A method and apparatus for determining water content of crude oil

Abstract

This invention relates to the field of petroleum extraction technology and discloses a method and apparatus for determining the water content of crude oil. The method includes: introducing calcium peroxide and crude oil of volume V ml into a reaction flask; then inserting a single-hole rubber stopper with a conduit into the mouth of the reaction flask to form a sealed condition and carry out a first chemical reaction; after the reaction is completed, introducing water of volume 1.6V ml into the reaction flask (2) for a second chemical reaction to obtain precipitate B; separating and purifying the precipitate B, and measuring the mass of precipitate B as M1 g; the volume of water in the reaction flask (2) that did not participate in the reaction is V1 ml; and calculating the water content Fw of the crude oil according to the formula. This invention provides a method and apparatus suitable for oilfield sites, capable of rapidly determining the water content of crude oil sampled from wellheads.

Description

Technical Field

[0001] This invention relates to the field of petroleum extraction technology, and specifically to a method and apparatus for determining the water content of crude oil. Background Technology

[0002] Crude oil water cut is one of the important dynamic parameters of oil well production. It is a direct basis for judging the production efficiency of oil wells and the state of reservoir development, and it affects the direction of oilfield development strategy adjustments. Currently, there are eight commonly used methods for measuring crude oil water cut.

[0003] One method is distillation: This involves heating the oil and water to separate them, then testing the mass of the crude oil and the mass of the evaporated water to calculate the water content. Its advantages are high precision, making it a commonly used laboratory method. However, its disadvantages include a complex and time-consuming process, the need for organic solvents which may pose hazards to the environment and personnel, and relatively large errors for crude oils with low water content.

[0004] The second method is centrifugation: This method uses centrifugal force to separate water and oil in crude oil, and determines the water content by measuring the volume or mass of the separated water. This method is simple to operate and suitable for crude oil with high water content; however, it is susceptible to secondary contamination and has lower measurement accuracy for crude oil with low water content.

[0005] Thirdly, there is the electro-dehydration method: using a high-voltage electric field and electro-demulsification technology to separate oil and water, thereby testing the water content of crude oil. This method is fast, adaptable, and allows for large volumes of analytical solution; however, it requires heating the oil sample during the dehydration process, resulting in lower accuracy.

[0006] Fourth is the Karl Fischer method: This method uses a solution containing iodine, sulfur dioxide, pyridine, and anhydrous methanol to react quantitatively with water in the sample. The water content of the crude oil is calculated based on the amount of Karl Fischer reagent consumed during the titration. This method has high accuracy for crude oils with low water content; however, it requires advanced technology, has limited applicability, increases the workload for crude oils with high water content, and the reagents may become ineffective, resulting in poor repeatability.

[0007] Fifth is the density method: based on the density difference between crude oil and water, the water content is estimated by measuring the density of crude oil. This method is direct, real-time, and requires simple equipment; however, it is greatly affected by factors such as temperature and crude oil composition, resulting in relatively low measurement accuracy.

[0008] Sixth is the capacitance method: This method utilizes the difference in dielectric constants between crude oil and water to determine the water content by measuring the capacitance value. It has the advantages of fast measurement speed and good real-time performance; however, it is easily affected by factors such as temperature, pressure, and crude oil viscosity, and the measurement accuracy will decrease under high water content conditions.

[0009] Seventh is the radio frequency (RF) method: This method measures water content by observing the interaction between radio frequency signals and water in crude oil. It is highly adaptable to factors such as crude oil viscosity and temperature, and has a wide measurement range; however, the equipment is expensive and may be susceptible to electromagnetic interference.

[0010] Eighth is the ultrasonic method: This method measures water content by utilizing the different propagation speeds and attenuation rates of ultrasonic waves in crude oil and water. The measurement process does not involve direct contact with the measured medium and is not sensitive to changes in the physical properties of crude oil; however, it is easily affected by factors such as temperature, pressure, and air bubbles, resulting in relatively low measurement accuracy.

[0011] Of the eight methods mentioned above, the first three require separation of crude oil, which increases the testing steps and time, making them unsuitable for rapid on-site testing. The fourth to eighth methods do not require separation of crude oil, but the composition of the crude oil itself, as well as external factors such as temperature, pressure, bubbles, and electromagnetic fields, can affect the test results to some extent. Summary of the Invention

[0012] The purpose of this invention is to overcome the problems of existing crude oil water content testing methods, which require precision testing instruments and professional experimental methods, are technically difficult, have time constraints, and are greatly affected by various internal and external factors.

