| CPC E21B 49/10 (2013.01) [E21B 17/1078 (2013.01); E21B 47/01 (2013.01); E21B 47/017 (2020.05); E21B 47/0175 (2020.05); E21B 49/00 (2013.01); G01J 3/0286 (2013.01); G01J 3/0291 (2013.01); G01J 3/18 (2013.01); G01J 3/44 (2013.01); G01J 3/4412 (2013.01); G01N 21/65 (2013.01); G01N 33/24 (2013.01); G01N 33/241 (2013.01); G01V 8/02 (2013.01); G01J 3/0264 (2013.01); G01J 2003/1208 (2013.01)] | 17 Claims |

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1. A method, comprising:
cutting a fresh surface in a wall of a borehole extending through a formation with one or more blades of a downhole tool;
taking a Raman spectroscopy measurement of the fresh surface from within the borehole extending through the formation before the fresh surface is exposed to borehole fluids with a Raman spectroscopy measurement system, the Raman spectroscopy measurement system including:
a light source disposed in a first cavity in an outer surface of a blade of the one or more blades, wherein the first cavity is enclosed by a first window flush with the outer surface of the blade;
a filter disposed in a second cavity in the outer surface of the blade, wherein the second cavity is enclosed by a second window flush with the outer surface of the blade; and
a light detector disposed in the second cavity;
generating a Raman spectrum from the Raman spectroscopy measurement; and
determining kerogen maturity in the formation from the Raman spectrum.
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