Petroleum Geo-Services

About: Petroleum Geo-Services is a company organization based out in Weybridge, United Kingdom. It is known for research contribution in the topics: Azimuth & Noise. The organization has 421 authors who have published 404 publications receiving 3496 citations.

The Pseudo-analytical Method: Application of Pseudo-Laplacians to Acoustic And Acoustic Anisotropic Wave Propagation

Abstract: Summary We generalize the pseudo-spectral method for the acoustic wave equation to create analytical solutions to the constant velocity acoustic wave equation in an arbitrary number of space dimensions. We accomplish this by modifying the Fourier Transform of the Laplacian operator so that it compensates exactly for the error due to the second-order finite-difference time marching scheme used in the conventional pseudo-spectral method. Of more practical interest, we show that this modified or pseudo-Laplacian is a smoothly varying function of the parameters of the acoustic wave equation (velocity most importantly) and thus can be further generalized to create near-analyticallyaccurate solutions for the variable velocity case. We call this new method the pseudo-analytical method. We further show that by applying this approach to the concept of acoustic anisotropic wave propagation, we can create scalar-mode VTI and TTI wave equations that overcome the disadvantages of previously published methods for acoustic anisotropic wave propagation. These methods should be ideal for forward modeling and reverse time migration applications.

Imaging of primaries and multiples using a dual-sensor towed streamer

Abstract: Summary Multiple reflections are commonly treated as noise in oneway imaging methods. High effort is put into research and data processing worldwide in an effort to suppress this source of noise. In a new perspective multiples are treated as valuable imaging information. Based on dual-sensor towed streamer measurement, we decompose the wavefield and apply up/down imaging of primary and multiple reflections. This approach is tested using shallow water synthetic data and finally applied on dual-sensor field data.

A Dual-Sensor, Towed Marine Streamer; Its Viable Implementation And Initial Results

Abstract: In 1947, Roy Paslay, George Pavey and Pershing Wipff invented the towed marine streamer (Lawyer et al, 2001; Paslay et al, 1956) Since that time, there have been many improvements in streamer technology However, one aspect of that technology has remained fixed during the intervening 60 years; the type of seismic detector has remained the hydrophone As a consequence, every recorded and finally processed reflection wavelet from marine streamers has been accompanied by a ghost reflection from the ocean’s surface And the resulting filter effect on the recorded data has restricted streamer towing depths to a range of about six to nine meters In this paper, we report on the successful addition of particle velocity sensors to a new dual-sensor towed marine streamer, and the geophysical improvements and advantages that result

Applications of RTM inverse scattering imaging conditions

Abstract: Reverse time migration (RTM) is achieved by a forward and reverse time propagation of source and receiver wavefields respectively, followed by an imaging condition. The quality of the image from any RTM implementation depends directly on the method’s ability to separate the true reflection data from the backscattered correlation noise between the source and receiver wavefields. In this paper we demonstrate the application of an inverse scattering imaging condition that significantly reduces this backscattered correlation noise and results in a much higher quality subsurface image than is achieved by typical RTM imaging conditions.

Stochastic joint inversion of 2D seismic and seismoelectric signals in linear poroelastic materials: A numerical investigation

Abstract: The interpretation of seismoelectrical signals is a difficult task because coseismic and seismoelectric converted signals are recorded simultaneously and the seismoelectric conversions are typically several orders of magnitude smaller than the coseismic electrical signals. The seismic and seismoelectric signals are modeled using a finite-element code with perfectly matched layer boundary conditions assuming a linear poroelastic body. We present a stochastic joint inversion of the seismic and seismoelectrical data based on the adaptive Metropolis algorithm, to obtain the posterior probability density functions of the material properties of each geologic unit. This includes the permeability, porosity, electrical conductivity, bulk modulus of the dry porous frame, bulk modulus of the fluid, bulk modulus of the solid phase, and shear modulus of the formations. A test of this approach is performed with a synthetic model comprising two horizontal layers and a reservoir partially saturated with oil, which is embedded in the second layer. The result of the joint inversion shows that we can invert the permeability of the reservoir and its mechanical properties.