[0013] The following methods are all in Figure 1 The process is carried out in the apparatus shown.

[0014] To achieve the above objectives, a first aspect of the present invention provides a method for determining the water content of crude oil, the method being carried out in a water content measuring device, the device comprising: a base on which a reaction flask is placed, the reaction flask having a single-hole rubber stopper with a conduit, the conduit connecting the reaction flask to a stopcock valve, a gas measuring tube, and a beaker, the method comprising: Calcium peroxide and crude oil with a volume of V ml were introduced into the reaction flask. Then, a single-hole rubber stopper with a conduit was inserted into the mouth of the reaction flask to form a sealed condition and carry out the first chemical reaction. After the reaction was completed, water with a volume of 1.6V ml was introduced into the reaction flask (2) to carry out the second chemical reaction and obtain precipitate B. The amount of calcium peroxide was controlled to be 1.2n g - 1.5n g, where n = 4V. The precipitate B was separated and purified, and its mass was measured to be M1 g; the volume of water that did not participate in the reaction in the reaction flask (2) was V1 ml; the water content Fw of the crude oil was calculated according to formula (1): Equation (1): Fw = 0.243 * (M1 - 6.576V + 4.11V1) / V × 100%.

[0015] A second aspect of the present invention provides an apparatus for determining the water content of crude oil, the apparatus comprising: Base; The reaction flask is mounted on the base. A single-hole rubber stopper that can be inserted into the mouth of the reaction flask; A conduit, one end of which passes through the single-hole rubber stopper to be inserted into the reaction flask, and the other end of which is connected to one end of a gas measuring tube; A beaker connected to the other end of the gas measuring tube; A stopcock valve is used to control the opening and closing of the conduit.

[0016] This invention proposes a method for calculating the water content of crude oil by reacting calcium peroxide with water in crude oil without separating the crude oil, and by measuring the content of the substances generated in the reaction. This method cleverly utilizes common chemical reactions to invert and determine the mass of water components in crude oil samples, thereby achieving rapid determination of the water content of crude oil.

[0017] This method cleverly utilizes the principle of generating easily measurable substances through chemical reaction with water. By adding an excessive amount of calcium peroxide to the crude oil sample, all the water in the crude oil is converted into other easily measurable substances through chemical reaction, thus avoiding the problem of accurately measuring the consumption of Karl Fischer reagent through titration, which is required in the Karl Fischer method.

[0018] Meanwhile, the crude oil water content determination method provided by this invention can improve the timeliness of crude oil water content detection, reduce the influence of various internal and external factors on the detection results, and can adapt to a wider range of water content from 5% to 100%. Attached Figure Description

[0019] Figure 1 This is a diagram of an apparatus used to determine the water content of crude oil.

[0020] Explanation of reference numerals in the attached figures 1. Base; 2. Reaction flask; 3. Conduit; 4. Single-hole rubber plug; 5. Stop valve; 6. Gas measuring tube; 7. Beaker; Detailed Implementation The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] As previously described, a first aspect of the present invention provides a method for determining the water content of crude oil, the method being carried out in a water content measuring device, the device comprising: a base on which a reaction flask is placed, the reaction flask having a single-hole rubber stopper with a conduit, the conduit connecting the reaction flask to a stopcock valve, a gas measuring tube, and a beaker, the method comprising: Calcium peroxide and crude oil with a volume of V ml were introduced into the reaction flask. Then, a single-hole rubber stopper with a conduit was inserted into the mouth of the reaction flask to form a sealed condition and carry out the first chemical reaction. After the reaction was completed, water with a volume of 1.6V ml was introduced into the reaction flask (2) to carry out the second chemical reaction and obtain precipitate B. The amount of calcium peroxide was controlled to be 1.2n g - 1.5n g, where n = 4V. The precipitate B was separated and purified, and its mass was measured to be M1 g; the volume of water that did not participate in the reaction in the reaction flask (2) was V1 ml; the water content Fw of the crude oil was calculated according to formula (1): Equation (1): Fw = 0.243 * (M1 - 6.576V + 4.11V1) / V × 100%.

