Nuclear magnetic resonance method for obtaining rock permeability profile

A technology of nuclear magnetic resonance and permeability, which is applied in the direction of permeability/surface area analysis, analysis by nuclear magnetic resonance, and measurement devices, which can solve the problems of difficult internal fluid flow and low permeability, and achieve the effect of improving the evaluation effect

Active Publication Date: 2018-01-09
北京青檬艾柯科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But for the real situation of the whole rock, due to the difference in pore size in these two regi

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  • Nuclear magnetic resonance method for obtaining rock permeability profile
  • Nuclear magnetic resonance method for obtaining rock permeability profile
  • Nuclear magnetic resonance method for obtaining rock permeability profile

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Experimental program
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Effect test

Embodiment 1

[0054] Regarding the novel nuclear magnetic resonance weighted imaging technology involved in this invention, such as figure 1 Shown, it is characterized in that, described method comprises:

[0055] Step 1. Apply a 90° radio frequency pulse to the hydrogen-containing proton spin system of the tested sample on the TRS channel to convert the macroscopic magnetization vector M 0 Turn to horizontal plane;

[0056] Step 2. After waiting for a very short time T, apply a 180° radio frequency pulse to the spin system on the TRS channel to regroup the transverse plane magnetization vector after dephasing; the very short time T is usually tens of microseconds .

[0057] Step 3, after waiting for a very short time T again, apply a 90° radio frequency pulse to the spin system on the TRS channel, and turn the reunited transverse plane magnetization vector by 90° to the vertical axis (in line with the static magnetic field in the same direction);

[0058] Step 4, applying a gradient pu...

Embodiment 2

[0078] On the basis of the first embodiment, the data acquisition method can be replaced by another implementation form, and other steps remain unchanged, and the pulse sequence diagram is as follows figure 2 As shown, the method includes:

[0079] Step 1. Apply a 90° radio frequency pulse to the hydrogen-containing proton spin system of the tested sample on the TRS channel to convert the macroscopic magnetization vector M 0 Turn to horizontal plane;

[0080] Step 2. After waiting for a very short time T, apply a 180° radio frequency pulse to the spin system of the sample under test on the TRS channel to re-gather the transverse plane magnetization vector after dephasing; the very short time T is usually tens of microseconds ;

[0081] Step 3. After waiting for a very short time T again, apply a 90° pulse to the spin system of the tested sample on the TRS channel, and turn the reunited transverse plane magnetization vector by 90° to the longitudinal axis (in line with the d...

Embodiment 3

[0088] On the basis of Embodiments 1 to 2, regarding the method for defining the local connectivity factor of the rock core involved in this invention, as Figure 4 As shown, it is characterized in that it can pass through the T of the adjacent layer 1 The degree of coupling of the distribution function is defined. This definition is based on a reasonable assumption that if the T 1 The higher the coupling degree of the distribution function, the better the pore connectivity in this local area and the higher the rock permeability; and vice versa. Therefore, the definition method of the local connectivity factor is as follows:

[0089]

[0090] Among them, p i,i+1 is the connectivity factor between the i-th layer rock and the i+1-th layer rock; represents the j-th T in the i-th layer of rock 1 Amplitude values ​​corresponding to the distribution; abcd represent the adjacent layers T 1 Interval values ​​of the AND logic operation and the Union logic operation of the dis...

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Abstract

The invention relates to a nuclear magnetic resonance method for obtaining a rock permeability profile. The method relies on a nuclear magnetic resonance weighted imaging method to obtain in situ porosity and pore size information of rock. A local connectivity factor is defined by a coupling relation of pore size distribution at adjacent layers, and the pore connectivity at adjacent locations is further considered, so that the evaluation effect of the permeability is improved, and a continuous permeability profile of the core in a certain axial direction is provided, thus the obtained permeation information is more detailed. The nuclear magnetic resonance method has important application space in the aspect of petroleum geological exploration and recovery efficiency improvement.

Description

technical field [0001] The invention relates to the field of geophysics, in particular to a nuclear magnetic resonance method for obtaining a rock permeability profile. technical background [0002] Rock permeability is an important petrophysical parameter, which is used to evaluate the difficulty of fluid-saturated fluids in rocks flowing in pores, so it can usually be used for reservoir modeling to optimize actual oil and gas development plans. In essence, rock permeability is a function of the flow of internally saturated fluid in the pore structure, which can be equivalently considered as the cross-sectional area of ​​the effective pore flow pipe. At present, there are two main methods to evaluate rock permeability in field development or laboratory. The first is direct flow measurement, in which the effective permeability of a certain cross-section of the rock can be obtained by aerating or watering it during the measurement process. This measurement mode relies on Da...

Claims

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Application Information

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IPC IPC(8): G01N24/08G01N15/08
Inventor 刘化冰宗芳荣汪正垛陈伟梁孙哲杨光
Owner 北京青檬艾柯科技有限公司
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