Baker Hughes Corporation

Saudi Arabian Oil Company

Exxonmobil Upstream Research Company

Baker Hughes, a Ge Compnay, LLC

Baker Hughes Holdings LLC

John Longo

David J Jacobi

Freddy Mendez

Maxim Vasilyev

Hao Zhang

Brian J LeCompte

Gary A Feuerbacher

Karla Schall Colle

Larry D Talley

Richard R Pemper

Xiaogang Han

Toyli Anniyev

Gabor Hursan

See Hong Ong

Mikhail N Gladkikh

Alfred I Khisamutdinov

Mikhail A Fedorin

Qiushi Sun

Eliseo Rodriguez

Jordan Kone

Methods and devices for estimating at least one property of a volume of interest of an earth formation from a radiation based measurement. Methods include using an optimization procedure to determine an optimal mineralogical model in dependence upon a secondary dependence relation between tool measurements, the mineralogical model including a mineralogical composition of the volume. The secondary dependence relation may include a relation between a plurality of estimated elemental concentrations for the volume. The mineralogical composition may include a concentration of each mineral of a plurality of minerals of the volume. The relation may include a ratio of a first elemental concentration of the plurality of estimated elemental concentrations and a second elemental concentration of the plurality of estimated elemental concentrations. Methods may include using at least one cost function to determine the optimal mineralogical model, wherein the at least one cost function is determined using the relation.

Geological constraint using probability functions in stochastic mineralogy modeling

An example method includes analyzing rock from an image of a sample region of the rock. The example method includes accessing element maps of the sample region in a database, with each element map including an array of pixels, and with each pixel having a value that represents how closely the pixel correlates to a chemical element; accessing a database storing threshold values for multiple chemical elements including the chemical element; determining a presence of a substance in a portion of the sample region corresponding to the pixel by determining whether a value of the pixel in each of the element maps is greater than, or less than, a threshold value for a corresponding chemical element; labeling the pixel based on the presence of the substance in the pixel; and outputting data representing the substance map for rendering on a graphical interface.

Analyzing a rock sample

Estimating a correction factor from logs of compensated thermal neutron porosity measurements, including modeling each measurement of the compensated thermal neutron porosity measurements of the log as resulting from at least: i) a first contribution correlated to an absorbance of a first portion of neutrons produced by irradiation of the volume attributable to interactions in the volume indicative of pore space in the matrix, and ii) a second contribution correlated to an absorbance of a second portion of the neutrons attributable to trace elements of at least one dominant neutron absorber in the formation; iii) a third contribution correlated to an absorbance of a third portion of the neutrons attributable to dry minerals in the matrix other than dominant neutron absorbers; and estimating the second contribution and determining the correction factor from the second contribution; and correcting a compensated thermal neutron porosity measurement using the correction factor.

Compensated neutron correction for contributions outside the petrophysical model

Systems, methods and devices for evaluating an earth formation intersected by a borehole. The method includes using a first radiation responsive component to detect gamma rays having an energy below a threshold energy; using a second radiation responsive component configured to detect gamma rays that traverse the first radiation responsive component; generating a reduced-Compton gamma ray spectrum by generating an anticoincidence gamma ray spectrum indicative of the gamma rays detected by the first radiation responsive component and the gamma rays detected by the second radiation responsive component. The anticoincidence gamma ray spectrum represents those gamma rays of the gamma rays detected by the second radiation responsive component that are not detected in coincidence with the gamma rays detected by the first radiation responsive component.

Measurement of downhole gamma radiation by reduction of compton scattering

Methods, systems and devices for estimating a parameter of interest from a gamma ray spectrum relating to a volume of matter using standard gamma ray spectra from reference samples, wherein there is at least one non-elemental characteristic that is different between the volume and at least one of the reference samples, wherein the non-elemental characteristic difference affects gamma ray interactions. Methods may include deconvolving a gamma ray spectrum obtained from the analysis volume into a plurality of elemental spectral yields, wherein deconvolution includes compensating for effects of the non-elemental characteristic difference. Methods may include using at least one compensation standard spectrum configured to compensate for the effects of the non-elemental characteristic of the at least one of the reference samples.

Methods to enhance nuclear spectroscopy analysis

A method for evaluating an earth formation from a well bore, that includes: collecting at least one of geochemical data, petrophysical data and geomechanical data from a wellbore; and identifying depositional facies of the earth surrounding the wellbore. A computer program product and a system are provided.

Method for petrophysical evaluation of shale gas reservoirs

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

Methods, systems, apparatus and processes for determining the lithology as well as the mineralogy of subterranean formations surrounding a borehole are described. According to the methods and processes, well log data measurements from neutron spectroscopy applications and associated tool response parameters are solved using an artificial intelligence system, such as an expert system, which in turn generates an appropriate discriminator and/or compositional model that estimates both general and specific lithology as well as the mineralogy constraints of the subterranean formation being analyzed. The methods exhibit good elemental correlation between conventional methods of lithology and mineralogy determination, and can provide numerous output data, including grain density and porosity data within zones of the formation.

Methods for quantitative lithological and mineralogical evaluation of subsurface formations

Elemental analysis of an earth formation is obtained using measurements from a gamma ray logging tool. From the elemental analysis, an estimate of the Calcium, Magnesium and Carbon content of the formation is determined. The amount of organic carbon in the formation is estimated from the total Carbon content and the inorganic carbon associated with minerals in the formation. An indication of source rock may be obtained from the Th/U ratio.

Determining organic carbon downhole from nuclear spectroscopy

A method for inhibiting the formation of gas hydrates in a petroleum fluid having hydrate-forming constituents is claimed. More specifically, the method can be used to treat a petroleum fluid, such as natural gas conveyed in a pipe, to inhibit the formation of a hydrate flow restriction in the pipe. The preferred hydrate inhibitors used for practicing the method comprise substantially water soluble homopolymers and copolymers of isopropylmethacrylamide derivatives which have a bimodal molecular weight distribution.

Method for inhibiting hydrate formation

A low value of Th/U ratio as determined from natural gamma radiation is indicative of deepwater sedimentation. This, together with estimates of total organic carbon from pulsed neutron measurements, is used to characterize source rocks. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understand that it will not be used to interpret or limit the scope or meaning of the claims.

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John Longo