Saudi Arabian Oil Company

Jin-Hong Chen

Stacey Marie Althaus

Mohammed Boudjatit

Jilin Jay Zhang

Houzhu Zhang

Hui-Hai Liu

Gary Eppler

John David Broyles

Younane N Abousleiman

Yang Zhao

Mohammad Delshad

Techniques for determining an uptake capacity of a core sample include measuring a nuclear magnetic resonance (NMR) spectrum signal of a test fluid at a particular pressure and entrained in a core sample enclosed in a test cylinder of an NMR pressure cell such that an annulus is defined between the core sample and the test cylinder; deconvolving the NMR spectrum signal into a first NMR spectrum signal portion that is associated with a first portion of the test fluid in the annulus and a second NMR spectrum signal portion that is associated with a second portion of the test fluid entrained in the core sample; and determining a mass of the second portion of the test fluid based at least in part on the first and second NMR spectrum signals.

Determining an uptake capacity of a core sample

A method and system for determining a mass of an absorbed gas and a mass of a pore gas in a sample using NMR spectroscopy is provided. The method includes acquiring a baseline NMR spectrum of a pressure cell containing the sample, saturating the sample with a gas, acquiring a saturated NMR spectrum and determining a differential NMR spectrum of the sample by subtracting the baseline NMR spectrum from the saturated NMR spectrum. The method also includes separating the differential NMR spectrum into an absorbed gas NMR spectrum to determine an absorbed gas NMR signal and a pore gas NMR spectrum to determine a pore gas NMR signal by performing a spectral deconvolution. The method further includes acquiring a normalization NMR spectrum of the pressure cell containing a gas to determine a gas calibration NMR signal and determining the mass of the absorbed gas and pore gas.

Method to determine a mass of an absorbed gas and a mass of a pore gas in a sample

Techniques for determining a geologic property of a rock sample include (i) measuring a mass of a processed rock sample that includes a solid matrix and a fluid entrained within the solid matrix; (ii) measuring, using nuclear magnetic resonance (NMR), a volume of the fluid entrained within the solid matrix; (iii) measuring, using a gas porosimeter, a volume of the solid matrix of the processed rock sample; (iv) measuring, with a mercury immersion porosimeter, a bulk volume of the processed rock sample; and (v) determining, based at least on the measured volume of the fluid, the measured volume of the solid matrix, and the measured bulk volume, at least one of a bulk density, a grain density, or a porosity of the processed rock sample.

Determining geologic properties of a rock sample

Techniques for determining at least one rock property of a core sample include measuring a first nuclear magnetic resonance (NMR) spectrum signal of a test fluid enclosed at a particular pressure in a cylinder of an NMR pressure cell; measuring a second NMR spectrum signal of a core sample immersed in the test fluid; removing a background NMR spectrum signal from the first and second NMR spectrum signals to determine a bulk test fluid NMR spectrum signal and a combined test fluid and core sample NMR spectrum signal; determining a porosity of the core sample based on the bulk test fluid NMR spectrum signal, the combined test fluid and core sample NMR spectrum signal, a dimension of the core sample, and a dimension of the cylinder; and determining a fluid intake capacity of the core sample based on the porosity and the dimension of the core sample.

Determining rock sample properties

A method and system for determining an uncorrupted NMR response from a sample at a predetermined measurement pressure is provided. The method includes obtaining a sample and a filler fluid with a negligible NMR response, determining a volume of filler fluid based on a dimension of the sample and an interior volume of a pressure cell, injecting the volume of filler fluid at a first temperature into the pressure cell and then changing the temperature of the volume of the filler fluid to a second temperature. The method also includes inserting the sample into the volume of filler fluid within the pressure cell, displacing an upper surface of filler fluid to a predetermined level within the interior volume of the pressure cell. The method still further includes establishing the predetermined measurement pressure within the pressure cell and determining the uncorrupted NMR response from the sample at the predetermined measurement pressure.

Method to determine an uncorrupted nuclear magnetic resonance response from a sample

A method may include obtaining, using a gamma-ray detector, first acquired gamma-ray data regarding a first core sample. The first acquired gamma-ray data may correspond to various sensor steps. The method may further include determining a sensitivity map based on the first acquired gamma-ray data. The method may further include obtaining, using the gamma-ray detector, second acquired gamma-ray data regarding a second core sample at the sensor steps. The method further includes generating a gamma-ray log using the sensitivity map and a gamma-ray inversion process.

Method and system for determining gamma-ray measurements using a sensitivity map and controlled sampling motion

Methods and systems for separating mud from drill cuttings are disclosed. The method includes collecting drill cuttings from a shale shaker or a wellhead, placing the drill cuttings in a fluid that matches the fluid in the drilling mud, and filtering the drill cuttings through a sieve having a first mesh size. The method further includes placing the filtered drill cuttings in a sieve basket having a second mesh size, wherein the second mesh size is smaller than the first mesh size, placing the sieve basket in a vessel, and adding the fluid to completely submerge the drill cuttings in the fluid. The method also includes placing the vessel including the sieve basket, the drill cuttings, and the fluid in a sonicator-shaker, and simultaneously sonicating and shaking the vessel to separate the drill cuttings from contaminants thereon.

