Time‐lapse seismic noise correlation tomography at Valhall

Abstract

We show that a reliable and statistically significant group velocity time‐lapse difference between 2004 and 2010 can be retrieved from ambient seismic noise in an offshore hydrocarbon exploitation setting. We performed a direct comparison of Scholte wave group velocity images obtained using regularized tomography. We characterize the expected variation in group velocity images from the 2004 or 2010 recordings that result from fluctuations in the cross correlations by looking at cross correlations of portions of the recordings. We prove that the time‐lapse difference is statistically significant. The time‐lapse group velocity image from ambient noise data shows strong similarities with a time‐lapse phase velocity map obtained from controlled source data. The most striking features are a northern and a southern group velocity increase due to compaction and subsidence as a result of reservoir production.

Transdimensional Love-wave tomography of the British Isles and shear-velocity structure of the East Irish Sea Basin from ambient-noise interferometry

“…First applied to observational data by Shapiro et al (2005) and Sabra et al (2005), ANT has been used at regional and continental scales to produce group-velocity maps using mainly Rayleigh-wave cross-correlations, but a number of studies have also used Love-wave cross-correlations to image Europe (Li et al 2010a), Asia (Cho et al 2007;Li et al 2010b), North America (Bensen et al 2008;Lin et al 2008;Roux 2009), and Australia (Saygin & Kennett 2010). In addition, ANT has been used successfully to produce images of smaller-scale structures such as volcanic edifices (Masterlark et al 2010;Jay et al 2012;Nagaoka et al 2012) and inhomogeneities in oil and gas fields (Haney & Douma 2010, as well as of local structures at engineering seismology scales (Picozzi et al 2009;Pilz et al 2012) and on the seabed (de Ridder & Dellinger 2011;Mordret et al 2013a,b;de Ridder et al 2014). …”

Rayleigh-wave tomography using traffic noise at Long Beach, CA

“…The success of these studies has encouraged investigation of this technique at the exploration scale. In ocean-bottom environments, de Ridder et al (2014) and Mordret et al (2014) obtained reliable time-lapse group and phase velocity maps, respectively, of the Valhall overburden, while de Ridder et al (2015) recovered phase velocity and anisotropy maps representative of subsidence patterns at Ekofisk. In these cases, the examined frequencies were less than 2 Hz.…”

Reflecting boundary conditions for interferometry by multidimensional deconvolution

“…6,21,28,33,34 In this section, we showcase the advantage of the alternative boundary conditions for the application of MDD to ambient seismic noise recorded by ocean-bottom cables. Their aperture and dense spatial sampling 35,36 make these deployments particularly well suited for the application of MDD.…”