1000 M Long Gas Blow-Out Pipes

Effects of rapid sedimentation on developing the Nyegga pockmark field: Constraints from hydrological modeling and 3‐D seismic data, offshore mid‐Norway

“…Considering the predicted, 3000-year-long period with considerably elevated fluid fluxes (Figure 12), the model is consistent with inferred vigorous fluid venting associated with the formation mode of pockmarks [e.g., Hovland et al, 2005]. Additionally, the endmember of acoustic chimneys that connect to overlying pockmarks, similar to the chimneys at Nyegga (Figure 6), have been interpreted as blowout structures since they typically link shallow gas compartments to large pockmarks (craters) at the seafloor [Løseth et al, 2001;Cartwright, 2007;Cartwright et al, 2007]. By analogy, active and vigorous degassing associated with a pockmark/ chimney structure is documented on the NW Svalbard passive margin [Hustoft et al, 2009].…”

3D seismic expression of fluid migration and mud remobilization on the Gjallar Ridge, offshore mid‐Norway

“…The three groups of mounded structures described above constitute clear evidence for focused £uid and/or gas migration in this part of the VÖring Basin at di¡erent times during the Cenozoic. A number of questions arise from the recognition of these structures, including the nature and source of the £uids involved in the mobilization of buried sediments, the nature of the conduits, the factors in£uencing the distribution of these structures and their conduits and any controls on the timing of the £uid migration.This type of £uid migration regime is also interesting in its own right, because the contemporaneity of the various groups of structures and their wide distribution argue powerfully for the development at least in some basins such as this, for highly discretized £uid migration cells, supplying a central conduit.Whereas highly focused vertical £uid migration is well known from highly faulted areas such as the growth-faulted provinces of the major Cenozoic deltas such as the Niger and Mississippi (Graue, 2000;LÖseth et al, 2001), the mechanisms of focused vertical migration in relatively undeformed strata are much more obscure, and the evidence in this paper may thus stimulate wider consideration of this type of £uid £ow regime.…”

“…The cross-sectional geometry and chaotic re£ection pattern of the succession below the structures is reminiscent of the seismic expression of gas chimneys and blow-out pipes as described by LÖseth et al (2001LÖseth et al ( , 2003 and Gay et al (2003). LÖseth et al (2003) interpreted this type of structure as evidence for vertical and deeply sourced £uid and/or gas migration.…”

Review of submarine cold seep plumbing systems: leakage to seepage and venting

“…The advent of three-dimensional seismic acquisition and improved migration algorithms have helped in the discovery of a new class of fluid conduits known as pipes ( Fig. 5) (Loseth et al, 2001;Berndt et al, 2003), which are very narrow vertical fluid conduits. Pipes were commonly ignored in two-dimensional seismic because the vertical to subvertical pipe geometry was easily confused with seismic artifacts such as migration anomalies, scattering artifacts, lateral velocity anomalies and attenuation variations related to shallow diffractions (Loseth et al, 2001(Loseth et al, , 2003.…”

“…5) (Loseth et al, 2001;Berndt et al, 2003), which are very narrow vertical fluid conduits. Pipes were commonly ignored in two-dimensional seismic because the vertical to subvertical pipe geometry was easily confused with seismic artifacts such as migration anomalies, scattering artifacts, lateral velocity anomalies and attenuation variations related to shallow diffractions (Loseth et al, 2001(Loseth et al, , 2003. Plumbing systems are often fully or partially covered by massive pavements or patches of carbonate crust (Mazzini et al, 2004), which inhibits the penetration of normal seismic incidences, giving no images beneath the crust and causing a problem with imaging (Riedel et al, 2002).…”