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2. Suitability analysis and revised strategies for marine environmental carbon capture and storage (CCS) monitoring

Author

Lichtschlag, Anna, Pearce, Christopher R., Suominen, Mikael, Blackford, Jerry, Borisov, Sergey M., Bull, Jonathan M., de Beer, Dirk, Dean, Marcella, Esposito, Mario, Flohr, Anita, Gros, Jonas, Haeckel, Matthias, Huvenne, Veerle A.I., James, Rachael H., Koopmans, Dirk, Linke, Peter, Mowlem, Matthew, Omar, Abdirahman M., Schaap, Allison, Schmidt, Mark, Sommer, Stefan, Strong, James, and Connelly, Douglas P.

Published
2021
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10. Multiscale characterisation of chimneys/pipes: Fluid escape structures within sedimentary basins

Author

Robinson, Adam H., Callow, Ben, Böttner, Christoph, Yilo, Naima, Provenzano, Giuseppe, Falcon-Suarez, Ismael H., Marín-Moreno, Héctor, Lichtschlag, Anna, Bayrakci, Gaye, Gehrmann, Romina, Parkes, Lou, Roche, Ben, Saleem, Umer, Schramm, Bettina, Waage, Malin, Lavayssière, Aude, Li, Jianghui, Jedari-Eyvazi, Farid, Sahoo, Sourav, Deusner, Christian, Kossel, Elke, Minshull, Timothy A., Berndt, Christian, Bull, Jonathan M., Dean, Marcella, James, Rachael H., Chapman, Mark, Best, Angus I., Bünz, Stefan, Chen, Baixin, Connelly, Douglas P., Elger, Judith, Haeckel, Matthias, Henstock, Timothy J., Karstens, Jens, Macdonald, Calum, Matter, Juerg M., North, Laurence, and Reinardy, Benedict

Published
2021
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11. Towards improved monitoring of offshore carbon storage: A real-world field experiment detecting a controlled sub-seafloor CO2 release

Author

Flohr, Anita, Schaap, Allison, Achterberg, Eric P., Alendal, Guttorm, Arundell, Martin, Berndt, Christian, Blackford, Jerry, Böttner, Christoph, Borisov, Sergey M., Brown, Robin, Bull, Jonathan M., Carter, Liam, Chen, Baixin, Dale, Andrew W., de Beer, Dirk, Dean, Marcella, Deusner, Christian, Dewar, Marius, Durden, Jennifer M., Elsen, Saskia, Esposito, Mario, Faggetter, Michael, Fischer, Jan P., Gana, Amine, Gros, Jonas, Haeckel, Matthias, Hanz, Rudolf, Holtappels, Moritz, Hosking, Brett, Huvenne, Veerle A.I., James, Rachael H., Koopmans, Dirk, Kossel, Elke, Leighton, Timothy G., Li, Jianghui, Lichtschlag, Anna, Linke, Peter, Loucaides, Socratis, Martínez-Cabanas, María, Matter, Juerg M., Mesher, Thomas, Monk, Samuel, Mowlem, Matthew, Oleynik, Anna, Papadimitriou, Stathys, Paxton, David, Pearce, Christopher R., Peel, Kate, Roche, Ben, Ruhl, Henry A., Saleem, Umer, Sands, Carla, Saw, Kevin, Schmidt, Mark, Sommer, Stefan, Strong, James A., Triest, Jack, Ungerböck, Birgit, Walk, John, White, Paul, Widdicombe, Steve, Wilson, Robert Euan, Wright, Hannah, Wyatt, James, and Connelly, Douglas

Published
2021
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20. Fine-scale Characterisation of an Active Gas Chimney within the Quaternary Sediments of the Central North-Sea; using Acoustic Full Waveform Inversion

Author

Jedari-Eyvazi, Farid, Plessix, Rene-Edouard, Bayrakci, Gaye, Minshull, Timothy A., and Bull, Jonathan M.

