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Method for calculating water saturation of porous medium

A calculation method and technology of porous media, applied in calculation, seismology for logging records, special data processing applications, etc., can solve problems such as large errors in calculation results

Inactive Publication Date: 2012-07-11
SOUTHWEST PETROLEUM UNIV
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  • Abstract
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  • Application Information

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Problems solved by technology

[0020] Analyzing the existing problems of the original calculation method: the debate on Archie’s formula has a long history, and there are two main views: the first view is that Archie’s formula is just an empirical formula, which is an empirical simulation of the relationship between rock electrical properties and water saturation. The second point of view is that each parameter in Archie’s formula has physical meaning, and the two parameters a and b reflect the pore structure of the rock
[0021] In summary, the original method for calculating the water saturation of porous media has flaws in theory and logic, which will lead to large errors in the calculation results.

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  • Method for calculating water saturation of porous medium
  • Method for calculating water saturation of porous medium
  • Method for calculating water saturation of porous medium

Examples

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Embodiment 1

[0093] It is known that in an oilfield where water injection development has ended, the sandstone reservoir at a depth of 1435m has a porosity Φ=23.92%, a permeability k=153.3mD, and an apparent resistivity R t = 1.638Ω·m. The well R is known from the water analysis data w =0.066Ω·m; regional rock electricity experiment (such as figure 2 ) to get: a=1.167, m=1.87, b=1.138, n=1.72. Calculate the water saturation of the reservoir.

[0094] (1) The regional lithoelectric test data of the reservoir are as follows: figure 2 , image 3 As shown, and it is known that the reservoir has been developed through long-term water injection, it can be determined that the reservoir rock is hydrophilic.

[0095] (2) Refitting figure 2 data in ( figure 2 dotted line in ) to get m=2, then calculate the formation factor F of the reservoir:

[0096] F=φ -2 =0.2392 -2 =17.48

[0097] (3) According to image 3 From the experimental data, the parameter a′ varies with the water saturat...

Embodiment 2

[0107] It is known that the porosity of a certain unconsolidated sandstone is Φ=24%, the permeability k=2100mD, and the formation factor F=12.4. The resistivity R of the experimental formation water w =0.21Ω·m; the rock electrical experiment data of the rock sample are as follows Figure 4 . Calculate the apparent resistivity R t =7.2Ω·m, the water saturation of the rock sample.

[0108] (1) The I-S of the rock-electric experiment of the rock sample w data such as Figure 4 shown. According to the self-priming method in the industry standard SY / T 5153-2007, the relative wettability index of the rock sample is measured to be 0.58, which can be judged that the rock sample is hydrophilic.

[0109] (2) The stratigraphic factor F of this rock sample is known, so there is no need to calculate F again.

[0110] (3) According to Figure 4 From the experimental data, the parameter a′ varies with the water saturation S w The changing relationship:

[0111] ...

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Abstract

The invention relates to a method for calculating water saturation of a porous medium, which is an explanation method of geophysical electrical logging data and sequentially comprises the steps of (1) selecting and cutting a rock sample, performing an rock electrical experiment on an A section rock sample, and applying a B section rock sample to wettability measurement; (2) calculating a formation factor F; (3) calculating a parameter a' and fitting change relation of the a' along with Sw; and (4) calculating the water saturation Sw. The parameter a' has clear physical significance, describes influence of the distribution of a pore structure and the pore fluid of the porous medium on a resistance increase coefficient, and changes along with the changes of the water saturation. Due to the fact that a water saturation calculation formula in the method defines the influence of the distribution pattern of the pore structure and the pore fluid in pores on the resistance increase coefficient I, calculating results are accurate, the explanation method and the technique of geophysical electrical logging are perfected, and a basis and a means are provided for quantitative calculation of the water saturation of a reservoir stratum.

Description

technical field [0001] The present invention relates to the calculation method of rock electrical properties and rock water saturation, especially the quantitative calculation of water saturation of oil and gas reservoirs based on rock electrical experiment data and electrical logging data, which is a kind of geophysical electrical logging data explain the method. Background technique [0002] Porous media widely exists in nature and human society, such as sedimentary rocks, metamorphic rocks, igneous rocks and artificial rock materials in natural rocks. A large amount of oil, gas, and water resources are stored in underground rock formations. These resources are usually detected and evaluated by geophysical methods. The most widely used method is to use electrical logging technology combined with petrophysical experiments to measure oil and gas saturation. Evaluation, this method is applied to all stages of oil and gas reservoir exploration and development. [0003] Accor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01V1/40G06F19/00
Inventor 李闽唐雁冰王念喜
Owner SOUTHWEST PETROLEUM UNIV
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