[0022] This invention uses calcium peroxide, which can chemically react with water under normal temperature and pressure, to measure the water content in crude oil. The method for determining the water content of crude oil provided by this invention has the advantages of simple reagent acquisition, low cost, no need for precision testing instruments and professional experimental methods, which greatly reduces the difficulty of technical implementation and improves the testing efficiency.

[0023] Preferably, the crude oil contains 45-70 wt% saturated hydrocarbons, 10-25 wt% aromatic hydrocarbons, and has a surface density of 0.834-0.859 g / cm³. 3 The surface viscosity is 4.5-8.4 mPa·S.

[0024] More preferably, the crude oil contains 60-70 wt% saturated hydrocarbons, 15-20 wt% aromatic hydrocarbons, and has a surface density of 0.84-0.85 g / cm³. 3 The surface viscosity is 5.0-7.0 mPa·S.

[0025] More preferably, the crude oil contains 0.3-2.5 wt% asphaltenes, 5.0-10.0 wt% non-hydrocarbons, has an initial boiling point of 60-65°C, and a freezing point of 20-30°C.

[0026] According to a particularly preferred embodiment of the present invention, the amount of calcium peroxide is controlled to be 1.25n-1.35n. The inventors have discovered that, in this preferred embodiment, calcium peroxide can react with water in the crude oil, and simultaneously, the remaining calcium peroxide reacts with the introduced water to generate the same precipitate B.

[0027] Preferably, the conditions for the first chemical reaction and the second chemical reaction independently include: a temperature of 20-30°C and a pressure of 0.09-0.11 MPa.

[0028] According to a particularly preferred embodiment of the present invention, the method further includes: after the second chemical reaction is completed, post-processing the obtained material; the post-processing method is heat treatment. In this preferred embodiment, the inventors have found that the reagent selected by the present invention can chemically react with water under normal temperature and pressure conditions, and can measure trace amounts of free water; for water droplets encapsulated in oil, the post-processing can assist the encapsulated water in the crude oil sample to become free, thereby allowing the reaction to occur. Therefore, the testing method provided by the present invention can measure water droplets encapsulated in oil and is still applicable to crude oil samples with complex compositions.

[0029] More preferably, the conditions for the heat treatment include: a temperature of 40-60°C and a time of 10-15 minutes.

[0030] More preferably, the heat treatment is carried out under stirring conditions. The present invention does not have special limitations on the stirring speed and time, as long as the mixture is homogeneous. For example, 15 rpm can be used.

[0031] Preferably, the separation and purification operation includes: sequentially filtering, washing and drying the solid obtained after the second chemical reaction to obtain the precipitate B.

[0032] More preferably, the washing liquid is petroleum ether and / or n-hexane.

[0033] According to one specific implementation, the separation and purification includes preliminary separation and deep separation.

[0034] Preferably, the preliminary separation operation includes: using medium-speed qualitative filter paper for atmospheric pressure filtration, collecting the filtrate in a beaker, and rinsing the filter residue with petroleum ether to remove residual crude oil.

[0035] Preferably, the preliminary separation operation includes: using a reduced pressure filtration method, washing the filter residue with petroleum ether to remove residual crude oil.

[0036] Preferably, the deep separation operation includes: vacuum filtration of the filtrate after preliminary filtration using a 0.45μm microporous membrane to trap fine solid particles; washing the residue on the membrane with petroleum ether or n-hexane until the washing liquid is colorless; if it is necessary to confirm that there are no residues, the final filtrate can be observed under a microscope, and the absence of solid particles is considered as complete separation.

[0037] More preferably, the filtrate after deep separation is placed in a beaker and left to stand for 30-60 minutes until the oil and water in the filtrate separate into layers. Then, the upper layer of oil is removed using a pipette, and the volume of the water that did not participate in the reaction is measured as V1.

[0038] More preferably, the drying conditions include: a temperature of 100-110°C and a time of 20-25 min.

