Has anyone done this? Seismic

MightyMoe · 2014-10-25T17:10:00Z

I have a client that is trying to "retract" a 1950's era seismic survey. The first task I did for them was to locate all the P&A wells. Easy enough to do, but what I found "shocked" them, the holes weren't near where the record showed them to be (imagine that, they were all record 660' x 1980' from section lines) and the elevations were all over the place. So putting together an underground map they realized that maybe the seismic lines also had problems. I only have a map of the shot points (where they set a charge) along the lines and a list of the points with a nearest degree bearing and nearest 10 foot distance between the points. I was able to rubber sheet in the map since it has section lines on it and I've located them and when I did the main east-west lines shot points hit on an old dozer scar that appears on photos. This is clearly the north location of the east-west line, but the east-west position of the points is really a guess. When I put my points on the ground, they simply don't relate to the old given elevations and shifting them doesn't help. It could be that the elevations for the seismic and well locations were done with an altimeter, that's my guess anyway. I wondered if anyone had seismic experience. Was an altimeter SOP for those surveys, and also for well locations?The geologist with me was sure we would find evidence of the old bore holes, but we found nothing. No doubt they tied to section corners but the company is the gate keeper of the records and can't find any record of ties and I'm not "allowed" to look at the records, they just dole out info a little at a time. I've explained that section ties had to have been done cause there would have been no other way to draw the section lines as close as they did in 1950 without doing it. The drawings don't show any ties but the section lines look good to me. Clearly the elevations are very crude, usually between 50-100' higher than mine but all over the place. And elevations are the critical data point.

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Strictly Surveying

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MightyMoe

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There is a set of first order bench marks a mile south, they run east west along a highway and "may" have been used, the 29 elevation is about 2,
.5' lower than the 88 elevations. But the shot points are 25-100 ft high, kinda all over the place.

Posted : October 27, 2014 8:28 pm

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Has anyone done this? Seismic

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