Device and method for determining radial permeability of compact rock core

A technology of permeability and core, applied in the field of geological exploration and oil and gas field development, can solve the problems of low accuracy of measurement results, large amount of data collection, high cost of instruments, etc., and achieve the effect of stable test results, convenient data collection, and large contact area

Inactive Publication Date: 2014-12-24
CHINA UNIV OF PETROLEUM (EAST CHINA) +1
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  • Abstract
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Problems solved by technology

Although this method can measure the permeability of low-permeability cores, it has two obvious disadvantages: one is that the amount of data collected is large and the requirements for instruments are high, resulting in increased measurement costs; the other is that the measured pressure wave attenuation and The post-processing of phase shift is more complex, resulting in low accuracy of measurement results
The disadvantages of this conventional pressure pulse method are: firstly, the measurement process requires multiple pressure sensors with high precision, which makes the instrument complex and expensive; secondly, the conventional pressure pulse method needs to know the porosity of the core before calculating Therefore, if the measurement of porosity is inaccurate, it will greatly affect the accuracy of the results; finally, in order to achieve accurate measurement, the conventional pressure pulse method needs to control the volume ratio of the upstream and downstream of the core at the same time, which leads to the actual It is easy to produce large measurement errors during operation, and the actual operation is also very troublesome

Method used

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  • Device and method for determining radial permeability of compact rock core
  • Device and method for determining radial permeability of compact rock core
  • Device and method for determining radial permeability of compact rock core

Examples

Experimental program
Comparison scheme
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example 1

[0095] Example 1: At the beginning of the experiment, the shale was saturated with He gas at a temperature of 30° C., and the pressure value was 5 MPa. Pulse pressure was applied to the core holding device 2 so that the pressure in the closed space of the core holding device 2 was 6.82 MPa. At this time, the gas in the confined space quickly flows into the shale. It should be noted here that the pressure value in the first short period of time is invalid. This is because the gas has not flowed through all the radial range of the shale, so the permeability measured during this period is not the radial value of the entire shale. The average permeability, while its size is changed with the length. The length of this period can be judged by the fitting degree of the model to the experimental data. Fitting the experimental data of the first group according to formula (1), the fitting result is as follows image 3 As shown, one can get a 1 =189m -1 , ξ=38.72KPa, γ=0.004, equilib...

example 2

[0103] Example 2: At the beginning of the experiment, the shale was saturated with He gas at a temperature of 30°C, and the pressure value was 8MPa, while the pressure in the closed space of the core holding device was 9.93MPa. According to the solution process of Example 1, the pressure of the core can be obtained The permeability is 3.62×10 -4 mD, the porosity is 3.49%, the fitting result is as Figure 4 shown.

example 3

[0104] Example 3: At the beginning of the experiment, the shale was saturated with He gas at a temperature of 30° C., and the pressure value was 10 MPa, while the pressure in the closed space of the core holding device was 11.64 MPa. According to the solution process of Example 1, the core can be obtained The permeability is 2.81×10 -4 mD, the porosity is 4.10%, the fitting result is as Figure 5 shown.

[0105] From the test core permeability and porosity results that three groups of examples obtain, it can be seen that the test result stability of the device of the present invention is very good. The average value of the permeability in the radial plane of the core is 2.5×10 -4 mD, and the porosity average value measured three times with the conventional porosity measuring instrument (instrument model is: fine and micro Gaobo JW-RB) that adopts the static volumetric method is 3.5%, and this result is very close to the device measurement result of the present invention, Th...

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Abstract

The invention relates to a device and a method for determining radial permeability of a compact rock core. The device comprises a rock core clamping device, an oil pressure pump, a pressurizing pump, an intermediate container, a pressure control system, a pressure acquisition system and a data analysis system, wherein the rock core clamping device is used for clamping a rock core, the oil pressure pump is used for applying confining pressure to the rock core from the axial direction to the end surface of the rock core, the pressurizing pump is used for applying air pressure to the rock core clamping device, the pressure control system is used for controlling the pressure, the pressure acquisition system is used for acquiring the air pressure of the rock core clamping device and the data analysis system is used for fitting data points of the pressure which is measured in an experiment and is varied along the time and calculating the permeability of the tested rock core in the radial direction.

Description

technical field [0001] The invention is mainly used in the fields of geological exploration and oil and gas field development, and in particular relates to a device and a testing method for low radial permeability in tight rock cores. Background technique [0002] Rock is a porous medium with a complex pore structure. The migration characteristics of fluids such as oil and natural gas in it are the focus of attention in the petroleum field, and permeability is the most critical physical parameter that characterizes the ability of fluid to migrate in rock. As unconventional oil and gas reservoirs gradually become the main source of gas reservoirs in my country, the measurement of tight core permeability is extremely important in the field of oil and gas field development. [0003] Tight cores have very low permeability due to small pores, and the measurement of rock ultra-low permeability is a difficult point in the study of oil and gas migration. The most commonly used metho...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N15/08
Inventor 董明哲杨泽皓宫厚健李亚军张少杰徐龙朱腾
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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