Real time cloud based hydraulic fracture monitoring for real

Came across a ppt slide showing some company is doing real time hydraulic fracture monitoring using cloud service. I think it is a neat technique all service companies can have, not just Schlumberger or Halliburton.

Background information:
(1) hydraulic fracturing is a technique to pump high pressurized fluid into petroleum reservoir to enhance oil recovery and at the same time reduce cost
(2) cloud technique is the computing facility offering the horsepower for data crunching and delivering processed results to terminals such as a desktop in a remote office or a smartphone in a manager’s pocket.
(3) the combination of the two enables geoscientists and managers in all scale enterprise to make real time decisions to assist field operations. Time and money are significantly reduced. Thousand hours or days of CPU time is no longer the privilege of a few rich corporations.

Two slides are here:

cloud based realtime hydraulic fracture monitoring

cloud based realtime hydraulic fracture monitoring


The original ppt is here

Use seismic Interferometry, reverse time migration, reverse time source imaging, time reversal mirror, back-projection method, back-propagation method, diffraction stacking, and adjoint method, to locate micro-earthquake

Believe it or not, when you are locating microseismic events without picking the arrivals you may be using one of the above techniques. More importantly they are actually describing the same thing (more or less) in the application of locating micro-earthquakes. Here is why (non-math version):
(1) Seismic Interferometry: is to calculate a green’s function by correlating a complex conjugate green function with another green’s function. In time domain, the complex conjugate green’s function is to back-propagate the other green’s function into the medium. If the complex conjugate green’s function is a natural green’s function recorded from the real medium, you are doing seismic interferometry.
(2) Reverse time migration: if the complex conjugate green’s function is based on a velocity model and the other green’s function is related to the reflection response of the medium, you are doing reverse time migration started since McMechan 1983.
(3) Reverse time source imaging: if the complex conjugate green’s function is based on a velocity model and the other green’s function is related to the transmission response of the medium, you are doing reverse time source imaging. In other field, people call it time reversal method, time reversal acoustics, or call the device that can reverse time signal time reversal mirror. Someone even finds that adding a “sink” (the opposite of source) at the original source location, super-resolution can be achieved. In other words, in a dark night you see a car 1~2 km away approaches you with its light on, you only see one big light not two till it gets closer. Now if your eye and brain can do time reverse, you see two lights crystal clear even when the car is still 1~2km away from you. Isn’t that cool? But you need more than your eye and brain to achieve this super-resolution.
(4) Time reversal mirror: see (3)
(5) Back-projection method: you use ray-tracing method to calculate the complex conjugate green’s function. In other words, you are lightening up the medium, the wavelength is zero and likely you only use the first arrivals. Some specific ray-tracing methods may give you later arrivals. So you can select what late arrivals include. The more the better, and of course, the complex conjugate green’s function from the natural medium include all multiples.
(6) Back-propagation method: the function of the complex conjugate green’s function, see (1).
(7) Diffraction stacking: it works like this, (a) define a source location, (b) use ray-tracing to calculate its first arrivals for all sensors, (c) sum up the amplitude along the arrival time curve. Obviously you are using ray-tracing to do the back-projection, so see (5).
(8) Adjoint method: it uses a model based complex conjugate green’s function and back-propagate the difference between modeled data and observed data into the medium, till the difference is reduced to a certain level. At the beginning, you have no idea about the source, so you just back-propagate the observation. Obviously, its first iteration is (3). After the first iteration, you have some ideas about the source so you add a sink at the estimated location and repeat back-propagation, this is similar to (4) with a sink. If it converged, you just did reverse time source inversion. If you are happy with the first iteration, you just finished the reverse time source imaging. The rest is somewhere in between, and I guess we don’t have a name for each of them yet. But considering that we already coined 8 different key words for basically the same thing, we will coin more fancy words for them in no time. Just keep an eye on the literature.

In summary, you are using seismic Interferometry, reverse time migration, reverse time source imaging, time reversal mirror, back-projection method, back-propagation method, diffraction stacking, and adjoint method, to locate micro-earthquakes; you are just unaware of it.

My weblog has a completely new face and support multi-languanges

1. The WordPress has been upgraded, and now provides a much better appearance.
2. Google language plugin has been installed and now support mulch-languages. Pick your favorite language to view this weblog using the menu on the right corner.

happy blogging…
快乐的博客…
快樂的博客…
幸せブログ…
blogging heureux…
Viel Spaß beim Bloggen….
Buon blogging…
hạnh phúc blog…
การเขียนบล็อกมีความสุข…