Seismic attributes for monitoring of a shallow heated heavy oil reservoir: A case study

Geophysics ◽  
1999 ◽  
Vol 64 (2) ◽  
pp. 368-377 ◽  
Author(s):  
Douglas R. Schmitt
Keyword(s):  
Heavy Oil ◽  
Structural Changes ◽  
Time Window ◽  
Oil Sand ◽  
Additional Information ◽  
Spectral Estimates ◽  
Reflection Profile ◽  
In Situ Conditions ◽  
Short Time Window

In production geophysics, detecting the zones of production or constraining the in‐situ conditions within a reservoir are often of greater importance than obtaining highly resolved seismic structural images. Standard seismic data processing distorts the signal and limits the potential for extracting additional information, especially for shallow targets. An alternative “shift‐stack” procedure is applied in the processing of a shallow 12-fold, 1-m common midpoint (CMP) spacing reflection profile acquired over a heated Athabasca heavy oil sand reservoir. The shift‐stack involves summing of CMP traces which have been flattened to an appropriate reference event. Simple modeling confirms that the prestack waveforms are better preserved by this process. Amplitude and frequency attributes are extracted from the reflection profile. Amplitudes of a continuous reservoir event vary by 600% over 35-m intervals along the profile. Bright spots correlate with heated regions. Apparent frequencies, as measured by the instantaneous frequency and by short time‐window power spectral estimates of the subreservoir event are 20–30 Hz lower in these same regions. These diminished apparent frequencies most probably result from interference of the subreservoir reflection with events related to structural changes within the reservoir. A complete interpretation of the results has not been attempted as knowledge of the in‐situ conditions is incomplete. However, changes in the seismic response at the well locations suggest that these attributes are useful in detection and mapping of heated zones. The shiftstack procedure may also be useful in environmental and geotechnical applications.

The effect of oil under in‐situ conditions on the seismic properties of rocks

Geophysics ◽  
1992 ◽  
Vol 57 (7) ◽  
pp. 894-901 ◽  
Author(s):  
Virginia A. Clark
Keyword(s):  
Elastic Properties ◽  
Oil Sands ◽  
Velocity Of Sound ◽  
Oil Sand ◽  
Seismic Properties ◽  
In Situ Conditions ◽  
Reservoir Conditions ◽  
Seismic Sections ◽  
Seismic Anomalies

Direct hydrocarbon indicators (DHIs) on seismic sections are commonly thought to be diagnostic only of gas. However, oil sands can also generate DHIs such as bright spots and flat events since oils under in‐situ conditions can contain large amounts of solution gas. This dissolved gas substantially decreases the velocity of sound and the density of the oils as compared to measurements of these properties at surface conditions. Hydrocarbon indicators caused by oil sands are investigated by first measuring the elastic properties of an oil as a function of gas‐oil ratio, next, calculating the elastic properties of additional oil compositions under in‐situ conditions using standard pressure‐volume‐temperature (PVT) measurements, and then calculating the compressional velocity in oil‐saturated rocks for several typical oils using Gaasmann’s equation. The potential for seismic anomalies caused by oil‐saturated rocks is higher than thought because the properties of oil under reservoir conditions can differ significantly from those of surface oils. Specifically: 1) The properties of oil depend on its composition: the higher the API gravity and the gas‐to‐oil ratio (GOR), the lower the density and velocity of sound (adiabatic bulk modulus) and the lower the velocity of a rock saturated with the oil. 2) Calculations of oil‐sand velocities using the in situ properties of oils show that areas having light oils and/or poorly consolidated rocks are the most likely areas in which to encounter oil DHIs. Since overpressured areas can have both poorly consolidated rocks and high GOR oils, they are especially prone to large oil responses.

scholarly journals Modeling the vertical soil organic matter profile using Bayesian parameter estimation

2012 ◽  
Vol 9 (8) ◽  
pp. 11239-11292 ◽  
Author(s):  
M. C. Braakhekke ◽  
T. Wutzler ◽  
C. Beer ◽  
J. Kattge ◽  
M. Schrumpf ◽  
...  
Keyword(s):  
Organic Matter ◽  
Parameter Estimation ◽  
Soil Organic Matter ◽  
Soil Carbon ◽  
Mineral Soil ◽  
Bayesian Parameter Estimation ◽  
Additional Information ◽  
Root Litter ◽  
In Situ Conditions

Abstract. The vertical distribution of soil organic matter (SOM) in the profile may constitute a significant factor for soil carbon cycling. However, the formation of the SOM profile is currently poorly understood due to equifinality, caused by the entanglement of several processes: input from roots, mixing due to bioturbation, and organic matter leaching. In this study we quantified the contribution of these three processes using Bayesian parameter estimation for the mechanistic SOM profile model SOMPROF. Based on organic carbon measurements, 13 parameters related to decomposition and transport of organic matter were estimated for two temperature forest soils: an Arenosol with a mor humus form (Loobos, The Netherlands), and a Cambisol with mull type humus (Hainich, Germany). Furthermore, the use of the radioisotope 210Pbex as tracer for vertical SOM transport was studied. For Loobos the calibration results demonstrate the importance of liquid phase transport for shaping the vertical SOM profile, while the effects of bioturbation are generally negligible. These results are in good agreement with expectations given in situ conditions. For Hainich the calibration offered three distinct explanations for the observations (three modes in the posterior distribution). With the addition of 210Pbex data and prior knowledge, as well as additional information about in situ conditions, we were able to identify the most likely explanation, which identified root litter input as the dominant process for the SOM profile. For both sites the organic matter appears to comprise mainly adsorbed but potentially leachable material, pointing to the importance of organo-mineral interactions. Furthermore, organic matter in the mineral soil appears to be mainly derived from root litter, supporting previous studies that highlighted the importance of root input for soil carbon sequestration. The 210Pbex measurements added only slight additional constraint on the estimated parameters. However, with sufficient replicate measurements and possibly in combination with other tracers, this isotope may still hold value as tracer for a SOM transport.

