Articles
A Review on Least Squares Prestack Migration and its Applications
Naser Yousefzadeh and John C. Bancroft
Kirchhoff least squares prestack migration (LSPSM) attenuates acquisition artifacts resulting from irregularities or sparseness in the wavefield sampling and improves image resolution. This paper provides a brief review on the advantages and disadvantages of using LSPSM. Using synthetic examples, a few applications of LSPSM including improvement in image resolution, the…
Overview on the Fundamentals of Imaging
Brian Schulte
The purpose of this paper is to review imaging, migration algorithms, and velocity model building. It gives an overview on the goals and techniques utilized in imaging of seismic data. The migration algorithms presented are based in the Gulf of Mexico but are applicable throughout the world. It is intended…
Introduction to the Processing – Noise Attenuation Focus Articles
Mauricio D. Sacchi
I am pleased to have observed a renewed interest in seismic signal processing at our latest annual convention. We had an unprecedented number of sessions devoted to seismic signal processing. All of these sessions were well attended, which signals a growing interest in reinvigorating the field of seismic signal processing.…
Rank Reduction of Unfolded Tensors for Pre-stack De-noising and Reconstruction
Nadia Kreimer and Mauricio D. Sacchi
Seismic data can be represented by a N-dimensional tensor that can be unfolded in N matrices. These N unfolded matrices (also called unfoldings) are low rank when the data are composed of a superposition of linear events. Noise and missing observations increase the rank of the unfolded matrices…
Footprint Attenuation with 5D Interpolation
Peter Cary and Mike Perz
In recent years, 5D interpolation has become a very popular method for regularizing seismic data before 3D prestack migration. In addition to its main purpose of reducing the generation of migration artifacts due to irregular spatial sampling, 5D interpolation also has the very beneficial sideeffect of attenuating acquisition footprint during…
Strong Noise – Removal and Replacement on Seismic Data
Patrick Butler
Strong noise on seismic data generally not only obscures the underlying signal but also is spread by subsequent linear processing into other traces. Consequently it is very important to nonlinearly remove it and if we can recover some of the signal underneath. Failing that at least we can use nearby…
White Noise Suppression in the Time Domain
Patrick Butler
White noise forms the basic limit to resolution for seismic data. However we are not usually trying to see a single event on a single trace. We recognise that seismic signal “looks” the same within a time window at least on some adjacent traces. We can use this to nonlinearly…
Preserving sensor vector fidelity using automated multicomponent receiver-azimuth detection
Jeff P. Grossman and Rodney Couzens
P-S converted-wave energy is recorded mainly on the two lateral components of the receiver. Conventional processing of converted-wave energy includes rotation of these laterally polarized data measurements into radial and transverse coordinates. To do this properly, knowledge of the in-situ receiver orientation is essential. However, substantial errors in the recorded…
Introduction to the Microseismic – Applications and Case Studies Focus Articles
Shawn C. Maxwell
Over the last several years, microseismic monitoring has evolved into the primary geophysical imaging method for hydraulic fracturing of unconventional reservoirs. Interest in the technology has also rapidly grown, and we are fortunate that Calgary has become a “hotbed” for technological development. The number and quality of microseismic presentations at…
Microseismic Monitoring of Ball Drops During Hydraulic Fracturing Using Sliding Sleeves
Shawn C. Maxwell and Richard Parker
A relatively new method of completing horizontal wells has recently emerged and is quickly gaining popularity. Unlike conventional well construction using a cemented liner and a series of perforations to create different frac stages along its length, openhole completions using multiple, mechanicallyactivated, sliding-sleeve fracports is increasing commonplace (e.g., Seale and…
Methods to Calibrate Low-Amplitude Surface Monitoring Microseismic Results via Integration of Geology, Production Data, and Reservoir Simulation
Sherilyn Williams-Stroud, Chet Ozgen and Randal L. Billingsley
An array of geophones on the surface above the reservoir was used to map hydraulic fractures by locating microseismic events in order to estimate the effectiveness of the stimulation. In general, hydraulic fracture orientations can be inferred from the geometry of the events when microseismicity forms linear or planar trends…
Do Hydraulic Fractures Induce Events Large Enough to be Felt on Surface?
