See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/328450132 Evolution model for the Absheron mud volcano (GIMS 14 - Presentation) Presentation · October 2018 CITATIONS READS 0 144 4 authors , including: Arthur Blouin Patrice Imbert Fugro France TOTAL 9 PUBLICATIONS 3 CITATIONS 112 PUBLICATIONS 1,152 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: The role of gas in mud volcanoes occurrence and growth, close-up on Azerbaijan edifices. View project Sivas Salt Tectonic project View project All content following this page was uploaded by Arthur Blouin on 25 February 2019. The user has requested enhancement of the downloaded file.
Evolution model for the Absheron mud volcano: from in-situ observations to numerical modeling Arthur Blouin 1,2,3 , Patrice Imbert 2 , Jean-Paul Callot 3 , Matthieu Dupuis 4 2 km 1 Ifremer, Lab. Aléas géologiques et Dynamiques sédimentaires, géosciences marines, REM, Centre de Bretagne, Pointe du diable, 29280 Plouzané 2 R&D/EP Total S.A., Avenue Larribau, 64000 Pau 3 E2S-UPPA, Lab. des Fluides Complexes et de leurs Réservoirs, IPRA, Univ . Pau & Pays Adour, Avenue de l’Université, 64013 Pau cedex 4 Lab. d’Océanologie et de Géosciences – Univ. Lille 1 – UFR Sciences de la Terre – 596355 Villeneuve d’ Asq
In Introduction • The South Caspian Basin • SCB: remnant of the Thetys sea • Maykop Fm: regional source rock with high TOC, gas mature, and detachment level for folding • Productive Series: 6 Km of Pliocene sediments deposited in 3 Myrs • Anticline crests: traps for HC and location of MVs Modified from Oppo et al., 2014 11/09/2018 GIMS 2018 - Haïfa 2
Evolu lution model for the Absheron mud volc lcano • Scientific questions • What is the stratigraphic source of the mud? Based on Deville, 2009 11/09/2018 GIMS 2018 - Haïfa 3
Evolu lution model for the Absheron mud volc lcano • Scientific questions • What is the stratigraphic source of the mud? • Can we reproduce field pore pressure measurements with a numerical model? Based on Deville, 2009 11/09/2018 GIMS 2018 - Haïfa 4
Evolu lution model for the Absheron mud volc lcano • Scientific questions • What is the stratigraphic source of the mud? • Can we reproduce field pore pressure measurements with a numerical model? • What mechanisms control the stratigraphic and lateral positions of the source? Based on Deville, 2009 11/09/2018 GIMS 2018 - Haïfa 5
Evolu lution model for the Absheron mud volc lcano • Scientific questions • What is the stratigraphic source of the mud? • Can we reproduce field pore pressure measurements with a numerical model? • What mechanisms control the stratigraphic and lateral positions of the source? • Based on observations and modeling results, can we propose a qualitative formation model for the Absheron mud volcano? Based on Deville, 2009 11/09/2018 GIMS 2018 - Haïfa 6
Evolu lution model for the Absheron mud volc lcano • Dataset and methodology • 3D seismic survey • Geotechnical survey with sediment cores in the mud Mineralogy Biostratigraphy Geomechanics (compressibility, permeability) • 2 exploration wells Pressure regime Temperature Hydraulic conductivity • Numerical modeling of overpressure distribution and methane migration 11/09/2018 GIMS 2018 - Haïfa 7
Evolu lution model for the Absheron mud volc lcano • Results – Seismic Interpretation 11/09/2018 GIMS 2018 - Haïfa 8
Evolu lution model for the Absheron mud volc lcano • Results – Seismic Interpretation Absheron anticline cored by a deep thrust Several folding phases based on thickness variations between flanks and crest Maximum folding activity during Absheron deposition Normal faults network on the fold extrados 11/09/2018 GIMS 2018 - Haïfa 9
Evolu lution model for the Absheron mud volc lcano • Results – Seismic Interpretation 11/09/2018 GIMS 2018 - Haïfa 10
Evolu lution model for the Absheron mud volc lcano • Results – Seismic Interpretation Blind seismic facies spreading horizontally into four distinct arm MV deposits Mud volcano located at the exact vertical from the main thrust First mudflows during post-Absheron interval, after the main folding stage 11/09/2018 GIMS 2018 - Haïfa 11
Evolu lution model for the Absheron mud volc lcano • Results – Seismic Interpretation 11/09/2018 GIMS 2018 - Haïfa 12
