ΑΝΑΚΟΙΝΩΣΕΙΣ
ΕΡΓΑΣΤΗΡΙΟΥ
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Τα μαθήματα αι τα Εργαστήρια για τους νέους φοιτητές θα γίνονται σύμφωνα με το πρόγραμμα της Γραμματείας του Γεωλογικού. Ως κύριο βιβλίο θα χορηγείται το Σύγγραμμα του Καθηγ. Άκη Τσελέντη ΣΥΓΧΡΟΝΗ ΣΕΙΣΜΟΛΟΓΙΑ (Εκδ. Παπασωτηρίου).
Το εργαστήριο θα χορηγήσει το τρέχον Ακαδημαϊκό έτος 2-5 διπλωματικές εργασίες σε ομάδες των 2 ατόμων. Τα θέματα είναι τα ακόλουθα: 1]Μελέτησεισμικής απόκρισης εδαφικών σχηματισμών Βαρθολομιού με την τεχνική του εδαφικού θορύβου (Microtremor Analysis). Η διπλωματική θα εκπονηθεί στα πλαίσια του έργου "Μικροζωνική Μελέτη Βαρθολομιού". Υπάρχει η δυνατότητα να χορηγηθούν επιπλέον αντίστοιχες διπλωματικές για τις πόλεις: α)Αμαλιάδα, β)Ναύπακτο, γ)Μεσολόγγι 2]Σύγκριση μετρήσεων σεισμικής τομογραφίας, cross-hole, και αναστροφής επιφανειακών κυμάτων για τον υπολογισμό ελαστικών ιδιοτήτων. 3]Εκτέλεση μετρήσεων σεισμικής τομογραφίας χρησιμοποιώντας διάφορες σεισμικές πηγές του Εργαστηρίου (Airgun, Sparker, Shear Sparker, Shear Hammer) και αξιολόγηση των αποτελεσμάτων σε σχέση με την ακρίβεια και την διακριτική ικανότητα για τον εντοπισμό αγκύλων και ασθενών ζωνών. Θα επιλεγούν μόνο οι έχοντες γνώσεις Η/Υ
Το εργαστήριο ζητά να προσλάβει πτυχιούχο ΤΕΙ, η Γεωλόγο με γνώσεις Η/Υ για την θέση του αναλυτή σεισμογραμμάτων. Απαραίτητη η κατοχή μέσου μεταφοράς και να είναι μόνιμος κάτοικος Πατρών.
The Lab within its recent activities in the fields of Hydrocarbon exploration, Hydrogeophysics, Soil Dynamics and Seismic Risc has the following three PhD positions: Joint inversion of seismic travel time tomography and first pulse width Magnetotelluric and Self Potential 3D modelling of deep carbonate aquifers Multispectral seismic crosshole tomography processing and neural based target recognition GIS applications in Seismic Risc Assessment. All PhD candidates will have a scholarship and insurance coverage. Candidates from Asia and other non EC countries are wellcome provided they have a strong mathematic-computing background.
The lab has the following PostDoc position sponsored by TOTAL - SHELL on the subject of: Tomographic inversion of first pulse width duration, amplitude and traveltime for assessing resrvoire properties The proposed project uses passive (natural) seismic sources
(earthquakes) and combines the latest travel time and attenuation tomographic
techniques to obtain high resolution images of the sub-surface geologic
structure at
a perspective hydrocarbon site. The objective of the project is to demonstrate that passive
seismic tomography methods can become a new low-cost and environmentally safe investigation
tool, that can be adopted by the oil industry in tectonically active
regions. This will be achieved by focusing to an area which is
selected based on the results of a preliminary seismic investigation and where a
2Km borehole has been drilled and performing the following tasks:
-install a 40-station 3-component, high resolution seismic network over a
200Km2 pilot region to record natural micro-seismicity over a period of 6
months;
-adapt and fine tune the passive tomography methodologies in order to
obtain not only the seismic velocities, but also the seismic attenuation, and to
achieve the highest possible resolution;
-compare with
conventional techniques and existing data, emphasizing the accuracy of
the
obtained results, cost reduction, and environmental benefits;
-attempt to derive reservoir parameters such as the presence of gas and
fluids in the formation from the recorded seismic parameters (e.g. variation of
Poisson’s ratio, quality factor, etc.);
-based on the above, derive field and processing procedures for
increasing the efficiency of this new exploration technique.
