CN105203742A - Deep well pitshaft wax-deposition analysis and testing device and analysis and testing method - Google Patents

Abstract

The invention belongs to the field of oil development and specifically relates to a deep well pitshaft wax-deposition analysis and testing device and an analysis and testing method. The device and the method are used for analyzing and testing wax-deposition in a deep well pitshaft under different conditions so as to summarize corresponding laws. The deep well pitshaft wax-deposition analysis and testing device comprises a testing vertical pitshaft string, an oil tank, a controllable thermostatic water bath and a recycling tank. The testing vertical pitshaft string provides a wax deposition environment; the oil tank provides preset crude oil; and the recycling tank recycles crude oil after wax deposition. The crude oil enters the testing vertical pitshaft string from the oil tank to undergo wax deposition, and the crude oil after wax deposition then enters the recycling tank to be recycled. The controllable thermostatic water bath adjusts temperature of the outside environment during the wax-deposition process. In comparison with the prior art, wax deposition on the inner wall of the deep well pitshaft under different conditions can be simulated in the invention.

Description

Deepwater Wellbore Waxing Analysis and Testing Device and Analysis and Testing Method

technical field

The invention belongs to the field of petroleum development, and in particular relates to a device and method for analyzing and testing wax deposition in deep-water well bores, which are used for analyzing and testing wax deposition in deep-water well bores under different conditions, thereby summarizing and inducing corresponding laws.

Background technique

When exploring and developing oil fields, wax deposition in the wellbore is often encountered. When crude oil is extracted from the formation to the surface, dissolved gas will escape and expand, resulting in a gradual decrease in temperature, and the wax in the crude oil will gradually crystallize and precipitate, agglomerating into blocks, and piled up on the inner wall of the wellbore, blocking the wellbore, resulting in a decrease in oil well production Even discontinued. From the perspective of energy, according to the principle of minimum energy consumption, the precipitated paraffin is usually condensed on the impurities in the crude oil and the rough inner wall of the wellbore.

Studies have shown that the factors affecting paraffin precipitation in crude oil mainly include crude oil components and their proportions, flow velocity, system temperature, system pressure and deposition surface properties. Among them, the more light fractions in crude oil, the lower the initial crystallization temperature of paraffin wax, and the less likely it is to precipitate. Since colloids and asphaltenes are surface active substances, they can effectively disperse the aggregation of paraffin crystals by adsorption; but when crude oil contains too much colloids and asphaltenes, the ability of crude oil to dissolve paraffin will be weakened, and more It is easy to precipitate paraffin, so the colloid and asphaltene in crude oil are not only beneficial to wax deposition, but also not conducive to wax deposition, and the influence of their content should be analyzed in combination with specific conditions. Sand, stone and other impurities in crude oil can provide crystal nuclei for the crystallization of paraffin, thereby promoting the precipitation of paraffin and intensifying the phenomenon of wax deposition. The water in the crude oil will not only increase the specific heat capacity of the whole system and slow down the temperature drop, but also form a water film on the inner wall of the wellbore to prevent the accumulation and deposition of paraffin. The roughness of the wellbore wall directly determines the difficulty of paraffin accumulation on the inner wall of the wellbore.

In recent years, offshore oil and gas exploration and development, especially deepwater exploration and development, has attracted the attention of countries all over the world and has become an emerging battlefield in the energy field. The potential of deepwater oil and gas resources is astonishing, but the cost of exploitation is high and the risks are high. Moreover, compared with onshore oilfields, deepwater exploration and development has environmental characteristics such as low temperature and high pressure. Once severe wax deposition occurs on the inner wall of the deepwater wellbore, there will be a risk of production reduction or even shutdown, resulting in considerable losses. What's more serious is that due to the influence of the deepwater site environment, it will be more difficult and costly to deal with deepwater wellbore wax than land mining. If the law of wax deposition on the inner wall of deepwater wellbore can be predicted and corresponding measures can be taken to avoid it, the overall benefit of deepwater exploration and development will be improved. At present, few domestic scholars have done relevant research.

In view of the above situation, it is necessary to design a set of devices capable of simulating the wax deposition on the inner wall of deep-water wellbore, and obtain wax deposition data by changing the corresponding parameters, so as to summarize the corresponding laws to guide the field practice of deep-water oil and gas field development.

