Geoelectrical properties of saline permafrost soil in the Adventdalen valley of Svalbard (Norway), constrained with in-situ well data

Laboratory data supported by granular-medium and inclusion theories indicate that Poisson’s ratio in gas-saturated sand lies within a range of 0–0.25, with typical values of approximately 0.15. However, some well log measurements, especially in slow gas formations, persistently produce a Poisson’s ratio as large as 0.3. If this measurement is not caused by poor-quality data, three in situ situations — patchy saturation, subresolution thin layering, and elastic anisotropy — provide a plausible explanation. In the patchy saturation situation, the well data must be corrected to produce realistic synthetic seismic traces. In the second and third cases, the effect observed in a well is likely to persist at the seismic scale.

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A systematic, science-driven approach for predicting subsurface properties

Interpretation ◽

10.1190/int-2019-0019.1 ◽

2020 ◽

Vol 8 (1) ◽

pp. T167-T181

Author(s):

Kelly Kathleen Rose ◽

Jennifer R. Bauer ◽

MacKenzie Mark-Moser

Keyword(s):

Language Processing ◽

A Priori ◽

Basin Scale ◽

Porosity And Permeability ◽

Priori Information ◽

Efficient Exploration ◽

Well Data ◽

Ideal Framework ◽

Discontinuous Data

As human exploration of the subsurface increases, there is a need for better data- and knowledge-driven methods to improve prediction of subsurface properties. Present subsurface predictions often rely upon disparate and limited a priori information. Even regions with concentrated subsurface exploration still face uncertainties that can obstruct safe and efficient exploration of the subsurface. Uncertainty may be reduced, even for areas with little or no subsurface measurements, using methodical, science-driven geologic knowledge and data. We have developed a hybrid spatiotemporal statistical-geologic approach, subsurface trend analysis (STA), that provides improved understanding of subsurface systems. The STA method assumes that the present-day subsurface is not random, but is a product of its history, which is a sum of its systematic processes. With even limited data and geologic knowledge, the STA method can be used to methodically improve prediction of subsurface properties. To demonstrate and validate the improved prediction potential of the STA method, it was applied in an analysis of the northern Gulf of Mexico. This evaluation was prepared using only existing, publicly available well data and geologic literature. Using the STA method, this information was used to predict subsurface trends for in situ pressure, in situ temperature, porosity, and permeability. The results of this STA-based analysis were validated against new reservoir data. STA-driven results were also contrasted with previous studies. Both indicated that STA predictions were an improvement over other methods. Overall, STA results can provide critical information to evaluate and reduce risks, identify and improve areas of scarce or discontinuous data, and provide inputs for multiscale modeling efforts, from reservoir scale to basin scale. Thereby, the STA method offers an ideal framework for guiding future science-based machine learning and natural language processing to optimize subsurface analyses and predictions.

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Modelling water-rock interactions due to long-term cooled-brine reinjection in the Dogger carbonate aquifer (Paris basin) based on in-situ geothermal well data

Geothermics ◽

10.1016/j.geothermics.2020.101899 ◽

2020 ◽

Vol 88 ◽

pp. 101899

Author(s):

Nicolas C.M. Marty ◽

Virginie Hamm ◽

Christelle Castillo ◽

Dominique Thiéry ◽

Christophe Kervévan

Keyword(s):

Carbonate Aquifer ◽

Paris Basin ◽

Geothermal Well ◽

Well Data

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Key controls on hydrocarbon retention and leakage from structural traps in the Hammerfest Basin, SW Barents Sea: implications for prospect analysis and risk assessment

Petroleum Geoscience ◽

10.1144/petgeo2019-094 ◽

2019 ◽

Vol 26 (4) ◽

pp. 589-606

Author(s):

Isabel Edmundson ◽

Atle Rotevatn ◽

Roy Davies ◽

Graham Yielding ◽

Kjetil Broberg

Keyword(s):

Barents Sea ◽

Threshold Pressure ◽

Specific Mechanism ◽

Gas Field ◽

Strength Based ◽

Fault Leakage ◽

Well Data ◽

Seal Strength

Evidence of hydrocarbon leakage has been well documented across the SW Barents Sea and is commonly associated with exhumation in the Cenozoic. While fault leakage is thought to be the most likely cause, other mechanisms are possible and should be considered. Further study is required to understand what specific mechanism(s) facilitate such leakage, and why this occurs in some locations and not others. In a case study of the Snøhvit Field, we use seismic and well data to quantify fault- and top-seal strength based on mechanical and capillary threshold pressure properties of fault and cap rocks. Magnitude and timing of fault slip are measured to acknowledge the role that faults play in controlling fluid flow over time. Results based on theoretical and in situ hydrocarbon column heights strongly indicate that across-fault and top-seal breach by capillary threshold pressure, and top-seal breach by mechanical failure are highly unlikely to have caused hydrocarbon leakage. Instead, top-seal breach caused by tectonic reactivation of identified faults is likely to have facilitated hydrocarbon leakage from structural traps. The results of this case study acknowledge the different mechanisms by which hydrocarbons can leak from a structural trap. Employing both a holistic and quantitative approach to assessing different seal capacities reduces the likelihood that a particular cause of hydrocarbon leakage is overlooked. This is particularly relevant for the Snøhvit Field in its dual capacity as a producing gas field and as a carbon sequestration site since both systems rely on a thorough understanding of seal capacity and leakage potential.

