Schlumberger Technology Corporation

Geoservices Equipements

Services Petroliers Schlumberger

Paul Ryan Craddock

Andrew Emil Pomerantz

Ravinath Kausik Kadayam Viswanathan

Robert L Kleinberg

Shin Utsuzawa

Frank Shray

Kamilla Fellah

Robert Allen Badry

MaryEllen Loan

Lalitha Venkataramanan

Wael Abdallah

James A Grau

Michael M Herron

Michael David Prange

Jeffrey Miles

Richard E Lewis

Susan L Herron

Shawn David Taylor

John Paul Horkowitz

Erik Rylander

Laurent Mosse

Harish Baban Datir

Stacy Lynn Reeder Blanco

Manuel Aboud

Bastian Christoph Eddie Sauerer

Salman Khalid

Prakhar Srivastava

Kenneth Faurschou

Methods and systems are provided that combine NMR and IR spectroscopy measurements on a rock sample to determine data representing at least one property of the rock sample. In one embodiment, cuttings can be split into first and second lots. Results of an NMR measurement performed on the first lot of cuttings without cleaning can be analyzed to determine pore volume of the cuttings. Results of an IR spectroscopy measurement performed on the second lot of cuttings after solvent cleaning can be analyzed to determine matrix density of the cuttings. Porosity can be determined from the pore volume and matrix density of the cuttings. In another embodiment, combined NMR and IR spectroscopy measurements can be performed on an unprepared rock sample (without solvent cleaning) to characterize properties of kerogen in the rock sample and porosity. In another aspect, a method is provided that employs multi-nucleic NMR measurements to determine porosity.

Methods and systems for characterizing properties of reservoir rock

A method for characterizing organic matter in a geological rock formation includes performing a Raman spectroscopy measurement on a rock sample to acquire a Raman spectrum of the rock sample. The method includes analyzing the Raman spectrum of the rock sample to determine data characterizing at least one Raman spectral feature corresponding to the rock sample, inputting the data characterizing the at least one Raman spectral feature corresponding to the rock sample into a computation model that determines a value of a property of organic matter in the rock sample, and storing or outputting or displaying the value of the property of organic matter in the rock sample. In embodiments, the property of organic material in the rock sample can be a property of kerogen in the rock sample, or a property of asphaltenes or bitumen in the rock sample.

Methods and systems for estimating properties of organic matter in geological rock formations

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.

Estimating mineralogy and reconstructing elements of reservoir rock from spectroscopy data

Embodiments of the present disclosure are directed towards a method for improving neutron interpretations in a subsurface formation. Embodiments may include estimating mineral concentrations and kerogen concentrations at one or more depths in the subsurface formation and determining kerogen properties at one or more depths in the subsurface formation. Embodiments may further include calculating mineral properties at one or more depths in the subsurface formation and calculating a neutron-based log response to a rock matrix based upon, at least in part, the kerogen properties and the mineral properties at one or more depths in the subsurface formation by subtracting.

Method for improving neutron interpretations in subsurface formations

The systems and methods provided herein relate to extracting maturity-based properties from input log data obtained by a downhole well logging tool. A maturity inversion is performed using the input log data, a log response model, and at least one maturity model to extract maturity-based properties from the input log data. The maturity-based properties are provided in an output log, such that subsequent down hole operation of the formation may account for the maturity-based properties.

Thermal maturity estimation via logs

Methods may include estimating the weight fractions of kerogen and inorganic mineral components of at least an interval of a subsurface formation; determining the grain density of kerogen and inorganic mineral components, wherein at least the grain density of kerogen is determined by one or more infrared measurements; and calculating the formation matrix density of at least an interval of the subsurface formation from the estimated weight fractions and the determined grain density. In another aspect, methods may include estimating the weight fractions of kerogen and inorganic mineral components of at least an interval of a subsurface formation; determining the grain density of kerogen and inorganic mineral components, wherein at least the grain density of kerogen is determined by one or more infrared measurements; and calculating the formation matrix density of at least an interval of the subsurface formation from the estimated weight fractions and the determined grain density; calculating the bulk density for at least an interval of the subsurface formation; and determining the total porosity of at least an interval of the subsurface formation as a function of depth by combining the calculated formation matrix density and the calculated bulk density.