[0039] As previously described, a second aspect of the present invention provides an apparatus for determining the water content of crude oil, the apparatus comprising: Base; The reaction flask is mounted on the base. A single-hole rubber stopper that can be inserted into the mouth of the reaction flask; A conduit, one end of which passes through the single-hole rubber stopper to be inserted into the reaction flask, and the other end of which is connected to one end of a gas measuring tube; A beaker connected to the other end of the gas measuring tube; A stopcock valve is used to control the opening and closing of the conduit.

[0040] The following combination Figure 1 The diagram illustrates a preferred embodiment of the method for determining the water content of crude oil according to the present invention.

[0041] Place the reaction flask on the base, insert the single-hole rubber stopper into the mouth of the flask to form a seal, then pass the tubing through the single-hole rubber stopper. After exiting the single-hole rubber stopper, the tubing is connected to the gas measuring tube. Distilled water is injected into the gas measuring tube and the beaker. The stopcock valve can open / close the connection between the tubing and the gas measuring tube. When the chemical reaction produces gas, open the stopcock valve, and the gas enters the gas measuring tube. Measure the volume of the gas produced by observing the scale of the gas measuring tube. When the volume no longer changes, the reaction is considered complete.

[0042] According to a specific embodiment of the present invention, the conduit, stopcock valve, and single-hole rubber stopper are pre-connected. The stopcock valve is closed, and the crude oil sample and calcium peroxide are added to the reaction flask. Then, the connected single-hole rubber stopper is inserted into the mouth of the reaction flask to form a seal. The end of the gas measuring tube is placed in a beaker, and distilled water is injected into the gas measuring tube. Then, the gas measuring tube is connected to the conduit. The stopcock valve is slowly opened, and the change in the distilled water level in the gas measuring tube is observed. When the water level no longer changes, it indicates that the calcium peroxide and the water in the crude oil sample have completely reacted, and the first chemical reaction is over. Close the stopcock valve, pull the tubing and the single-hole rubber stopper from the mouth of the reaction flask, add water to the reaction flask, then insert the single-hole rubber stopper into the mouth of the reaction flask to form a seal, inject distilled water into the gas measuring tube, slowly open the stopcock valve, and observe the change in the water level of the distilled water in the gas measuring tube. When the water level no longer changes, it indicates that the remaining calcium peroxide in the first chemical reaction has completely reacted with the added water. Measure the mass of precipitate B and the volume of water that did not participate in the reaction in the reaction flask.

[0043] The present invention will be described in detail below through embodiments. Unless otherwise specified, all instruments and materials used in the following embodiments are commercially available products.

[0044] In this article, room temperature or normal temperature means 25±2℃; normal pressure means 0.1±0.01MPa.

[0045] Calcium peroxide: purity 98.9 wt%.

[0046] Magnesium peroxide: purity 95.0 wt%.

[0047] Barium peroxide: purity 95.0 wt%.

[0048] The composition of the crude oil used in this invention is shown in Table 1. Table 1

[0049] In the following embodiments, the present invention employs Figure 1 The apparatus shown is used to perform the method of the present invention.

[0050] Example 1 Remove the single-hole rubber stopper that has been inserted into the tubing, add 18 mL (V) of crude oil sample I and 90 g of calcium peroxide to the reaction flask, then insert the single-hole rubber stopper that has been inserted into the tubing into the mouth of the reaction flask to form a seal, and start the first chemical reaction at room temperature and pressure; slowly open the stopcock valve and observe the change in the distilled water level in the gas measuring tube. When the water level no longer changes, it indicates that the first chemical reaction has ended. Close the stopcock valve, remove the single-hole rubber stopper from the mouth of the reaction flask, add 28.8 mL (i.e., 1.6V) of water to the reaction flask, and then insert the single-hole rubber stopper back into the mouth of the reaction flask to form a seal. The second chemical reaction will begin at room temperature and pressure. Then, slowly open the stopcock valve and observe the change in the distilled water level in the gas measuring tube. When the water level no longer changes, it indicates that the second chemical reaction has ended.

