A method and device for testing physical properties of reservoir fluids

Abstract

The application discloses a kind of oil reservoir fluid physical property test method and oil reservoir fluid physical property test device, solve the technical problem of low precision of existing PVT test.The oil reservoir fluid physical property test method includes: step S1, into the test cylinder with visual area into raw material;Step S2, the temperature in the cylinder of test cylinder is adjusted to set temperature, the pressure in the cylinder of test cylinder is adjusted to set pressure, so that oil and gas in raw material are compatible or separated;Step S3, the image in visual area is photographed by camera device, when the image photographed is first image, test cylinder is exhausted and collected, until the image photographed becomes second image, it is determined that exhaust is completed, stop exhaust;Step S4, data determination is carried out to oil and / or collected gas.The application utilizes the different refraction of light penetrating gas and the refraction when penetrating oil, and the visualization of judgment can be realized by the light bright and dark change, to accurately control the discharge of gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas reservoir fluid testing analysis, and particularly relates to an oil reservoir fluid physical property testing method and an oil reservoir fluid physical property testing device. BACKGROUND

[0002] In oilfield exploitation, it is extremely important to test and analyze the oil and gas reservoir fluid of an oilfield, and the PVT test result provides great help for understanding the gas injection development mechanism, the crude oil swelling characteristics and the reserve calculation. At present, for some heavy oil and super heavy oil with high formation temperature and high pressure, a formation sampling method is adopted for measurement, and no compounding test is performed. However, the sampling is difficult and requires high requirements, and only a flowing well meets the requirements.

[0003] At present, a new technology is urgently needed to test the oilfield in the production period, but the test difficulty mainly lies in improving the test precision during the compounding and test process. The test in the prior art has the technical problem of low precision, and the test result error is large, which greatly affects the subsequent analysis and calculation. SUMMARY

[0004] To solve the above technical problems, the purpose of the present application is to overcome the shortcomings of the prior art and provide an oil reservoir fluid physical property testing method and an oil reservoir fluid physical property testing device, which realize dynamic visual judgment. The method is simple and convenient, has a wider test range, better precision and significantly improved safety.

[0005] The scheme for achieving the technical purpose of the present application is an oil reservoir fluid physical property testing method, comprising:

[0006] Step S1, introducing raw materials into a test cylinder with a visible area;

[0007] Step S2, adjusting the temperature in the test cylinder to a set temperature and adjusting the pressure in the test cylinder to a set pressure, so that the oil and gas in the raw materials are dissolved or separated;

[0008] Step S3, capturing an image in the visible area by a camera device, when the captured image is a first image, performing exhaust and collection on the test cylinder until the captured image becomes a second image, determining that the exhaust is completed, stopping the exhaust, the first image is a bright white image in a light transmission state, and the second image is a dim black image in a light blocking state;

[0009] Step S4, performing data measurement on the oil and / or the collected gas.

[0010] Further, two visible windows are symmetrically arranged on the test cylinder, one of the visible windows is externally provided with a light source, and the camera device is arranged outside the other visible window;

[0011] In the step S2, the image in the visual window is captured by the camera, specifically including: turning on the light source, and capturing the image in the visual window by the camera.

[0012] Further, in the step S2, the temperature in the test cylinder is set to a set temperature, specifically including: heating the raw material by the heating coil arranged in the test cylinder, and monitoring the temperature change by the temperature sensor.

[0013] Further, the step S2 further includes: controlling the test cylinder to be turned over, and stirring and mixing the raw material by the stirring device arranged in the test cylinder.

[0014] Further, the viscosity of the oil is greater than 100 mPa·s.

[0015] Further, the oil reservoir fluid property test is specifically a degassing test.

[0016] In the degassing test method, the raw material is a formation sample or a compounded sample.

[0017] In the step S2, the pressure in the test cylinder is adjusted to a set pressure, specifically including: performing at least one pressure reduction process on the test cylinder at a set pressure reduction gradient, until the pressure in the test cylinder is reduced from a preset formation pressure to atmospheric pressure.

[0018] The step S3 and the step S4 are continuously performed during the pressure reduction process.

[0019] Further, the raw material is a compounded sample, and the preparation method of the compounded sample specifically includes:

[0020] Step A1, introducing oil and gas into the test cylinder respectively;

[0021] Step A2, adjusting the temperature in the test cylinder to a set formation temperature, and pressurizing the pressure in the test cylinder from atmospheric pressure to a set formation pressure, so that the oil and the gas are compatible.

[0022] Step A3, capturing the image in the visual area by the camera, when the captured image is a first image, performing exhaust on the test cylinder and collecting, until the captured image changes to a second image, determining that the exhaust is completed, stopping the exhaust, recording the amount of introduced gas V0 and the amount of collected exhaust L0; and taking the oil in the test cylinder as the compounded sample.

[0023] Further, the step A3 specifically includes: capturing the image in the visual area by the camera.

[0024] a. When the first image is the first image, the test cylinder is exhausted and collected until the image becomes the second image, and then the exhaust is determined to be complete and the exhaust is stopped;

[0025] b. When the first image is the second image, the test cylinder is supplied with the gas, and the image is observed after a set time. If the image after the set time is the first image, the test cylinder is exhausted until the image becomes the second image, and then the exhaust is determined to be complete and the exhaust is stopped.

