US 11,946,360 B2
Determining the likelihood and uncertainty of the wellbore being at a particular stratigraphic vertical depth
Stefan Maus, Boulder, CO (US); Alexander Michael Mitkus, Denver, CO (US); and Timothy William Gee, Englewood, CO (US)
Assigned to Magnetic Variation Services, LLC, Denver, CO (US)
Filed by Magnetic Variation Services, LLC, Denver, CO (US)
Filed on May 7, 2020, as Appl. No. 16/869,385.
Application 16/869,385 is a continuation in part of application No. 16/821,397, filed on Mar. 17, 2020.
Claims priority of provisional application 62/985,224, filed on Mar. 4, 2020.
Claims priority of provisional application 62/932,134, filed on Nov. 7, 2019.
Claims priority of provisional application 62/844,488, filed on May 7, 2019.
Prior Publication US 2020/0355066 A1, Nov. 12, 2020
Int. Cl. E21B 44/00 (2006.01); E21B 7/04 (2006.01); E21B 47/04 (2012.01); G01B 21/18 (2006.01); G05B 13/04 (2006.01)
CPC E21B 47/04 (2013.01) [E21B 7/04 (2013.01); E21B 44/00 (2013.01); G01B 21/18 (2013.01); G05B 13/04 (2013.01); G05B 13/041 (2013.01); E21B 2200/20 (2020.05)] 31 Claims
OG exemplary drawing
 
1. A computer system, comprising:
a processor enabled to access memory media storing instructions executable by the processor for:
for a subject wellbore, generating a misfit curve between stratigraphic vertical depth of an offset wellbore, SVDow and a measured depth of the subject wellbore, MDsw;
based on the misfit curve, calculating a plurality of likelihoods that respective target measured depths for the subject wellbore, TMDsw, are equal to or within a tolerance of respective stratigraphic vertical depths of the subject wellbore, SVDsw, respectively corresponding to a plurality of interpretations of stratigraphic vertical depth of the subject wellbore, SVDsw based on a subject well log for the subject wellbore and an offset well log respectively for at least one offset wellbore, wherein the interpretations are paths through the misfit curve;
assigning, to the subject wellbore, a likelihood calculated using a starting measured depth of the subject wellbore, MDsw1, and the target measured depth for the subject wellbore, TMDsw, from the plurality of likelihoods that a target measured depth for the subject wellbore, TMDsw, is equal to or within a tolerance of a stratigraphic vertical depth of the subject wellbore, SVDsw, associated with the target measured depth for the subject wellbore, TMDsw; and
based on the misfit curve and the assigned likelihood, adjusting at least one drilling parameter during drilling of the subject wellbore.