Conventional seismic exploration methods represent one of
the most difficult and expensive components of hydrocarbon exploration. Not
surprisingly, in regions featuring complex topography such as fold and thrust
belts (which are also generally characterized by high levels of tectonic
activity), the cost of a conventional 2D seismic line can be of the order
of
$30,000/Km, not mentioning the cost of a 3D survey which can be
prohibited. There are also cases where conventional seismic methods fail
to reveal the underground structure. Most commonly, this occurs where there is
strong attenuation of the seismic energy (e.g., soft surficial geological
strata), or where the subsurface layers screen the deeper layers because of high
contrasting seismic velocities (carbonate outcropping).
The use of a new investigation tool which uses
microearthquakes as seismic sources can be the alternative solution to the problems
described above. In a tectonically active region, this investigation tool can be
used in the initial phases of the field investigation in a manner similar to the
other low cost methodologies (e.g. gravity and magnetics). However, the model
resolution attainable with this technique is by far higher than that which can
be obtained using the other low cost methodologies. Therefore, the improved
model resolution and the fact that the technique resolves seismic velocities
directly, make this approach extremely competitive for the hydrocarbon
exploration business.
-
More
accurate initial identification of the potential hydrocarbon structures on which
to pursue further evaluations.
-
Optimal
design of the seismic reflection lines (i.e., fewer, closer to the target, and
shorter).
-
Drastic
reduction of the exploration costs (at least one order of magnitude).
-
Evaluate
rock properties in a prospect, by utilizing Vp/Vs (velocity ratio)/Poisson’s
ratio.
-
Reliable
data can be obtained from the most mountainous and difficult terrains with no
extra cost.
-
Used
in frontier geopolitical exploration areas, in order to build a pre-project plan
at minimum cost.
The seismic exploration phase during a hydrocarbon
investigation project is one of the most crucial and expensive parts. The basic
concept behind the project is that of replacing artificial seismic sources with
natural ones (microearthquakes) and of using state-of-the art passive tomography
methodologies (both traveltime and amplitude) to image the subsurface.
The goal of this project is to show that in tectonically active
regions, passive seismic tomography can:
-
Reduce
consistently the time-to first-oil
because the results of this methodology can improve significantly the design and
planning of the high resolution 2D seismic lines required to pinpoint the
borehole drilling.
-
Lower
the exploration costs because fewer Km of expensive reflection seismic lines
become necessary, and
-
Dramatically
decrease the environmental impact. The objectives of the project can be summarized as
follows:
1.
Establish
a methodology for data processing in order to extract the relevant information
from both travel times and amplitudes;
2.
Further
develop the existing traveltime and attenuation tomography techniques to reach
the maximum velocity model resolution;
3.
Develop
a protocol for assessing the amount
of model resolution;
4.
Integrate
and compare with conventional methods (electromagnetic, seismic reflection,
gravity);
5.
Correlate
seismic properties (velocity, amplitude) to rock properties such as porosity,
clay content, saturation, partial saturation, stress and pressure, Hydrocarbon
type, temperature, phase transformation, fracture detection. All of the above
parameters characterize the site of interest (reservoir).
6.
Objective
assessment of the passive tomography potentials for hydrocarbon exploration
purposes. |
Το
Εργαστήριο πρόκειται να προτείνει στο Γεωλογικό το Μάθημα
ΓΕΩΦΥΣΙΚΗ ΤΕΧΝΙΚΩΝ ΕΡΓΩΝ
όπου θα παρουσιάζονται εκτός από την βασική θεωρεία και πολλά
παραδείγματα από τεχνικά έργα στα οποία η Γεωφυσική έδωσε λύση. Στην
περίπτωση που δεν εγκριθεί το εν λόγω μάθημα θα δοθεί υπό την μορφή
διαλέξεων.
ΠΡΟΚΥΡΗΞΗ ΘΕΣΗΣ ΑΝΑΛΥΤΗ ΣΕΙΣΜΟΓΡΑΜΜΑΤΩΝ