阅读说明：本技术 一种可实时确定活塞位置的中间容器 (Intermediate container capable of determining position of piston in real time ) 是由 郭平 周茹 田正坤 汪周华 刘煌 石磊 孙博文 于 2021-09-29 设计创作，主要内容包括：本发明涉及一种可实时确定活塞位置的中间容器,包括上端盖2、筒体8、活塞6、下端盖11、压敏元件5、转换元件3、计算机10和底部支架14,筒体8位于底部支架14上,筒体与上端盖、下端盖之间设置密封垫圈,活塞6位于筒体内,将筒体内分为互不连通的两个空间,样品置于上部空间,传动介质置于下部空间,上端盖中心位置设有样品出口阀1连接岩心夹持器,下端盖中心位置设有传动介质出口阀13连接驱替泵；压敏元件5和转换元件3组成电阻式压力传感器,计算机确定活塞在移动过程中的准确位置。本发明可实时确定中间容器的活塞位置,对于连续驱替需定量化确定样品注入量、提高实验稳定性、延长中间容器使用寿命具有重要意义。(The invention relates to an intermediate container capable of determining the position of a piston in real time, which comprises an upper end cover 2, a cylinder 8, a piston 6, a lower end cover 11, a pressure-sensitive element 5, a conversion element 3, a computer 10 and a bottom support 14, wherein the cylinder 8 is positioned on the bottom support 14, a sealing gasket is arranged between the cylinder and the upper end cover as well as between the cylinder and the lower end cover, the piston 6 is positioned in the cylinder and divides the interior of the cylinder into two spaces which are not communicated with each other, a sample is arranged in the upper space, a transmission medium is arranged in the lower space, a sample outlet valve 1 is arranged at the central position of the upper end cover and connected with a rock core holder, and a transmission medium outlet valve 13 is arranged at the central position of the lower end cover and connected with a displacement pump; the pressure sensitive element 5 and the conversion element 3 constitute a resistance type pressure sensor, and the computer determines the accurate position of the piston in the moving process. The method can determine the position of the piston of the intermediate container in real time, and has important significance for determining the sample injection amount quantitatively in continuous displacement, improving the experimental stability and prolonging the service life of the intermediate container.)

1. An intermediate container capable of determining the position of a piston in real time comprises an upper end cover (2), a cylinder body (8), a piston (6), an annular rubber gasket (7), a lower end cover (11), a pressure-sensitive element (5), a conversion element (3), a computer (10) and a bottom support (14), and is characterized in that the cylinder body (8) is positioned on the bottom support (14), the cylinder body is respectively connected with the upper end cover (2) and the lower end cover (11) through threads, sealing gaskets (4 and 12) are arranged between the cylinder body and the upper end cover and between the cylinder body and the lower end cover, the piston (6) is positioned in the cylinder body, the annular rubber gasket (7) is arranged between the piston and the inner wall of the cylinder body, the piston divides the cylinder body into two spaces which are not communicated with each other, a sample is arranged in the upper space, a transmission medium is arranged in the lower space, a sample outlet valve (1) is arranged at the central position of the upper end cover and connected with a core holder, and the sample is controlled to enter a core by adjusting the valve in the displacement process, a transmission medium outlet valve (13) is arranged at the center of the lower end cover and connected with the displacement pump to control the transmission medium to enter and exit the lower space of the cylinder body; the pressure-sensitive element (5) and the conversion element (3) form a resistance-type pressure sensor, the pressure-sensitive element is sintered on the inner wall of the cylinder body at high temperature to directly sense pressure change caused by the piston in the up-and-down moving process to the inner wall of the cylinder body, the conversion element converts a pressure change signal into a voltage signal and transmits the voltage signal to the computer (10), and the computer determines the accurate position of the piston in the moving process.

2. The intermediate container capable of determining the position of the piston in real time as claimed in claim 1, wherein the pressure sensitive elements are vertically and uniformly distributed on the symmetrical two sides of the inner wall of the cylinder body at a distance of 0.5 cm.

3. The intermediate container capable of determining the position of the piston in real time as claimed in claim 1, wherein when a displacement experiment is performed, the piston generates a certain pressure on the pressure-sensitive element on the inner wall of the cylinder, when the pressure-sensitive element is subjected to external pressure change, a pressure-sensitive resistance effect is generated to cause a resistance value to change, the conversion element converts a resistance change signal into a voltage signal to be output, and the computer acquires the voltage signal output by the conversion element to determine the accurate position of the piston in the moving process.

Technical Field

The invention belongs to the technical field of oil and gas exploitation, and relates to an intermediate container capable of determining the position of a piston in real time.