Abstract

Integrity of overburden formations to the underlying reservoir rocks plays a vital role in permanent storage of CO2 within geological traps. Focused fluid escape structures (also known as chimney and pipe structures) are highly permeable (sub-)vertical geological features within the sedimentary rocks that can represent a substantial risk to geological CO2 storage projects. Despite the importance of such structures to the subsurface hydraulic system, their internal structures and fluid flow properties are poorly constrained to date. In this study, we examined the internal structure of a representative gas chimney underlying the Scanner Pockmark Complex in the North Sea, where methane is currently leaking to the seabed. We recovered an acoustic velocity model of the chimney structure and the host formations, using 3-D full waveform inversion (FWI) technique. The inverted data consists of ~125000 seismic traces from 23 ocean bottom seismometers (OBS) covering an area of 66 km2. We set the FWI scheme to include only diving waves at offsets of 1300-4600 m, corresponding to incident angles of about 60º to 80º respectively at the maximum well-resolved depth of 700 mbsl. The inverted model, at the maximum frequency of 7 Hz, revealed a complex fluid escape structure with an indirect vertical gas migration pathway that manifested itself as a simple gas pipe structure on a coinciding seismic reflection image. In addition, integration of the recovered velocity structures with a calibrated Gassmann model suggested a patchy gas saturation within the area., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023

33. Permeability heterogeneity of sandstone intrusion fluid‐escape systems, Panoche Hills, California: Implications for sedimentary basins globally

Author

Callow, Ben, Falcon Suarez, Ismael, Bull, Jonathan M., Gernon, Thomas M., Ruffell, Sean, Grippa, Antonio, Hurst, Andrew, and Taylor, Kevin

Subjects
Stratigraphy, General Earth and Planetary Sciences, Geology, General Environmental Science
Abstract

Natural surface gas seeps provide a significant input of greenhouse gas emissions into the Earth’s atmosphere and hydrosphere. The gas flux is controlled by the properties of underlying fluid-escape conduits, which are present within sedimentary basins globally. These conduits permit pressure-driven fluid flow, hydraulically connecting deeper strata with the Earth’s surface; however they can only be fully resolved at sub-seismic scale. Here, a novel ‘minus cement and matrix permeability’ method using three-dimensional X-ray micro-computed tomography imaging enables the improved petrophysical linkage of outcrop and sub-surface data. The methodology is applied to the largest known outcrop of an inactive fluid-escape system, the Panoche Giant Intrusion Complex in Central California, where samples were collected along transects of the 600 to 800 m stratigraphic depth range to constrain porosity and permeability spatial heterogeneity. The presence of silica cement and clay matrix within the intergranular pores of sand intrusions are the primary control of porosity (17 to 27%) and permeability (≤1 to ca 500 mD) spatial heterogeneity within the outcrop analogue system. Following the digital removal of clay matrix and silica (opal-CT and quartz) cement derived from the mudstone host strata, the sand intrusions have porosity−permeability ranges of ca 30 to 40% and 10 3 to 10 4 mD. These calculations are closely comparable to active sub-surface systems in sedimentary basins. Field observations revealed that, at decreasing depth, the connected sand intrusion network reduces in thickness and becomes carbonate cemented, terminating at carbonate mounds formed from methane escape at the seafloor. A new conceptual model integrates the pore-scale calculations and field-scale observations to highlight the key processes that control sand intrusion permeability, spatially and temporally. The study demonstrates the control of matrix and cement addition on the physical properties of fluid-escape conduits, which has significance for hydrocarbon reservoir characterization and modelling, as well as subsurface CO 2 and energy storage containment assessment.

Published
2022
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45. Evolution of the offshore western Gulf of Corinth

Author

Bell, Rebecca E., McNeill, Lisa C., Bull, Jonathan M., and Henstock, Timothy J.

Subjects
Gulf of Corinth -- Natural history, Earth sciences
Abstract

The young Gulf of Corinth rift in central Greece is an ideal place to study processes occurring during the initiation and early stages of continental extension. At the east end of the 100-km-long E-W rift, Holocene extension on N-dipping faults equates to geodetic extension rates. At the western end, however, estimated extension rates on N-dipping onshore faults account for only ~20 % -40% of the geodetically measured rates (~10-15 mm/ yr). We use high-quality, multichannel, seismic reflection and swath bathymetry data to investigate the tectonics of the western Gulf and quantify the contribution of offshore fault activity toward total-rift extension. Five major offshore faults generate the variable basement topography, and a ca. 0.4-Ma unconformity separates stratigraphy into two main packages. Basin-fill geometry indicates that during the early stages of subsidence of the offshore western Gulf, S-dipping faults were the dominant border-fault structure. This is still the case at the western end of the western Gulf; however, elsewhere, N-dipping faults on the south margin are now relatively more dominant and cause stratigraphy to tilt south. The temporally and spatially varying rift structure contrasts with the simple, consistently N-dipping, border-fault, half-graben geometry of the east Gulf of Corinth. Combined west Gulf offshore and onshore Holocene fault extension rates total 5-14.5 mm/yr, within the range calculated geodetically, and render enhanced slip on a low-angle detachment surface beneath the western Gulf unnecessary. Keywords: Gulf of Corinth, normal fault, seismic reflection, seismic stratigraphy, rift evolution

Published
2008

47. Faulting and extension rate over the last 20,000 years in the offshore Whakatane Graben, New Zealand continental shelf

Author

Lamarche, Geoffroy, Barnes, Philip M., and Bull, Jonathan M.

