High-temperature and high-pressure visual seepage experimental device and method for real sandstone

Abstract

The invention relates to a high-temperature and high-pressure visual seepage experimental device and method for real sandstone. The device comprises a real sandstone high-temperature and high-pressuremicroscopic visual model arranged in a high-temperature and high-pressure kettle; the high-temperature and high-pressure kettle is connected with a pressure system for pressurizing the real sandstonehigh-temperature and high-pressure microscopic visual model; the high-temperature and high-pressure kettle is provided with a microscope; the real sandstone high-temperature and high-pressure microscopic visual model comprises a rock sheet; the lower surface of the rock sheet is provided with first glass; the first glass and the rock sheet are connected through an adhesive; two holes are formed in the first glass; a distance between a model fluid inlet and a model fluid outlet is greater than the length of the rock sheet; the upper surface of the rock sheet is provided with second glass; andthe side walls of the rock sheet are respectively provided with a box dam with an inlet guide groove and a box dam with an outlet guide groove along the width direction of the rock sheet. Because therock sheet is a real reservoir sample, the rock sheet has real reaction performance, and a corresponding visual seepage experiment can be carried out under high temperature and high pressure. The device has the advantages of simple structure, flexible operation and high efficiency.

Description

technical field [0001] The invention relates to a seepage experiment method, in particular to a real sandstone high temperature and high pressure visualization seepage experiment device method. Background technique [0002] In order to implement the spirit of the central government’s instructions on increasing domestic oil and gas exploration and development, ensuring national energy security, better serving the decision-making and deployment of oil and gas companies’ development and production, fighting the offensive battle of oil and gas development, and adding oil and gas to the country, Northwest University Geology On the basis of long-term teaching and research in the laboratory, the team of Professor Zhu Yushuang from the Department of Science and Technology creatively designed and mastered the real sandstone high-temperature and high-pressure visual seepage experimental device. This technology has successfully achieved the purpose of using real sandstone models to stu...

AI Technical Summary

Problems solved by technology

However, due to the model making process, model style and materials used, the shortcomings of this model are reflected in: 1) Seepage experiments cannot be carried out under high pressure (reservoir pressure) conditions, and corresponding experiments can only be carried out under normal pressure environments. It is also the biggest deficiency of the model; 2) The displacement pressure is low, and the maximum displacement pressure is only 0.20MPa; 3) The experimental temperature is limited, and the maximum temperature that can be tolerated is about 80°C, and it cannot be used in a higher reservoir temperature environment Various seepage experiments were carried out; 4) The length of the model is short, which is not conducive to the development of gas flooding under high pressure (CO 2 Drive, N 2 Flooding and air flooding, etc.) and polymer flooding isotonic flow mechanism

[0006] 2. Other models commonly used in visual seepage experimental devices can withstand high pressure and high displacement pressure, but they are not realistic

When studying the microscopic seepage mechanism of ultra-low, ultra-low permeability and tight oil and gas reservoirs, the pore-throat structure of the reservoir has become very complex, and the flat glass photolithography model and the quartz sand or formation sand grain bonding model cannot meet the existing research requirements. Therefore, it is impossible to accurately understand the occurrence state and seepage law of various displacement agents in the process of displacing crude oil

[0008] 3. The "core clip" that is occasionally used in the visual seepage experimental device is just sandwiching the core chip between two pieces of sapphire, which is not only expensive, but also prone to surface flow between the core clip and the glass. "core sandwich", but cannot reflect the seepage characteristics of the real pore space

The shortcoming of this model is: 1) make complex

3) The use of this high-temperature firing to form a seepage model will cause changes in the pore structure

It is reported in the literature that ore can produce structural thermal stress under high temperature conditions of 400-600°C, which damages the original microstructure of ore, and micro-cracks grow and develop. For example, when magnetite and quartzite are heated at high temperature (above 400°C), The efficiency of thermal crushing is higher, which is beneficial for mining when using fire drilling, but it is not good for maintaining the pore structure when firing at high temperature into a percolation model

[0012] 5. In the visual seepage experimental device, 3D printing technology is used to make pore seepage slices, which cannot be completely replicated, which reduces the credibility of seepage characteristics

The current real sandstone microscopic model cannot be used for seepage experiments under high temperature and high pressure conditions (the model is real, but it cannot withstand high temperature and high pressure), and the flat glass photolithography model and quartz sand or formation sand bonding model used, although resistant to high pressure and high temperature , but due to the material of the experimental model itself, the characteristics of the pore throat structure and surface physical properties are too far from the real reservoir (it can withstand high pressure, but the model is not real), which greatly reduces the credibility of the research results. Unable to meet the research needs of low-permeability, especially tight reservoir microscopic seepage mechanism

Other "true or quasi-real" models cannot truly reflect the real pore structure and its internal seepage

[0015] At present, the seepage model of real sandstone high temperature and high pressure microscopic seepage test equipment is scarce, and the corresponding supporting experimental technology is also impossible to talk about. , ultra-low permeability and tight oil and gas reservoirs corresponding exploration and development research work

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