CN102865899B - Method and device for in-situ measurement of fluid volume during high temperature and high pressure core displacement - Google Patents

Abstract

The invention discloses a kind of method that can carry out fluid volume in site measurement in High Temperature High Pressure rock core displacement process, and the method can be used to carry out the device of fluid volume measurement.The method is divided into three steps, and the first step is the preparation before formal displacement, it is therefore an objective to make fluid and fluid in container in fluid in rock core, conduit be under corresponding high temperature and high pressure environment；Second step starts formal displacement, squeezes into displacement liquid by compression pump, and the fluid (especially gas and oil) that displacement goes out from rock core comes together in an airtight transparent vessel；3rd step is for measuring each fluid volume, after oil gas water is fully layered, owing to the color of three kinds of fluids is different, can be read the volume of three by the scale on container.Designed fluid volume measurement apparatus simple in construction, only need to increase by four valves, two conduits, two pressure-measuring devices, a collection container, a buffer container and a semi-permeable plate on the basis of conventional high temperature high pressure rock core displacement test device.

Description

Method and device for in-situ measurement of fluid volume during high temperature and high pressure core displacement

technical field

The invention also relates to a fluid volume measuring device, in particular to a fluid volume measuring device during high temperature and high pressure rock core displacement.

Background technique

Under high temperature and high pressure, especially the existence of high temperature, the expelled fluid in the process of core displacement has two phases of gas and liquid. At present, the displacement fluid is mostly directly measured by an open small measuring cylinder, so that the capture and measurement of the gas phase cannot be realized; in addition, at high temperature, the liquid is volatile, so the measurement error of the liquid is relatively large, especially in the tight sandstone displacement experiment. Due to the slow displacement speed and the small amount of expelled liquid, the error caused by the volatilization of liquid will be larger. Aiming at the shortcomings of the open small measuring cylinder measurement method, a closed measurement method is proposed, that is, a section of viscous liquid (such as aviation kerosene) is added to the thin glass tube to block it. Although this method can capture and measure the gas, it can also avoid the volatilization of the liquid, but there are still many problems in this measurement method. It has a great impact, and also affects the solubility of gas in liquid, thereby changing the gas-liquid volume ratio. Therefore, the volume of each phase fluid measured in this way is still inaccurate, and cannot truly reflect the fluid volume inside the core under high temperature and high pressure. .

Contents of the invention

The object of the present invention is to provide a method for in-situ measurement of fluid volume during high temperature and high pressure rock core displacement, and a device capable of measuring fluid volume using the method.

The purpose of the present invention is achieved through the following technical solutions: do the following preparatory work before the official displacement, set the temperature of the incubator as the high temperature required for the experiment, and wait for the temperature to rise to the set value and keep it for a certain period of time. Inject liquid into each conduit and container from both ends of the core holder, in which the trapped air can be released by opening the valve on the upper end of the collection container to ensure that there is no air in the collection container, and then apply ring pressure and shaft to the core holder Pressure, adjust the opening pressure of the back pressure valve to be greater than the pressure of the liquid to be pressurized, and then pressurize the liquid from both ends of the core holder to the predetermined pressure synchronously, but the pressure of the liquid after pressurization should be lower than the applied ring pressure and Axial pressure, so that the fluid in the core, the fluid in the conduit and the fluid in the container are in a corresponding high temperature and high pressure environment. In order to ensure that the displaced gas collects as much as possible in the closed container, a semi-permeable partition is added in the conduit to Stop the passage of gas; after the above preparatory work is completed, the formal displacement starts. First, lower the opening pressure of the back pressure valve to the pressure of the fluid in the core after pressurization, and then pressurize the displacement liquid through the pressure pump. When the pressure rises to the pressure of the fluid in the core, the valve leading to the core holder can be opened, and the pressure pump can continue to pressurize the displacement liquid, so that the displacement liquid enters the core, and the fluid displaced from the core (especially Gas and oil) are collected in a closed transparent container under the action of gravity before flowing out of the back pressure valve; before measuring the volume of each fluid, it is best to stop the displacement and stand still for a certain period of time to ensure that the oil, gas and water are fully contained in the closed container. After stratification, oil, gas and water are stratified, and the colors of the three fluids are different, and the volumes of the three fluids can be read through the scale on the container. Due to the complexity of the core pore structure, the pressure of the fluid fluctuates during the entire displacement process , In order to slow down the fluctuation of fluid pressure, a buffer container is added, and the container is filled with air.

The inventive method specifically comprises the steps:

Step 1: Before formal displacement, under high temperature environment, fill liquids in each conduit and collection container in advance, and apply ring pressure and axial pressure to the core holder, and then add liquid simultaneously from both ends of the core holder. Pressure, so that the fluid in the core, the fluid in the conduit and the fluid in the container are in a corresponding high temperature and high pressure environment;

Step 2: start the formal displacement, and the fluid (especially gas and oil) displaced from the core is collected through a closed container before flowing out of the back pressure valve;

Step 3: Interrupt the displacement. After standing still for a certain period of time, the different densities of oil, gas and water cause the three to stratify in a closed container, and measure the volume of the three through the scale on the container.

Before the present invention pressurizes the liquid synchronously from both ends of the core holder, the opening pressure of the back pressure valve is greater than the pressure of the liquid after pressurization, and the pressure of the liquid after pressurization is lower than the applied ring pressure and axial pressure, and the formal driving begins. When replacing, turn down the opening pressure of the back pressure valve to be the pressure of the fluid in the rock core after pressurization.

