Baker Hughes Corporation

Carbo Ceramics Inc.

Bp Corporation North America Inc.

Xiaogang Han

Harry D Smith, Jr

Robert Duenckel

Richard R Pemper

Brian J LeCompte

Daniel T Georgi

Feyzi Inanc

David J Jacobi

W Allen Gilchrist, Jr

John Longo

Jeremy Zhang

Freddy Mendez

Alfred I Khisamutdinov

Fusheng Li

Gary A Feuerbacher

Mikhail A Fedorin

Brady Lanclos

Adrian Zett

Qianmei (Jeremy) Zhang

Jeanine Galvan Amaya

Methods and associated systems are disclosed for performing a logging operation within a subterranean wellbore extending within a subterranean reservoir. In an embodiment, the method includes (a) emitting neutrons into the subterranean wellbore or the subterranean reservoir, and (b) detecting gamma rays emitted from atoms disposed within the subterranean wellbore or the subterranean reservoir. In addition, the method includes (c) determining a first gamma ray count within a first energy window of the gamma rays detected at (b), and (d) determining a second gamma ray count within a second energy window of the gamma rays detected at (b). The second energy window is different than the first energy window. Further, the method includes (e) calculating a ratio of the first gamma ray count to the second gamma ray count.

Systems and methods for pulsed neutron logging in a subterranean wellbore

Methods are provided for determining the location and height of cement in a subterranean borehole region using pulsed neutron capture (PNC) logging tools. The methods include obtaining a pre-cementing data set, placing in the borehole region a cement slurry that includes a liquid a thermal neutron absorbing material, obtaining a post-cementing data set, comparing the pre-cementing data set and the post-cementing data set to determine the location of the cement, and correlating the location of the cement to a depth measurement of the borehole to determine the location and height of the cement placed in the borehole region.

Identification of cement in subterranean borehole regions using a ratio of capture to inelastic gamma rays

Methods are provided for determining the location and height of a fracture in a subterranean formation using pulsed neutron capture (PNC) logging tools. The methods include obtaining a pre-fracture data set, hydraulically fracturing the formation with a slurry that includes a liquid and a proppant in which at least a portion of the proppant is tagged with a thermal neutron absorbing material, obtaining a post-fracture data set, comparing the pre-fracture data set and the post-fracture data set to determine the location of the proppant, and correlating the location of the proppant to a depth measurement of the borehole to determine the location and height of the propped fracture.

Identification of proppant in subterranean fracture zones using a ratio of capture to inelastic gamma rays

Methods are provided for identifying the location and height of induced subterranean formation fractures and the presence of any associated frac-pack or gravel pack material in the vicinity of the borehole using pulsed neutron capture (PNC) logging tools. The proppant/sand used in the fracturing and packing processes is tagged with a thermal neutron absorbing material. When proppant is present, increases in detected PNC formation and/or borehole component cross-sections, combined with decreases in measured count rates, are used to determine the location of the formation fractures and the presence and percent fill of pack material in the borehole region. Changes in measured formation cross-sections relative to changes in other PNC parameters provide a relative indication of the proppant in fractures compared to that in the borehole region.

Use of PNC tools to determine the depth and relative location of proppant in fractures and the near borehole region

Disclosed is a method for estimating a density of an earth formation penetrated by a borehole. The method includes: emitting a pulse of fast neutrons into the formation during a neutron-pulse time interval; detecting gamma-rays due to inelastic scattering and thermal capture of the emitted neutrons in the formation to provide a gamma-ray energy spectrum due to the inelastic scattering and the thermal capture during a first time interval within the neutron-pulse time interval and to provide a time spectrum of counts or count rates due to thermal capture during a second time interval occurring after the neutron-pulse time interval; determining a macroscopic capture cross section of the formation from a decay in the time spectrum of counts or count rates; determining an elemental weight fraction from the gamma-ray energy spectrum; and estimating the density of the formation using the macroscopic capture cross section and the elemental weight fraction.

Methods for sourceless density downhole measurement using pulsed neutron generator

A method for estimating a concentration of carbon dioxide (CO) in a formation penetrated by a borehole, the method includes: conveying a carrier through the borehole; irradiating the formation with neutrons from a neutron source disposed at the carrier; detecting photons from the formation resulting from the irradiating; and estimating the concentration of COfrom data acquired from the detecting.

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A method for estimating a lithotype of an earth formation, the method includes: obtaining at least two different energy spectra of radiation received from the earth formation using the logging tool, each energy spectrum having at least one of a natural gamma-ray spectrum, a fast neutron-induced inelastic spectrum, and a thermal neutron induced capture spectrum; establishing at least one geochemically-based constraint related to elemental spectral yields to be determined; determining the elemental spectral yields from the at least two different energy spectra by decomposing the at least two different energy spectra over weighted sum of monoelemental standards wherein at least one weight is constrained by the at least one geochemically-based constraint and each weight represents a proportion of one monoelemental standard; converting the elemental spectral yields to elemental concentrations; and using a classifier to receive the elemental concentrations as input and to provide a lithotype as output.

Use of chemically and geologically consistent constraints for obtaining elemental chemistry downhole

A method for estimating resistivity of a formation includes: selecting spectra collected by pulsed neutron instrument disposed down a wellbore traversing the formation, the spectra including capture interactions and inelastic interactions; deconvolving the spectra to estimate an elemental yield; converting the elemental yield to a total concentration value; subtracting a concentration value for drilling mud and a concentration value for the formation from the total concentration value to estimate a concentration in fluid within the formation; and converting the fluid concentration value to a resistivity value. A computer program product and an instrument are provided.

Method for determining formation water resistivity from a wireline pulsed neutron device

A method for correcting data collected with a neutron emitting instrument, includes: obtaining characterization data for the instrument, the characterization data including inelastic background data of the instrument; and correcting the collected data according to the characterization data. A computer program product and an instrument are provided.

Growing community of inventors

Tomball, TX, United States of America

Xiaogang Han