Contents of the invention

In order to overcome the defects existing in the prior art, the present invention provides a deep-water wellbore waxing analysis and testing device and analysis and testing method, which are used to simulate the phenomenon of deep-water wellbore waxing, and analyze and summarize relevant laws by changing parameter conditions, so as to provide deep-water exploration Theoretical research on the prediction and prevention of wax deposition on the inner wall of the wellbore during development provides a basis.

In order to solve the problems of the technologies described above, the technical scheme adopted in the present invention is as follows:

Deep-water wellbore waxing analysis and testing device, including: testing straight pipe string, oil tank, controllable constant temperature water bath, recovery tank; testing the straight-through pipe string to provide a waxing environment, the oil tank provides preset crude oil, and the recovery tank recovers after waxing Crude oil, the crude oil enters the test straight-through pipe column from the oil tank for wax deposition, and then enters the recovery tank for recovery, and the controllable constant temperature water bath box adjusts the external temperature during the wax deposition process.

Compared with the prior art, the present invention has the following beneficial effects: it can simulate the wax deposition on the inner wall of the deep-water wellbore under different conditions, specifically including:

1. By changing the components of crude oil including wax, colloid, asphaltene, sediment, and water, and configuring different crude oils, it is possible to simulate and analyze the influence of these components and their contents on the wax formation on the inner wall of deep-water wellbore, And explore its microscopic mechanism through magnification imaging technology;

2. By changing the temperature of the test system, it is possible to simulate and analyze its influence on the wax deposition on the inner wall of the deep-water wellbore, and to explore its microscopic mechanism through magnified imaging technology;

3. By changing the flow rate of crude oil, it is possible to simulate and analyze its influence on the wax deposition on the inner wall of deep-water wellbore, and explore its microscopic mechanism through zoom-in imaging technology;

4. By changing the pressure of the test system, it is possible to simulate and analyze its influence on the wax deposition on the inner wall of the deep-water wellbore, and to explore its microscopic mechanism through magnified imaging technology;

5. By changing the roughness of the inner wall of the wellbore in the test system, it is possible to simulate and analyze its influence on the wax deposition on the inner wall of the deep-water wellbore, and explore its microcosmic mechanism through magnified imaging technology.

Description of drawings

Figure 1 is a schematic diagram of a deepwater wellbore wax analysis test device;

In the figure, 1. Test straight tube string, 101, annular space insulation layer, 102, visualization window, 103, first sampling port, 104, second sampling port, 105, third sampling port, 106, fourth sampling port, 2. Oil tank, 201, heating device, 3. Controllable constant temperature water bath box, 401, first delivery pipeline, 402, second delivery pipeline, 403, third delivery pipeline, 404, fourth delivery pipeline, 405, fifth Delivery pipeline, 501, first control valve, 502, second control valve, 503, third control valve, 504, fourth control valve, 505, fifth control valve, 601, first mass flow meter, 602, second Mass flow meter, 701, first peristaltic pump, 702, second peristaltic pump, 703, third peristaltic pump, 801, first temperature sensor, 802, second temperature sensor, 803, third temperature sensor, 804, fourth Temperature sensor, 805, fifth temperature sensor, 901, first differential pressure sensor, 902, second differential pressure sensor, 903, third differential pressure sensor, 10, back pressure valve, 11, recovery tank, 12, centrifugal pump, 13. Buffer tank.

Detailed ways

As shown in Figure 1, the deep-water wellbore wax analysis test device includes: test straight pipe string 1, oil tank 2, controllable constant temperature water bath box 3, recovery tank 11; test straight pipe string 1 provides a wax deposition environment, and oil tank 2 Preset crude oil is provided, and the recovery tank 11 recovers the waxed crude oil. The crude oil enters the test straight-through column 1 from the oil tank 2 to deposit wax, and then enters the recovery tank 11 for recovery. The controllable constant temperature water bath 3 regulates the wax deposition process outside temperature.

Among them, the test straight pipe string 1 is an upright pipe string with closed upper and lower ends, the lower end is an oil inlet, and the upper end is an oil outlet, which can simulate a wellbore in a deep water environment and provide a wax deposition environment.