Background

In the field of oil and gas exploitation, a core displacement experiment is one of important physical simulation means. Through a rock core displacement experiment, the distribution rule of oil, gas and water and a microcosmic displacement mechanism can be simulated in a microcosmic manner; on a macroscopic level, reservoir production mechanisms can be analyzed. The physical simulation device with excellent performance is researched and developed, and the stability, safety and accuracy of a physical simulation experiment can be effectively improved. The middle container is an important component of the physical simulation device and mainly comprises a cylinder body, an upper end cover, a lower end cover, a piston, a sample outlet valve, a transmission medium inlet and outlet valve, a bottom support and the like. The piston can divide the cylinder into a sample end and a transmission medium end, the transmission medium end is connected with the displacement pump, and the sample end is connected with the experimental device. The working principle is as follows: the displacement pump presses the hydraulic medium into the intermediate container drive medium end to drive the piston, thereby pressing the sample in the intermediate container sample end into the experimental apparatus. At present, the conventional intermediate container is greatly improved in the aspects of high temperature resistance, high pressure resistance, sealing property and the like, and in order to ensure the temperature resistance and pressure resistance, the intermediate container is mostly made of high-strength non-transparent materials such as alloy and the like, so that the position of a piston cannot be observed in real time. Although the middle container piston can be observed by additionally arranging the sapphire visual window, the sapphire visual window has higher process requirement and cost. When a physical simulation experiment is performed, if an experimenter cannot observe the position of the piston in real time, the following problems may occur: (1) when the displacement experiment needs to sample for multiple times, a specific displacement state needs to be achieved (for example, in a water flooding experiment, the displacement is needed until oil is not discharged any more), the sample injection amount is different every time, and the length of a connecting pipeline can also influence the residual sample amount in the intermediate container, so that an experimenter can not judge whether the residual sample amount in the intermediate container meets the requirement of the next sample injection amount, and can only open the intermediate container for sample injection for multiple times, which can cause influence on the experiment period, stability and error, and meanwhile, the intermediate container can be mechanically damaged due to repeated assembly and disassembly of the intermediate container, and the service life is reduced; (2) in the process of carrying out the core displacement experiment, the position of the piston cannot be determined, whether the sample is used up or not can be judged only by displaying the pressure surge through the sensor, and when the pressure surge occurs, the piston of the intermediate container is in a state of jacking the end cover of the container, so that the end cover can be damaged (Jian, prevent the piston from jacking the intermediate container P of the container cover in the core displacement experiment, Chinese patents: 201821268977.1 and 2018.08.08).

Disclosure of Invention

The invention aims to provide an intermediate container capable of determining the position of a piston in real time, which can determine the position of the piston of the intermediate container in real time under the condition of ensuring the high temperature resistance, high pressure resistance and sealing performance of the intermediate container and has important significance for continuously replacing the requirement of quantitatively determining the injection amount of a sample, improving the experimental stability, reducing the mechanical damage of the intermediate container and prolonging the service life of the intermediate container.

In order to achieve the technical purpose, the invention adopts the following technical scheme.

An intermediate container capable of determining the position of a piston in real time mainly comprises an upper end cover, a cylinder body, a lower end cover, a sealing washer, the piston, an annular rubber washer, a sample outlet valve, a transmission medium inlet and outlet valve, a resistance-type pressure sensor, a computer and a bottom support.

The upper end surface and the lower end surface of the cylinder body are connected with the upper end cover and the lower end cover through threads, and the upper end cover, the lower end cover and the cylinder body are made of stainless steel materials.

The upper end cover is provided with a sealing gasket, and the sealing gasket is arranged between the cylinder body and the upper end cover during installation, so that a sample is prevented from leaking between the inside of the cylinder body and the upper end cover due to untight sealing.

Similarly, the lower end cover is also provided with a sealing gasket, and the sealing gasket is arranged between the cylinder body and the lower end cover during installation, so that the transmission medium is prevented from leaking between the inside of the cylinder body and the lower end cover due to poor sealing.

The piston divides the cylinder into two closed parts, one end is provided with an experimental sample, the other end is provided with a driving medium, and the piston can move up and down along the axial direction of the cylinder; and an annular rubber gasket is arranged at the middle groove of the piston to prevent liquid from flowing between the upper end and the lower end of the cylinder.

The sample outlet valve is positioned at the opening of the round center of the upper end cover, and can control the flow rate of the sample in the displacement experiment process.

Similarly, the transmission medium inlet and outlet valve is positioned at the opening of the round center of the lower end cover, and controls the inlet and outlet of the transmission medium when a displacement experiment and sample adding are carried out.

The transmission medium is generally composed of hydraulic oil or silicone oil, and can be regarded as a rigid medium without compressibility.

The resistance-type pressure sensor consists of a pressure-sensitive element and a conversion element, and the working principle is as follows: the pressure sensitive element is sintered on the inner wall of the cylinder body at high temperature, can directly sense the pressure change of the inner wall of the cylinder body caused by the up-and-down movement process of the piston, converts the pressure change signal into a voltage signal through the conversion element and collects the voltage signal by a computer. The resistance type pressure sensors are vertically and uniformly distributed on two symmetrical sides of the inner wall of the cylinder body, and the distribution distance is 0.5 cm.

