Patent ID: 9228430
Filing Date: 2016-01-05
CPC Classification: E21B

Claim Text:
1. A method for identifying a change in cuttings density while drilling, the method comprising: (a) rotating a drill bit in a subterranean wellbore, the drill bit being deployed in a drill string including first and second axially spaced along string pressure sensors, said rotating operative to drill the wellbore and produce formation cuttings which are transported to a surface location via circulating drilling fluid in a wellbore annulus; (b) using the first and second along string pressure sensors to make first and second subsurface annular pressure measurements while drilling in (a); (c) transmitting the annular pressure measurements to a processor; (d) processing the annular pressure measurements to compute an annular interval density of the circulating drilling fluid while drilling in (a); (e) repeating (b), (c), and (d) and monitoring the computed annular interval densities with time while drilling in (a); and (f) evaluating a change in the annular interval densities computed in (d) as an indicator of a change in a density of the formation cuttings.