Core nuclear magnetic resonance T2 spectrogram relaxation time and mercury porosimetry pore-throat radius conversion method

A technology of nuclear magnetic resonance and pore throat radius, which is applied in the field of oil and gas reservoir physics, can solve the problems of complex calculation, many steps, and large error in the final fitting result, and achieve reliable fitting results, accurate results, and reliable results

Active Publication Date: 2019-06-21
XI'AN PETROLEUM UNIVERSITY
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Problems solved by technology

This conversion method is computationally complex, has many steps, and the error of the final fitting result is large

Method used

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  • Core nuclear magnetic resonance T2 spectrogram relaxation time and mercury porosimetry pore-throat radius conversion method
  • Core nuclear magnetic resonance T2 spectrogram relaxation time and mercury porosimetry pore-throat radius conversion method
  • Core nuclear magnetic resonance T2 spectrogram relaxation time and mercury porosimetry pore-throat radius conversion method

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Embodiment

[0035] The core NMR T of this embodiment 2 The conversion method of spectral relaxation time and mercury intrusion pore throat radius includes the following steps:

[0036] (1) Select a sandstone core, wash the sandstone core with oil, dry it and saturate it with kerosene in turn, and then carry out the nuclear magnetic resonance experiment to measure the transverse relaxation time T of the nuclear magnetic resonance 2 and signal strength. Take the part of the non-zero value of the signal intensity, in order to correspond to the pore throat radius of the high-pressure mercury intrusion data, the NMR data is divided into the transverse relaxation time T 2 Arrange them in descending order, and calculate the cumulative percentage of signal strength, as shown in Table 1;

[0037] Table 1

[0038]

[0039]

[0040]

[0041] (2) Wash the core and dry it again, and then carry out the high-pressure mercury intrusion experiment to measure the pore throat radius r and the merc...

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Abstract

The present invention discloses a core nuclear magnetic resonance T2 spectrogram relaxation time and mercury porosimetry pore-throat radius conversion method. The method comprises the steps of: processing a core, performing nuclear magnetic resonance experiment for the core to measure the transverse relaxation time T2 and the signal intensity of the nuclear magnetic resonance and calculate the signal intensity accumulated percentage; processing the core again and performing the high-pressure Hg injection experiment of the core to measure a pore-throat radius r, the mercury injection saturability Shg and a high-pressure Hg injection curve; allowing the signal intensity accumulated percentage at any moment T2 of the nuclear magnetic resonance transverse relaxation time T2 to be Sheci (i), taking the Sheci (i) as standard to perform interpolation for the high-pressure Hg injection curve to obtain a pore-throat radius r(i) corresponding to the transverse relaxation time T2(i); and respectively selecting the two end values of the transverse relaxation time T2(i) and the pore-throat radius r(i) obtained through interpolation, and performing segmentation fitting for the two end values toobtain a relation of the transverse relaxation time and the pore-throat radius at the two ends, and calculating r(i) corresponding to the rest of T2(i) by employing the obtained relation. The method is small in calculation difficulty and accurate in result, and can effectively convert the nuclear magnetic resonance T2 time to the pore-throat radius.

Description

technical field [0001] The invention belongs to the technical field of oil and gas layer physics, and in particular relates to core nuclear magnetic resonance T 2 Spectral relaxation time and mercury intrusion pore throat radius conversion method. Background technique [0002] The NMR mechanism shows that when the sample pores are filled with fluid, H + Transverse relaxation motion in the pores, H + There will be collision with the pore wall, and the movement will cause H + energy loss so that H + From a high energy state back to a low energy state, i.e. H + the transverse relaxation process. The more frequent the collision, the H + The faster the energy loss, obviously, the size of the pores determines the H + The number of collisions with the pore wall, the smaller the pore, the H + In the process of transverse relaxation, the probability of collision with pores is greater, so it can be considered that the size of pores is related to H + The relaxation rate is inv...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N24/08G01V5/00
CPCY02A90/30
Inventor 任晓娟张鑫
Owner XI'AN PETROLEUM UNIVERSITY
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