Method and device for determining dissolution rate of solid wax inhibitor

Abstract

The embodiment of the present invention provides a method and device for determining the dissolution rate of a solid wax inhibitor. The method includes: preparing condensate gas according to standards by using single degassing and condensate oil, and placing the prepared condensate gas in a condensate gas intermediate container, and then filling the solid wax inhibitor and the proppant into a core model after uniformly mixing, and weighing the filled core model to obtain a first core model weight, and then setting the experimental pressure, and under the action of the pressure difference, the condensate gas in the condensate gas intermediate container flows through the core model at a preset flow rate and contact time, and the core model is weighed again to obtain a second core model weight, and finally the solid wax inhibitor dissolution rate is calculated based on the first core model weight, the second core model weight, the total condensate gas volume flowing through the core model, and the contact time between the condensate gas and the solid wax inhibitor, thereby realizing the effect evaluation of the solid wax inhibitor.

Description

Technical Field

[0001] The invention relates to the field of oil and gas exploitation, and in particular to a method and a device for measuring the dissolution rate of a solid wax inhibitor. Background Art

[0002] During the oil and gas production process, wax deposition in the wellbore will have an adverse effect on the normal exploitation of the oil and gas wells. Severe wax deposition will lead to complicated situations such as pipe string jamming and surface pipeline blockage. With the continuous development of condensate gas wells, the formation temperature and pressure of the oil and gas wells will inevitably drop, and the phenomenon of wax deposition in deep, high-temperature and high-pressure condensate gas will become more and more common.

[0003] At present, solid wax inhibitors are used in oil wells as wax removal and prevention measures. There are few studies on the application of solid wax inhibitors in condensate gas wells, and there is a lack of measurement devices and methods for the dissolution rate of solid wax inhibitors related to condensate gas under high temperature and high pressure conditions. At present, domestic patents related to solid wax prevention are mainly focused on the development of solid wax inhibitors for reducing condensate and viscosity and installation devices for solid wax inhibitors in oil wells. For example, patent CN103450864B proposes a solid wax inhibitor for reducing condensate viscosity, which can reduce the viscosity of highly waxy crude oil. Patent CN105298419A discloses a casting and catching device for a solid wax inhibitor for a rodless lifting well and its casting and catching process.

[0004] It can be seen from this that currently no solid wax inhibitor has been proposed for use in condensate gas wells, and there is no method or device for determining the dissolution rate of solid wax inhibitors in condensate gas under high temperature and high pressure conditions. This can easily lead to inaccurate evaluation of the wax inhibitor effect of solid wax inhibitors, thereby affecting oil and gas production. Summary of the invention

[0005] The present invention provides a method and device for determining the dissolution rate of a solid wax inhibitor, which is used to solve the problem that the method and device for determining the dissolution rate of a solid wax inhibitor with condensate gas under high temperature and high pressure conditions have not been proposed in the prior art, resulting in inaccurate evaluation of the solid wax inhibitor, thus affecting oil and gas production.

[0006] The first aspect of the present invention provides a device for measuring the dissolution rate of a solid wax inhibitor, comprising:

[0007] Condensate gas intermediate container, drying tube, gas flow meter, core model and back pressure valve;

[0008] The condensate gas intermediate container is connected to one end of the drying tube, and the other end of the drying tube is connected to the gas flow meter. The condensate gas intermediate container is used to contain condensate gas, and the drying tube is used to dry the gas passing therethrough;

[0009] The other end of the gas flow meter is connected to the core model, and the gas flow meter is used to measure the flow rate of the passing gas;

[0010] The other end of the core model is connected to the back pressure valve, and the back pressure valve is provided with a pump for controlling the pressure in the pipeline.

[0011] Optionally, the device further comprises:

[0012] A recovery intermediate container for recovering condensed gas, wherein the recovery intermediate container is connected to the other end of the back pressure valve.

[0013] Optionally, a piston is also provided inside the recovery intermediate container.

[0014] Optionally, a pressure gauge is further provided on the recovery intermediate container, and the piston divides the cavity in the recovery intermediate container into two chambers. The pressure of the condensate gas in the recovery intermediate container is ensured by controlling the pressure gauge.

[0015] Optionally, a pressure gauge is provided on the condensate gas intermediate container to control the pressure of the condensate gas.

[0016] Optionally, the pump provided on the back-pressure valve is a hand pump.

[0017] Optionally, the device further comprises a thermostat, which is used to control the experimental temperature.

[0018] A second aspect of the present invention provides a method for measuring the dissolution rate of a solid wax inhibitor, comprising:

[0019] Using single degassing and condensate oil to prepare condensate gas according to standards, and placing the prepared condensate gas in a condensate gas intermediate container;

[0020] The solid wax inhibitor and the proppant are uniformly mixed and filled into the core model, and the filled core model is weighed to obtain a first core model weight;

[0021] Setting a test pressure, allowing the condensate gas in the condensate gas intermediate container to flow through the core model at a preset flow rate and contact time under the action of a pressure difference, and weighing the core model again to obtain a second core model weight;

[0022] The dissolution rate of the solid wax inhibitor is calculated according to the weight of the first core model, the weight of the second core model, the total volume of condensate gas flowing through the core model, and the contact time between the condensate gas and the solid wax inhibitor.