[0026] Further, the preparation method of the compound sample further comprises step A4:

[0027] Step A41, the test cylinder is emptied;

[0028] Step A42, steps A1 to A3 are repeated, and the volume of the oil introduced is the same as that in step A1.

[0029] Step A5:

[0030] A51, the amount of gas dissolved v is calculated, and the calculation formula is v=V-L, wherein V is the amount of gas introduced in step A4, and L is the amount of exhaust collected in step A4.

[0031] A52, whether the difference between v and v0 is within a set range is determined, wherein v0=V0-L0; if the difference is within the set range, the oil in the test cylinder is used as the compound sample; if the difference exceeds the set range, steps A4 and A51 are repeated, and the difference between the amount of gas dissolved in the current step A4 and the amount of gas dissolved in the previous step A4 is determined until the difference is within the set range, and the oil in the test cylinder in the last step A4 is used as the compound sample.

[0032] Based on the same inventive concept, the application also provides a test device for implementing the oil reservoir fluid property test method described above, comprising:

[0033] A test cylinder for introducing the raw material, wherein a visible area is formed on the test cylinder;

[0034] A heater for adjusting the temperature in the cylinder to the set temperature, wherein the heater is arranged on the inner wall of the test cylinder;

[0035] A light source device arranged outside the test cylinder and irradiating the visible area;

[0036] A camera device for shooting the image in the visible area, wherein the camera device is arranged outside the test cylinder and directly opposite the visible area.

[0037] Further, two visual windows are symmetrically arranged on the test cylinder; the light source device and the camera device are respectively arranged outside the two visual windows.

[0038] Further, the connection lines of the light source device and the camera device are parallel to the center lines of the two visual windows.

[0039] Further, the distance between the light source device / camera device and the corresponding visual window is less than 15 cm.

[0040] Further, the test cylinder is further provided with a support; the support comprises a sleeve, a first mounting position for mounting the light source device, a second mounting position for mounting the camera device, and at least four connecting rods; the sleeve and the first mounting position are connected by at least two connecting rods; and the sleeve and the second mounting position are connected by at least two connecting rods.

[0041] Further, the distance between the first mounting position and the test cylinder is less than the distance between the sleeve and the test cylinder; and the distance between the second mounting position and the test cylinder is less than the distance between the sleeve and the test cylinder.

[0042] Further, the oil reservoir fluid property test device further comprises a stirring device arranged in the test cylinder; the stirring device comprises a motor and a rotating fan blade driven by the motor; and the cutting surface of the rotating fan blade is arranged at an angle with the cross section of the test cylinder.

[0043] Further, the cutting surface of the rotating fan blade is parallel to the axis of the test cylinder.

[0044] According to the above technical solution, the present application provides an oil reservoir fluid property test method, which comprises:

[0045] Step S1: introducing raw materials into a test cylinder with a visual area;

[0046] Step S2: adjusting the temperature in the test cylinder to a set temperature, and adjusting the pressure in the test cylinder to a set pressure, so as to make the oil and gas in the raw materials soluble or separated; and simulating the dissolution of the oil and gas in the raw materials under the set formation conditions.

[0047] Step S3, the image in the visual area is photographed by the camera, when the photographed image is the first image, the test cylinder is exhausted and collected, until the photographed image becomes the second image, it is determined that the exhaust is completed, and the exhaust is stopped; when there is gas in the test cylinder, the ambient light source can penetrate, a relatively obvious white light is formed on one side of the camera, and the display in the software; the gas is exhausted, the light source cannot penetrate the oil, and the camera side is dark, which is used to measure the gas exhaust and dissolution state, the zero point of the unsolved single-phase gas exhaust is judged by the intuitive observation method, the gas exhaust is accurately controlled, and the technical problems of false discharge of oil, pressure change in the cylinder caused by loss of oil, backflow of discharged gas and large test error are avoided.

[0048] Step S4, data measurement is performed on the oil and / or collected gas, and the gas-dissolved oil, the gas discharged out of the test cylinder and the like are detected according to the required data.

[0049] The oil reservoir fluid physical property test method provided by the application can be used in the test of compounding, degassing and the like of oil and gas, is used to judge the dissolution of gas in oil under the set pressure and temperature, and the discharge of the unsolved single-phase gas, and the visualization of the judgment can be realized through the difference between the refraction of the light penetrating the gas and the refraction of the light penetrating the oil, the light and dark degree and the light and dark change, the method is simple and convenient, the test range is wider, the accuracy is better, and the safety is significantly improved. The application of the innovative achievement can make the test result more accurate, especially for thick oil and super thick oil, and can provide great help for understanding the gas injection development mechanism, the swelling characteristics of crude oil and the calculation of reserves. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 The oil reservoir fluid physical property test method provided by the application for example 1;

[0051] Figure 2 The structural schematic diagram of the oil reservoir fluid physical property test device provided by the application for example 2.

[0052] BRIEF DESCRIPTION OF DRAWINGS: 1-test cylinder, 11-visual window, 12-oil discharge pipe, 13-gas discharge pipe; 2-heating device; 3-camera; 4-light source device; 5-bracket, 51-ferrule, 52-second mounting position, 53-connecting rod. DETAILED DESCRIPTION

[0053] In order to make the person skilled in the art to which the application belongs more clearly understand the application, the technical scheme of the application is described in detail below with specific examples combined with the drawings.

