Search found 66 matches

by Seismic101
Thu Apr 12, 2018 12:28 am
Forum: Oil and Gas Exploration
Topic: Using stacking velocity for time-depth conversion
Replies: 0
Views: 916

Using stacking velocity for time-depth conversion

Hi. I know a little about stacking velocity i. - Is it a "real velocity"? - Is it interval or average velocity things? Does it equal any of them? - Can we use for time-depth conversion if we don't have other velocity measurements or even a sonic log? - What if we have other velocity measurements, do...
by Seismic101
Thu Nov 16, 2017 11:05 am
Forum: Oil and Gas Exploration
Topic: Accurate job title for geoscience data specialist
Replies: 1
Views: 611

Accurate job title for geoscience data specialist

What is the accurate job title for a senior geophysicist who takes care of all kinds of geoscience data (management, security, QC, etc.)
by Seismic101
Thu Nov 16, 2017 6:55 am
Forum: Oil and Gas Exploration
Topic: Role of Geophysics (seismic) in the development of oil fields
Replies: 4
Views: 830

Re: Role of Geophysics (seismic) in the development of oil fields

Thanks, everyone! Very helpful!
GuyM wrote:
Wed Nov 15, 2017 4:48 pm
... The goal is usually refinement and update off the reservoir model being used in production ...
How else do they do this if seismic is not available?
by Seismic101
Thu Nov 16, 2017 6:46 am
Forum: Oil and Gas Exploration
Topic: Managing Geoscience data
Replies: 1
Views: 553

Managing Geoscience data

How do you start about managing Geoscience data for a client whose data archives are not well maintained (a complete disarray actually!)? Data files (seismic, well measurements, location data, surface Geology data, etc.) need to be collected, classified, quality-controlled, renamed in a standard way...
by Seismic101
Wed Nov 15, 2017 7:18 am
Forum: Oil and Gas Exploration
Topic: Role of Geophysics (seismic) in the development of oil fields
Replies: 4
Views: 830

Role of Geophysics (seismic) in the development of oil fields

Geophysics is mainly associated with exploration activities. I would like to know how Geophysicists get involved in activities related to the development of oil field? Any resources on this would be highly appreciated.
by Seismic101
Tue Oct 24, 2017 4:37 am
Forum: Oil and Gas Exploration
Topic: Cost of 2D/3D seismic processing
Replies: 4
Views: 1562

Re: Cost of 2D/3D seismic processing

Thanks, GuyM- very useful. So it is different from how VSP data is processed. We normally charge by interval (i.e., the depth of the well) and the number of traces being processed, and adding a fixed flat charge on top of that plus printing/packaging costs. (PS: I haven't been here for a while! I li...
by Seismic101
Mon Oct 23, 2017 11:36 am
Forum: Oil and Gas Exploration
Topic: Cost of 2D/3D seismic processing
Replies: 4
Views: 1562

Cost of 2D/3D seismic processing

How much does 2D/3D seismic data processing cost? How do they calculate it?
by Seismic101
Fri Mar 17, 2017 12:17 pm
Forum: Oil and Gas Exploration
Topic: Do we have a SeismicLab forum on the web?
Replies: 0
Views: 639

Do we have a SeismicLab forum on the web?

I have recently started using SeismicLab, a set of Matlab codes to process seismic data. I used to work with Seismic Unix. This package supports data in SU format (as well as SEGY) and the commands are somewhat similar to that of SU. I could not find any support forums online. I thought maybe you ca...
by Seismic101
Fri Mar 17, 2017 11:53 am
Forum: Oil and Gas Exploration
Topic: Ghost reflections travel time and frequency
Replies: 3
Views: 1111

Re: Ghost reflections travel time and frequency

Thanks for the comprehensive response and for sharing the amazing GLOBE Claritas blog- I bookmarked it! treating this delay time as a time period (T) What is the science behind this assumption? Or is it just empirical? I was thinking maaaayyyyybe since the energy goes upward (from the source) then r...
by Seismic101
Fri Mar 17, 2017 10:27 am
Forum: Oil and Gas Exploration
Topic: Where do we plot the stacked seismic trace?
Replies: 3
Views: 909

Re: Where do we plot the stacked seismic trace?

Yes. We plot that trace at the CDP location " Thanks so much for the validation. to be more accurate the "common mid point" Why? The reflection came the CDP subsurface location, right? The CMP is the surface projection of the CDP, right? Also, since migration shifts subsurcace reflection points bot...
by Seismic101
Tue Mar 14, 2017 2:13 pm
Forum: Oil and Gas Exploration
Topic: How do we remove refracted arrivals from data and when?
Replies: 2
Views: 879

How do we remove refracted arrivals from data and when?

In the field we record airwaves, ground rolls (same as direct arrivals?), refracted, and reflected arrivals. Since only reflected arrivals are used in reflection seismology, how do we remove the rest? I read that velocity filters are used. What are they? And At what stage in the processing do we app...
by Seismic101
Tue Mar 14, 2017 1:35 pm
Forum: Oil and Gas Exploration
Topic: Where do we plot the stacked seismic trace?
Replies: 3
Views: 909

Where do we plot the stacked seismic trace?