[0023] Optionally, before weighing the core model again, the method further includes:

[0024] The condensate gas flowing out of the core model is recovered into the recovery intermediate container through the back pressure valve.

[0025] Optionally, the solid wax inhibitor dissolution rate is calculated based on the weight of the first core model, the weight of the second core model, the total condensate gas volume flowing through the core model, and the contact time between the condensate gas and the solid wax inhibitor, including:

[0026] use The solid wax inhibitor dissolution rate v is obtained by formula calculation;

[0027] Wherein, v is the dissolution rate of the solid wax inhibitor, M 1 is the weight of the first core model, M 2 is the weight of the second core model, V g · is the total volume of condensate gas flowing through the core model, and t is the contact time between the condensate gas and the solid paraffin inhibitor.

[0028] The third aspect of the present invention provides a device, comprising: a processor, a memory and a computer program; the computer program is stored in the memory, and the processor executes the computer program to implement the method for determining the dissolution rate of a solid wax inhibitor as described in any one of the first aspects.

[0029] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program, wherein a terminal device executes the method for determining the dissolution rate of a solid wax inhibitor as described in any one of the first aspects of the computer program.

[0030] The method and device for determining the dissolution rate of a solid wax inhibitor provided in an embodiment of the present invention adopt single degassing and condensate oil to prepare condensate gas according to standards, and place the prepared condensate gas in a condensate gas intermediate container, then evenly mix the solid wax inhibitor and the proppant and fill them into a core model, and weigh the filled core model to obtain a first core model weight, and then set a test pressure, and under the action of the pressure difference, the condensate gas in the condensate gas intermediate container flows through the core model at a preset flow rate and contact time, and the core model is weighed again to obtain a second core model weight, and finally, according to the first core model weight, the second core model weight, the total condensate gas volume flowing through the core model and the contact time between the condensate gas and the solid wax inhibitor, the dissolution rate of the solid wax inhibitor is calculated, thereby realizing the effect evaluation of the solid wax inhibitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 A schematic diagram of the structure of a first embodiment of a device for measuring the dissolution rate of a solid wax inhibitor provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the structure of a second embodiment of a device for measuring the dissolution rate of a solid wax inhibitor provided in an embodiment of the present invention;

[0034] Figure 3 A flow chart of a method for determining the dissolution rate of a solid wax inhibitor provided in an embodiment of the present invention;

[0035] Figure 4 This is a flow chart of Example 2 of the method for determining the dissolution rate of a solid wax inhibitor provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] The method for determining the dissolution rate of a solid paraffin inhibitor provided by the present invention is applied to the field of oil and gas production. The paraffin component in crude oil dissolves in the crude oil under certain temperature and pressure conditions in the oil layer. In the process of oil and gas production, the crude oil flows from the oil layer to the bottom of the well, and the production process of flowing from the bottom of the well to the ground is a process of pressure and temperature reduction. When paraffin is precipitated from the crude oil, it is likely to adhere to the surface of rock particles in the oil layer, which will reduce or even block the oil flow channel, increase oil flow resistance, and affect the normal production of the oil well. Severe wax deposition will also cause wax deposition in underground and ground equipment or even blockage, forcing production to be stopped.

[0038] In order to prevent wax from forming in the wellbore of an oil well, three aspects can be taken into consideration. First, prevent the precipitation of oil crystals. During crude oil production, measures can be taken to increase the wellbore temperature so that the oil flow temperature is higher than the initial crystallization temperature of the wax, thereby preventing the wax from precipitating. Second, inhibit the aggregation of paraffin crystals. When paraffin crystals have precipitated, chemical agents can be added to inhibit the aggregation of wax crystals. Third, create conditions that are not conducive to the deposition of paraffin. Anti-wax coatings can be applied to the wellbore. Anti-wax agents are usually added from the annulus of the oil casing or through the gap pumping rod, which will not affect the normal production and other operations of the oil well. Common anti-wax agents include liquid anti-wax agents and solid anti-wax agents. Taking solid anti-wax agents as an example, the implementation process of anti-wax agents is explained.