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In situ creep properties in ice-rich permafrost soil

Canadian Geotechnical Journal ◽

10.1139/t86-080 ◽

1986 ◽

Vol 23 (4) ◽

pp. 504-514 ◽

Cited By ~ 19

Author(s):

K. W. Savigny ◽

N. R. Morgenstern

Keyword(s):

Canadian Arctic ◽

Permafrost Soil ◽

Creep Properties ◽

Factors Affecting ◽

Naturally Occurring ◽

Permafrost Soils ◽

Bear River ◽

Creep Deformations ◽

Significant Factors

An in situ analysis of naturally occurring creep has been carried out at the proposed Canadian Arctic Gas pipeline crossing of Great Bear River in the Northwest Territories. This is the third of four papers that describe the study. The borehole inclinometer system and monitoring procedures used to determine in situ movement are described. Significant factors affecting the accuracy of the system are assessed. External factors causing movement of the inclinometer casing are also assessed and movements caused by these factors are separated from natural ground movements. The magnitude and nature of naturally occurring creep deformations are discussed. Key words: Mackenzie Valley, pipelines, slopes, permafrost, soils, geotechnical, inclinometers, creep.

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The Genome Sequence of Psychrobacter arcticus 273-4, a Psychroactive Siberian Permafrost Bacterium, Reveals Mechanisms for Adaptation to Low-Temperature Growth

Applied and Environmental Microbiology ◽

10.1128/aem.02101-09 ◽

2010 ◽

Vol 76 (7) ◽

pp. 2304-2312 ◽

Cited By ~ 108

Author(s):

HÃ¯Â¿Â½ctor L. Ayala-del-RÃ¯Â¿Â½o ◽

Patrick S. Chain ◽

Joseph J. Grzymski ◽

Monica A. Ponder ◽

Natalia Ivanova ◽

...

Keyword(s):

Amino Acid ◽

Low Temperatures ◽

Permafrost Soil ◽

Membrane Composition ◽

Terrestrial Environment ◽

Subzero Temperatures ◽

Shock Proteins ◽

Siberian Permafrost

ABSTRACT Psychrobacter arcticus strain 273-4, which grows at temperatures as low as −10Ã¯Â¿Â½C, is the first cold-adapted bacterium from a terrestrial environment whose genome was sequenced. Analysis of the 2.65-Mb genome suggested that some of the strategies employed by P. arcticus 273-4 for survival under cold and stress conditions are changes in membrane composition, synthesis of cold shock proteins, and the use of acetate as an energy source. Comparative genome analysis indicated that in a significant portion of the P. arcticus proteome there is reduced use of the acidic amino acids and proline and arginine, which is consistent with increased protein flexibility at low temperatures. Differential amino acid usage occurred in all gene categories, but it was more common in gene categories essential for cell growth and reproduction, suggesting that P. arcticus evolved to grow at low temperatures. Amino acid adaptations and the gene content likely evolved in response to the long-term freezing temperatures (−10Ã¯Â¿Â½C to −12Ã¯Â¿Â½C) of the Kolyma (Siberia) permafrost soil from which this strain was isolated. Intracellular water likely does not freeze at these in situ temperatures, which allows P. arcticus to live at subzero temperatures.

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Response of cold-adapted microbial populations in a permafrost profile to hydrocarbon contaminants

Polar Record ◽

10.1017/s0032247400027261 ◽

2001 ◽

Vol 37 (202) ◽

pp. 239-248 ◽

Cited By ~ 12

Author(s):

A.G. Rike ◽

M. Børresen ◽

A. Instanes

Keyword(s):

Microbial Populations ◽

Contaminated Site ◽

Permafrost Soil ◽

Limiting Factor ◽

Cold Adapted ◽

Degrading Bacteria ◽

Population Sizes ◽

Different Depths ◽

High Concentrations

AbstractHeterotrophic and hydrocarbon-degrading microbial populations in soils from different depths in a permafrost soil profile at a hydrocarbon-contaminated site at Ny-Ålesund, Svalbard, were examined and compared to the populations present at a pristine site. The objective was to investigate whether the populations were enhanced after 12 years of exposure to hydrocarbons. Based on air and soil temperature data, it is concluded that the microorganisms living in these environments are cold-adapted. Proliferation of the populations by a factor of 100–1000 was measured in the layers where mineral oil was present in high concentrations. This indicates that the populations responded to the additional carbon source by degradation and growth on hydrocarbons or hydrocarbon metabolites. A high number of intrinsic heterotrophic and hydrocarbon-degrading bacteria is a prerequisite forin situbioremediation of contaminated sites. Although the hydrocarbon-degrading activities of the populations are not known, the results show that the population sizes probably do not represent the limiting factor in a bioremedial action at this contaminated Arctic permafrost site.