The oil tank 2 is connected to the oil inlet of the test straight tube string 1 through the first delivery pipeline 401, and the first delivery pipeline 401 is sequentially equipped with first peristaltic pumps in the direction from the oil tank 2 to the oil inlet of the test straight tube string 1 701, the first control valve 501, the back pressure valve 10, the second control valve 502, the first mass flow meter 601; the oil tank 2 contains crude oil with preset configuration, the oil tank 2 is equipped with a heating device 201, and the oil tank 2 There is a first temperature sensor 801 on it, and after the crude oil is heated to a preset temperature by the heating device 201, it is pumped into the test straight tube string 1 by the first peristaltic pump 701; the first temperature sensor 801 monitors the temperature of the crude oil in the oil tank 2, and returns to The pressure valve 10 controls the pressure of crude oil flow, the first mass flow meter 601 measures the mass of crude oil flowing through, and the first control valve 501 and the second control valve 502 control the flow of crude oil in the first delivery pipeline 401 .

The oil outlet of the test straight tube string 1 is connected to the top of the recovery tank 11 through the second delivery pipeline 402, and the second delivery pipeline 402 is sequentially installed on the second delivery pipeline 402 from the oil outlet of the test straight tube column 1 to the top of the recovery tank 11. Two mass flowmeters 602, the third control valve 503; the bottom end of the recovery tank 11 is connected to the position between the back pressure valve 10 and the second control valve 502 on the first delivery pipeline 401 through the third delivery pipeline 403, and is recovered by A centrifugal pump 12, a fourth control valve 504, a buffer tank 13, a second peristaltic pump 702, and a fifth control valve 505 are successively provided on the third delivery pipeline 403 in the direction from the tank 11 to the first delivery pipeline 401; the recovery tank 11 recovers crude oil, The second mass flow meter 602 measures the crude oil flow rate flowing out from the test straight tube string 1, and the third control valve 503 controls the flow of crude oil in the second delivery pipeline 402. After the test, the second peristaltic pump 702 is used to test the straight tube string. The residual crude oil in 1 is pumped into the buffer tank 13, and then the crude oil in the buffer tank 13 is pumped into the recovery tank 11 by the centrifugal pump 12, and the fourth control valve 504 and the fifth control valve 505 control the crude oil in the third delivery pipeline 403 flow.

The test straight tube column 1 is provided with a visualization window 102, a first sampling port 103, a second sampling port 104, a third sampling port 105, and a fourth sampling port 106. The visualization window 102 is resistant to high temperature and high pressure, and the first sampling port 103, The second sampling port 104, the third sampling port 105, and the fourth sampling port 106 are equidistantly installed on the test straight tube string 1 from bottom to top, and the test straight tube string 1 is divided into three sections, which can be taken out for testing during the test process. The crude oil samples at various positions in the straight tube column 1 are tested for their composition changes and rheological properties; the second temperature sensor 802, the third temperature sensor 803, the fourth temperature sensor 804, and the fifth temperature sensor 805 are installed equidistantly from bottom to top On the test straight tube column 1, it is aligned with the first sampling port 103, the second sampling port 104, the third sampling port 105, and the fourth sampling port 106 respectively, and the entire length of the test straight tube column 1 is divided into three sections; A differential pressure sensor 901, a second differential pressure sensor 902, and a third differential pressure sensor 903 are respectively installed between the four temperature sensors from bottom to top to measure the differential pressure of the pipe string, wherein the first differential pressure sensor 901 is installed on the second Between the temperature sensor 802 and the third temperature sensor 803, the second differential pressure sensor 902 is installed between the third temperature sensor 803 and the fourth temperature sensor 804, and the third differential pressure sensor 903 is installed between the fourth temperature sensor 804 and the fifth temperature sensor In the middle of 805; through the visualization window 102, the wax deposition phenomenon in the straight pipe string 1 can be observed and tested, the parameters of the wax deposition in each section of the wellbore can be tested through the temperature sensor and the pressure difference sensor, and the crude oil samples in various parts of the wellbore can be obtained through the sampling port .

