[Proj] Deepwater Horizon. Where is the bottom of the well?

[Clifford J Mugnier]

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.
 
I do not know if IXsea has any downhole applications yet, though ...
 
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.
 
Clifford J. Mugnier, C.P., C.M.S.
Chief of Geodesy,
Center for GeoInformatics
Department of Civil Engineering 
Patrick F. Taylor Hall 3223A
LOUISIANA STATE UNIVERSITY 
Baton Rouge, LA  70803
Voice and Facsimile:  (225) 578-8536 [Academic] 
Voice and Facsimile:  (225) 578-4578 [Research] 
Cell: (225) 238-8975 [Academic & Research]
Honorary Life Member of the 
Louisiana Society of Professional Surveyors 
Fellow Emeritus of the ASPRS 
Member of the Americas Petroleum Survey Group


________________________________

From: proj-bounces at lists.maptools.org on behalf of Karney, Charles
Sent: Mon 14-Jun-10 13:08
To: PROJ.4 and general Projections Discussions
Subject: [Proj] Deepwater Horizon. Where is the bottom of the well?



Here are some questions related to the Deepwater Horizon accident and
the drilling of relief wells for the readers of this list in the oil
industry.

(1) What is the method of determining the position of an instrument 3km
down a well?  Is it seismic, dead reckoning, or what?

(2) What is the typical absolute accuracy of the measured position,
horizontally and vertically (and, if possible, specifically with
reference to the leaking well)?  What is the *relative* accuracy?
(I.e., I can imagine that the absolute accuracy is poor because of the
unknown properties of the intervening rock.  However, it might be
possible to "find" the same position when drilling the relief well if
the same method is used.)

(3) Is the drill bit instrumented to return the position?  How?  Or does
a separate logging package need to be inserted into the well?  At what
frequency would this be done?

I can piece together some of the answers from wikipedia.  However, maybe
I can get more autoritative and more specific answers from this list.

          --Charles

--
Charles Karney <ckarney at sarnoff.com>
Sarnoff Corporation, Princeton, NJ 08543-5300

Tel: +1 609 734 2312
Fax: +1 609 734 2662
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