[0039] Since the solid wax inhibitor is mainly composed of high molecular weight polyethylene, stabilizer and ethylene-vinyl ester polymer, it can be made into granules, or mixed and pressed into a certain shape in a mold. Wax inhibitors are placed in a certain temperature area of ​​the oil well or put into the bottom of the well. They gradually dissolve at the temperature of the oil well to release the agent and dissolve in the oil. The polyethylene used as a wax inhibitor requires a relative molecular weight of 5000-30000, preferably around 20000, a relative density of 0.86-0.94, a melting point between 102-107°C, and relatively few crystals, or amorphous type is preferred. The ethylene-vinyl ester polymer in the wax inhibitor has a (CH2-CH2)n chain similar to the wax structure and a certain number of polar groups, so it dissolves in crude oil. When cooled, it produces a eutectic effect with the wax in the crude oil, and then inhibits the growth of wax crystals through the polar groups extending outward. The polyethylene dissolved in crude oil will precipitate first when the oil temperature drops, and become the paraffin crystal nucleus that precipitates later. The wax crystals are adsorbed on the carbon chains of the polyethylene. Due to spatial barriers and barrier effects, the growth and aggregation of the crystals are also hindered, and the adhesion between the ethylene-vinyl ester polymer and the wax crystals is reduced, thereby reducing the wax deposition in the oil well and achieving the purpose of wax prevention.

[0040] With respect to solid wax inhibitors, there has been no proposal for their application in condensate gas wells and for methods and devices for determining their dissolution rate in condensate gas under high-pressure and high-pressure conditions. The present invention mainly studies the dissolution rate of solid wax inhibitors in condensate gas wells, provides a method and device for determining the dissolution rate of solid wax inhibitors in condensate gas wells, and realizes the evaluation of the wax-proofing effect of solid wax inhibitors.

[0041] The present solution is described in detail below through several specific implementation methods.

[0042] Figure 1 The schematic diagram of the structure of the first embodiment of the device for measuring the dissolution rate of the solid wax inhibitor provided by the embodiment of the present invention is as follows: Figure 1 As shown, the device 10 for determining the dissolution rate of a solid wax inhibitor provided in this embodiment comprises:

[0043] Condensate gas intermediate container 1, drying pipe 2, gas flow meter 3, core model 4, back pressure valve 5, pump 6.

[0044] The condensate gas intermediate container 1 is used to contain condensate gas, which can be formulated to simulate the composition of condensate gas in oil wells, so that the experimental results are closer to reality. In the first step, standard gas can be prepared according to the existing reference basis "GB_5274-2008_Gas Analysis_Preparation of Mixed Gas for Calibration_Weighing Method", and then according to the existing reference basis "GBT_26981-2011_Oil and Gas Reservoir Fluid Physical Property Analysis Method", condensate gas is prepared using condensate oil provided at the actual oil and gas production site and the standard gas prepared in the first step. It can be understood by those skilled in the art that condensate oil can be a liquid phase component condensed from the associated natural gas in the condensate gas field, that is, condensate oil exists in the gas phase below, and is also in liquid state after being produced to the ground, and wax formation will occur under high temperature and high pressure conditions in the condensate gas formation.

[0045] The drying tube 2 is used to dry the gas passing through it to eliminate the influence of moisture on the experimental results. In one implementation, the time for the gas passing through it to be completely dried is controlled according to the historical drying time, or a fixed drying time is preset to ensure that the gas passing through is completely dried, thereby improving the accuracy of the experimental results.

[0046] The gas flow meter 3 can be used to control the volume of gas passing through it within a preset time. For example, the volume of gas passing through the gas flow meter 3 within 1 minute can be preset to be 1 L. When setting the flow rate of the gas, the time for the gas to pass through the drying tube 2 must be fully considered to ensure that the gas can be completely dried after passing through the drying tube 2.

[0047] The core model 4 can be a model containing a mixture of solid wax inhibitor and proppant, i.e., a model simulating an actual oil well. It will be appreciated by those skilled in the art that the proppant can be a ceramic particle with a certain particle size and gradation, with characteristics such as high temperature resistance, high pressure resistance, corrosion resistance, and high flow conductivity, so when oil and gas are produced, the proppant is used to enter the stratum and fill it in the rock stratum cracks, which plays a good flow conductivity, makes oil and gas unblocked, and increases production. Since solid wax inhibitor is usually used to clear wax in the actual production process of oil and gas, the solid wax inhibitor and proppant will be mixed together, and the mixture of solid wax inhibitor and proppant is used to fill the core model 4 to simulate the actual oil well model.

[0048] The back pressure valve 5 is provided with a pump for controlling the pressure in the pipeline. The pressure in the pipeline is set by controlling the pump. Optionally, the pump can be a hand pump. A pressure gauge is connected above the back pressure valve 5 and is used to display the experimental pressure.

[0049] In this embodiment, the drying tube 2 can have two connection ports, the condensate gas intermediate container 1 is connected to one end of the drying tube 2, and a valve can be provided between them to prevent the condensate gas in the condensate gas intermediate container from flowing into the drying tube before the experiment starts, and the other end of the drying tube 2 is connected to the gas flow meter 3, and the other end of the gas flow meter 3 is connected to the core model 4, and the other end of the core model 4 is connected to the back pressure valve 5, and the other end of the back pressure valve 5 may not be connected.

