Method to determine the water saturation using the t1/t2 ratio for conventional and unconventional formations
AssigneeSchlumberger Technology Corporation
InventorsFarhan Ali, Chiara Cavalleri, Mohammed AL-HAMAD
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Abstract
Aspects of the disclosure relate to workflows and analytical methods for characterizing conventional and unconventional geological formation water saturation values through advanced laboratory measurements and correlation techniques of nuclear magnetic resonance value ratios.
Claims20
A method for determining a water saturation value of a geological formation, comprising:
- obtaining at least one sample of the geological formation;
- subjecting the at least one sample to a first nuclear magnetic resonance evaluation, wherein cutoff values are obtained when the at least one sample is saturated;
- desaturating the at least one sample;
- performing a second nuclear magnetic resonance evaluation of the desaturated at least one sample;
- comparing the first nuclear magnetic resonance evaluation to the second nuclear magnetic resonance evaluation;
- generating at least one correlation between the first and second nuclear magnetic resonance evaluations;
- and
- determining the water saturation value of the geological formation based on the at least one correlation.
The method according to 4, wherein the cutoff values are compared in the saturated and desaturated samples.
A method for determining a water saturation value of a geological formation, comprising:
- obtaining at least one sample of the geological formation;
- subjecting the at least one sample to a first nuclear magnetic resonance evaluation, wherein cutoff values are obtained when the at least one sample is in a native state;
- obtaining a porosity and a permeability of the at least one sample;
- selecting a first of the at least one sample based upon the obtained porosity and permeability;
- spinning the first sample in air to remove fluid from the sample;
- performing a second nuclear magnetic resonance evaluation of the spun first sample;
- saturating the first sample;
- obtaining a saturation porosity of the first sample;
- conducting a third nuclear magnetic resonance evaluation;
- spinning the first sample at least one time;
- conducting a nuclear magnetic resonance evaluation after each spinning of the first sample;
- performing cutoff measurements of the first sample;
- comparing the nuclear magnetic resonance evaluations in the saturated state and the spun state;
- generating at least one correlation based on the comparing;
- and
- determining the water saturation value of the geological formation based on the at least one correlation.
An article of manufacture configured to provide instructions that will be performed on a computing device, wherein the article of manufacture has a non-transitory memory configured to retain the instructions, the instructions comprising, at least in part:
- obtaining at least one sample of the geological formation;
- subjecting the at least one sample to a first nuclear magnetic resonance evaluation, wherein cutoff values are obtained when the at least one sample is saturated;
- desaturating the at least one sample;
- performing a second nuclear magnetic resonance evaluation of the desaturated at least one sample;
- comparing the first nuclear magnetic resonance evaluation to the second nuclear magnetic resonance evaluation;
- generating at least one correlation between the first and second nuclear magnetic resonance evaluations;
- and
- determining the water saturation value of the geological formation based on the at least one correlation.
Dependencies are inferred from the claim text.