primary, that is a subevent of a recorded multiple, unrecorded multiples that are subevents of the recorded multiple must be removed, for exactly the same problem and reason that recorded multiples are needed to be eliminated. Direct inverse methods are employed to derive this new comprehensive perspective on primaries and multiples. Direct inverse methods not only assure that the problem of interest is solved, but equally important, that the problem of interest is the relevant problem that we (the petroleum industry) need to be interested in.

Geophysics ◽  
2016 ◽  
Vol 81 (4) ◽  
pp. V283-V302 ◽  
Author(s):  
Arthur B. Weglein

Migration and migration inversion are the seismic processing methods for structural determination and subsequent amplitude analysis, respectively. To date, the most well-founded and physically interpretable migration method is based on predicting a coincident source and receiver experiment at depth at time equals zero. We have extended that migration method for heterogeneous media and to accommodate two-way propagation in a local sense at every point from the source to the target reflector and back from the reflector to the receiver and in a global sense, separately for each of the two legs from the source to the reflector and from the reflector to the receiver. That provides the first migration method that avoids high-frequency assumptions in the imaging principle and how it is implemented, and hence, it is equally effective at all frequencies at the target or reservoir. This advance for two-way wave propagation migration then provides a tool to quantitatively, unambiguously, and definitively define the role of primaries and multiples in migration. Our conclusion was that with data consisting of primaries and multiples, for an accurate discontinuous velocity model, only primaries contribute to migration with the same image and inversion results independent of whether multiples are kept or removed. However, for a smooth and continuous velocity model (i.e., generally assumed in practice), every multiple will result in a false, misleading, and potentially injurious subsurface image and hence must be removed before migration. In practice, we migrate with a smooth velocity model, and hence multiples must be removed. When the collection of primaries is incomplete, a multiple can be used to provide an approximate image of an unrecorded primary. However, it is always the migration of primaries that provides subsurface structure and amplitude information.


Geophysics ◽  
1996 ◽  
Vol 61 (6) ◽  
pp. 1846-1858 ◽  
Author(s):  
Claudio Bagaini ◽  
Umberto Spagnolini

Continuation to zero offset [better known as dip moveout (DMO)] is a standard tool for seismic data processing. In this paper, the concept of DMO is extended by introducing a set of operators: the continuation operators. These operators, which are implemented in integral form with a defined amplitude distribution, perform the mapping between common shot or common offset gathers for a given velocity model. The application of the shot continuation operator for dip‐independent velocity analysis allows a direct implementation in the acquisition domain by exploiting the comparison between real data and data continued in the shot domain. Shot and offset continuation allow the restoration of missing shot or missing offset by using a velocity model provided by common shot velocity analysis or another dip‐independent velocity analysis method.


2007 ◽  
Author(s):  
Tadeusz J. Ulrych ◽  
Sam Kaplan ◽  
Mauricio D. Sacchi ◽  
Elwin Galloway

Geophysics ◽  
1996 ◽  
Vol 61 (4) ◽  
pp. 1237-1240

Faruq E. Akbar received his BS (1988) in civil engineering from Bangladesh University of Engineering and Technology and his MS (1992) in geophysics from the University of New Orleans, Louisiana. He is currently a PhD student in the Department of Geological Sciences, University of Texas at Austin. His professional interests are seismic data processing, modeling, migration, and inversion.


2014 ◽  
Vol 69 (6) ◽  
Author(s):  
Sudra Irawan ◽  
Sismanto Sismanto ◽  
Adang Sukmatiawan

Seismic data processing is one of the three stages in the seismic method that has an important role in the exploration of oil and gas. Without good data processing, it is impossible to get seismic image cross section for good interpretation. A research using seismic data processing was done to update the velocity model by horizon based tomography method in SBI Field, North West Java Basin. This method reduces error of seismic wave travel time through the analyzed horizon because the existence velocity of high lateral variation in research area. There are three parameters used to determine the accuracy of the resulting interval velocity model, namely, flat depth gathers, semblance residual moveout that coincides with the axis zero residual moveout, and the correspondence between image depth (horizon) with wells marker  (well seismic tie). Pre Stack Depth Migration (PSDM) form interval velocity model and updating using horizon-based tomography method gives better imaging of under-surfaced structure results than PSDM before using tomography. There are three faults found in the research area, two normal faults have southwest-northeast strike and the other has northwest-southeast strike. The thickness of reservoir in SBI field, North West Java Basin, is predicted between 71 to 175 meters and the hydrocarbon (oil) reserve is predicted about  with 22.6% porosity and 70.7% water saturation. 


1992 ◽  
Vol 32 (1) ◽  
pp. 276
Author(s):  
T.J. Allen ◽  
P. Whiting

Several recent advances made in 3-D seismic data processing are discussed in this paper.Development of a time-variant FK dip-moveout algorithm allows application of the correct three-dimensional operator. Coupled with a high-dip one-pass 3-D migration algorithm, this provides improved resolution and response at all azimuths. The use of dilation operators extends the capability of the process to include an economical and accurate (within well-defined limits) 3-D depth migration.Accuracy of the migration velocity model may be improved by the use of migration velocity analysis: of the two approaches considered, the data-subsetting technique gives more reliable and interpretable results.Conflicts in recording azimuth and bin dimensions of overlapping 3-D surveys may be resolved by the use of a 3-D interpolation algorithm applied post 3-D stack and which allows the combined surveys to be 3-D migrated as one data set.


Geophysics ◽  
2001 ◽  
Vol 66 (3) ◽  
pp. 973-975
Author(s):  
Adrianus T. de Hoop

Reciprocity is an important property of elastodynamic, electromagnetic, and acoustic wavefields. Combined with optimization techniques, reciprocity theorems can be regarded as providing the basic ingredients to imaging and inversion methods in geophysical exploration and remote sensing (de Hoop, M. V. and de Hoop, A. T., 2000). Furthermore, reciprocity serves as the basis for the elimination procedures of surface‐related multiples in marine seismic data processing (Fokkema and van den Berg, 1993). In view of all this, a thorough and elucidating discussion on the configurations to and the conditions under which reciprocity applies, and what reciprocity leads to, like the recent paper by Arnsten and Carcione (2000), serves a useful purpose. In this paper, also a number of interesting applications are worked out in detail. The aim of this discussion is to indicate briefly how some of the results obtained in that paper are related to the ones that the present author has presented in de Hoop (1995), a reference that does not appear in Arntsen and Carcione (2000).


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