Halliburton Energy Services, Inc.

Saudi Arabian Oil Company

Weijun Guo

Yike Hu

Jeffrey James Crawford

Daniel Francois Dorffer

Mayir Mamtimin

Dongwon Lee

Juan Navarro-Sorroche

Larry Alan Jacobson

Da Luo

James Elmer Galford

Zilu Zhou

Jerome Allen Truax

Zhijuan Zhang

Sriram Srinivasan

Qingzhen Guo

Burkay Donderici

Lesley Allison Fessler

Juan Navarro Sorroche

Philip D Nguyen

Jay Paul Deville

Dingding Chen

James Martin Price

Shouxiang Mark Ma

John Andrew Quirein

Paul Andrew Cooper

Natasa Mekic

Ronald Eugene Cherry

KwokShan Kwong

Steve Zannoni

Stephen A Zannoni

Aixa Maria Rivera-Rios

Jimmy W Anders

Carlos Haramboure

Jerome A Truax

Ali E Abdou

Nacer Guergueb

Da Lou

Christopher S McIlroy

Dennis Durbin

Kwok-Shan Kwong

A downhole neutron generator includes a housing, a gas reservoir positionable within the housing, a target rod positionable within the housing and having a longitudinal axis aligned with a central axis of the housing, an ion source positionable adjacent to the gas reservoir and between the target rod and the gas reservoir, and a target positionable on a surface of the target rod facing the ion source. The target includes a first metal layer on the surface of the target rod and a second metal layer positionable adjacent to the first metal layer facing the ion source. The second metal layer is a scandium layer.

Scandium target for a neutron generator for wellbore logging

The techniques as described herein enhance the accuracy and precision of mineralogy analysis in elemental spectroscopy logging by utilizing oxide standards and/or rock-forming mineral compounds as reference materials that provide more representative and realistic signatures of geological formations. A method comprises logging a wellbore with a tool and fitting reference spectra from oxide compounds and/or rock-forming mineral compounds against measured gamma spectra obtained with the tool, to characterize a subterranean formation that the wellbore extends through.

Pulsed neutron logging mineralogy using oxide standards

Systems and methods are provided for operating and constructing a neutron generator. In some examples, an ion source within a neutron generator may include a hot cathode; at least one cylindrical sleeve coupled to an exterior surface of the hot cathode; at least one electrode coupled to an interior surface of the neutron generator; and at least one mounting flange, wherein a proximal end of the at least one mounting flange is coupled to the at least one cylindrical sleeve and a distal end of the at least one mounting flange is coupled to the at least one electrode.

Hot cathode for an ion source of a neutron generator

Systems and techniques are provided for optimizing the performance of a target for a downhole neutron generator. An example method can include disposing a first source material and a first substrate in a vacuum chamber at an initial temperature, evaporating the first source material to be deposited onto a surface of the first substrate, monitoring a temperature of the first substrate during the evaporation of the first source material, and determining a thermal equilibrium process temperature at which the temperature of the first substrate is stabilized. The example method can further include disposing a second source material and a second substrate in the vacuum chamber at the thermal equilibrium process temperature, evaporating the second source material to be deposited onto a surface of the second substrate, and obtaining the second substrate deposited with the second source material for a target of a downhole neutron generator.

Optimization of a target of a downhole neutron generator

A method and system for identifying one or more petrophysical properties in a formation. The method and system may include disposing a pulsed-neutron logging tool into a borehole that is disposed in a formation, emitting a neutron from a neutron source on the pulsed-neutron logging tool into the formation, and capturing one or more gammas expelled from formation in response to the neutron from the neutron source to form a plurality of pulsed neutron logging (PNL) measurements in a log. The method and system may further include comparing the log to a database with a cost function to form a solution; and identifying a plurality of petrophysical properties based at least in part on the solution.

Algorithm-free, data-centric multivariate inversion for pulsed neutron logging

The techniques as described herein result in a single set of intrinsic carbon-oxygen (CO) measurements that can be used for various borehole and formation saturation conditions, enhancing the reliability and robustness of formation evaluation in oil and gas wells. A method comprises formulating an intrinsic CO ratio for a subterranean formation, based on theoretical atomic concentrations of carbon and oxygen, and porosity and fluid saturation parameters.