[0050] Reference Figure 1 The condensate gas intermediate container 1 can be a chemical container with a volume of 2L, a pressure resistance of 70MPa, a temperature resistance of 150℃ and a pressure gauge connected to the top. Under the action of the pressure difference, the condensate gas in the condensate gas intermediate container 1 passes through the drying tube 2 and the gas flow agent 3 into the core model 4 with a length of 200mm and an inner diameter of 25mm. The solid wax inhibitor and the proppant are mixed evenly according to a mass percentage of 2% and filled into the core model 4, and weighed as M1. A back pressure valve 5 is connected to the outlet end of the core model 14, and a pressure gauge is connected to the top of the back pressure valve 5. The pressure of the control experiment is applied to the back pressure valve 5 by a hand pump 6. After the experiment, the core model 4 is weighed again, recorded as M2, so as to calculate and obtain the dissolution rate of the solid wax inhibitor:

[0051]

[0052] Where, v is the dissolution rate of the solid paraffin inhibitor in the condensate gas, M 1 is the total mass of the core model before the experiment, M 2 V is the total mass of the core model after the experiment, and t is the contact time between the condensate gas and the solid paraffin inhibitor. g · is the total condensate volume flowing through the core model during the experiment, which can be obtained by referring to PV=nRT, where P is the gas pressure, V is the gas volume, n is the amount of gas, T is the temperature, and R is the proportionality coefficient. Under ideal conditions, it is a constant. The total condensate volume flowing through the core model is

[0053] Furthermore, experiments can be conducted with different pressures, condensate flow rates, and contact times between condensate gas and solid wax inhibitors, while keeping other variables unchanged. A graph can be drawn with the experimental pressure or condensate flow rate or contact time between condensate gas and solid wax inhibitor as the horizontal axis and the dissolution rate of the solid wax inhibitor in the condensate gas well as the vertical axis, so as to intuitively obtain the changing trend of the dissolution rate of the solid wax inhibitor with the change of the variables.

[0054] The device for determining the dissolution rate of a solid wax inhibitor provided in this embodiment includes: a condensate gas intermediate container, a drying tube, a gas flow meter, a core model, and a back-pressure valve. The condensate gas intermediate container is connected to one end of the drying tube, and the other end of the drying tube is connected to the gas flow meter. The condensate gas intermediate container is used to contain condensate gas, and the other end of the gas flow meter is connected to the core model, and the other end of the core model is connected to the back-pressure valve. The dissolution rate of the solid wax inhibitor under pressure, condensate gas flow rate, and contact time is determined, and the wax-proofing effect of the solid wax inhibitor is analyzed, thereby realizing the effect evaluation of the solid wax inhibitor under different experimental conditions.

[0055] Figure 2 The schematic diagram of the structure of the second embodiment of the device for measuring the dissolution rate of the solid wax inhibitor provided by the embodiment of the present invention is as follows: Figure 2 As shown, the device 20 for determining the dissolution rate of a solid wax inhibitor provided in this embodiment comprises:

[0056] Condensate gas intermediate container 1, drying tube 2, gas flow meter 3, core model 4, back pressure valve 5, hand pump 6, recovery intermediate container 7, piston 8, constant temperature box 9.

[0057] The specific description of the condensate gas intermediate container 1, the drying tube 2, the gas flow meter 3, the core model 4, the back pressure valve 5, and the hand pump 6 refers to the specific description of the above embodiment 1, which will not be repeated here.

[0058] In addition, the condensate gas intermediate container 1 contains prepared condensate gas, which is made of standard gas and condensate oil provided on site according to the standard, wherein the standard gas can be prepared according to the existing reference basis "GB_5274-2008_Gas Analysis_Preparation of Mixed Gas for Calibration_Weighing Method", and then according to the existing reference basis "GBT_26981-2011_Oil and Gas Reservoir Fluid Physical Property Analysis Method", the condensate gas is prepared using the condensate oil provided on site and the standard gas prepared in the first step. Those skilled in the art can understand that the condensate gas can be tested using the existing test method to obtain some basic parameters, or the basic parameters of the condensate gas, such as the wax content and wax precipitation point of the condensate gas, can be calculated using the existing method based on the standard gas used to prepare the condensate gas and the condensate oil provided at the actual oil and gas production site.

[0059] On the basis of the above-mentioned embodiment 1, optionally, the device 20 for determining the dissolution rate of the solid paraffin inhibitor further comprises a recovery intermediate container 7, which is connected to the other end of the back pressure valve 5 and can be used to recover the condensate gas. Optionally, a valve can be provided between the recovery intermediate container 7 and the back pressure valve 5 to control the condensate gas passing through the back pressure valve 5 to enter the recovery intermediate container 6.

