China Petroleum Chemical Corporation

Jeremy Zhang

Sheng Zhan

Xianghua Liu

Zongqi Chen

A method for obtaining elemental concentration and determining the formation mineralogy uses a tool having multiple dual-function detectors that can detect both neutrons and gamma rays simultaneously. The method includes emitting neutrons into the formation, detecting neutron and gamma ray signals from the formation and discriminating the neutron signal and the gamma ray signal, obtaining the space, time and energy dependent fluence rates for fast neutrons and thermal neutrons, obtaining gamma ray energy spectra from inelastic scattering and neutron capture reactions from one or more detectors, obtaining the energy spectrum of inelastic gamma rays and/or capture gamma rays from a single element, calculating concentration of the element in the formation using its energy spectrum of inelastic gamma rays or capture gamma rays from one or more detectors and the space, time and energy dependent fluence rate of fast neutrons or thermal neutrons, and determining the formation mineralogy.

Method and apparatus for using pulsed neutron generators and dual-function detectors to obtain formation mineralogy

A method for obtaining a gas saturation value of a subterrain formation involves a tool having multiple dual-function detectors that detect neutrons and gamma rays. The method includes steps of emitting neutrons into the formation, detecting neutrons and gamma ray signals form the formation using the detectors, determining formation parameters including the formation type and formation porosity, and further determining parameters such as the ratio of thermal neutron count rates from at least two of three detectors, the ratio of capture gamma count rates from at least two of three detectors, and calculating the real-time gas saturation value using the determined parameters.

Method and apparatus for obtaining real-time formation gas saturation

A method for measuring an oil saturation value of a subterrain formation uses a tool having multiple dual-function detectors that detect neutrons and gamma rays. The method includes emitting neutrons into the formation, detecting neutrons and gamma ray signals form the formation using the detectors, determining formation parameters including the formation type and formation porosity, and further determining parameters such as C/O ratios at each of the detectors, a total neutron count rate at each of detectors, a fast neutron count rate at each of detectors, and a thermal neutron count rate at each of the three or more detector, and calculating the oil saturation value using the determined parameters.

Method and apparatus for obtaining real-time downhole oil saturation

A method for measuring subterranean formation porosity includes the steps of: deploying a nuclear logging tool having one or more neutron sources and two or more dual-function detectors disposed in into a subterranean formation; causing the one or more neutron sources to emit neutrons in a plurality of neutron pulses into the subterranean formation and generating neutrons and gamma rays in the subterranean formation; obtaining one or more neutron count rates for each of the two or more detectors; determining a formation type of the subterranean formation based on gamma rays received at the one or more detectors; calculating one or more neutron count rate ratios between the neutron count rates of two detectors selected from the two or more detectors; and obtaining one or more formation porosities based on the formation type and the one or more neutron count rate ratios.

Apparatus and method for obtaining real-time true formation porosity using pulsed neutron well logging tool having dual-function detectors

A nuclear logging tool has a housing, one or more neutron sources, one or more shields, and two or more detectors disposed about the housing. Each of the one or more neutron sources is configured to generate neutrons in pulses or continuously and each of the two or more detectors is operable to detect neutrons and gamma rays. The two or more detectors include a first detector disposed at a first distance from a first neutron source and a second detector disposed at a second distance from the first neutron source. The first distance is shorter than the second distance. The first distance and the second distance is measured in the longitudinal direction of the housing. Each shield is operable to absorb neutrons and gamma rays and is disposed inside the housing between one of the one or more neutron source and one of the one or more detectors.

Nuclear logging tools and applications thereof

Formation porosity is measured using a logging tool that has a pulsed neutron generator and multiple dual-function detectors that detect both neutrons and gamma rays. Ratios of thermal neutrons, epithermal neutrons, and capture gamma rays from multiple detectors are utilized to obtain multiple neutron porosities and multiple gamma-ray porosities within different depth of investigations. The neutron porosity and the gamma-ray porosity may be further corrected by excluding peak areas attributable to hydrogen and/or chlorine to reduce the shale effect and/or the chlorine effect. The neutron porosity and the gamma-ray porosity may be combined to provide improved porosity evaluations within different depth of investigations into the formation in the entire porosity measurement range (0-100 p.u.).

Method and apparatus for enhanced formation porosity measurement using pulsed neutron source and dual-function detectors

A method for wireline or logging-while-drilling systems that uses pulsed neutron sources coupled to multiple dual-function radiation detectors of neutrons and gamma rays, as well as a non-transitory computer readable memory device that can distinguish using pulse shape discrimination techniques the neutrons from the gamma rays in order to measure thermal neutron time-decay signals and thermal neutron capture gamma ray time-decay signals that are later further process using the non-transitory computer readable memory device to obtain a borehole sigma and formation sigma that are not affected by near-wellbore environments.

Method for obtaining near-wellbore true borehole sigma and true formation sigma by using a nuclear logging tool during oil and gas exploration

A computer-implemented method that uses a preprogrammed neural network and a trained neural network computer program product to predict and then compared borehole and formation sigmas, when using a pulse neutron source and at least three dual-function radiation detectors. These dual-function radiation detectors are used for detecting both neutrons and gamma rays and further pre-programmed to distinguish between neutrons and gamma rays by using pulse shape discrimination techniques. The trained neural network computer program product can be used on above-surface systems, as well as below surface systems like borehole assemblies in logging-while-drilling systems. Once thermal neutron time-decay signals and capture gamma ray time-decay signals are measured by the at least three-dual function radiation detectors, a non-transitory computer readable memory device with the trained neural network computer program product is used to obtain a true borehole sigma and true formation sigma as the measurements are not affected by near-wellbore environments.

Computer-implemented method of using a non-transitory computer readable memory device with a pre programmed neural network and a trained neural network computer program product for obtaining a true borehole sigma and a true formation sigma

A method and apparatus of logging downhole formation and obtaining formation porosity using a pulsed neutron generator and multiple dual-function detectors that detect both neutrons and gamma rays. Ratios of thermal neutrons, epithermal neutrons, and capture gamma rays from multiple detectors are utilized to obtain neutron porosity, gamma porosity and formation porosity by using a trained neural network. The method can provide formation porosity measurements independent of environmental factors, such as borehole size, tool standoff, salinity, temperature, pressure, etc. Effects from environmental factors can be automatically corrected by employing multiple dual-function detectors that detect both neutrons and gamma rays.

Growing community of inventors

Houston, TX, United States of America

Jeremy Zhang