In the present invention, the valve can only be opened when the pressure of the displacement liquid injected by the pressure pump is equal to the pressure of the fluid in the rock core, and the displacement liquid enters the rock core when the pressure of the displacement liquid is further increased.

The present invention uses a semi-permeable partition to prevent gas from passing through, so as to ensure that the displaced gas is collected in a closed container.

In order to slow down the fluctuation of fluid pressure during displacement, a buffer container is added, and the container is filled with air.

The device used in the in-situ measurement method of fluid volume in the high-temperature and high-pressure rock core displacement process of the present invention is to increase four valves (2, 8, 10, 14) on the basis of conventional high-temperature and high-pressure rock core displacement experimental devices, and two conduits ( 7, 13), two pressure gauges (6, 15), a collection vessel (9), a buffer vessel (12) and a semi-permeable partition (4).

The collecting container (9) of the present invention has a wide entrance, a slender main body, and an air release port (11) on the top.

The buffer container (12) of the present invention has a large volume, and the manufacturing material is resistant to high temperature and high pressure and is not easily deformed.

Compared with the prior art, the beneficial effect of the present invention is that the displacement fluid can be measured in situ during the high temperature and high pressure core displacement process, the fluid volume measurement accuracy is high, and the high temperature and high pressure can be truly reflected. In addition, the designed device has a simple structure and only needs to add a few accessories on the basis of the conventional high-temperature and high-pressure core displacement experimental device.

Description of drawings

Fig. 1 is a structural schematic diagram of the fluid volume in-situ measurement device during the high temperature and high pressure core displacement process of the present invention.

detailed description

Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

In the experimental device in the accompanying drawings, except for the pressure pump 1, other devices are placed in the thermostat. Before formal displacement, first set the temperature of the thermostat to the high temperature required for the experiment, close the valve 2, adjust the opening pressure of the back pressure valve 5 to be greater than the pressure of the liquid to be pressurized, and wait until the temperature rises to the set value And keep it for a certain period of time, open the valves 8 and 14, and inject liquid into each conduit and container from both ends of the core holder 3 through the conduits 7 and 13, during which the trapped fluid is released by opening the valve 10 on the upper end of the collection container 9 Ensure that there is no air in the collection container 9, then close the valve 10, then apply ring pressure and axial pressure to the core holder 3, and then pressurize the liquid synchronously through the conduits 7 and 13 respectively, and the liquid pressure rises to a predetermined After pressure, close the valves 8 and 14, and the pressure of the liquid can be observed in real time by two pressure measuring instruments 6 and 15. In order to ensure that the displaced gas gathers as much as possible in the airtight container 9, a semi-permeable barrier is added in the conduit. plate 4 to prevent the passage of gas; when formal displacement, first lower the opening pressure of the back pressure valve 5 to the pressure of the fluid in the core after pressurization, and then pressurize the displacement liquid through the pressure pump 1, the pressure of the liquid to be displaced When the pressure of the fluid in the core is increased, open the valve 2 leading to the core holder, and continue to pressurize the displacement liquid through the pressure pump 1. Before the valve 5, under the action of gravity, they are collected in the collection container 9; the collection container 9 is transparent and has a scale on it. After standing still for a certain period of time to separate the oil, gas and water, the volume of the three can be read through the scale on the collection container 9.

Claims (2)

1. The method for in-situ measurement of fluid volume during high temperature and high pressure core displacement, characterized in that it comprises the following steps: Step 1: Before the official displacement, first set the temperature of the thermostat to the high temperature required for the experiment, after the temperature rises to the set value and maintains it for a certain period of time, then through the conduits (7), (13) from the core clamp Fill the two ends of the holder (3) with displacement fluid into each conduit and collection container (9), then apply ring pressure and axial pressure to the core holder (3), and adjust the opening pressure of the back pressure valve (5) to be greater than After pressurization, the pressure of the liquid is then simultaneously pressurized to the predetermined pressure from the two ends of the core holder (3) through the conduits (7), (13), and the pressure of the liquid can be measured by two pressure measuring instruments (6 ) and (15) are observed in real time, but the pressure of the liquid after pressurization is lower than the applied annular pressure and axial pressure, so that the fluid in the core, the fluid in the conduit and the fluid in the collection container (9) are in a corresponding high temperature and high pressure environment , in order to ensure that the displaced gas gathers as much as possible in the airtight collection container (9), a semi-permeable partition (4) is added in the conduit to prevent the passage of gas; Step 2: When formally displacing, first lower the opening pressure of the back pressure valve (5) to the pressure of the fluid in the core after pressurization, and then pressurize the displacement fluid through the pressure pump (1). When the pressure of the fluid in the core is increased, open the valve (2) leading to the core holder (3), and continue to pressurize the displacement fluid through the pressure pump (1), so that the displacement fluid enters the core and flows from the core The displaced fluid is collected in the collection container (9) under the action of gravity before flowing out of the back pressure valve (5); Step 3: Stop displacement and stand still for a certain period of time. The density of oil, gas and water is different so that the three are fully separated in the airtight collection container (9). After the oil, gas and water are separated, they can pass through the scale on the collection container (9). Measure the volume of the three. 2. the fluid volume in-situ measurement method in the high temperature and high pressure rock core displacement process according to claim 1 is characterized in that, the inlet of collection container (9) is wide, and main body is thin, and the top is provided with air vent (11), and making material It is resistant to high temperature and high pressure, not easily deformed and transparent, with reinforced steel plates on the periphery, and an oil-repellent layer on the inner wall.