Presentation on theme: "In the next series I present this set of cutouts and try to explain that each shows a refraction event that was lifted off. To see the events on the full."— Presentation transcript:
In the next series I present this set of cutouts and try to explain that each shows a refraction event that was lifted off. To see the events on the full screen, each gather trace had to be shifted by the amount computed from the linear refraction slope illustrated on the previous slide. These slopes are very extreme (ranging upwards to a couple thousand samples per spread). As I said, without correction you wouldn’t see the events at all, yet here they show their intractable truth. I am sure this explains why nobody has done this type of removal before. In any case I cut them out to save space. I just chose these few (out of the hundreds the system lifted off) to make the following crucial points: 1. No shaping after the fact was used, so, as I say above, the mere presence of these obvious events, way into the spread, is firm logical proof that they are coherent noise and that they will affect the stack. The fact that my logic does not see them on it’s next iteration is internal verification that they have all been effectively removed. This passes the programmer honesty test. 2.The last 5 start from within the band of noise the industry commonly attributes to ground roll. As the system removes event after event, this strong inside band gets eventually (almost) eliminated. Again this proves this overpowering energy is traveling vertically through the section (shear wave) rather than along the surface (ground roll). So this is what my logic removes from the gathers. I mentioned the nature of the task was such that all the shot points affecting a gather had to be treated before final answers could be prepared (and that is a bunch). Watching the system removing tons of energy from the data made me wonder if anything would be left. To find out we now jump into those final results and see the answer is a strong yes! Just keep in mind that the detected noise was generally a lot stronger than the signal, even way into the spread.
A deep well to the south of this Louisiana salt dome project project indicates that the prolific shale play strata I show below extends into this area. The well log match comparison comes from work I did up North. The deep stratigraphic pinch-out we see on my noise removal results (to the right) does not even appear on the unresolved input. There’s no way my system could have invented that. No one thought to tell my system this was a salt dome project. It took it upon itself to delineate the outlines of the dome. The green delimiter is mine, of course. In the main results report you will see many examples where noise loops over this boundary. I have included one on the final slide here. At interpretation time what the system takes out is often as important as what it uncovers. The next slide continues this thought. Honest continuity is another form of proof. While migration mixes heavily, every trace here is completely independent, They all go through the same manipulations, but never are aware what is going on next door. So when you see strong events that did not even show up before, and when these events make great geologic sense there evolves a truth that defies words. What is even more crucial is the knowledge of how much energy was lifted off before these reflections became visible.
Closing out the double intro – To begin, the green delineation line is in the same place on both. I just cut off the rest of the salt to save space. So let me just cover several points of interest. 1. Unfortunately the strong apparent dips at the edge of the dome were the geologists target. The system threw them out to his intense displeasure. 2. Careful study shows the dips and the events are not the same. This introduces the problem of close overlap of noise and signal, probably the primary challenge to the logic. 3. Point 2 applies here in spades (meaning extremely). Here we see the noise continuing into no-mans land. 4. Both points strongly apply here.To the left of the demarcation, where there is virtually nothing showing on the input, our results are strong. To the right we see nothing, meaning the input was pure noise. Now, reasonable people should see we are dealing with a major discovery here – one that opens new exploration possibilities. (at least that is how it seems to me.)
Allow them time to load! A PowerPoint compendium of seismic topics Basic reflection theory the experts seemed to have missed. Inversion and integration – the all important sonic log simulation. Coherent noise background – an explanation of types. Removal of coherent noise on Gulf Coast – a breakthrough. Vibroseis de-noising – another (but similar) breakthrough. Strike slip faulting – salt dome association – new thinking. North Sea strike slip interpretation – the importance of resolution. About Paige - MS in geology,spent 7 years in Venezuela for Mobil,& then Phillips Maracaibo interpretation found Phillips’ major field there. Back to states, joined Phillips computing, became project manager for exploration. Hired by Western Geo. To start digital operations in Shreveport. Wrote first predictive deconvolution program that put Western on the map in digital processing (and formed the non-linear basis for later ADAPS software), After brief sojourn in commercial processing (where he wrote a table driven programming system), joined Dresser Olympic as both manager of processing and of research. Went on his own to start non=linear development. Consulting package consists of Paige’s personal time, his open-ended software and use of his processing hardware. Unless full segy detail is requested (segy output), the product is a series of PowerPoint studies. He can be reached at