[0054] In order to solve the technical problems of great compounding difficulty and low test precision in the prior art reservoir fluid test, the present application provides a reservoir fluid physical property test method and a reservoir fluid physical property test device, which can accurately control the stopping point of exhaust by shooting images, taking the change of the images as the judgment standard, observe intuitively, and improve the test precision. The content of the present application is described in detail through two specific embodiments.

[0055] Embodiment 1

[0056] The reservoir fluid physical property test method provided in the present embodiment comprises:

[0057] Step S1, introducing raw materials into a test cylinder with a visible area;

[0058] Step S2, adjusting the temperature in the test cylinder to a set temperature and adjusting the pressure in the test cylinder to a set pressure, so as to make the oil and gas in the raw materials soluble or separated; and simulating the dissolution of the oil and gas in the raw materials under the set formation conditions.

[0059] Step S3, continuously shooting images in the visible area by a camera device, when the shot image is a first image, performing exhaust and collection on the test cylinder, until the shot image becomes a second image, determining that the exhaust is completed and stopping the exhaust; when there is gas in the test cylinder, the ambient light source can penetrate, forming a relatively obvious white light on one side of the camera device and displaying in the software; when the gas is exhausted, the light source cannot penetrate the oil, and the one side of the camera device appears dark, which is used to measure the exhaust and dissolution of the gas, and the zero point of the exhaust of the unsolved single-phase gas is judged by the intuitive observation method, the gas exhaust is accurately controlled, and the technical problems of misdischarge of the oil, change of the pressure in the cylinder caused by loss of the oil, backflow of the exhausted gas and large test error are avoided.

[0060] Step S4, performing data measurement on the oil and gas, and detecting the oil or the gas according to the required data.

[0061] The oil reservoir fluid physical property test method provided by the application can be used in tests such as compounding, degassing and the like of oil and gas, is used to judge the dissolution of gas in oil at a set pressure and a set temperature, and the discharge of undissolved single-phase gas, and the judgment can be visualized by using the difference between the refraction of light penetrating the gas and the refraction of light penetrating the oil, and by the light and dark degree of light and the light and dark change. The method is simple and convenient, has a wider test range, better accuracy and significantly improved safety. The application of the innovative achievement can make the test result more accurate, especially for thick oil with a ground oil viscosity of 100-10000 mPa.s and super-thick oil with a ground oil viscosity of 10000-50000 mPa.s, and provides great help for understanding the gas injection development mechanism, the swelling characteristics of crude oil and the calculation of reserves.

[0062] It should be noted that the light transmittance and refraction and the like of light in the gas and the oil are very different, and the brightness of the first image is much higher than that of the second image. Generally, the first image is captured in a bright state, and the second image is captured in a dim state, and the change is obvious, which is convenient for shooting and clear judgment, and the exhaust can be stopped when the brightness suddenly changes.

[0063] There are two basic means for judging whether the gas is exhausted in the prior art, the first means is to judge that the gas is exhausted when it is detected that part of the oil is discharged through the exhaust port, and the second means is to monitor the volume change rate in the cylinder, because there is a difference in the compressibility of the gas and the liquid, when the gas is exhausted and directly compresses the oil, the volume change rate in the cylinder will suddenly change, but these two means have a problem of lag, and the shooting is late, which easily leads to test error and affects the test accuracy. When it is judged that the exhaust is stopped, there is a problem that the oil has been partially discharged into the test cylinder, on the one hand, the oil rises to the exhaust port and a part of it may be discharged, which leads to a decrease in the amount of oil, changes the test reference and seriously affects the test accuracy; on the other hand, the exhaust of the gas or the compression of the oil easily leads to a change in the pressure in the test cylinder, backflow of the gas and the like, which destroys the internal pressure balance and leads to a large test result error.

[0064] Compared with the prior art, the oil reservoir fluid physical property test method provided by the embodiment can be used in various measurement tests for test analysis, and is suitable for processes that need to judge the mixing degree of oil and gas or the gas discharge condition, and is used as a judgment point for operation to determine whether the gas needs to be supplemented or exhausted, and monitors the gas discharge condition in the exhaust process, accurately controls the gas discharge, avoids the discharge of oil, avoids the change in the pressure in the cylinder caused by excessive discharge, and avoids the backflow of the gas. The shooting is simple, the judgment standard is simple, and the control accuracy is good.

[0065] The oil reservoir fluid physical property test method provided in the embodiment can also be used to judge mutual solubility, and the image in the visible area is captured by the camera device, and specifically includes: when the captured image is the second image, i.e., the dim state, it is judged that all the injected gas is completely dissolved in the oil, forming a gas-liquid miscible phase fluid, which is used to judge the mutual solubility of the gas and the oil.

[0066] In order to reduce the influence of environmental light, make the judgment standard more accurate and more in line with the actual situation, and facilitate the shooting of brightness changes, while making the image state changes more accurately reflect the complete discharge of the gas, in the embodiment, two visible windows are symmetrically arranged on the test cylinder, one of which is provided with a light source, and the camera device is arranged outside the other visible window. In step S2, the image in the visible window is captured by the camera device, specifically including: turning on the light source, and capturing the image in the visible window by the camera device. Preferably, the visible window has a small area, and the first image and the second image are obviously contrasted by the external light source close to the visible window, and the camera device is close to the visible window, reducing the influence of environmental light. The influence of natural environmental light on the camera device shooting the situation in the cylinder can also be reduced by auxiliary cover and other structures.