This is basic but I am not I get it right. So, we have numerous shots that send seismic energy that reflect at the same subsurface CDP, and then the reflected energy is recorded at different receivers. After that we correct and stack all traces to produce one trace . Where do plot (or place) that tr...
by Seismic101
Tue Mar 14, 2017 1:30 pm
Forum: Oil and Gas Exploration
Topic: Ghost reflections travel time and frequency
Replies: 3
Views: 1111

Ghost reflections travel time and frequency

I have been reading a course about seismic data processing and I stumbled upon this paragraph: "Given that the actual ray paths will have more curvature than those shown in the diagram, the ray paths from the shot to the surface and back down again will be almost vertical.  If we assume that they ar...
by Seismic101
Wed Nov 23, 2016 10:14 am
Forum: Oil and Gas Exploration
Topic: What type of decon does not use least square filter?
Replies: 1
Views: 704

What type of decon does not use least square filter?

hello- this question comes straight from my professor and I am not sure what he wants: he is asking us about a type of deconvolution that does not use 'least squares' filter. Spiking and predictive decon both use least square. Is their a type of decon that uses other filters?
by Seismic101
Mon Nov 21, 2016 6:18 am
Forum: General Geophysics and Geoscience
Topic: Why do critically refracted seismic rays reflect upward?
Replies: 1
Views: 685

Why do critically refracted seismic rays reflect upward?

hello- when the angle of incidence equals the critical angle we get a critical refraction in which the ray path travels along the interface. Why does this path, at some point, reflect back to the surface? Why not just continue forward until it fully attenuates?
by Seismic101
Sat May 21, 2016 2:36 am
Forum: General Geophysics and Geoscience
Topic: Dependence of seismic velocity on frequency
Replies: 1
Views: 838

Dependence of seismic velocity on frequency

Hi there - we know we can get interval seismic velocity from checkshots or sonic logs. However, both are acquired at a different frequency with sonic frequency is very much higher that checkshot ad VSP. That means internal velocity calculated from sonic will always be much higher than that calculate...
by Seismic101
Sat May 07, 2016 4:28 am
Forum: General Geophysics and Geoscience
Topic: Equation of triangulation method to locate earthquake epicenter
Replies: 3
Views: 1532

Re: Equation of triangulation method to locate earthquake epicenter

How do you think they obtain P and S velocity information in earthquake seismology? IS that done in a similar manner to what we do in reflection seismology?
by Seismic101
Mon May 02, 2016 4:23 pm
Forum: General Geophysics and Geoscience
Topic: Why Python beats MATLAB for geophysics
Replies: 1
Views: 895

Re: Why Python beats MATLAB for geophysics

I use matlab for two reasons: 1- Easy with tons of built-in functions 2- There are many ready-to-use codes developed by Geophysicists, and that makes my life easier. Problem w/ Matlab it's not free- for example I need the seismic processing toolbox but I cannot afford it. Can't find a cracked copy e...
by Seismic101
Mon May 02, 2016 4:10 pm
Forum: General Geophysics and Geoscience
Topic: Equation of triangulation method to locate earthquake epicenter
Replies: 3
Views: 1532

Equation of triangulation method to locate earthquake epicenter

Hello, I am doing some research about how to locate earthquake epicenter using triangulation (or trilateration?) method. I am trying to convert this concept into a Matlab code. My friends told me there is an equation that uses the P and S wave arrival times separation to calculate the radii of the c...
by Seismic101
Mon May 02, 2016 3:59 pm
Forum: Oil and Gas Exploration
Topic: What does "charge related" mean?
Replies: 2
Views: 907

Re: What does "charge related" mean?

"Charge" means "hydrocarbon charge" In this context it would mean that there was a "trap" of some kind (structural or stratigraphic) with a decent "seal" rock that could support a nice hydrocarbon column under pressure, and that a good reservoir interval with reasonable porosity was encountered.......
by Seismic101
Tue Apr 26, 2016 5:13 pm
Forum: Oil and Gas Exploration
Topic: What does "charge related" mean?
Replies: 2
Views: 907

What does "charge related" mean?

Hi all- "The vast majority (>80%) of the prospects the industry have drilled are dry holes, and most are charge related." What does "charge related" mean here? Googled it with no luck!
by Seismic101
Sat Mar 26, 2016 5:02 pm
Forum: General Geophysics and Geoscience
Topic: Is PHASE constant for periodic waves?
Replies: 1
Views: 784

Is PHASE constant for periodic waves?

Hi everyone - I am having "fun" with Fourier transforms this week, but I stumbled upon this question. I drew a signal (S) using the formula S(t)=A*cos(2*pi*f*t+p) where: A = Amplitude (constant) f= Frequency (constant) t= Time (changing) p= Phase My question is about Phase. Is the phase constant for...
by Seismic101
Sat Mar 26, 2016 4:09 am
Forum: Oil and Gas Exploration
Topic: petroWEB Announces the Launch of globalseismiclibrary.com, A Free Access Seismic Data Library
Replies: 0
Views: 745

petroWEB Announces the Launch of globalseismiclibrary.com, A Free Access Seismic Data Library

DENVER--(BUSINESS WIRE)--petroWEB Inc. today announced Global Seismic Library (GSL) will now be available as a free service via www.globalseismiclibrary.com. GSL is a global catalog of commercial multi-client seismic and gravity/magnetic data coverage. Now, rather than spending hours searching for a...
by Seismic101
Fri Mar 25, 2016 12:48 pm
Forum: Oil and Gas Exploration
Topic: Why don't we always see 'fault plane reflection' on seismic sections
Replies: 1
Views: 702

Why don't we always see 'fault plane reflection' on seismic sections

Hi- I have been working with multiple datasets with faults. I have observed that some faults planes have seismic reflections along them but some don't, why is that?
by Seismic101
Thu Mar 03, 2016 4:52 pm
Forum: General Geophysics and Geoscience
Topic: Reservoir Geomechanics course from Stanford
Replies: 0
Views: 3368

Reservoir Geomechanics course from Stanford

Hi, I have taken this MOOC about Reservoir Geomechanics course from Stanford before and thought it was very interesting. If interested, here is the link to enroll http://online.stanford.edu/course/clone-reservoir-geomechanics?utm_source=iContact&utm_medium=email&utm_campaign=Stanford%20Online&utm_co...