<br><font size=2 face="sans-serif">Thanks. Very interesting.</font>
<br>
<br>
<br>
<br>
<br>
<table width=100%>
<tr valign=top>
<td><font size=1 color=#5f5f5f face="sans-serif">From:</font>
<td><font size=1 face="sans-serif">"Clifford J Mugnier" <cjmce@lsu.edu></font>
<tr valign=top>
<td><font size=1 color=#5f5f5f face="sans-serif">To:</font>
<td><font size=1 face="sans-serif">"PROJ.4 and general Projections
Discussions" <proj@lists.maptools.org></font>
<tr valign=top>
<td><font size=1 color=#5f5f5f face="sans-serif">Date:</font>
<td><font size=1 face="sans-serif">06/14/2010 01:05 PM</font>
<tr valign=top>
<td><font size=1 color=#5f5f5f face="sans-serif">Subject:</font>
<td><font size=1 face="sans-serif">Re: [Proj] Deepwater Horizon. Where
is the bottom of the well?</font>
<tr valign=top>
<td><font size=1 color=#5f5f5f face="sans-serif">Sent by:</font>
<td><font size=1 face="sans-serif">proj-bounces@lists.maptools.org</font></table>
<br>
<hr noshade>
<br>
<br>
<br><font 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>
<br><font size=3> </font>
<br><font size=2>I do not know if IXsea has any downhole applications yet,
though ...</font>
<br><font size=3> </font>
<br><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>
<br><font size=3> </font>
<br><font size=2 face="Times New Roman">Clifford J. Mugnier, C.P., C.M.S.<br>
Chief of Geodesy,</font>
<br><font size=2 face="Times New Roman"><b>Center for GeoInformatics</b></font>
<br><font size=2 face="Times New Roman">Department of Civil Engineering
<br>
Patrick F. Taylor Hall 3223A<b><br>
LOUISIANA STATE UNIVERSITY</b> <br>
Baton Rouge, LA 70803<br>
Voice and Facsimile: (225) 578-8536 [Academic] <br>
Voice and Facsimile: (225) 578-4578 [Research] </font>
<br><font size=2 face="Times New Roman">Cell: (225) 238-8975 [Academic
& Research]<br>
Honorary Life Member of the <br>
Louisiana Society of Professional Surveyors <br>
Fellow Emeritus of the ASPRS <br>
Member of the Americas Petroleum Survey Group</font>
<br><font size=3><br>
</font>
<hr><font size=2 face="Tahoma"><b>From:</b> proj-bounces@lists.maptools.org
on behalf of Karney, Charles<b><br>
Sent:</b> Mon 14-Jun-10 13:08<b><br>
To:</b> PROJ.4 and general Projections Discussions<b><br>
Subject:</b> [Proj] Deepwater Horizon. Where is the bottom of the well?</font><font size=3><br>
</font>
<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>
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