[0067] In order to be applied to the compounding and testing of heavy oil, in the embodiment, the viscosity of the oil in the raw material is greater than 100 mPa.s, i.e., heavy oil. The oil reservoir fluid physical property test method provided in the embodiment can also be applied to ultra-heavy oil with a viscosity greater than 50000 mPa.s, which can make the test results more accurate, especially for heavy oil and ultra-heavy oil, which can provide great help for understanding the mechanism of gas injection development, the swelling characteristics of crude oil and the calculation of reserves.

[0068] Because the heavy oil or ultra-heavy oil has high viscosity and weak flowability, only the top surface of the oil is in contact with the gas, in order to make the mixing sufficient, the oil reservoir fluid physical property test method further includes: controlling the test cylinder to be turned over, and stirring and mixing the raw material by the stirring device arranged in the test cylinder to accelerate the dissolution, and making the raw material fully miscible or demixing by stirring.

[0069] In order to simulate the specific formation environment of heavy oil and ultra-heavy oil for testing, in the embodiment, the temperature in the test cylinder is set to a set temperature in step S2, specifically including: heating the raw material by the heating coil arranged in the test cylinder, and monitoring the temperature change by the temperature sensor.

[0070] When the oil reservoir fluid property test method is specifically a degassing test method, and in the degassing test method, the raw material is a qualified formation sample or a compounded sample. The pressure in the test cylinder is adjusted to a set pressure, specifically including at least one pressure reduction treatment on the test cylinder at a set pressure reduction gradient until the pressure in the test cylinder is reduced from the preset formation pressure to atmospheric pressure; steps S3 and S4 are continuously performed during the pressure reduction process, that is, after each pressure reduction treatment, the oil and gas are fully separated, and then the exhaust, collection of the exhaust gas, and data measurement are performed.

[0071] When a single degassing test is performed, the principle of the single degassing test is to keep the total composition of the system constant during the oil-gas separation process, flash the formation fluid to atmospheric conditions instantaneously, and measure the volume and gas-liquid quantity changes. For formation crude oil, the purpose of the experiment is to determine the oil, gas composition, single degassing gas-oil ratio, volume coefficient, formation oil density and other parameters; for condensate gas reservoirs, the purpose of the experiment is to determine the composition of condensate oil and gas, the deviation factor of condensate gas reservoir fluid and other parameters.

[0072] The multiple degassing test is to degas the formation oil by staged pressure reduction at the formation temperature, exhaust, and measure the changes of oil and gas properties and composition with pressure. This experiment is to determine the dissolved gas-oil ratio at each pressure level, the volume coefficient and density of saturated oil, the deviation factor of the outgassed gas, the relative density and volume coefficient, and the oil-gas two-phase volume coefficient and other parameters. According to the size of the bubble point pressure, the interval of the staged pressure is determined, and the degassing stages are generally divided into 3-12 stages. Finally, the residual oil is discharged and weighed, and the composition, average molecular weight and density at 20°C of the residual oil are measured, and other parameters can be referred to the prior art.

[0073] Since the oilfield generally changes during the production period, most of them need to be tested to obtain qualified formation oil samples. In this embodiment, the raw material is a compounded sample, and in order to accurately compound the oil that is closer to the crude oil, the compounding method of the compounded sample specifically includes:

[0074] Step A1, introducing oil and gas into the test cylinder respectively;

[0075] Step A2, adjusting the temperature in the test cylinder to a set formation temperature, and single-stage pressurizing the pressure in the test cylinder from atmospheric pressure to a set formation pressure, that is, a sudden change in pressure, and setting the temperature to a set formation temperature, to simulate the gas-oil ratio of the gas-liquid miscible phase sample under the current set formation condition.

[0076] Step A3, taking the image in the visual area by the camera, when the image is the first image, the test cylinder is exhausted and collected until the image becomes the second image, it is determined that the exhaust is completed, the exhaust is stopped, the amount of gas V0 and the exhaust amount L0 are recorded; the oil in the test cylinder is used as a compound sample.

[0077] It should be noted that the embodiment can also determine whether the gas is completely dissolved in the oil by the visual area and the image. When the gas is completely dissolved, the oil rises under the internal pressure, and if the second image is taken after the gas phase is mixed, it is determined that the gas has been completely dissolved. However, due to some recording data and original test data itself, the deviation caused by the equipment measurement and other factors cannot determine whether it reaches the limit under the formation condition, i.e. saturation. At this time, the injected oil may still be able to dissolve part of the gas. In order to make the gas-liquid mixed phase sample obtained by the compound close to the amount ratio of the oil and gas of the formation crude oil, preferably, more gas than the standard ratio is introduced into the test cylinder during the compound to ensure that the gas is fully mixed in the oil to obtain a gas-liquid two-phase mixed sample, and then the excess gas is discharged.

[0078] Since the test standard is based on the original recording data of the crude oil, part of the data may have test errors itself, which may result in insufficient gas being introduced during the compound, and the gas dissolved in the oil after the exhaust is insufficient and does not reach the best, still having errors with the crude oil. In order to improve the accuracy, step A3 specifically comprises: taking the image in the visual area by the camera;

[0079] a. When the first image is the first image, the test cylinder is exhausted and collected until the image becomes the second image, it is determined that the exhaust is completed, the exhaust is stopped;

[0080] b. When the first image is the second image, the gas is supplemented into the test cylinder, and the image is taken after a set time, if the image taken after the set time is the first image, the test cylinder is exhausted until the image becomes the second image, it is determined that the exhaust is completed, the exhaust is stopped. To ensure that the gas dissolved in the compound final sample obtained by single compound reaches the highest, by supplementing at least once gas into the test cylinder, repeated exhaust is carried out, so that the final oil product is closer to the crude oil.