[0051] Measure the mass M1 of the precipitate calcium hydroxide and the volume V1 of the unreacted water in the reaction flask: (1) Pretreatment: Heat the sample in the reaction flask to 45°C (i.e., heat treatment), stir thoroughly (stirring speed is 15 rpm, time is 10 min) to mix well, and avoid the sample adhering to the flask wall; (2) Preliminary separation: use medium-speed qualitative filter paper for atmospheric pressure filtration, collect the filtrate into a beaker. If the filtration speed is slow, vacuum filtration (reduced pressure filtration) can be used to accelerate the process. The filter residue is rinsed 4 times with petroleum ether at the same temperature to remove residual crude oil. (3) Deep separation: The filtrate after preliminary filtration is vacuum filtered using a 0.45μm microporous membrane to trap fine solid particles. The residue on the membrane is washed repeatedly with petroleum ether 6 times until the washing liquid is colorless. (4) After separation, the filtrate is placed in a beaker and left to stand for 40 minutes until the oil and water in the filtrate separate into layers. Then, the upper layer of oil is removed with a pipette, and the volume of the lower layer of water that did not participate in the reaction is measured as 10.8 mL (i.e., V1). (5) Drying: Combine the two filter residues and put them into a drying oven. Dry at 105±2℃ for 25 minutes until constant weight. If it is necessary to confirm that there is no residue, the final filtrate can be observed under a microscope. If there are no solid particles, it is considered that the separation is complete. The final mass of the precipitate calcium hydroxide M1 is 92.10g. According to formula (1), the water content of crude oil Fw is calculated to be 24.46%. Formula (1): Fw = 0.243 * (M1 - 6.576V + 4.11V1) / V × 100%; The specific raw material usage and process parameters for this embodiment are shown in Table 2.

[0052] Examples 2-5 The crude oil water content was determined using the same procedure as in Example 1, except that the types or amounts of raw materials were different, as shown in Table 2.

[0053] Example 6 The procedure is the same as in Example 1, except that in this example, no heating treatment is performed after the chemical reaction is complete. All other steps are the same as in Example 1. Specifically, Remove the single-hole rubber stopper that has been inserted into the tubing, add 18 mL (V) of crude oil sample I and 90 g of calcium peroxide to the reaction flask, then insert the single-hole rubber stopper that has been inserted into the tubing into the mouth of the reaction flask to form a seal, and start the first chemical reaction at room temperature and pressure; slowly open the stopcock valve and observe the change in the distilled water level in the gas measuring tube. When the water level no longer changes, it indicates that the first chemical reaction has ended. Close the stopcock valve, remove the single-hole rubber stopper from the mouth of the reaction flask, add 28.8 mL (i.e., 1.6V) of water to the reaction flask, and then insert the single-hole rubber stopper back into the mouth of the reaction flask to form a seal. The second chemical reaction will begin at room temperature and pressure. Then, slowly open the stopcock valve and observe the change in the distilled water level in the gas measuring tube. When the water level no longer changes, it indicates that the second chemical reaction has ended.

[0054] Measure the mass M1 of the precipitate calcium hydroxide and the volume V1 of the unreacted water in the reaction flask: (1) No heat treatment is performed; (2) Preliminary separation: use medium-speed qualitative filter paper for atmospheric pressure filtration, collect the filtrate into a beaker. If the filtration speed is slow, vacuum filtration (reduced pressure filtration) can be used to accelerate the process. The filter residue is rinsed 4 times with petroleum ether at the same temperature to remove residual crude oil. (3) Deep separation: The filtrate after preliminary filtration is vacuum filtered using a 0.45μm microporous membrane to trap fine solid particles. The residue on the membrane is washed repeatedly with petroleum ether 6 times until the washing liquid is colorless. (4) After separation, the filtrate is placed in a beaker and left to stand for 40 minutes until the oil and water in the filtrate separate into layers. Then, the upper layer of oil is removed with a pipette, and the lower layer of water that has not participated in the reaction is measured as 10.5 mL (i.e., V1). (5) Drying: Combine the two filter residues and put them into a drying oven. Dry at 105±2℃ for 25 minutes until constant weight. If it is necessary to confirm that there is no residue, the final filtrate can be observed under a microscope. If there are no solid particles, it is considered that the separation is complete. The final mass of the precipitate calcium hydroxide M1 is 90.50g. According to formula (1), the water content of crude oil, Fw, is calculated to be 20.64%. The specific raw material usage and process parameters for this embodiment are shown in Table 2.

[0055] Comparative Example 1 The same process as in Example 1 was used, except that in this example, the amount of calcium peroxide used was 80g (i.e., 1.11n). The remaining steps were the same as in Example 1. The water content of the crude oil was calculated. The specific raw material dosage and process parameters of this comparative example are shown in Table 2.

