Abstract: A method for characterizing a subsurface interval where drilling fluid is being lost includes receiving surface drilling values captured while drilling a wellbore through the subsurface interval. The method also includes analyzing the surface drilling values and identifying on-bottom surface drilling values and on-bottom mechanical specific energy (MSE) values. The method also includes identifying a first changepoint in the on-bottom surface drilling values. The method also includes identifying a second changepoint in the on-bottom MSE values. The method also includes determining a cause of a lost circulation event in the subsurface interval based upon the first and second changepoints.

Abstract: A method to design well trajectories includes determining dogleg severity as a function of inclination, and a corresponding rate of penetration performance of the tool by a hybrid model including physical modelling and machine learning correction. The method includes solving for optimal steering parameters to predict a dogleg severity as close as possible to a desired dogleg severity at a given inclination of the trajectory, which is repeated for dogleg severity and inclination combinations of interest. The rate of penetration for feasible points is also determined and a rate of penetration (or time-to-target) map can be produced. Potential trajectories are then evaluated relative to the map to estimate drilling time-to-target, and an optimal trajectory can be selected that has a lowest time-to-target while also being feasible for the tool and optionally avoiding risks or downhole obstacles.

Abstract: A method includes receiving information that includes elastic property information and that includes sonic data acquired via a tool disposed at a plurality of depths in a bore in a subterranean environment that includes at least one anisotropic formation; processing the information to generate processed information where the processed information includes variance information associated with the elastic property information and where the processed information includes velocity information and orientation information associated with the sonic data; performing an inversion based at least in part on the processed information; and outputting values for elastic parameters based at least in part on the inversion.

Abstract: A downhole wellbore planner builds a fracture model of a wellbore using fracture data identified from geological information. Using the fracture model and a target wellbore location at the formation, the wellbore planner may identify or select one or more lost circulation materials (LCMs). The drilling operator may then procure the LCMs before drilling the wellbore. In this manner, the impact of a lost circulation event may be reduced by having the LCMs on site or nearby.

Abstract: A method to design well trajectories includes determining dogleg severity as a function of inclination, and a corresponding rate of penetration performance of the tool by a hybrid model including physical modelling and machine learning correction. The method includes solving for optimal steering parameters to predict a dogleg severity as close as possible to a desired dogleg severity at a given inclination of the trajectory, which is repeated for dogleg severity and inclination combinations of interest. The rate of penetration for feasible points is also determined and a rate of penetration (or time-to-target) map can be produced. Potential trajectories are then evaluated relative to the map to estimate drilling time-to-target, and an optimal trajectory can be selected that has a lowest time-to-target while also being feasible for the tool and optionally avoiding risks or downhole obstacles.

Abstract: A downhole wellbore planner builds a fracture model of a wellbore using fracture data identified from geological information. Using the fracture model and a target wellbore location at the formation, the wellbore planner may identify or select one or more lost circulation materials (LCMs). The drilling operator may then procure the LCMs before drilling the wellbore. In this manner, the impact of a lost circulation event may be reduced by having the LCMs on site or nearby.

Abstract: A method includes receiving information that includes elastic property information and that includes sonic data acquired via a tool disposed at a plurality of depths in a bore in a subterranean environment that includes at least one anisotropic formation; processing the information to generate processed information where the processed information includes variance information associated with the elastic property information and where the processed information includes velocity information and orientation information associated with the sonic data; performing an inversion based at least in part on the processed information; and outputting values for elastic parameters based at least in part on the inversion.

Abstract: A method can include receiving data that characterizes anisotropy of a formation; receiving a model that models one or more planes of weakness in an anisotropic formation; and, based at least in part on the model and the data, outputting information germane to stability of a bore in an anisotropic formation.

Abstract: The subject disclosure relates to determining an optimum orientation for perforations around the circumference of a subsurface borehole and optimum wellbore fluid initiation pressure for hydraulic fracturing in anisotropic formations.

Abstract: Methods and apparatus for estimating borehole mud slownesses are disclosed. An example method includes estimating a borehole drilling fluid slowness value based on a tube wave modulus value, a tube-wave slowness value, and a drilling fluid density value. The borehole is associated with an anisotropic elastic medium.

Abstract: The subject disclosure relates to determining an optimum orientation for perforations around the circumference of a subsurface borehole and optimum wellbore fluid initiation pressure for hydraulic fracturing in anisotropic formations.

Abstract: A method can include receiving data that characterizes anisotropy of a formation; receiving a model that models one or more planes of weakness in an anisotropic formation; and, based at least in part on the model and the data, outputting information germane to stability of a bore in an anisotropic formation.

Abstract: The subject disclosure relates to determining an optimum orientation for perforations around the circumference of a subsurface borehole and optimum wellbore fluid initiation pressure for hydraulic fracturing in anisotropic formations.