[0060] Optionally, a piston 8 may be further provided inside the recovery intermediate container 7, and the piston 8 may divide the cavity inside the recovery intermediate container into two chambers. Before the experiment, the piston 8 is at the top of the recovery intermediate container 7, and there is an aqueous solution below the piston. As the experiment proceeds, the condensate gas from the core model 4 reaches the recovery intermediate container 7 through the back pressure valve 5, and the piston will move to the bottom of the recovery intermediate container 7. There may be a pressure gauge above the recovery intermediate container to measure the pressure of the condensate gas in the recovery intermediate container 7.

[0061] Furthermore, the condensed gas in the recovery intermediate container can be repeatedly utilized. Specifically, the condensed gas in the recovery intermediate container can be used as the condensed gas in the condensed gas intermediate container for conducting experiments, and then subsequent experiments can be conducted.

[0062] Optionally, the condensate gas in the recovery intermediate container 7 is subjected to a temperature and pressure reduction treatment. Specifically, the intermediate container 7 can be placed in a low temperature box so that the condensate gas precipitates condensate oil. This process is similar to the oil and gas production process, that is, when the condensate gas deep underground with high temperature and pressure reaches the ground, the condensate gas will precipitate condensate oil due to the decrease in temperature and pressure. Therefore, the condensate gas is subjected to a temperature and pressure reduction treatment to facilitate the condensate oil precipitated from the condensate gas. In addition, the condensate oil can be tested by comparing the basic parameters of the condensate gas prepared in the condensate gas intermediate container 1, and then referring to the standards Q / SY 158-2013 "Technical Specifications for Clear and Wax Inhibitors for Oil Production" and SY / T 6300-2009 "Technical Conditions for Clear and Wax Inhibitors for Oil Production" to test the wax prevention rate and freezing point depression value of the oil sample, and analyze the wax prevention effect of the solid wax inhibitor.

[0063] On the basis of the above-mentioned embodiment one, optionally, the device 20 for determining the dissolution rate of the solid wax inhibitor also includes a constant temperature box 9 for controlling the temperature of the experiment, so as to simulate the different temperatures corresponding to different formation depths during actual oil and gas production. The condensate gas intermediate container 1, the drying tube 2, the gas flow meter 3, the core model 4, the back pressure valve 5, the hand pump 6, the recovery intermediate container 7, and the piston 8 are all placed in the constant temperature box 9.

[0064] The second embodiment is described in detail below. Condensate gas is prepared. The specific preparation is as described in the first embodiment. The basic data such as wax content and wax precipitation point of the prepared condensate gas are tested, or the basic data is directly provided on site. The solid wax inhibitor and the proppant are mixed evenly according to a mass percentage of 2% and then filled into the core model 4. The core model 4 is weighed and recorded as M. 1 , place the prepared condensate gas in the condensate gas intermediate container 1, and Figure 2All devices are placed in a thermostatic box, the temperature of the thermostatic box is preset to 80°C, and the experimental temperature is maintained at 80°C for 4 hours, so that the experimental temperature is maintained at 80°C without fluctuations. The experimental pressure is applied to the back pressure valve 15 by a hand pump, and the preset experimental pressure is 60MPa. The experimental pressure should be greater than the pressure of the condensate gas in the condensation intermediate container 11, so that under the action of the pressure difference, the condensate flows through the core model at a flow rate of 1mL / min and a contact time of 1h with the core model, and then enters the recovery intermediate container 6 through the back pressure valve 5. After the experiment, the core model 4 is weighed, which is M 2 The mass difference between the two times is the amount of solid wax inhibitor dissolved, and the dissolution rate of the solid wax inhibitor is obtained as follows:

[0065]

[0066] Where, v is the dissolution rate of the solid paraffin inhibitor in the condensate gas, M 1 is the mass of the core model before the experiment, M 2 is the weight of the core model after the experiment, and t is the contact time between the condensate gas and the core model, which is 1h in this case. g is the total volume of condensate gas flowing through the core model during the experiment under standard atmospheric pressure, referring to the above formula Get.

[0067] In this embodiment, the temperature of the thermostatic box can be changed, the pressure of the back pressure valve can be controlled, the flow rate of the condensate gas measured by the gas flowmeter, the contact time of the solid wax inhibitor and the condensate gas in the core model can be adjusted, the dissolution rate of the solid wax inhibitor under different conditions can be measured respectively, and the dissolution rate of the solid wax inhibitor under different experimental conditions can be plotted, which intuitively reflects the dissolution rate of the solid wax inhibitor in the condensate gas well.

[0068] The device for determining the dissolution rate of a solid wax inhibitor provided in this embodiment includes: a condensate gas intermediate container, a drying tube, a gas flow meter, a core model, a back pressure valve, a recovery intermediate container and a constant temperature box. The condensate gas intermediate container is connected to one end of the drying tube, and the other end of the drying tube is connected to the gas flow meter. The condensate gas intermediate container is used to contain condensate gas, and the other end of the gas flow meter is connected to the core model, and the other end of the core model is connected to the back pressure valve, and the recovery intermediate container is connected to the other end of the back pressure valve. All devices are placed in a constant temperature box, and the dissolution rate of the solid wax inhibitor under different temperatures, pressures, condensate gas flow rates, and contact times is determined, and the anti-wax effect of the solid wax inhibitor is analyzed, thereby realizing the effect evaluation of the solid wax inhibitor under different experimental conditions.