Evolu lution model for the Absheron mud volc lcano • Results – Seismic Interpretation Bowl-like geometry for all the horizons between Top Absheron and Top Productive Series Anhydritic Surakhany is discontinuous and downlap on the younger interval Continuous horizons below 3.5 sec TWTT Normal faults flanking the bowl- shaped area 11/09/2018 GIMS 2018 - Haïfa 13
Evolu lution model for the Absheron mud volc lcano • Results – Mud properties • All natural mud samples have the same compressibility and hydraulic conductivity • Coarse material input decrease the compressibility and increase the hydraulic conductivity • Mud mineralogy composed essentially of clays (illite and I/S) and quartz • Biostratigraphy: Productive Series origin 11/09/2018 GIMS 2018 - Haïfa 14
Evolu lution model for the Absheron mud volc lcano • Results – In-situ physical data Anhydritic Surakhany: 380 m of interstratified claystones and evaporites. Shale overpressure peaks near fracturing pressure (notably in Anhydritic Surakhany) CONFIDENTIAL Shallow reservoirs in equilibrium with shales. Deep reservoirs are 20 Mpa below shale pressure Unstable interval during drilling with a mineralogy close to the one of the mud 11/09/2018 GIMS 2018 - Haïfa 15
Evolu lution model for the Absheron mud volc lcano • Results – Numerical modeling Modeling of the physical conditions before extrusion Results of 1D sedimentation-related overpressure calculation injected at the South of the structural model (Structural model from Green et al., 2009 ) 11/09/2018 GIMS 2018 - Haïfa 16
Evolu lution model for the Absheron mud volc lcano • Results – Numerical modeling Modeling of the physical conditions before extrusion Results of 1D sedimentation-related overpressure calculation injected at the South of the structural model (Structural model from Green et al., 2009 ) Overpressure propagates at different rates depending on hydraulic conductivities Faults designed to model advection. Fast methane circulation in faults, slow diffusion through the sediments Near fracturing conditions in the area of methane saturation 11/09/2018 GIMS 2018 - Haïfa 17
Evolu lution model for the Absheron mud volc lcano • Discussions • The Anhydritic Surakhany is the more plausible source for the mud. • 2D diffusion model is able to reproduce the measured overpressure trend but not the exact pressure magnitudes • High values of D u / s ’ v fit with high dissolved methane concentrations (similar to Lusi eruption model) • Hydrofracturing in this area would lead to P decrease and gas exsolution/expansion critical factor for sediment damage (Sultan et al., 2012) • Initiation and location of the mud volcano is controlled by the superposition of overpressure and gas saturated zones 11/09/2018 GIMS 2018 - Haïfa 18
Evolu lution model for the Absheron mud volc lcano • Discussion – Conceptual model for the mud volcano formation 2 km 11/09/2018 GIMS 2018 - Haïfa 19
Evolu lution model for the Absheron mud volc lcano • Discussion – Conceptual model for the mud volcano formation 2 km 11/09/2018 GIMS 2018 - Haïfa 20
Evolu lution model for the Absheron mud volc lcano • Discussion – Conceptual model for the mud volcano formation 2 km 11/09/2018 GIMS 2018 - Haïfa 21
Evolu lution model for the Absheron mud volc lcano • Discussion – Conceptual model for the mud volcano formation 2 km 11/09/2018 GIMS 2018 - Haïfa 22
Evolu lution model for the Absheron mud volc lcano • Discussion – Conceptual model for the mud volcano formation 2 km 11/09/2018 GIMS 2018 - Haïfa 23
Evolu lution model for the Absheron mud volc lcano • Conclusions, limits and perspectives Stratigraphic mud source : Anhydritic Surakhany Overpressured and methane-saturated areas may explain the mud volcano location (e.g. 2-D model and LUSI) Trigger: hydrofracturing. Necessary preliminary condition: clay-rich sediment saturated with methane Roles of methane: exsolution creates the mud from clay-rich layers; lowers sediment density ; expansion keeps mud pressure high Conceptual formation model closely fits the observations and the analysis of the available dataset and is partly based on the numerical modeling results BUT… Dataset could be improved Numerical model is not complete and can be improved What are the gas saturation, pressure and pre-consolidation of the sediments allowing mud generation? Laboratory tests… 11/09/2018 GIMS 2018 - Haïfa 24
Thank you for your attention! 11/09/2018 GIMS 2018 - Haïfa 25
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