Subjects
Faults (Geology) -- Research, Continental shelf -- Research, Earth sciences
Abstract

[1] Oblique rifting in the offshore Taupo Volcanic Zone, New Zealand, is expressed in widely distributed active normal faulting in the 20-km-wide Whakatane Graben. Active faults are identified along seafloor scarps and displacements of the post-last glacial transgressive ravinement surface (400 faults. We derive an extension rate at seismogenic depths (6-10 km) across the graben of 13 [+ or -] 6 mm [yr.sup.-1] , by summing surface measurements, assuming an average crustal fault dip of 45 [+ or -] 15[degrees], and correcting for the discrepancies between surface and deep crustal extension estimates. Structural and kinematic data implies an extension direction 20[degrees] oblique to the rift axis, resulting in up to 4.6 [+ or -] 2.1 mm [yr.sup.-1] of dextral motion parallel to the rift axis. The strike-slip motion is accommodated by dip-slip displacements on oblique faults in the center of the graben, and oblique-slip faulting along the rift margins. Pure dip-slip in the graben center represents >50% of the total slip, with the Rangitaiki Fault accommodating 25% of the total extension in the graben. Citation: Lamarche, G., P. M. Barnes, and J. M. Bull (2006), Faulting and extension rate over the last 20,000 years in the offshore Whakatane Graben, New Zealand continental shelf, Tectonics, 25, TC4005, doi: 10.1029/2005TC001886.

Published
2006

48. Magmatic and tectonic history of Iceland's western rift zone at Lake Thingvallavatn

Author

Bull, Jonathan M., Minshull, Timothy A., Mitchell, Neil C., Dix, Justin K., and Hardardottir, Jorunn

Subjects
Iceland -- Environmental aspects, Neotectonics -- Research, Faults (Geology) -- Research, Earth sciences
Abstract

High rates of Holocene sedimentation in a lake spanning the Thingvellir rift zone of western Iceland provide an unusual opportunity to study the interaction of tectonic and magmatic processes on time scales of thousands of years. Lake Thingvallavatn is oriented SW-NE, parallel to the trend of normal faults and fissures, which extend northeast from Hengill, a central volcano system. Thingvallavatn's lake sediments provide a continuous high-fidelity record of tectono-magmatic processes. Chirp subbottom profiler and sidescan records, together with sediment core information, enabled us to improve constraints on lake stratigraphy since the emplacement of a postglacial lava at 9.1 [+ or -] 0.3 ka. This lava, together with three younger horizons, enabled detailed study of the main tectonic and magmatic events. A major Hengill volcanic event, which controlled the development of the present-day lake morphology, occurred at 1.9 ka, with the eruption of a scoria cone within the lake (Sandey). During this event, the Nesjahraun lava was erupted into the southern part of the lake, the Sandey scoria cone was formed, and major faulting and subsidence occurred in the northern part of the lake, resulting in the formation of an asymmetrical rift. Within the southern part of the lake, a deformed sequence of sediments aged 2.9-1.5 ka, between undeformed younger and older sediments, indicates that liquefaction phenomena are associated with the emplacement of the Nesjahraun lava. Analysis of fault displacement reveals that the total throw summed over all faults across the width of the rift zone is approximately constant (110-130 m) along the long axis of the rift. We estimate an extension rate on the faults of 3.3-8.2 mm [yr.sup.-1] since 9.1 ka, assuming fault dips of 60-75[degrees], which represents 17%-43% of the total plate boundary extension estimated from global plate motion inversion. We speculate that the remaining extension must either be taken up elsewhere in Iceland, for example in the eastern rift zone or along the South Iceland seismic zone, or that extension estimated over the last 9 k.y. underestimates the long-term extension rate due to incomplete sampling of the episodic magmatic component. Keywords: neotectonics, dikes, subsidence, normal faults, Iceland, liquefaction.

Published
2005

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