[0056] Comparative Example 2 The same process as in Example 1 was used, except that the amount of calcium peroxide used in this example was 72g (i.e., n). The remaining steps were the same as in Example 1. The water content of the crude oil was calculated. The specific raw material dosage and process parameters of this comparative example are shown in Table 2.

[0057] Comparative Example 3 The same process as in Example 1 was used, except that in this example, the amount of calcium peroxide used was 115g (i.e., 1.6n). The remaining steps were the same as in Example 1. The water content of the crude oil was calculated. The specific raw material dosage and process parameters of this comparative example are shown in Table 2.

[0058] Comparative Example 4 The same process as in Example 1 was used, except that in this example, calcium peroxide was replaced with an equal mass of magnesium peroxide, the heating temperature was 45°C, the washing liquid was petroleum ether, and the remaining steps were the same as in Example 1. The water content of crude oil was calculated. The specific raw material dosage and process parameters of this comparative example are shown in Table 2.

[0059] Comparative Example 5 The same process as in Example 1 was used, except that in this example, calcium peroxide was replaced with an equal mass of barium peroxide, the heating temperature was 45°C, the washing liquid was petroleum ether, and the remaining steps were the same as in Example 1. The water content of crude oil was calculated. The specific raw material dosage and process parameters of this comparative example are shown in Table 2.

[0060] Table 2

[0061] Accuracy of the measurement method: The test results were compared using established and authoritative methods to measure relative error and recovery rate.

[0062] The formula for calculating relative error is: Relative error = |Measured value - Standard value| / Standard value × 100%.

[0063] The recovery rate is calculated as follows: Recovery rate = |Moisture content of spiked sample - Moisture content of original sample| / Amount of water added × 100%.

[0064] The water content of crude oil I was determined to be 24.70% (standard value) using the method in GB / T 8929-2006 Determination of Water Content in Crude Oil. The relative measurement error compared with the method in this paper (24.46%) was 0.97%.

[0065] 10 mL of water was added to the crude oil sample in Example 1. The water content of the spiked sample tested by this method was 14.2 mL, the water content of the original sample was 4.4 mL, and the recovery rate was 98%.

[0066] Detection range of the assay method: The detection range of the testing method provided by this invention is determined by measuring crude oil with different water contents.

[0067] The water content of crude oil determined by the method in GB / T 8929-2006 "Determination of Water Content in Crude Oil" was used as the standard value. The method in Example 1 was used for the determination. The test results are shown in Table 3, which shows that the method has good measurement accuracy in the range of water content from 5% to 100%.

[0068] Table 3

[0069] Precision of the measurement method: Repeatability: The method of Example 1 was followed, and six parallel measurements were performed under the same experimental conditions. The moisture contents of the six parallel measurements were 24.68%, 24.66%, 24.72%, 24.70%, 24.74%, and 24.70%, respectively. The relative standard deviation (RSD1) was calculated to be 0.18%. Intermediate precision: The moisture content was measured three times by different experimenters according to the method in Example 1. The moisture content of the three parallel measurements were 24.73%, 24.67%, and 24.70%, respectively. The relative standard deviation between groups (RSD2) was calculated to be 0.14%.

[0070] Experimental results show that the relative standard deviation of the moisture content determination results is small, proving that the test method is repeatable and reproducible, and the precision meets the analytical requirements.

[0071] Stability of the test method: The test measures the influence of various internal and external factors on the test results, such as external temperature, pressure, bubbles, and electromagnetic fields.

