Abstract:
Techniques for log squaring using both directional and non-directional electromagnetic measurements are disclosed. The techniques described herein can be used for determining bed boundary locations and assigning resistivity values to each layer in a layered earth model, regardless of well deviation. Potential bed boundary locations can be derived from both directional and non-directional electromagnetic measurement data. The bed boundary locations from the directional and non-directional measurements can then be consolidated using a weighted averaging scheme, where weight can be dependent based on apparent formation dip. By combining the results from both directional and non-directional measurements, the log squaring techniques described herein can be used in most wells regardless of the well angle (the angle can be arbitrary). Once bed boundaries are selected, formation properties, such as horizontal resistivity (Rh) and vertical resistivity (Rv) can be assigned to the model layers.
Abstract:
A method can include receiving data for a geologic region; based at least in part on the data, selecting a model from a plurality of models using a trained machine learning model, and inverting the data using the selected model to determine parameters of the selected model.
Abstract:
Methods, computer-readable media, and systems are disclosed for applying 1D processing in a non-1D formation. In some embodiments, a 3D model or curtain section of a subsurface earth formation may be obtained. A processing window within the 3D model or curtain that is suitable for 1D inversion processing is determined, and a local 1D model for the processing window is built. A 1D inversion is performed on the local 1D model, and inverted formation parameters are used to update the 3D model or curtain section.
Abstract:
A multi-step electromagnetic inversion method is provided for determining formation resistivity, anisotropy and dip. An electromagnetic logging tool is used to obtain non-directional, anisotropy, and directional (including symmetrized and anti-symmetrized resistivity measurements) in a formation using an electromagnetic logging tool. Bed boundaries of the formation are first identified. A horizontal resistivity profile is obtained using the non-directional resistivity measurements, and a vertical resistivity profile is obtained using the anisotropy resistivity measurements. The vertical resistivity profile is improved using the directional resistivity measurements, while dip values are also obtained via an inversion using the directional resistivity measurements. Then, an inversion for each of vertical resistivity, horizontal resistivity, dip values, and bed boundaries is performed using all of the non-directional, anisotropy, and directional resistivity measurements to obtain a formation model.
Abstract:
Embodiments set forth in this disclosure providing techniques for determining formation parameters, such as horizontal resistivity (Rh), vertical resistivity (Rv), and dip, in high angle and horizontal wells using non-directional resistivity measurements. For example, a method is provided that may include using an electromagnetic logging tool to acquire non-directional resistivity measurements in a wellbore of a high angle or horizontal well. The method may also include defining a processing window that corresponds to a measurement point of the electromagnetic logging tool along a well trajectory that intersects a at least one bed boundary between two layers of a subsurface formation. The method may also include defining a formation structure and defining an initial set of formation parameters for each layer in the formation structure. Furthermore, the method may include inverting the formation parameters for each layer.
Abstract:
Identifying the dielectric constant and/or the electrical resistivity of part of a geological formation may reveal useful characteristics of the geological formation. This disclosure provides methods, systems, and machine-readable media to determine dielectric constant or electrical resistivity, or both, using contraction mapping. Specifically, contraction mapping may be used with a function of wavenumber k to iteratively solve for values of dielectric constant and electrical resistivity until convergence is achieved. This may allow for convergence to a solution without computing partial derivatives and/or with fewer iterations than previous techniques.
Abstract:
A method for estimating EM measurement uncertainty includes evaluating EM logging measurements with a trained machine learning model to estimate the measurement uncertainties of the EM logging measurements. The trained machine learning model is trained using a training data set made up of modeled EM logging measurements and corresponding measurement uncertainties.
Abstract:
A method for making electromagnetic directional resistivity measurements includes rotating an electromagnetic logging tool in a subterranean wellbore penetrating the formation. The logging tool includes a transmitting antenna and a receiving antenna spaced along a tool body with at least one of the transmitting antenna and the receiving antenna being a tiltted antenna. The electromagnectic logging tool is used to make a plurality of electromagnetic measurements at a corresponding plurality of frequencies while rotating in the wellbore. The plurality of measurements made at the corresponding plurality of frequencies is processed to compute a combined apparent resistivity of the subterranean formation. The processing includes minimizing a difference between a plurality of modeled measurements and the plurality of wellbore measurements in which the modeled measurements are computed using a model assuming a homogenous formation.
Abstract:
Methods, computer-readable media, and systems are disclosed for applying 1D processing in a non-1D formation. In some embodiments, a 3D model or curtain section of a subsurface earth formation may be obtained. A processing window within the 3D model or curtain that is suitable for 1D inversion processing is determined, and a local 1D model for the processing window is built. A 1D inversion is performed on the local 1D model, and inverted formation parameters are used to update the 3D model or curtain section.
Abstract:
A system and method of performing a fracture operation at a wellsite about a subterranean formation is disclosed. The method involves, obtaining wellsite measurements by placing a downhole tool in a wellbore and using the downhole tool to acquire measurements of the subterranean formation, simulating the obtained wellsite measurements to determine formation parameters comprising conductivity tensors based on a formation model of the measured subterranean formation, validating the formation model by comparing the obtained wellsite measurements with the simulated wellsite measurements, generating fracture parameters and triaxiality indicators based on the validated formation model, and fracturing the subterranean formation based on the generated fracture parameters and triaxiality indicators.