<HTML dir=ltr><HEAD><TITLE>[Proj] Deepwater Horizon. Where is the bottom of the well?</TITLE>
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<DIV dir=ltr><FONT color=#000000 size=2 face="Times New Roman">Inertial systems and their accuracies degrade as a function of time, so it's pretty easy to calculate the expected error envelope in all three components. Numerous ZUPTs (Zero velocity Update PoinTs) can help. The fiber optic ring lasers with absolutely zero moving parts, although more expensive, are the best alternative to the ring laser gyros that indeed have one moving part.</FONT></DIV>
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<DIV dir=ltr><FONT size=2>I do not know if IXsea has any downhole applications yet, though ...</FONT></DIV>
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<DIV dir=ltr><FONT size=2>I used to sell UTM/State Plane transformation software that would run on an HP-41 calculator to Directional Drilling companies in the Gulf of Mexico about 25 years ago. They were quite concerned with correcting for magnetic declination and Grid System convergence angles back then before small inertial strapdown packages were available for non-DoD applications.</FONT></DIV>
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<DIV><FONT color=#000000 size=2 face="Times New Roman"><SPAN style="FONT-SIZE: 10pt">Clifford J. Mugnier, C.P., C.M.S.<BR>Chief of Geodesy,</SPAN></FONT></DIV>
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<DIV><FONT color=#000000 size=2 face="Times New Roman"><SPAN style="FONT-SIZE: 10pt"><SPAN style="FONT-VARIANT: small-caps; FONT-FAMILY: 'Times New Roman','serif'; COLOR: black; FONT-SIZE: 10pt; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 'Times New Roman'; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: EN-US"></SPAN>Department of Civil Engineering <BR>Patrick F. Taylor Hall 3223A<BR><STRONG>LOUISIANA STATE UNIVERSITY</STRONG> <BR>Baton Rouge, LA 70803<BR>Voice and Facsimile: (225) 578-8536 [Academic] <BR>Voice and Facsimile: (225) 578-4578 [Research] </SPAN></FONT></DIV>
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<FONT size=2 face=Tahoma><B>From:</B> proj-bounces@lists.maptools.org on behalf of Karney, Charles<BR><B>Sent:</B> Mon 14-Jun-10 13:08<BR><B>To:</B> PROJ.4 and general Projections Discussions<BR><B>Subject:</B> [Proj] Deepwater Horizon. Where is the bottom of the well?<BR></FONT><BR></DIV>
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<P><FONT size=2>Here are some questions related to the Deepwater Horizon accident and<BR>the drilling of relief wells for the readers of this list in the oil<BR>industry.<BR><BR>(1) What is the method of determining the position of an instrument 3km<BR>down a well? Is it seismic, dead reckoning, or what?<BR><BR>(2) What is the typical absolute accuracy of the measured position,<BR>horizontally and vertically (and, if possible, specifically with<BR>reference to the leaking well)? What is the *relative* accuracy?<BR>(I.e., I can imagine that the absolute accuracy is poor because of the<BR>unknown properties of the intervening rock. However, it might be<BR>possible to "find" the same position when drilling the relief well if<BR>the same method is used.)<BR><BR>(3) Is the drill bit instrumented to return the position? How? Or does<BR>a separate logging package need to be inserted into the well? At what<BR>frequency would this be done?<BR><BR>I can piece together some of the answers from wikipedia. However, maybe<BR>I can get more autoritative and more specific answers from this list.<BR><BR> --Charles<BR><BR>--<BR>Charles Karney <ckarney@sarnoff.com><BR>Sarnoff Corporation, Princeton, NJ 08543-5300<BR><BR>Tel: +1 609 734 2312<BR>Fax: +1 609 734 2662<BR>_______________________________________________<BR>Proj mailing list<BR>Proj@lists.maptools.org<BR><A href="http://lists.maptools.org/mailman/listinfo/proj">http://lists.maptools.org/mailman/listinfo/proj</A><BR></FONT></P></DIV></BODY></HTML>