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Influence of faulting on reservoir overpressure distribution in the Northern Carnarvon Basin

The APPEA Journal ◽

10.1071/aj14003 ◽

2015 ◽

Vol 55 (1) ◽

pp. 35

Author(s):

Edward Hoskin ◽

Stephen O'Connor ◽

Stephen Robertson ◽

Jurgen Streit ◽

Chris Ward ◽

...

Keyword(s):

Pore Pressure ◽

Hanging Wall ◽

Foot Wall ◽

Geological History ◽

Pore Pressure Prediction ◽

Northern Carnarvon Basin ◽

Well Data ◽

Carnarvon Basin

The Northern Carnarvon Basin has a complicated geological history, with numerous sub-basins containing varying formation thicknesses, lithology types, and structural histories. These settings make pre-drill pore pressure prediction problematic; the high number of kicks taken in wells shows this. Kicks suggest unexpected pore pressure was encountered and mudweights used were below formation pressure. The horst block penetrated by the Parker–1 well is focused on in this peer-reviewed paper. This horst is one of many lying along Rankin Trend’s strike. In this well, kicks up to 17.2 ppg (pounds per gallon) were taken in the Mungaroo reservoir. The authors investigate whether the kicks represent shale pressure—or rather, represent pressure transferred into foot-wall sandstones—by using well data from Forrest 1/1A/1AST1 and Withnell–1, and wells located in the Dampier Sub-basin and the hanging-wall to the horst. This anomalous pressure could result from either cross-fault flow from juxtaposed overpressured Dingo Claystone or transfer up faults from a deeper source. Using a well data derived Vp versus VES trend, the authors establish that the kicks taken in Parker–1 are more likely to result from pressure transfer using faults as conduits. These data lie off a loading trend and appear unloaded but likely represent elevated sand pressures and not in situ shale pressure. Pressure charging up faults in the Northern Carnarvon Basin has been recognised in Venture 1/1ST1, however, this paper presents a focused case study. Pressure transfer is noted in other basins, notably Brunei. From unpublished data, the authors believe that buried horst blocks, up-fault charging and adjacent overpressured shale may explain high reservoir pressures in other basins, including Nam Con Son in Vietnam.

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In situ creep properties in ice-rich permafrost soil

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts ◽

10.1016/0148-9062(87)90955-7 ◽

1987 ◽

Vol 24 (5) ◽

pp. 183

Keyword(s):

Permafrost Soil ◽

Creep Properties

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Azimuthal anisotropy analysis of P-wave seismic data and estimation of the orientation of the in situ stress fields: An example from the Rock-Springs uplift, Wyoming, USA

Geophysics ◽

10.1190/geo2015-0268.1 ◽

2017 ◽

Vol 82 (2) ◽

pp. B63-B77 ◽

Cited By ~ 10

Author(s):

Subhashis Mallick ◽

Debraj Mukherjee ◽

Luke Shafer ◽

Erin Campbell-Stone

Keyword(s):

Seismic Data ◽

In Situ Stress ◽

P Wave ◽

Stress Fields ◽

Hydraulic Fractures ◽

Rock Springs Uplift ◽

Naturally Fractured ◽

Well Data ◽

Rock Springs

Estimating the orientation and magnitude of maximum and minimum horizontal in situ stress is important for characterizing naturally fractured, unconventional, and carbon-sequestered reservoirs. For naturally fractured reservoirs, they are needed to guide directional drilling; for unconventional reservoirs, they are used for optimal placements of hydraulic fractures; and for carbon-sequestered reservoirs, they are used to avoid fracturing of overlying seal rocks. In addition, a knowledge of stress fields can be used to induce fractures within the target reservoirs and enhance additional storage for carbon-sequestration experiments. The orientation and magnitude of in situ stress can be calculated at the well locations. For locations, away from the wells, analysis of the azimuthal dependence of the amplitude-variation-with-angle gradient or azimuthal angle stacks are used to quantify anisotropy, which are then related with well data and other geologic information for stress estimation. Such azimuthal analysis requires accurate conversion of offset-domain seismic data into angles. We use isotropic prestack waveform inversion for an accurate offset-to-angle transformation along different source-to-receiver azimuths followed by azimuthal analysis. Applying our method to the real seismic data from the Rock-Springs uplift, Wyoming, USA, and relating the results to the well data, we find that our results are favorably related to the orientation of the maximum in situ horizontal stress field measured at the well location.

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