[0081] It should be noted that after each exhaust is completed, the "target object" remaining in the test cylinder is the oil and the gas fully mixed into the oil. At this time, the oil is still in liquid state, the gas is still in gaseous state, and only the gas is dissolved in the oil, and the phase state of the gas does not change.

[0082] The number of repetitions of step S5 is not specifically limited in the embodiment, and is at least repeated more than once, that is, at least once gas is supplemented and twice exhaust is carried out.

[0083] Due to the time difference caused by human judgment and control of the start and stop of exhaust, there will inevitably be errors. In order to ensure that the gas-liquid mixed phase sample obtained by compounding is qualified, and to ensure the accuracy of subsequent tests, at least two compounded final samples are required. At the same time, in order to ensure that the compounded sample is close to the state of crude oil, the compounded product needs to be verified and measured. In this embodiment, at least two compounding processes are carried out. Specifically, the preparation method of the compounded sample further includes step A4:

[0084] Step A41, empty the test cylinder;

[0085] Step A42, repeat steps A1 to A3, and ensure that the volume of the oil introduced is the same as that in step A1. Since the volume and environmental conditions remain unchanged, strict control of the error caused by variables is required.

[0086] Step A5:

[0087] A51, calculate the gas dissolution amount v, the calculation formula is v=V-L, wherein V is the amount of gas introduced in step A4, and L is the amount of exhaust gas collected in step A4;

[0088] A52, determine whether the difference between v and v0 is within the set range, wherein v0=V0-L0; if the difference is within the set range, the oil in the test cylinder in the current step A4 is taken as the compounded sample; if the difference exceeds the set range, repeat steps A4 and A51 to determine the difference between the gas dissolution amount obtained in the current step A4 and the gas dissolution amount obtained in the previous step A4, until the difference is within the set range. The oil in the test cylinder in the last step A4 is taken as the compounded sample. That is, the gas dissolution amount of the previous order is taken as the reference, and the gas dissolution amount of the next order is compared with the gas dissolution amount of the previous order. When the difference is within the error range, it is determined that the gas-liquid mixed phase sample obtained by compounding is qualified.

[0089] In this embodiment, when the difference is within 0.02, it is considered to be qualified.

[0090] The oil reservoir fluid property test method provided in this embodiment is specifically operated as follows:

[0091] First, open the computer, light source, camera and tool software; the second step is to prepare the PVT before the process. That is, oil injection, gas injection and the use of a fan blade stirring device to accelerate oil and gas dissolution; the third step is to open the corresponding phase control system of the tool software in the control machine, and wait for the camera to stabilize; the fourth step is to perform various tests of the PVT test. In the process of matching balance, single degassing, constant quality expansion and other tests, the method of direct observation is used, that is, when there is gas in the test cylinder, the light source can penetrate, forming a white light on the camera side, which is displayed in the control software. When the gas is exhausted, the light source cannot penetrate the crude oil, and the camera side is black. To measure the gas exhaust and dissolution status. At this point, the visual high-pressure fluid PVT testing device can be used to accurately complete the PVT test.

[0092] The oil reservoir fluid physical property test method provided in the embodiment can complete formation fluid sample preparation and PVT analysis and testing of different gas-oil ratio reservoir fluid samples such as heavy oil and super heavy oil under high temperature and high pressure conditions by improving main technical indicators, using visual technology and a new stirring method, and according to different selection configurations. Compared with the prior art, the oil reservoir fluid physical property test method provided in the embodiment can be used in various measurement tests for test analysis, and the brightness of the light source is photographed, which is suitable for processes that need to judge the mixing degree of oil and gas or the gas exhaust condition, so as to serve as a judgment point for operation, determine whether the gas needs to be supplemented and introduced or the gas needs to be exhausted, monitor the gas exhaust condition during the exhaust process, accurately control the gas exhaust, avoid oil removal, avoid changes in the pressure in the cylinder caused by excessive exhaust, avoid backflow of the gas, the photographing is simple, the judgment standard is simple, and the control precision is favorable.

[0093] Embodiment 2

[0094] Based on the same inventive concept, the embodiment provides a test device for the oil reservoir fluid physical property test method in the embodiment 1. The oil reservoir fluid physical property test device comprises a light source device 4, a camera device 3, a heating device 2 and a test cylinder 1 for introducing raw materials. The test cylinder 1 is provided with a visible area. The light source device 4 and the camera device 3 are arranged outside the test cylinder 1 and close to the visible area, and the light source device 4 irradiates the visible area. The camera device 3 faces the visible area and receives the light signal of the light source device 4 to photograph the image in the visible area. The heating device 2 is arranged on the inner wall of the test cylinder 1 and is used to heat the raw materials in the test cylinder 1 to adjust the temperature in the cylinder to a set temperature. The changes in the test cylinder 1 are monitored by the camera device 3 and the visible window 11, and the different penetration of light in two media can be used to judge the position of the two media rising in the test cylinder 1. When the image monitored by the camera device 3 changes obviously in brightness, it can be judged that the interface between the unsoluble single-phase medium (that is, the gas in the embodiment) and the mutually soluble two-phase mixed medium reaches the detection point, and the unsoluble single-phase medium is completely exhausted to the outside of the test cylinder 1.

