Abstract: A first method is provided for determining a lithology of a subterranean formation into which a wellbore has been drilled. The method includes receiving a set of measurement logs including one or more measurement logs, each representing a measured characteristic of the wellbore plotted according to depth. The method also includes segmenting the wellbore into regions based on identified change of trend in one or more of the measurement logs of the set, and sub-segmenting at least one region into zones based on detection of appearance or disappearance of a rock type in the cuttings percentage log, The method also includes determining, in each zone, a location, length and rock type of one or more layers based on a total percentage of each rock type in the zone in the cuttings percentage log and at least one of the additional measurement logs.

Abstract: A method is provided for determining a lithology of a subterranean formation into which a wellbore has been drilled. The method includes receiving a set of measurement logs including one or more measurement logs, each representing a measured characteristic of the wellbore plotted according to depth. The method also includes segmenting the wellbore into regions based on identified change of trend in one or more of the measurement logs of the set, and sub-segmenting at least one region into zones based on detection of appearance or disappearance of a rock type in the cuttings percentage log, The method also includes determining, in each zone, a location, length and rock type of one or more layers based on a total percentage of each rock type in the zone in the cuttings percentage log and at least one of the additional measurement logs.

Abstract: The disclosure relates to a method for estimating a transit time of an element circulating in a borehole during the drilling of the borehole. The transit time is representative of a time period for the element to move from the bottom of the borehole to its exit at the surface. The method comprises measuring a plurality of drilling parameters, computing a first signal of a first indicator based on a first set of measured drilling parameters and a second signal of a second indicator based on a second set of measured drilling parameters versus time. The first indicator is representative of a first type of events happening at the bottom of the borehole and the second indicator is representative of a second type of events happening at the exit of the borehole linked to the first type of events. The method also comprises characterizing a correlation between the first and second signals and determining a shift between the first and second signals. An estimated transit time is then determined from the shift.

Abstract: The disclosure relates to a first method for determining a lithology of a subterranean formation into which a wellbore has been drilled. The method comprises receiving a set of measurement logs comprising one or more measurement logs, each representing a measured characteristic of the wellbore plotted according to depth. The measured characteristic include at least cuttings percentage and one or more additional measured characteristics. The method also includes segmenting the wellbore into regions based on identified change of trend in one or more of the measurement logs of the set, and sub-segmenting at least one region into zones based on detection of appearance or disappearance of a rock type in the cuttings percentage log, The method also includes determining, in each zone, a location, length and rock type of one or more layers based on a total percentage of each rock type in the zone in the cuttings percentage log and at least one of the additional measurement logs.

Abstract: A method includes receiving information during a drilling operation for a drillstring disposed in a bore in a formation; estimating uncertainty associated with the information; analyzing at least a portion of the information using a physics-based model to generate a result; computing, via a Bayesian network, a risk probability of the drilling string sticking in the bore in the formation based at least in part on the result and the estimated uncertainty; and, based at least in part on the risk probability, issuing a signal.

Abstract: The disclosure relates to a method for estimating a transit time of an element circulating in a borehole during the drilling of the borehole. The transit time is representative of a time period for the element to move from the bottom of the borehole to its exit at the surface. The method comprises measuring a plurality of drilling parameters, computing a first signal of a first indicator based on a first set of measured drilling parameters and a second signal of a second indicator based on a second set of measured drilling parameters versus time. The first indicator is representative of a first type of events happening at the bottom of the borehole and the second indicator is representative of a second type of events happening at the exit of the borehole linked to the first type of events. The method also comprises characterizing a correlation between the first and second signals and determining a shift between the first and second signals. An estimated transit time is then determined from the shift.