It is an object to provide an imaging method and system. According to an embodiment, an imaging method comprises emitting neutrons into a material, wherein the material converts at least part of the emitted neutrons into a first plurality of gamma ray photons, and wherein at least part of the emitted neutrons pass through the material. Based on the neutrons passed through the material and the gamma ray photons, at least one property of the material can be deduced. An imaging method and an imaging system are provided.

Methods and systems are provided to learn and apply a mapping function from data representing concentrations of atomic elements in a geological formation (or other data corresponding thereto) to mineral component concentrations in the geological formation (and/or from mineral component concentrations to reconstructed elemental concentrations in the geological formation). The mapping function can be derived from a trained neural network (such as an autoencoder). The output of the mapping function can be used to determine estimates of one or more formation properties, such as formation matrix density, formation porosity, matrix Sigma, formation saturation, other formation property, or combinations thereof.

A method for identifying defects in a multi-barrier wellbore includes receiving log data, the log data corresponding to one or more wellbore operations, the log data including data from at least one measurement modality corresponding to a present measurement modality. The method also includes training, using the log data, a machine learning model. The method further includes acquiring wellbore data, via the present measurement modality, during a logging operation. The method also includes processing at least a portion of the wellbore data using the trained machine learning model. The method includes identifying one or more features of interest in the wellbore data, via the trained machine learning model.

Systems and methods employed measure borehole density by neutron induced gammas using a pulsed neutron tool. Traditional nuclear density methods only measure a bulk average density of the surrounding material. As discussed below, methods to measure only the borehole density excluding the contamination from the formation are disclosed. Specifically, the proposed methods use unique signatures from each geometric region to directly measure the borehole density or compensate for the contamination from formation. This method may be achieved by a borehole density measurement using differential attenuation of capture gamma from casing iron, a borehole density measurement using differential attenuation of inelastic gamma from oxygen, a differential attenuation of any induced gamma from any element from borehole and formation, or any combination thereof.

Systems and methods for determining holdup in a wellbore using a neutron-based downhole tool. In examples, the tool includes nuclear detectors that may measure gammas induced by highly energized pulsed-neutrons emitted by a generator. The characteristic energy and intensity of detected gammas indicate the elemental concentration for that interaction type. A detector response may be correlated to the borehole holdup by using the entire spectrum or the ratios of selected peaks. As a result, measurements taken by the neutron-based downhole tool may allow for a two component (oil and water) or a three component (oil, water, and gas) measurement. The two component or three component measurements may be further processed using machine learning (ML) and/or artificial intelligence (AI) with additional enhancements of semi-analytical physics algorithms performed at the employed network's nodes (or hidden layers).

A method, including emitting from a source of ultrafast neutrons within a logging tool deployed in a borehole, a pulse of ultrafast neutrons into an irradiated portion of a formation surrounding the borehole. The method further includes detecting, with one or more gamma ray detectors located at increasing distances from the source of ultrafast neutrons, a flux of stimulated gamma rays generated within the irradiated portion of the formation by the pulse of ultrafast neutrons; and determining, from the detected flux of stimulated gamma rays, one or more petrophysical properties of the irradiated portion of the formation.

It is an object to provide an imaging method and system. According to an embodiment, an imaging method comprises emitting neutrons into a material, wherein the material converts at least part of the emitted neutrons into a first plurality of gamma ray photons, and wherein at least part of the emitted neutrons pass through the material. Based on the neutrons passed through the material and the gamma ray photons, at least one property of the material can be deduced. An imaging method and an imaging system are provided.

Methods and systems for reservoir characterization use identification of lithostratigraphic layers within a subterranean formation based on rock geochemistry of the subterranean formation. This approach includes: collecting rock samples related to lithostratigraphy of target wells in the subterranean formation; measuring geochemical/mineralogical parameters of the rock samples with laboratory equipment; measuring geochemical/mineralogical parameters of the subsurface formation using wellbore geochemical logging tools in the target wells; measuring formation acoustic velocities for the target wells; generating characteristic rock sample and log signature patterns for different lithostratigraphic layers based on the measured geochemical/mineralogical parameters and acoustic velocities associated with the different lithostratigraphic layers identified in the target wells; combining the characteristic log signatures for the different lithostratigraphic layers into a lithographic interpretation using neutron capture spectroscopy model; and identifying the lithostratigraphic layers within the subterranean formation by applying the model to well logs of non-target wells.

An approach for reservoir characterization is based on rock geochemistry of the subterranean formation. This approach includes: collecting rock samples related to lithostratigraphy of target wells; measuring geochemical/ mineralogical parameters of the rock samples; measuring geochemical/mineralogical parameters of the subsurface formation; measuring formation acoustic velocities for the target wells; generating characteristic rock sample and log signature patterns for different lithostratigraphic layers based on the measured geochemical/mineralogical parameters and acoustic velocities associated with the different lithostratigraphic layers identified in the target wells; combining the characteristic log signatures for the different lithostratigraphic layers into a lithographic interpretation using neutron capture spectroscopy model; and identifying the lithostratigraphic layers within the subterranean formation by applying the model to well logs of non-target wells.

A gamma ray spectrum unfolding method for elemental capture spectroscopy logging and a device therefor including the steps of first preprocessing the data obtained from an elemental capture spectrometry instrument; constructing a primary element group and an auxiliary element group according to the degree of interactions among the elements via theoretical analysis and numerical calculation of spectrum profiles, characteristic peak channels, and backgrounds of different elements; unfolding by using the least square method based on the construction of the primary element group and the auxiliary element group; and finally reconstructing the spectrum based on theory according to the yield of each element obtained by unfolding with the least square method, and comparing the measured gamma ray spectrum with the reconstructed gamma ray spectrum for error control, thereby improving the spectrum unfolding precision.