pH Driven self-assembly of aza-BODIPY J-aggregates

2019 ◽  
Vol 23 (04n05) ◽  
pp. 518-525
Author(s):  
Miffy H. Y. Cheng ◽  
Shuozhen Bao ◽  
Gang Zheng ◽  
Juan Chen
Keyword(s):  
Self Assembly ◽  
Structural Changes ◽  
Near Infrared ◽  
Time Window ◽  
Morphological Changes ◽  
Spectral Shifts ◽  
Short Time Window ◽  
J Aggregates ◽  
Ion Effects ◽  
Short Time

A pH-driven self-assembly of a simple aza-BODIPY was discovered in PBS solution, whereby ion-specific J-aggregated nanostructures were generated at very low dye concentration (2.5–20 [Formula: see text]M). The aggregation process was investigated in different conditions (pH, temperature and time) by monitoring absorption spectral shifts and associated nanostructure morphological changes. The pH-driven self-assembly process demonstrated an instantaneous thermodynamic phenomenon associated with three characteristic structures, each with distinctive optical properties. When the sample was first formulated within a short time window, a thermodynamically less stable intermediate with an unusual morphology of triangular nanoplates and broad absorption was observed. The formation of these structures was independent of the ions in PBS solution (Na[Formula: see text], K[Formula: see text], thus indicating that the triangular structure was inherent to the anisotropic structure of aza-BODIPY scaffolds. The second structure associated with a metastable pathway generated a uniform population of spherical nanovesicles, while the third structure, generated through a more thermodynamically stable pathway consisted of fibers. The absorption spectra suggested that both spherical and fiber structures contributed to the J-aggregation band at 735 nm in the near infrared optical spectrum and their population in each formulation was concentration dependent. The results highlighted the significance of ion effects in self-assembly of aza-BODIPY and the mechanistic structural changes of the morphology. Furthermore, this fundamental discovery offers a versatile method for the self-assembly of aza-BODIPY J-aggregates as a new nanoplatform with potential photonic applications.

scholarly journals Rock Surface Fungi in Deep Continental Biosphere—Exploration of Microbial Community Formation with Subsurface In Situ Biofilm Trap

2020 ◽  
Vol 9 (1) ◽  
pp. 64
Author(s):  
Maija Nuppunen-Puputti ◽  
Riikka Kietäväinen ◽  
Lotta Purkamo ◽  
Pauliina Rajala ◽  
Merja Itävaara ◽  
...  
Keyword(s):  
Significant Proportion ◽  
Debaryomyces Hansenii ◽  
Fungal Communities ◽  
Fungal Colonization ◽  
Rock Surface ◽  
Mica Schist ◽  
Deep Subsurface ◽  
Bacterial Phyla ◽  
In Situ Conditions

Fungi have an important role in nutrient cycling in most ecosystems on Earth, yet their ecology and functionality in deep continental subsurface remain unknown. Here, we report the first observations of active fungal colonization of mica schist in the deep continental biosphere and the ability of deep subsurface fungi to attach to rock surfaces under in situ conditions in groundwater at 500 and 967 m depth in Precambrian bedrock. We present an in situ subsurface biofilm trap, designed to reveal sessile microbial communities on rock surface in deep continental groundwater, using Outokumpu Deep Drill Hole, in eastern Finland, as a test site. The observed fungal phyla in Outokumpu subsurface were Basidiomycota, Ascomycota, and Mortierellomycota. In addition, significant proportion of the community represented unclassified Fungi. Sessile fungal communities on mica schist surfaces differed from the planktic fungal communities. The main bacterial phyla were Firmicutes, Proteobacteria, and Actinobacteriota. Biofilm formation on rock surfaces is a slow process and our results indicate that fungal and bacterial communities dominate the early surface attachment process, when pristine mineral surfaces are exposed to deep subsurface ecosystems. Various fungi showed statistically significant cross-kingdom correlation with both thiosulfate and sulfate reducing bacteria, e.g., SRB2 with fungi Debaryomyces hansenii.

scholarly journals Discrete element analysis of the punching behaviour of a secured drapery system: from laboratory characterization to idealized in situ conditions

2021 ◽  
Author(s):  
Antonio Pol ◽  
Fabio Gabrieli ◽  
Lorenzo Brezzi
Keyword(s):  
Mechanical Response ◽  
Steel Wire ◽  
Discrete Element ◽  
Wire Mesh ◽  
Steel Plates ◽  
Loading Conditions ◽  
Element Analysis ◽  
In Situ Conditions ◽  
Wire Meshes

AbstractIn this work, the mechanical response of a steel wire mesh panel against a punching load is studied starting from laboratory test conditions and extending the results to field applications. Wire meshes anchored with bolts and steel plates are extensively used in rockfall protection and slope stabilization. Their performances are evaluated through laboratory tests, but the mechanical constraints, the geometry and the loading conditions may strongly differ from the in situ conditions leading to incorrect estimations of the strength of the mesh. In this work, the discrete element method is used to simulate a wire mesh. After validation of the numerical mesh model against experimental data, the punching behaviour of an anchored mesh panel is investigated in order to obtain a more realistic characterization of the mesh mechanical response in field conditions. The dimension of the punching element, its position, the anchor plate size and the anchor spacing are varied, providing analytical relationships able to predict the panel response in different loading conditions. Furthermore, the mesh panel aspect ratio is analysed showing the existence of an optimal value. The results of this study can provide useful information to practitioners for designing secured drapery systems, as well as for the assessment of their safety conditions.

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