Method for improving computed tomography (CT) measured fluid saturation precision

A technology of saturation and precision, which is applied in the field of accurate measurement of fluid saturation by CT, can solve the problems of sensitive damage, cumbersome experiment process, etc., and achieve the effect of reducing operation steps and improving accuracy

Active Publication Date: 2011-09-14
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the usual core displacement experiments need to create irreducible water, and this method makes the corresponding experimental process too cumbersome. Before the displacement experiment, it needs to be saturated with liquid twice and dried, and it will also affect the sensitive core samples. cause some damage

Method used

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  • Method for improving computed tomography (CT) measured fluid saturation precision
  • Method for improving computed tomography (CT) measured fluid saturation precision
  • Method for improving computed tomography (CT) measured fluid saturation precision

Examples

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Embodiment 1

[0054] Example 1 Using CT scanning technology to accurately measure the oil-water two-phase saturation and make an oil-water phase

[0055] Permeability Curve

[0056] (1) Sample: Sandstone core sample 32# from Well Pu I4D in Daqing Oilfield.

[0057] (2) Instruments: GE LightSpeed ​​8-slice spiral medical CT scanner; carbon fiber core holder; Quzix SP-5000 high-pressure metering pump.

[0058] (3) CT scanning conditions: scanning voltage: 100kV, scanning current: 100mA, scanning method: axial scanning, scanning layer thickness: 1.25mm, number of slices per scanning: 49.

[0059] (4) Experimental process:

[0060] 1. After the core sample is dried and weighed, and the porosity and air permeability are measured, it is placed outside the core holder for scanning, and the scanning direction, position and CT value of each scanning slice are recorded;

[0061] 2. Put the core sample into the core holder, increase the confining pressure to 5MPa with distilled water, scan the core i...

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Abstract

The invention relates to a method for improving computed tomography (CT) measured fluid saturation precision. The method comprises the following steps of: a, performing CT scanning on a dry core sample inside and outside a core holder respectively to acquire CT values; b, performing CT scanning on a core of complete saturated brine inside and outside the core holder respectively to acquire CT values; c, making bound water by using the core in the holder, measuring the CT value of the core in a bound water state, and calculating the saturation of the bound water according to the water or liquid outlet volume after the bound water is made completely; d, performing CT scanning on brine for saturation, oil for experiments and peripheral air respectively to acquire CT values, wherein the CT value of the air is a constant value in any medium; e, calculating the CT value of the brine and the CT value of the oil in the core holder by using formulas III and V; and f, calculating the oily watersaturation in the displacement process by using the formula V according to the corrected brine and oil CT values acquired in the step e, wherein the relative error of the saturation is within 1 percent.

Description

technical field [0001] The invention relates to a method for testing rock core fluid saturation, in particular to a CT method for accurately measuring fluid saturation. Background technique [0002] As a routine testing technique in core analysis, CT technology is widely used in core description, core heterogeneity determination, core sample selection, fracture quantitative analysis, online saturation measurement, flow experiment research, etc. The use of CT to measure fluid saturation in rocks has become one of the most common and effective experimental methods for CT technology in the petroleum industry. [0003] The basic principle of CT scanning of rocks is: the X-ray beam generated by the X-ray tube in the CT machine is irradiated from multiple directions along a selected fault layer of the object. By measuring the amount of transmitted X-rays, it is calculated after digitization. These absorption coefficients can form different digital matrices; through the digital-to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N23/04
Inventor 吕伟峰张祖波严守国罗蔓莉刘庆杰
Owner PETROCHINA CO LTD
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