[0095] In order to ensure the sealing and visibility, in the embodiment, the visible window 11 is a light-transmissive glass, the area of the visible window 11 is sealed by the transparent glass, and the glass is made of a material resistant to high temperature, high pressure and corrosion, and is not easy to be hung on the wall, and will not affect the light transmittance in the process of oil and gas PVT test for many years and many times.

[0096] The heating device 2 is arranged on the inner wall of the test cylinder 1, and the camera device 3 is arranged outside the test cylinder 1 and close to the visible area. The size of the visible area is not specifically limited in the embodiment, and only needs to be arranged at a position that can meet the judgment requirements, that is, first, the light outside can be detected when the gas penetrates, and is relatively bright, so that the image generated by the light of the oil has a relatively obvious difference; second, the setting position of the visible area needs to meet that when the image state occurs, the gas is just exhausted, and the top surface of the oil rising reaches the low point of the exhaust port. It needs to be explained that the "just" here is an ideal state, and in fact, there can be a small error, but it needs to be ensured that the oil will not be higher than the low point of the exhaust port, so as to avoid a series of problems caused by the misdischarge of the oil.

[0097] In some schemes, the top surface of the visible window 11 can be basically flat with the low point of the exhaust port, at this time, the first image is a bright light state, and the second image is close to a full black state, which indicates that the oil has risen close to the top surface of the visible window 11, but at this time, there is a judgment process, and there will be human error. In the embodiment, preferably, the axis of the visible window 11 and the axis of the exhaust port are located on the same cross section of the test cylinder 1, and the light bright state of the light penetrating the air is the first image, as long as the second image is formed by the sudden change of the brightness, that is, it is judged that the gas is exhausted.

[0098] In the embodiment, the heating device 2 is at least two heating coils arranged in the test cylinder 1, and each heating coil is arranged in the form of a ring on the inner wall of the test cylinder 1.

[0099] In order to reduce the influence of the environmental light, ensure the reference authenticity of the image, and make the change of the first image and the second image more obvious, facilitate the judgment, and improve the accuracy of the test, in the embodiment, two visible windows 11 are symmetrically arranged on the test cylinder 1, and the light source device 4 and the camera device 3 are respectively located outside the two visible windows 11.

[0100] In the embodiment, an exhaust port is radially arranged at the top of one end of the test cylinder 1, the two visible windows 11 are distributed with the axis of the exhaust port as the axis of symmetry, the two visible windows 11 are square windows with a length of 10 cm and a width of 10 cm, and the windows are covered with glass. It needs to be noted that the visible window 11 should avoid the heating coil in the cylinder.

[0101] In some more preferable embodiments, the visual window 11 can be smaller in size so that the mutation of the first image and the second image can better reflect the oil rising position, such as the center line of the visual window 11 and the center line of the exhaust port being on the same cross section, and the size of the visual window 11 being 3 cm long and 3 cm wide.

[0102] In order to ensure that the positions of the light source device 4 and the camera device 3 are fixed during the rolling stirring of the test cylinder 1, in the present embodiment, the test cylinder 1 is further provided with a support 5 for fixing the light source device 4 and the camera device 3; the support 5 includes a sleeve 51, a first mounting position for mounting the light source device 4, a second mounting position 52 for mounting the camera device 3, and at least four connecting rods 53, the sleeve 51 and the first mounting position being connected by at least two connecting rods 53, and the sleeve 51 and the second mounting position 52 being connected by at least two connecting rods 53, so as to form at least one triangular structure between the at least two connecting rods 53 and the support 5, thereby enhancing the strength of the support 5 and ensuring the fixation of the light source device 4 and the camera device 3.

[0103] Preferably, the material of the support 5 is stainless steel. The support 5 is fixedly connected to the cylinder body of the test cylinder 1 through a gasket and a threaded connecting piece, so as to ensure the stability of the support 5 during the rolling process of the cylinder body. The support 5 extends 10 cm forward and backward of the cylinder, and forms a right-angle bend downward to extend to the position corresponding to the glass window. At the position of the glass window, in the present embodiment, the first mounting position and the second mounting position 52 are both hollow square frames with a length and a width of 10 cm. The light source device 4 and the camera device 3 are both connected to the corresponding frames through at least four bolts, so as to maintain the rigidity of the connection. In the present embodiment, the distance between the first mounting position and the second mounting position 52 and the cylinder wall is smaller than the distance between the sleeve 51 and the cylinder wall.

[0104] In order to minimize the influence of ambient light on the second influence, in the present embodiment, the oil reservoir fluid property test method further includes controlling the distance between the light source device 4, the camera device 3 and the corresponding visual window 11 to be less than 15 cm.

[0105] Further preferably, the distance between the light source device 4 / camera device 3 and the corresponding visual window 11 is less than 10 cm.

[0106] Since the test cylinder 1 is vertically placed during exhaust, in order to ensure the light trajectory, in the present embodiment, in order to make the test accuracy higher, the connecting line of the light source device 4 and the camera device 3 is parallel to the center lines of the two visual windows 11.