[0069] Figure 3 The flowchart of the method for measuring the dissolution rate of a solid wax inhibitor provided in the embodiment of the present invention is as follows: Figure 3As shown, the method for measuring the dissolution rate of the solid wax inhibitor specifically comprises the following steps:

[0070] S101, using single degassing and condensate oil to prepare condensate gas according to standards, and placing the prepared condensate gas in a condensate gas intermediate container.

[0071] In this step, the single degassing is standard gas, which can be prepared according to the existing standard "GB_5274-2008_Gas Analysis_Preparation of Mixed Gas for Calibration_Weighing Method". The condensate oil can be provided at the actual oil and gas production site. According to the existing reference "GBT_26981-2011_Analysis Method of Physical Properties of Oil and Gas Reservoir Fluids", the condensate oil and the prepared standard gas are used to prepare condensate gas. Those skilled in the art can understand that condensate oil can be a liquid phase component condensed from the associated natural gas in the condensate gas field, that is, condensate oil exists in the gas phase below, and is in liquid state after being produced to the ground, and the condensate gas formation will have wax formation under the high temperature and high pressure conditions.

[0072] Furthermore, the prepared condensate gas is installed in a condensate gas intermediate container for subsequent use. The prepared condensate gas can be prepared to simulate the composition of condensate gas in an oil well, making the experimental results closer to reality.

[0073] S102, uniformly mixing the solid wax inhibitor and the proppant and filling the mixture into a core model, and weighing the filled core model to obtain a first core model weight.

[0074] Those skilled in the art can understand that the proppant can be a ceramic particle with a certain particle size and gradation, and has the characteristics of high temperature resistance, high pressure resistance, corrosion resistance, high conductivity, etc. Therefore, when oil and gas are produced, the proppant is used to enter the formation and fill in the cracks in the rock formation, which has a good conductivity, makes the oil and gas flow smoothly, and increases the output. Since solid wax inhibitors are usually used to remove wax in the actual oil and gas production process, the solid wax inhibitor and the proppant will be mixed together. Here, a mixture of solid wax inhibitor and proppant is used to fill the core model to simulate the actual oil well model.

[0075] In this step, the solid wax inhibitor is mixed evenly with the proppant and filled into the core model, and the filled core model is weighed to obtain the first core model weight, so as to obtain the mass difference of the core model after testing the solid wax inhibitor dissolving in the condensate gas in subsequent experiments.

[0076] S103, setting a test pressure, allowing the condensate gas in the condensate gas intermediate container to flow through the core model at a preset flow rate and contact time under the action of the pressure difference, and weighing the core model again to obtain a second core model weight.

[0077] In this step, a pressure gauge may be provided on the upper part of the condensate gas intermediate container to display the pressure of the condensate gas in the condensate gas intermediate container. A back pressure valve may be provided behind the core model, and a pump for controlling the pressure in the pipeline is provided on the back pressure valve. The pressure in the control pipeline is set by controlling the pump. Optionally, the pump may be a hand pump, and a pressure gauge is connected above the back pressure valve to display the experimental pressure.

[0078] The condensate gas intermediate container can be connected to one end of a drying tube, which can be used to dry the gas passing through it to eliminate the influence of moisture on the experimental results. In one implementation method, the time for the gas passing through it to be completely dried is controlled according to the historical drying time, or a fixed drying time is preset to ensure that the gas passing through is completely dried, thereby improving the accuracy of the experimental results.

[0079] The other end of the drying tube can be connected to a gas flow meter, which can be used to control the volume of gas passing through it within a preset time. For example, the volume of gas passing through the gas flow meter 3 within 1 minute can be preset to be 1 L. When setting the gas flow rate, the time for the gas to pass through the drying tube 2 should be fully considered to ensure that the gas can be completely dried after passing through the drying tube 2.

[0080] In a specific implementation, when the experimental pressure is greater than the pressure in the condensate gas intermediate container, the condensate gas in the condensate gas intermediate container can enter the core model through the drying tube and the gas flow meter according to the preset flow rate and contact time, and then the core model is weighed to measure the mass difference of the core model after the solid wax inhibitor is dissolved in the condensate gas.

[0081] Optionally, before weighing the core model again, the method for determining the dissolution rate of the solid wax inhibitor also includes: recovering the condensate gas flowing out of the core model into a recovery intermediate container through a back pressure valve; optionally, after the condensate gas is prepared, the condensate gas can be tested by existing testing methods to obtain some basic parameters, such as wax content, wax precipitation point, etc., or, the basic parameters of the condensate gas can be calculated by existing methods based on the standard gas used to prepare the condensate gas and the condensate oil provided at the actual oil and gas production site.