An annular thermal insulation layer 101 is set outside the test straight pipe string 1, the top of the thermal insulation annular layer 101 is connected to the controllable constant temperature water bath 3 through the fifth delivery pipeline 405, and the bottom end of the thermal insulation annular layer 101 is connected to the controllable constant temperature water bath box through the fourth delivery pipeline 404. The constant temperature water bath box 3 is connected, and the third peristaltic pump 703 is installed on the fourth delivery pipeline 404; the annular space insulation layer 101 makes the test straight tube string 1 in a stable temperature environment, thereby simulating the deep water environment of different temperatures, and the constant temperature water bath can be controlled The tank 3 adjusts the temperature of the fluid to a preset value, and uses the third peristaltic pump 703 to realize circulation in the thermal insulation annular layer 101 to simulate a deep water environment.

The deep-water wellbore waxing analysis and testing method adopts the above-mentioned deep-water wellbore waxing analysis and testing device, and the specific steps are as follows:

(1) Simulate the phenomenon of wax deposition on the inner wall of deep water wellbore

Turn on the controllable constant temperature water bath 3, set the specified temperature, and after the temperature is stable, turn on the third peristaltic pump 703, and form a cold water circulation in the annular space between the thermal insulation annular layer 101 and the test straight tube string 1, simulating the deep water environment;

Open the heating device 201, preheat the crude oil prepared in the oil tank 2, observe the reading of the first temperature sensor 801 on the oil tank 2, until the test preset value is reached; open the first control valve 501, the second control valve 502 , turn on the first peristaltic pump 701, set the test preset pressure, use the back pressure valve 10 to control the actual pressure of the fluid flowing through, inject crude oil into the test straight tube string 1, and use the computer data processing system to record the first mass flowmeter 601 reading;

Open the third control valve 503, and when the second mass flowmeter 602 begins to read, use the computer data processing system to record the second temperature sensor 802, the third temperature sensor 803, the fourth temperature sensor 804, the The readings of five temperature sensors 805, the first differential pressure sensor 901, the second differential pressure sensor 902, the third differential pressure sensor 903 and the second mass flow meter 602 are observed and recorded through the visualization window 102 at the same time. The phenomenon of internal waxing occurs until the waxing effect meets the test expectations;

According to the test requirements, the first sampling port 103, the second sampling port 104, the third sampling port 105 and the fourth sampling port 106 are opened, and the crude oil samples corresponding to each section in the test straight column 1 are respectively taken to measure the real-time composition and rheological changes;

(2) Recovery of crude oil after waxing in the wellbore

Turn off the heating device 201 and the first peristaltic pump 701 , and turn off the first control valve 501 and the third control valve 503 . Open the fifth control valve 505, turn on the second peristaltic pump 702, import the crude oil in the test straight column 1 into the buffer tank 13, then open the fourth control valve 504 and the centrifugal pump 12, and import the crude oil in the buffer tank 13 for recovery tank 11.

(3) Calculation of wax deposition thickness, quality and deposition rate

It is known that the initial pipe wall diameter of the test straight pipe string 1 is D ₀ ; under ideal conditions, the flowing crude oil is a homogeneous medium; a differential pressure sensor (including the first differential pressure sensor 901, the second differential pressure sensor 902, and the third differential pressure sensor 903) is the initial reading of ΔP ₀ , since the nature and flow velocity of the crude oil are the same, in the test straight tube 1, the actual crude oil flow at the corresponding part of the differential pressure sensor satisfies the following formula:

${\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}^{\mathrm{<span\; class="notranslate">\; 5</span>}}}$

The pressure drop caused by the temperature change can then be calculated:

${\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&Delta;ZQ</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}^{\mathrm{<span\; class="notranslate">\; 5</span>}}}$

In the formula:

ΔP ₀ ——the initial reading of the differential pressure sensor,

ΔZ——The length of the fixed section corresponding to the differential pressure sensor,

ΔP _T ——pressure drop caused by temperature change,

ρ ₀ ——the density of crude oil,

Q—crude oil flow rate,

D ₀ ——the initial pipe wall diameter of the test straight pipe string 1,

λ ₀ —— drag coefficient along the way;