[0107] In this embodiment, the light source device 4 includes a point light source LED lamp, a power supply circuit, and achieves reasonable lamp power in the range of the glass window outside the test cylinder 1. The LED lamp power is 3W, the length is 60cm-100cm, and the LED lamp is installed at the center of the glass window behind the cylinder. The light source point is 10cm away from the back of the glass. The light source is fixed by a support 5. The power supply circuit includes a power supply line, a transformer, a multi-position socket, a switch, and the like. The circuit and the like in the support 5 are selected to be black devices, or wrapped in black, painted black, or the like. The multi-position socket, the switch, and the like are installed in the PVT other test device, and the switch is controlled by a computer.

[0108] The application does not make specific limitations to the camera 3. As an optional solution, in this embodiment, the camera 3 is generally selected to be a Canon digital camera, and a 16mm-35mm zoom lens is configured. The camera is connected to the computer by a data line, and the captured image can be directly connected to the computer.

[0109] In order to obtain imaging in the test software, in this embodiment, the oil reservoir fluid property test method further includes connecting the camera 3 to the imaging control system, so that the image captured by the camera can be directly observed in the PVT test software installed in the available portable computer or desktop computer.

[0110] In order to expand the application range of the device and provide an optional solution for the test and analysis of heavy oil and super heavy oil with large viscosity, since the flowability of the heavy oil and super heavy oil is weak due to the large viscosity, it is not convenient for the phase solubility and separation of the oil and gas. In order to ensure the test accuracy of the heavy oil and super heavy oil, in this embodiment, the oil reservoir fluid property test device further includes a stirring device arranged in the test cylinder 1. The stirring device includes a motor and a rotating blade driven by the motor. The cutting surface of the rotating blade is arranged at an angle with the cross section of the test cylinder 1, that is, has a component projection parallel to the axial direction of the test cylinder 1, and can be used to cut and stir the heavy oil and super heavy oil, accelerate the phase solubility during pressurization, and separate during depressurization.

[0111] Since the oil and gas are only phase soluble and separated by the contact surface of the two phases, in order to ensure the cutting effect during the rolling and stirring and achieve the best acceleration effect, preferably, the cutting surface of the rotating blade is parallel to the axis of the test cylinder 1.

[0112] Since the end of the exhaust is manually or electrically controlled to close the exhaust port after the image state changes, the error is inevitable. In order to avoid the volume change of the oil caused by the misdischarge of the oil, in this embodiment, one end of the test cylinder 1 is provided with an exhaust pipe 13 communicating with the test cylinder 1, and the other end is provided with an oil discharge pipe 12 communicating with the test cylinder 1. The exhaust pipe 13 and the oil discharge pipe 12 protrude from the outer wall of the test cylinder 1. In this embodiment, the exhaust pipe 13 protrudes by 3cm, and the opening and closing of the exhaust pipe 13 and the opening and closing of the oil discharge pipe 12 are arranged at the corresponding pipe ports. A part of the oil can be stored, and under the action of depressurization and other operations, the oil at the pipe port naturally flows back.

[0113] Through the above-mentioned embodiments, the present application has the following beneficial effects or advantages:

[0114] 1) The oil reservoir fluid physical property test method and the oil reservoir fluid physical property test device provided by the present application can be used in the test of oil and gas compounding, degassing and the like, for judging the dissolution of gas in oil under a set pressure and a set temperature, and the discharge of undissolved gas, and the visualization of the judgment can be realized through the light and dark degree and the light and dark change of light by using the difference between the refraction of light penetrating gas and the refraction of light penetrating oil. The method is simple and convenient, has a wider test range, better precision, and significantly improved safety. The application of the innovative achievement can make the test result more accurate, especially for thick oil and super thick oil, and provides great help for understanding the gas injection development mechanism, the swelling characteristics of crude oil and the calculation of reserves.

[0115] 2) The oil reservoir fluid physical property test method and the oil reservoir fluid physical property test device provided by the present application can convert the data change in the test cylinder into an intuitive visual effect, and the change of the image can facilitate the shooting of whether the gas is completely discharged, and the innovative achievement can be applied in many fields of PVT test. The special stirring method can accelerate the dissolution of thick oil and super thick oil, and the thick oil and super thick oil can be compounded under indoor conditions. Compared with the prior art, the method is simple and convenient, has a wider test range, better precision, and significantly improved safety. The application of the innovative achievement can make the test result more accurate, especially for thick oil and super thick oil. It provides great help for understanding the gas injection development mechanism, the swelling characteristics of crude oil and the calculation of reserves.

[0116] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all changes and modifications falling within the scope of the present application.

[0117] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A method for testing the physical properties of reservoir fluids, characterized in that, include: Step S1: Pass raw material into the test cylinder with a visible area; Step S2: Adjust the temperature inside the test cylinder to the set temperature and adjust the pressure inside the test cylinder to the set pressure, so that the oil and gas in the raw material can be mixed or separated. Step S3: Capture an image within the visible area using a camera device. When the captured image is the first image, vent the test tube and collect the image until the captured image becomes the second image. Determine that the venting is complete and stop venting. The first image is a bright white image in a light-transmitting state, and the second image is a dark image in a light-blocking state. Step S4: Measure the data of the oil and / or the collected gas.