[0082] Optionally, the condensate gas flowing out of the core model is recovered into the recovery intermediate container through the back pressure valve, and the condensate gas is subjected to temperature and pressure reduction treatment. Specifically, the intermediate container can be placed in a low temperature box so that the condensate gas precipitates condensate oil. This process is similar to the oil and gas production process, that is, when the condensate gas deep underground with high temperature and pressure reaches the ground, the condensate gas will precipitate condensate oil due to the decrease in temperature and pressure. Therefore, the condensate gas is subjected to temperature and pressure reduction treatment to facilitate the condensate oil precipitated from the condensate gas. In addition, the condensate oil can be tested by comparing the basic parameters of the condensate gas prepared in the condensate gas intermediate container, and then referring to the standards Q / SY 158-2013 "Technical Specifications for Clear and Wax Inhibitors for Oil Production" and SY / T 6300-2009 "Technical Conditions for Clear and Wax Inhibitors for Oil Production" to test the wax prevention rate and freezing point depression value of the oil sample, and analyze the wax prevention effect of the solid wax inhibitor.

[0083] Furthermore, the condensate gas in the recovery intermediate container can be repeatedly utilized. Specifically, the condensate gas in the recovery intermediate container can be used as the condensate gas in the experimental condensate gas intermediate container to conduct experiments on the dissolution rate of the solid wax inhibitor under different pressures, condensate gas flow rates, and contact times.

[0084] S104, calculating and obtaining the dissolution rate of the solid wax inhibitor according to the weight of the first core model, the weight of the second core model, the total volume of condensate gas flowing through the core model, and the contact time between the condensate gas and the solid wax inhibitor.

[0085] In this step, the total condensate gas volume flowing through the core model can be obtained through the condensate gas intermediate container, specifically, it can be obtained according to the ideal gas state equation PV=nRT, where P is the gas pressure, V is the gas volume, n is the amount of gas substance, T is the temperature, and R is the proportionality coefficient, which is a constant under ideal conditions. Then the total condensate gas volume flowing through the core model is

[0086] In a specific implementation method, the obtained weight of the first core model and the second core model can be subtracted to obtain a difference, and then the difference is divided by the product of the total volume of condensate gas flowing through the core model and the contact time of the condensate gas with the solid wax inhibitor to obtain the dissolution rate of the solid wax inhibitor; or, the weight of the first core model and the second core model are subtracted to obtain a difference, and then the difference is divided by the total volume of condensate gas flowing through the core model and the condensate gas, and the result is divided by the contact time of the solid wax inhibitor to obtain the dissolution rate of the solid wax inhibitor.

[0087] The method for determining the dissolution rate of a solid wax inhibitor provided in this embodiment is applied to the device for determining the dissolution rate of a solid wax inhibitor provided in any of the above embodiments. The implementation principle and technical effects thereof are similar and will not be described in detail herein.

[0088] Figure 4 Flow chart of Example 2 of the method for determining the dissolution rate of a solid wax inhibitor provided in an embodiment of the present invention. Figure 4 As shown, in another specific implementation of the method for determining the dissolution rate of the solid wax inhibitor, the following steps are included:

[0089] S201, using single degassing and condensate oil to prepare condensate gas according to standards, and placing the prepared condensate gas in a condensate gas intermediate container.

[0090] S202, uniformly mixing the solid wax inhibitor and the proppant and filling the mixture into a core model, and weighing the filled core model to obtain a first core model weight.

[0091] S203, setting the experimental pressure, allowing the condensate gas in the condensate gas intermediate container to flow through the core model at a preset flow rate and contact time under the action of the pressure difference, and weighing the core model again to obtain a second core model weight.

[0092] The specific implementation process of the above steps S101-S103 can be found in the relevant description of the first embodiment of the method of the present invention, and will not be repeated here.

[0093] S204, use The dissolution rate v of the solid wax inhibitor is obtained by calculation using the formula.

[0094] In this step, v is the dissolution rate of the solid wax inhibitor, M 1 is the weight of the first core model, M 2 is the weight of the second core model, V g · is the total condensate volume flowing through the core model, t is the contact time between the condensate gas and the solid paraffin inhibitor, the weight of the first core model and the weight of the second core model can be obtained through the above steps S102-S103, and the total condensate volume flowing through the core model can be obtained by the formula Calculated and obtained, wherein P is the gas pressure, V is the gas volume, n is the amount of gas substance, T is the temperature, and R is the proportional coefficient, which is a constant under ideal conditions. The contact time between the condensate gas and the solid anti-wax agent can be a preset time.

[0095] Specifically, the weight of the first core model and the weight of the second core model are subtracted to obtain the difference, and then the difference is divided by the multiplication of the total condensate gas volume flowing through the core model and the contact time of the condensate gas and the solid wax inhibitor to obtain the dissolution rate of the solid wax inhibitor. The experimental temperature, pressure, condensate gas flow rate, and contact time can be controlled to measure the dissolution rate of the solid wax inhibitor under different conditions, and the dissolution rate of the solid wax inhibitor under different experimental conditions is plotted to intuitively reflect the dissolution rate of the solid wax inhibitor in the condensate gas well.