Adam M. Baig, Ted Urbancic, and Gisela Viegas
Hydraulic fracturing is known to generate seismic events, with magnitudes that typically range up to magnitude M0. The presence of these events has been widely exploited and interpreted in terms of fracture geometries and efficiency of stimulations. However, the reported magnitude ranges are dependent on the instrumentation used to capture…
Cardium Microseismic West Central Alberta: A Case History
John L. J. Duhault
In 2010, Petrobakken Energy acquired several companies with resource play potential in the Cardium formation in West Central Alberta. After the first year of encouraging results the company set out to further evaluate these properties in 2011 and drilled an additional 120 wells into the Cardium. Multistage hydraulic fracture stimulations…
An introduction to this special section: Seismic acquisition
R. Malcolm Lansley
This section on seismic acquisition is based on the papers that were presented under the Data Acquisition Session at the CSEG GeoConvention 2012: Vision in May, 2012. Of the five papers that were presented, the authors of three agreed to publish their material in a more complete format in The…
The Hussar low-frequency experiment
G.F. Margrave, L. Mewhort, T. Phillips, M. Hall, M.B. Bertram, D.C. Lawton, K. Innanen, K.W. Hall, K.Bertram
In early September of 2011, CREWES (Consortium for Research in Elastic-Wave Exploration Seismology) collaborated with Husky Energy, Geokinetics, and INOVA, to conduct a seismic experiment designed to study the initiation and recording of very low frequency seismic reflections. The motivation was to collect a dataset that will be useful to…
BroadSeis: Enhancing interpretation and inversion with broadband marine seismic
R. Soubaras, R. Dowle, and R. Sablon
BroadSeis™ variable-depth streamer acquisition is a CGGVeritas solution for broadband marine seismic which uses a proprietary cable shape and a novel deghosting technique to remove the receiver ghost and extends the usable primary bandwidth up to six octaves. This solution benefits from towing streamers at depths of up to 50…
The Benefits of Receiver Infill Stations: A Technical Case Study
Keith Millis and Andrea Crook
Seismic acquisition is frequently being conducted in areas with extensive infrastructure as well as numerous environmental restrictions. Although some restrictions to seismic acquisition affect both sources and receivers, receivers are generally unencumbered due to their relatively small environmental footprint and ease of deployment. Accordingly, receiver infill stations can be used…
Identifying Fault Activation in Shale Reservoirs Using Microseismic Monitoring during Hydraulic Stimulation: Source Mechanisms, b Values, and Energy Release Rates
Michael Kratz, Arifandy Aulia, and Andrew Hill
Microseismic monitoring is an important tool for developing unconventional resources such as shale gas and understanding the geomechanical properties of the reservoir. Identification of fault planes that intersect horizontal wellbores is critical for optimizing formation stimulation and avoiding the establishment of fluid flow pathways into nontarget formations, such as aquifers.…
Fourier Domain Regularization 5D and More
Valentina Khatchatrian
Global multi dimensional regularization has become a widely used tool in seismic data processing. Many advantages of regularization in the Fourier domain come with some serious problems. In this paper we consider the intrinsic properties of the Fourier transform to identify problems and limitations of the method. A practical and…
Non-hyperbolic MultiFocusing Improves Depth Imaging
Alex Berkovitch, Kostya Deev, Marianne Rauch-Davies, and Evgeny Landa
MultiFocusing technology can dramatically improve the quality of seismic imaging especially in cases of low fold data, poor signal- to- noise ratio and sparse 3D acquisition. At the same time, local parameters of the observed wavefield in prestack seismic records are of great interest for many seismic applications such as…