Methods and systems for preparing drill cuttings for measuring petrophysical properties of subsurface formations

A method for determining maximum recoverable hydrocarbon (EMR) in a tight reservoir is disclosed. The method includes determining, based on downhole logs, a total measure of hydrocarbon amount within the tight reservoir, determining, by at least attributing fluid loss during core surfacing of the core sample to hydrocarbons, a non-recoverable measure of hydrocarbon amount within a core sample of the tight reservoir, and determining an EMR measure based on the total measure of hydrocarbon amount and the non-recoverable measure of hydrocarbon amount, wherein during the core surfacing pore pressure reduces from a reservoir condition to a surface condition.

Determination of estimated maximum recoverable (EMR) hydrocarbons in unconventional reservoirs

Techniques for determining grain density of a rock sample include identifying an untreated rock sample that includes a solid matrix and a fluid entrained within the solid matrix; measuring, using a gas porosimeter, a grain density of the untreated rock sample; measuring, using nuclear magnetic resonance (NMR), a volume of the fluid entrained within the solid matrix; and determining, based on the measured grain density of the untreated rock sample and the measured volume of the fluid, a grain density of the solid matrix of the untreated rock sample.

Systems and methods for determining grain density of an untreated rock sample using a gas porosimeter and nuclear magnetic resonance

A method for analyzing unconventional rock samples using nuclear magnetic resonance (NMR), tracking fluid change in the rock sample over a time period, calculating transverse relaxation time (T) generating fluid distribution profiles by the computer processor and based on a NMR imaging, where the fluid distribution profiles representing a movement of the fluid, and obtaining, quantification of fracture volume by the computer processor and based on the NMR imaging.

Nuclear magnetic resonance method quantifying fractures in unconventional source rocks

Methods and systems for determining fluid content in a formation sample are disclosed. The method includes disposing the formation sample with a standard sample of a known chemical composition and one or more nuclear magnetic resonance (NMR) attributes in a NMR coil or probe, and acquiring NMR signals for the formation sample and the standard sample simultaneously. The system includes a NMR probe or NMR coil, a formation sample, and a standard sample with known chemical composition and one or more nuclear magnetic resonance (NMR) attributes, wherein the formation sample and the standard sample are disposed in the NMR coil or probe, and wherein NMR signals are acquired for the formation sample and the standard sample simultaneously.

Methods and systems for determining fluid content in formation samples using low field nuclear magnetic resonance

Herein methods and systems for determining matrix or grain density of a subsurface formation are described. This includes measuring in-air mass of a fluid-saturated sample of the subsurface formation, wherein the in-air mass comprises mass of matrix or grains of the sample, mass of a fluid surrounding the sample, and mass of the fluid inside the sample. The volume of the fluid inside the sample, V, and volume of the fluid surrounding the sample, V, are determined using nuclear magnetic resonance (NMR). The fluid-saturated sample can then be submerged in a predetermined volume of a weighing fluid and mass of the fluid-saturated sample without the surrounding fluid in the weighing fluid, mis measured. Using the measured and determined values one can determine the volume of the sample without the surrounding fluid, V, the bulk density of the fluid-saturated sample without the surrounding fluid, &#x3c1;, the volume of the matrix, V, and the matrix or grain density of the subsurface formation, &#x3c1;.

Methods and systems for determining bulk density, porosity, and pore size distribution of subsurface formations

Techniques for determining geologic formation permeability include determining particular permeability values from an NMR log permeability data and particular permeability values of the core permeability measurements; determining a selected NMR permeability transform that includes inputs including the determined particular permeability values; minimizing a cost function to optimize the selected NMR permeability transform; calculating new permeability values for the wellbore between the terranean surface and a true vertical depth of the wellbore with the optimized NMR permeability transform; comparing the calculated new permeability values at particular depths between the terranean surface and the true vertical depth that match depths of the core permeability measurements; based on the comparison meeting a particular threshold, generating a user interface that renders one or more graphical representations of the optimized NMR permeability transform and the calculated new permeability values; and transmitting data that represents the one or more graphical representations.

Determining geologic formation permeability

Certain techniques for Nuclear Magnetic Resonance (NMR) whole core logging are described. NMR tests are performed on a standard sample using a NMR radio frequency (rf) coil having a length. A response map of the NMR rf coil is determined. The response map relates multiple relative NMR rf coil positions to multiple relative signal intensities. The NMR tests are performed using the NMR rf coil on a rock sample containing fluid. A length of the rock sample is greater than the NMR rf coil. Fluid content in the sample is determined using results of the NMR tests using the NMR rf coil on the rock sample and using the response map for the NMR rf coil and a mathematical deconvolution to obtain high resolution. The same method can be used to obtain high spatial resolution NMR log measurement in the reservoir.

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Katy, TX, United States of America

Jin-Hong Chen