The pressure-sensitive element is of a sandwich structure consisting of a stainless steel substrate, a dielectric layer, a piezoresistor, a conductor and a protective layer. The working principle is as follows: the piezoresistor is fixedly connected on the elastic stainless steel substrate in a sputtering or micro-melting glass mode and is connected through the conductor to form the Wheatstone bridge, when external pressure acts on the substrate, the substrate is slightly deformed to cause the resistance value of the piezoresistor to change, the Wheatstone bridge is caused to change to cause the output electric signal to change, and therefore the position change of the piston of the intermediate container in the moving process can be accurately detected.

The main component of the dielectric layer is ceramic, also called an insulating layer, and the insulating layer is required to be printed and fired because the stainless steel substrate is a conductor which can not be directly adhered with the piezoresistor and the conductor.

The piezoresistors are connected into a Wheatstone bridge through conductors, and the resistance value changes when the piezoresistors are subjected to external pressure, so that the change of an electric signal is caused.

The conductor has good compatibility with the piezoresistor and strong adhesion with the substrate, and can ensure the stability of the circuit.

The protective layer has good sealing property, insulating property and stability of protective resistance, is resistant to temperature, pressure and corrosion, and can work in high-temperature and high-pressure environments.

The bottom support is used for supporting the intermediate container and has certain stability.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention designs an intermediate container capable of determining the position of a piston in real time, and the position of the piston of the intermediate container in the cylinder can be accurately determined by introducing a pressure sensor;

(2) the piston position is determined, so that mechanical damage to a container cover when the intermediate container works in a high-pressure environment can be prevented, and the safety and the stability of an experiment are improved;

(3) the invention does not change the simple and convenient structure of the intermediate container, improves the practicability of the device and ensures the good sealing property of the intermediate container.

Drawings

Fig. 1 is a schematic view of an intermediate container structure capable of determining the position of a piston in real time.

In the figure: 1-a sample outlet valve; 2-upper end cover; 3-a conversion element; 4. 12-a sealing gasket; 5-a pressure sensitive element; 6-a piston; 7-ring-shaped rubber gasket; 8-barrel body; 9-a transmission medium; 10-a computer; 11-lower end cap; 13-transmission medium outlet valve; 14-bottom support.

Detailed Description

The present invention is further described below with reference to the accompanying drawings so as to facilitate understanding of the present invention by those skilled in the art. It is to be understood that the invention is not limited in scope to the specific embodiments, but is intended to cover various modifications within the spirit and scope of the invention as defined and defined by the appended claims, as would be apparent to one of ordinary skill in the art.

An intermediate container capable of determining the position of a piston in real time comprises an upper end cover 2, a cylinder 8, the piston 6, an annular rubber gasket 7, a lower end cover 11, a pressure-sensitive element 5, a conversion element 3, a computer 10 and a bottom bracket 14.

The cylinder 8 is positioned on the bottom support 14, the cylinder is connected with the upper end cover 2 and the lower end cover 11 through threads respectively, sealing gaskets 4 and 12 are arranged between the cylinder and the upper end cover and between the cylinder and the lower end cover, the piston 6 is positioned in the cylinder, an annular rubber gasket 7 is arranged between the piston and the inner wall of the cylinder, the piston divides the interior of the cylinder into two spaces which are not communicated with each other, a sample is arranged in the upper space, a transmission medium is arranged in the lower space, a sample outlet valve 1 connected with a rock core holder is arranged at the central position of the upper end cover, the sample is controlled to enter a rock core through adjusting the valve in the displacement process, a transmission medium outlet valve 13 connected with a displacement pump is arranged at the central position of the lower end cover, and the transmission medium 9 is controlled to enter and exit from the lower space of the cylinder. The pressure sensitive element 5 and the conversion element 3 form a resistance type pressure sensor, the pressure sensitive element is sintered on the inner wall of the cylinder body at high temperature to directly sense the pressure change of the inner wall of the cylinder body caused by the up-and-down movement process of the piston, the conversion element converts the pressure change signal into a voltage signal and transmits the voltage signal to the computer 10, and the computer determines the accurate position of the piston in the movement process.

The pressure-sensitive elements are vertically and uniformly distributed on two symmetrical sides of the inner wall of the cylinder body, and the distribution distance is 0.5 cm.

When a displacement experiment is carried out, the piston generates certain pressure on the pressure-sensitive element on the inner wall of the cylinder, when the pressure-sensitive element bears the external pressure change, the pressure-sensitive resistance effect is generated to cause the resistance value to change, the conversion element converts the resistance change signal into a voltage signal to be output, and the computer acquires the voltage signal output by the conversion element to determine the accurate position of the piston in the moving process.

Because the volume of the sample added into the intermediate container or the volume of the transmission medium is determined, the residual volume of the sample can be further determined according to the volume of the space of the cylinder body through which the piston moves, and therefore the continuous quantitative rock core displacement experiment is carried out.