Methods are provided for determining properties of an anisotropic formation (including both fast and slow formations) surrounding a borehole. A logging-while-drilling tool is provided that is moveable through the borehole. The logging-while drilling tool has at least one dipole acoustic source spaced from an array of receivers. During movement of the logging-while-drilling tool, the at least one dipole acoustic source is operated to excite a time-varying pressure field in the anisotropic formation surrounding the borehole. The array of receivers is used to measure waveforms arising from the time-varying pressure field in the anisotropic formation surrounding the borehole. The waveforms are processed to determine a parameter value that represents shear directionality of the anisotropic formation surrounding the borehole.

Methods are provided for determining properties of an anisotropic formation (including both fast and slow formations) surrounding a borehole. A logging-while-drilling tool is provided that is moveable through the borehole. The logging-while drilling tool has at least one dipole acoustic source spaced from an array of receivers. During movement of the logging-while-drilling tool, the at least one dipole acoustic source is operated to excite a time-varying pressure field in the anisotropic formation surrounding the borehole. The array of receivers is used to measure waveforms arising from the time-varying pressure field in the anisotropic formation surrounding the borehole. The waveforms are processed to determine a parameter value that represents shear directionality of the anisotropic formation surrounding the borehole.

Systems and methods include a computer-implemented method for determining relative productivity. A thorium-uranium ratio for a region of interest is determined by a diagenesis-calibrated rock quality (DCRQ) system using exploration and production (E&P) data. A percentage of siltstone in a lithology matrix for the region of interest is determined using the E&P data. A difference between a neutron porosity and a sandstone density porosity for the region of interest is determined using the E&P data. A rock testability index for the region of interest is determined. Relative productivity for the region of interest is determined using i) the thorium-uranium ratio, ii) the percentage of siltstone in the lithology matrix, iii) the difference between the neutron porosity and the sandstone density porosity, and iv) the rock testability index. Drilling parameters for use in upcoming drilling operations for wells in the region of interest are determined using the relative productivity.

An embodiment of the present disclosure is an acoustic logging tool for determining a characteristic of a ground formation during a drilling operation. The acoustic logging tool includes a transmitter section that houses a transmitter that is configured to emit an acoustic signal and a receiver section spaced from the transmitter section along an axial direction. The receiver section includes a receiver that is configured to receive at least a portion of the acoustic signal. The acoustic logging tool also includes an isolator section positioned between the transmitter section and the receiver section along the axial direction.

A method, computing system, and non-transitory computer-readable medium, of which the method includes receiving offset well data collected while drilling one or more offset wells, generating a machine learning model configured to predict drilling risks from drilling measurements or inferences, based on the offset well data, receiving drilling parameters for a new well, determining that the drilling parameters are within an engineering design window, generating a drilling risk profile for the new well using the machine learning model, and adjusting one or more of the drilling parameters for the new well, after determining the drilling parameters are within the engineering design window, and after determining the drilling risk profile, based on the drilling risk profile.

A method of probabilistically estimating a velocity of a plunger of a beam pump may comprise continuously monitoring well acoustics using a plurality of passive acoustic sensors attached to external structures of the beam pump; digitizing outputs of the plurality of passive acoustic sensors and sending the digitized outputs to a computing device for storage and processing; and using the digitized outputs of the plurality of passive acoustic sensors, estimating a probability of the velocity of the plunger using a hidden Markov model (HMM) to represent a probability of a position and the probability of the velocity of the plunger, the HMM comprising a state space model and an observational model.

Disclosed is a system and method for calculating a formation shear-wave slowness. The system includes a borehole sonic logging tool and an information handling system. The borehole sonic logging tool may comprise a transmitter comprising one or more elements disposed at one or more radial distances from an axis of the borehole sonic logging tool and the transmitter is configured to transmit a first mode into a borehole. The sonic logging tool may further include one or more receivers disposed at a second radial distance from the axis of the borehole sonic logging tool and are configured to detect a second mode that one or more lobes than is a higher order than the first mode. A method may comprise broadcasting the first mode into the borehole, recording the second mode from the borehole with the one or more receivers, and calculating the formation shear-wave slowness from the second mode.

A method evaluating borehole subsurface geologies can include receiving a total response signal by a sensor array disposed in a borehole, the response signal represents a pressure wave propagating in the borehole. A secondary signal can be extracted from the total response signal and a depth location for at least one secondary source that corresponds to the secondary signal is determined. An estimated reflectivity response for the secondary signal as a function of frequency is determined and the estimated reflectivity response is inverted to determine the secondary source includes at least one of a potential fracture or a potential washout. The at least one of a fracture conductivity or a washout volume for the secondary source is compared to one or more borehole images corresponding to the depth location of the secondary source to determine the potential fracture is an actual fracture or the potential washout is an actual washout.

An apparatus, method, and system for determining body wave slowness from guided borehole waves. The method includes selecting a target axial resolution based on the size of a receiver array, obtaining a plurality of waveform data sets corresponding to a target formation zone and each acquired at a different shot position, computing a slowness-frequency 2D dispersion semblance map for each waveform data set, stacking the slowness-frequency 2D dispersion semblance maps to generate a stacked 2D semblance map, and determining a body wave slowness from the extracted dispersion curve. The method may also include generating a self-adaptive weighting function based on a dispersion model and the extracted dispersion curve, fitting the weighted dispersion curve and the dispersion model to determine a body wave slowness that minimizes the misfit between the weighted dispersion curve and the dispersion model. The method can be applied to both frequency-domain and time-domain processing.

Methods are provided for determining properties of an anisotropic formation (including both fast and slow formations) surrounding a borehole. A logging-while-drilling tool is provided that is moveable through the borehole. The logging-while drilling tool has at least one dipole acoustic source spaced from an array of receivers. During movement of the logging-while-drilling tool, the at least one dipole acoustic source is operated to excite a time-varying pressure field in the anisotropic formation surrounding the borehole. The array of receivers is used to measure waveforms arising from the time-varying pressure field in the anisotropic formation surrounding the borehole. The waveforms are processed to determine a parameter value that represents shear directionality of the anisotropic formation surrounding the borehole.