[0096] The method for determining the dissolution rate of a solid wax inhibitor provided in this embodiment is applied to the device for determining the dissolution rate of a solid wax inhibitor provided in any of the above embodiments. The implementation principle and technical effects thereof are similar and will not be described in detail herein.

[0097] The present invention provides a terminal device, comprising: a processor, a memory and a computer program; the computer program is stored in the memory, and the processor executes the computer program to implement the method for determining the dissolution rate of a solid wax inhibitor provided in any of the aforementioned embodiments.

[0098] The present invention also provides a computer-readable storage medium storing a computer program, and a terminal device executes the computer program to implement the method for determining the dissolution rate of a solid wax inhibitor provided in any of the aforementioned method embodiments.

[0099] In the above terminal device, it should be understood that the processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiment of the present invention can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring the dissolution rate of a solid wax inhibitor, characterized in that: A device for measuring the dissolution rate of a solid wax inhibitor, the device comprising: Condensate gas intermediate container, drying tube, gas flow meter, core model and back pressure valve; The condensate gas intermediate container is connected to one end of the drying pipe, the other end of the drying pipe is connected to the gas flow meter, the condensate gas intermediate container is used to contain condensate gas, the condensate gas is made of single degassing and condensate oil according to the standard, and the drying pipe is used to dry the gas passing therethrough; The other end of the gas flow meter is connected to the core model, and the gas flow meter is used to measure the flow rate of the passing gas; The other end of the core model is connected to the back pressure valve, and the back pressure valve is provided with a pump for controlling the pressure in the pipeline; The core model is filled with a uniformly mixed fixed wax inhibitor and a proppant, and the filled core model is used to obtain a first core model weight and a second core model weight, wherein the first core model weight is the weight of the core model before the condensate gas is introduced, and the second core model weight is the weight of the core model after the test, wherein the test includes the steps of setting the test pressure, flowing the condensate gas in the condensate gas intermediate container through the core model at a preset flow rate and contact time under the action of the pressure difference, and weighing the core model again, and the first core model weight and the second core model weight are used to calculate the dissolution rate of the solid wax inhibitor in combination with the total condensate gas volume flowing through the core model and the contact time between the condensate gas and the solid wax inhibitor; The method for measuring the dissolution rate of the solid wax inhibitor comprises: Using single degassing and condensate oil to prepare condensate gas according to standards, and placing the prepared condensate gas in a condensate gas intermediate container; The solid wax inhibitor and the proppant are uniformly mixed and filled into the core model, and the filled core model is weighed to obtain a first core model weight; Setting a test pressure, allowing the condensate gas in the condensate gas intermediate container to flow through the core model at a preset flow rate and contact time under the action of a pressure difference, and weighing the core model again to obtain a second core model weight; The dissolution rate of the solid wax inhibitor is calculated according to the weight of the first core model, the weight of the second core model, the total volume of condensate gas flowing through the core model, and the contact time between the condensate gas and the solid wax inhibitor.

2. The method according to claim 1, characterized in that Also includes: A recovery intermediate container for recovering condensed gas, wherein the recovery intermediate container is connected to the other end of the back pressure valve.

3. The method according to claim 2, characterized in that A piston is also arranged inside the recovery intermediate container.

4. The method according to claim 3, characterized in that The recovery intermediate container is also provided with a pressure gauge, and the piston divides the cavity in the recovery intermediate container into two chambers. The pressure of the condensate gas in the recovery intermediate container is ensured by controlling the pressure gauge.

5. The method according to claim 1, characterized in that The condensate gas intermediate container is provided with a pressure gauge for controlling the pressure of the condensate gas.

6. The method according to any one of claims 1 to 5, characterized in that: The pump arranged on the back pressure valve is a hand pump.

7. The method according to claim 1, characterized in that The device also includes a thermostat, which is used to control the experimental temperature.

8. The method according to claim 1, characterized in that Before weighing the core model again, the method further comprises: The condensate gas flowing out of the core model is recovered into the recovery intermediate container through the back pressure valve.

9. The method according to claim 1 or 8, characterized in that: The method of calculating the dissolution rate of the solid wax inhibitor according to the weight of the first core model, the weight of the second core model, the total volume of condensate gas flowing through the core model, and the contact time between the condensate gas and the solid wax inhibitor comprises: use The solid wax inhibitor dissolution rate v is obtained by formula calculation; Wherein, v is the dissolution rate of the solid wax inhibitor, M1 is the weight of the first core model, M2 is the weight of the second core model, and V g · is the total volume of condensate gas flowing through the core model, and t is the contact time between the condensate gas and the solid paraffin inhibitor.

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