[0072] The water content of the crude oil was determined to be 40% using the method in GB / T 8929-2006, "Determination of Water Content in Crude Oil". Using this crude oil sample as a standard, the stability of this method under the influence of external factors such as temperature, pressure, air bubbles, and electromagnetic fields was tested, as detailed below: To verify the effect of temperature, the reaction apparatus was placed in environments with temperatures of 20°C, 25°C, and 32°C, respectively, and measurements were performed according to the method in Example 1. The deviations of the test values ​​(specifically 40.5%, 39.5%, and 40%) from the standard value (40%) were ±1.3%. To verify the effect of pressure, the reaction apparatus was placed in environments with atmospheric pressure, slightly positive pressure (105.0 kPa), and slightly negative pressure (98.0 kPa), respectively, and measurements were performed according to the method in Example 1. The deviations of the test values ​​(specifically 39.56%, 39.48%, and 39.52%) from the standard value (40%) were -1.2%. To verify the effect on bubbles, nitrogen was blown into the sample to simulate a gas-containing state, and the measurements were performed according to the method in Example 1. The deviations of the test values ​​(specifically 39.68%, 40.32%, and 40.00%) from the standard value (40%) were ±0.8%. To verify the effect on the electromagnetic field, the reaction device was placed in a strong electromagnetic field environment of a mobile phone call, and the measurement was carried out according to the method of Example 1. The deviation of the test values ​​(specifically 40.05%, 40.03%, and 40.05%) from the standard value (40%) was 0.1%.

[0073] The results above show that by using the testing device and following the technical method described in this invention, it is possible to rapidly test the water content of crude oil samples without separation.

[0074] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for determining the water content of crude oil, characterized in that, The method is carried out in a moisture content measuring device, which includes: a base (1) on which a reaction flask (2) is placed, the reaction flask (2) having a single-hole rubber stopper (4) with a conduit (3) providing communication between the reaction flask (2) and a stopcock valve (5), a gas measuring tube (6) and a beaker (7), the method comprising: Calcium peroxide and crude oil with a volume of V ml were introduced into the reaction flask (2). Then, a single-hole rubber stopper (4) with a conduit (3) was inserted into the mouth of the reaction flask (2) to form a sealed condition and carry out the first chemical reaction. After the reaction was completed, water with a volume of 1.6V ml was introduced into the reaction flask (2) to carry out the second chemical reaction and obtain precipitate B. The amount of calcium peroxide was controlled to be 1.2n g to 1.5n g, where n = 4V. The precipitate B was separated and purified, and its mass was measured to be M1 g; the volume of water that did not participate in the reaction in the reaction flask (2) was V1 ml; the water content Fw of the crude oil was calculated according to formula (1): Equation (1): Fw = 0.243 * (M1 - 6.576V + 4.11V1) / V × 100%.

2. The method according to claim 1, characterized in that, The crude oil contains 45-70 wt% saturated hydrocarbons, 10-25 wt% aromatic hydrocarbons, and has a surface density of 0.834-0.859 g / cm³. 3 The surface viscosity is 4.5-8.4 mPa·S.

3. The method according to claim 2, characterized in that, The crude oil contains 60-70 wt% saturated hydrocarbons, 15-20 wt% aromatic hydrocarbons, and has a surface density of 0.84-0.85 g / cm³. 3 The surface viscosity is 5.0-7.0 mPa·S.

4. The method according to any one of claims 1-3, characterized in that, The amount of calcium peroxide used is controlled to be 1.25n g to 1.35n g.

5. The method according to any one of claims 1-3, characterized in that, The conditions for the first chemical reaction and the second chemical reaction independently include: a temperature of 20-30°C and a pressure of 0.09-0.11 MPa.

6. The method according to any one of claims 1-3, characterized in that, The method further includes: after the second chemical reaction is completed, post-processing the resulting material; the post-processing method is heat treatment.

7. The method according to claim 6, characterized in that, The conditions for the heat treatment include: a temperature of 40-60℃ and a time of 10-15 minutes.

8. The method according to any one of claims 1-3, characterized in that, The separation and purification operation includes: sequentially filtering, washing and drying the solid obtained after the second chemical reaction to obtain the precipitate B.

9. The method according to claim 8, characterized in that, The washing solution is petroleum ether and / or n-hexane; And / or, the drying conditions include: a temperature of 100-110°C and a time of 20-25 min.

10. An apparatus for determining the water content of crude oil, characterized in that, The device includes: Base (1); The reaction flask (2) is placed on the base (1); A single-hole rubber stopper (4) is inserted into the mouth of the reaction flask (2); One end of the conduit (3) passes through the single-hole rubber stopper to be inserted into the reaction flask (2), and the other end is connected to one end of the gas measuring tube (6); A beaker (7) is connected to the other end of the gas measuring tube (6); A plug valve (5) is used to control the opening and closing of the conduit (3).

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