Methods for improving matrix density and porosity estimates in subsurface formations

A method for estimating a value of a kerogen property in a subsurface formation where the value of the kerogen property is unknown. The method includes: measuring spectral intensity values over an infrared (IR) spectral range for a selected sample from the subsurface formation; determining a range of values representing the measured spectral intensity values corresponding to a vibrational mode attributable to kerogen in the selected sample, the range of values including values representing uncertainty in the measured spectral intensity over the portion of the spectral range; and inputting values from the range of values into a stochastic or simple regression model to determine an estimated value of the kerogen property in the selected sample.

Method for estimating a value of a kerogen property in subsurface formations

A method for analyzing a geological formation having at least one hydrocarbon therein may include determining a total organic carbon mass over a depth range of the geological formation, and determining a mass fraction of the at least one hydrocarbon over the depth range of the geological formation based upon the total organic carbon mass. The method may further include determining a volume of the at least one hydrocarbon over the depth range of the geological formation, and determining a density of the at least one hydrocarbon over the depth range of the geological formation based upon the mass fraction and the volume of the at least one hydrocarbon.

Hydrocarbon density determination method

Levels of kerogen and bitumen are computed in a sample of rock from DRIFTS measurements on the sample. The DRIFTS spectrum of a rock sample is measured, resulting in an estimate of bitumen and kerogen. Bitumen is then washed from the rock and DRIFTS is re-measured, resulting in an estimate of kerogen. Bitumen quantity is calculated by subtracting the washed sampled results from first DRIFTS measurements.

Bitumen quantification using vibrational spectroscopy

Techniques for calculating metrics for reservoir quality based on light oil and total organic carbon in tight oil reservoirs are described. The techniques include calculating quantities of light oil and total organic carbon from logging data and generating therefrom a continuous log for reservoir quality metric. Additionally new reservoir quality indices are presented that more accurately predict reservoir quality in tight oil plays.

Quality metrics for tight oil reservoirs

The accurate determination of formation hydrocarbon or water saturation is a useful step in the petrophysical evaluation of petroleum reservoirs. This disclosure presents a new method for estimating hydrocarbon saturation directly from a porosity log and a total organic carbon (TOC) log. The method is enabled by the recent development of a geochemical spectroscopy logging tool that combines inelastic and capture gamma ray measurements to provide a robust and accurate TOC log. The method differs from the prior approach of using carbon-to-oxygen ratios that is most often applied in cased hole evaluation. The main advantages of this method are that it does not use knowledge of formation water resistivity, it does not rely on a resistivity model, it does not use an extensive calibration database, and it is largely independent of clay or other lithology effects. Here, the principles of the method and the main challenges are described, and calculations that explore uncertainties in the saturation estimates arising from uncertainties in the log inputs are presented. The statistical uncertainty in the estimate of hydrocarbon saturation is as good as 10 saturation units (s.u.) in conventional reservoirs with porosities of 15 porosity units (p.u.) or greater. The method has been applied to the determination of hydrocarbon saturation in a variety of formations, including bitumen-filled dolomite, heavy oil sand, and shaly-sands with both open hole and cased hole wells. The method works equally well in formations drilled and logged with either oil- and water-based mud. The saturation estimates have been benchmarked against a combination of conventional and new logging approaches (e.g., resistivity, magnetic resonance and dielectric logs) and core measurements, with generally excellent agreement among independent determinations. Hydrocarbon saturations can be determined accurately using the method in a number of formation types where conventional methods and models for estimating fluid saturation commonly fail, such as freshwater and unknown water salinity in formations under enhanced oil recovery. The case studies included herein demonstrate that a TOC log derived from geochemical spectroscopy logs can be used to obtain reliable estimates of hydrocarbon saturation in a wide range of environmental conditions and formations.

Growing community of inventors

Somerville, MA, United States of America

Paul Ryan Craddock