Intrinsic carbon oxygen for formation saturation and borehole holdup

Aspects of the subject technology relate to performing gamma spectral analysis based on machine learning. Gamma spectrum data, which can be associated with a gamma spectrum can be gathered. The gamma spectrum data can include an energy channel and a count rate for gamma rays detected by one or more gamma detectors. A spectral image can be constructed based on the gamma spectrum data. One or more machine learning models can be trained based on the spectral image. Additionally, one or more features of the gamma spectrum can be extracted from the spectral image through the one or more machine learning models.

Gamma spectral analysis

Aspects of the subject technology relate to determining holdup compensated formation saturation while refraining from calculating holdup. Inelastic gamma spectrum data for an inelastic gamma spectrum generated downhole in a wellbore can be accessed. Further, capture gamma spectrum data for one or more capture gamma spectrums generated downhole in the wellbore can be accessed. A model that accounts for holdup measurement can be applied to both the inelastic gamma spectrum data and the capture gamma spectrum data to identify a compensated oil saturation for a formation surrounding at least a portion of the wellbore based on both the inelastic gamma spectrum and the one or more capture gamma spectrums.

Compensated formation saturation using assisted physics and neural networks

Aspects of the subject technology relate to determining a holdup measurement based on a gamma spectrum through machine learning. A spectral image based on a gamma spectrum generated downhole in a wellbore can be accessed. A component of a holdup measurement for the wellbore can be classified into a specific quantized level through application of a machine learning classification model to the spectral image. A continuous value for the component of the holdup measurement for the wellbore can be quantified by applying a machine learning quantization model associated with the quantized level.

Holdup measurement using quantized classification and categorized local regression

Systems and methods may utilize information collected by a pulsed-neutron logging tool along with modeling a characterization of a borehole to form a 3-stage correction algorithm. This algorithm may be used to find an oil, water, and gas holdup in the borehole. During operations, a pulsed neutron logging tool which emits neutrons to interact with nuclei inducing gamma radiation. The gamma radiation is detected into a response which may be correlated to the location of a holdup in a borehole by using the entire spectrum or ratios of selected peaks. In examples, a borehole density index may be implemented to complement the response and improve accuracy and measurement confidence.

Three-component holdup measurement using pulsed neutron tool

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.

Borehole density measurement using pulsed neutron tool

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).

Holdup algorithm using assisted-physics neural networks

A neutron tube. At least some of the illustrative embodiments including: generating, from a neutron tube, a first neutron burst having a first characteristic energy spectra; and generating, from the neutron tube, a second neutron burst having a second characteristic energy spectra different than the first characteristic energy spectra, the generating the second neutron burst within one second of generating the first neutron burst.

Method and system of a neutron tube

The disclosure provides a well integrity monitoring tool for a wellbore, a method, using a nuclear tool and an EM tool, for well integrity monitoring of a wellbore having a multi-pipe configuration, and a well integrity monitoring system. In one example, the method includes: operating a nuclear tool in the wellbore to make a nuclear measurement at a depth of the wellbore, operating an EM tool in the wellbore to make an EM measurement at the depth of the wellbore, determining a plurality of piping properties of the multi-pipe configuration at the depth employing the EM measurement, determining, employing the piping properties, a processed nuclear measurement from the nuclear measurement, and employing the processed nuclear measurement to determine an integrity of a well material at the depth and within an annulus defined by the multi-pipe configuration.

Apply multi-physics principle for well integrity evaluation in a multi-string configuration

The inelastic and capture ratio is optimized for porosity measurements in downhole applications. Pulsed-neutron data is acquired using a pulsed-neutron downhole tool. At each sampling point or log depth, the inelastic count rates and capture rates are computed. The inelastic count rate is corrected for the capture count background to increase porosity sensitivity. The capture count rate is computed by summing a range of time windows in the decay curve. In this process, the inelastic and capture responses are matched for borehole sensitivity. The ratio of inelastic and capture counts is computed. This ratio is the input to the characterized transform algorithm to compute measured porosity.

Growing community of inventors

Houston, TX, United States of America

Weijun Guo