2. The reservoir fluid property testing method as described in claim 1, characterized in that, The test cylinder has two symmetrically arranged viewing windows, one of which has a light source outside it, and the camera device is located outside the other viewing window; In step S2, capturing the image within the viewing window using a camera device specifically includes turning on the light source and capturing the image within the viewing window using the camera device.

3. The reservoir fluid property testing method as described in claim 2, characterized in that, In step S2, setting the internal temperature of the test cylinder to a set temperature specifically includes: heating the raw material by means of a heating coil installed inside the test cylinder, and monitoring temperature changes by means of a temperature sensor.

4. The reservoir fluid property testing method as described in claim 2, characterized in that, Step S2 further includes: controlling the test cylinder to flip over, and stirring and mixing the raw materials by means of a stirring device provided in the test cylinder.

5. The reservoir fluid property testing method as described in claim 1, characterized in that, The viscosity of the oil is greater than 100 mPa·s.

6. The reservoir fluid property testing method according to any one of claims 1-5, characterized in that, The reservoir fluid property test specifically refers to a degassing test; In the degassing test method, the raw material is a formation sample or a compound sample; In step S2, adjusting the pressure inside the test cylinder to a set pressure specifically includes performing a pressure reduction process on the test cylinder at least once with a set pressure reduction gradient until the pressure inside the test cylinder is reduced from the preset formation pressure to atmospheric pressure. Steps S3 and S4 are performed continuously during the pressure reduction process.

7. The reservoir fluid property testing method as described in claim 6, characterized in that, The raw material is a compound sample, and the preparation method of the compound sample specifically includes: Step A1: Introduce oil and gas into the test cylinder respectively; Step A2: Adjust the internal temperature of the test cylinder to the set formation temperature, and increase the internal pressure of the test cylinder from atmospheric pressure to the set formation pressure to make the oil and the gas miscible; Step A3: Capture an image within the visible area using a camera device. When the captured image is the first image, vent and collect the gas from the test cylinder until the captured image becomes the second image. Determine that venting is complete, stop venting, and record the amount of gas introduced (V0) and the amount of gas collected (L0). Use the oil in the test cylinder as the compound sample.

8. The reservoir fluid property testing method as described in claim 7, characterized in that, Step A3 specifically includes: capturing an image within the visible area using the camera device; a. When the first image captured is the first image, the test tube is vented and collected until the captured image becomes the second image. At this point, the venting is considered complete and the venting is stopped. b. When the first captured image is the second image, the gas is introduced into the test tube, and the image captured after a set time is observed. If the image captured after the set time is the first image, the test tube is vented until the captured image becomes the second image. At this point, the venting is considered complete and the venting is stopped.

9. The reservoir fluid property testing method as described in claim 7 or 8, characterized in that, The method for preparing the compound sample further includes step A4: Step A41: Empty the test cylinder; Step A42: Repeat steps A1 to A3, ensuring that the volume of oil introduced is the same as the volume of oil introduced in step A1. Step A5: A51. Calculate the amount of gas dissolved, v. The calculation formula is v=VL, where V is the amount of gas introduced in step A4 and L is the amount of exhaust gas collected in step A4. A52. Determine whether the difference between v and v0 is within the set range, where v0 = V0 - L0; if the difference is within the set range, then use the oil in the test cylinder as the compound sample; if the difference exceeds the set range, repeat steps A4 and A51, determine the difference between the gas dissolved amount obtained in the current step A4 and the gas dissolved amount obtained in the previous step A4, until the difference is within the set range, and use the oil in the test cylinder in the last step A4 as the compound sample.

10. A test apparatus for implementing the reservoir fluid property testing method according to any one of claims 1-9, characterized in that, include: A test tube is used to introduce the raw material, and a visible area is provided on the test tube; A heater is used to adjust the temperature inside the cylinder to the set temperature, and the heater is disposed on the inner wall of the test cylinder; A light source device is disposed outside the test cylinder and illuminates the visible area; A camera device is used to capture images within the visible area. The camera device is positioned outside the test tube and directly facing the visible area.

11. The test apparatus as described in claim 10, characterized in that, The test tube has two symmetrically arranged viewing windows; the light source device and the camera device are respectively located outside the two viewing windows.

12. The test apparatus as described in claim 11, characterized in that, The line connecting the light source device and the camera device is parallel to the center line of the two viewing windows.

13. The test apparatus as described in claim 11, characterized in that, The distance between the light source device / the camera device and the corresponding viewing window is less than 15cm.

14. The test apparatus as described in claim 10, characterized in that, The test cylinder is also provided with a bracket; the bracket includes a sleeve, a first mounting position for mounting the light source device, a second mounting position for mounting the camera device, and at least four connecting rods. The sleeve and the first mounting position are connected by at least two of the connecting rods, and the sleeve and the second mounting position are connected by at least two of the connecting rods.

15. The test apparatus as described in claim 14, characterized in that, The distance between the first mounting position and the test cylinder is less than the distance between the sleeve and the test cylinder; the distance between the second mounting position and the test cylinder is less than the distance between the sleeve and the test cylinder.

16. The test apparatus as described in claim 10, characterized in that, The reservoir fluid property testing device also includes a stirring device installed inside the test cylinder. The stirring device includes a motor and a rotating fan blade driven by the motor. The cutting surface of the rotating fan blade is set at an angle to the cross-section of the test cylinder.

17. The test apparatus as described in claim 16, characterized in that, The cutting surface of the rotating fan blade is parallel to the axis of the test cylinder.

Images