Since the temperature of the crude oil is constant, the pressure drop ΔP _T caused by the temperature change can be regarded as a fixed value. Assuming that when the wax deposition time is t, the reading of the differential pressure sensor is ΔP _t , then the pipe wall diameter of the test straight pipe string 1 at time t can be calculated by the following formula:

${\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&Delta;ZQ</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}^{\mathrm{<span\; class="notranslate">\; 5</span>}}}$

In the formula:

ΔP _t - the reading of the differential pressure sensor at time t,

ΔZ——The length of the fixed section corresponding to the differential pressure sensor,

ΔP _T ——pressure drop caused by temperature change,

ρ ₀ ——the density of crude oil,

Q—crude oil flow rate,

D _t ——test the diameter of the inner wall of the straight pipe string 1 at time t,

λ ₀ —— drag coefficient along the way;

The wax thickness is:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}$

In the formula:

ΔD——measure the thickness of the wax deposit on the inner wall of the straight pipe string 1 at time t,

D ₀ ——the initial pipe wall diameter of the test straight pipe string 1,

D _t ——measure the inner wall diameter of the straight pipe string 1 at time t.

From the ΔD-t corresponding relationship curve, the wax deposition rate on the inner wall of the test straight tube string 1 can be calculated by the following formula:

$\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; t</span>}}$

In the formula, v—wax deposition rate on the inner wall of the test straight pipe string 1;

In the test straight column 1, the wax deposition point can be deduced by the following formula:

${\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}^{\mathrm{<span\; class="notranslate">\; 5</span>}}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;D</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 5</span>}}}$

In the formula:

ΔP _t - the reading of the differential pressure sensor at time t,

ΔZ——The length of the fixed section corresponding to the differential pressure sensor,

ΔP _T ——pressure drop caused by temperature change,

ρ ₀ ——the density of crude oil,

Q—crude oil flow rate,

D ₀ ——the initial inner wall diameter of the test straight pipe string 1,

ΔD _t ——measure the wax deposition thickness inside the straight pipe string 1 at time t,

λ ₁ ——The drag coefficient along the way without wax deposition,

λ ₂ —— drag coefficient along the way during wax deposition,

Z _t - the position height of the waxing point at time t;

By recording the readings of the mass flowmeter and the corresponding time in each link of the test process, the mass of wax deposition can be calculated by the following formula:

m＝∫Q ₁ dt ₁ -∫Q ₂ dt ₁ -∫Q ₁ 'dt ₂

In the formula:

m——Test the wax deposition quality on the inner wall of the straight pipe string 1,

Q ₁ ——the reading of the first mass flow meter 601 during the test,

Q ₂ ——the reading of the second mass flow meter 602 during the test,

Q ₁ '——the reading of the first mass flow meter 601 during the recovery process,

t ₁ ——the time used for the test,

t ₂ ——the recovery time;

Using the corresponding software in the computer data processing system, the image collected from the visualization window 102 is optimized for amplification, high-definition, and noise removal, and the microscopic mechanism involved in the wax deposition phenomenon is explored;

Prepare crude oil with different specified components (including wax, colloid, asphaltene, mud, sand and water) and component ratios, put them into oil tank 2, and conduct comparative tests to explore the different components and components in crude oil. The effect of the proportion on the waxing phenomenon.

By adjusting the setting temperature of the heating device 201 and the controllable constant temperature water bath 3 and conducting a comparative test, the influence of the temperature difference between the inner and outer walls of the wellbore on the wax deposition phenomenon can be explored.

By adjusting the setting pressure of the back pressure valve 10 and the first peristaltic pump 701 and conducting a comparative test, the influence of the crude oil pressure on the wax deposition can be explored.

By adjusting the setting pressure of the third peristaltic pump 703 and conducting a comparative test, the influence of the system pressure on the wax deposition can be explored.

By adjusting the set flow rate of the first peristaltic pump 701 and conducting a comparative test, the influence of the crude oil flow rate on the wax deposition phenomenon can be explored.

By replacing the test straight pipe string 1 with different materials and inner wall roughness, and conducting comparative tests, the influence of the wellbore pipe wall properties on the wax deposition phenomenon can be explored.

By measuring the components and rheological parameters of crude oil samples taken from the first sampling port 103, the second sampling port 104, the third sampling port 105, and the fourth sampling port 106, explore the real-time variation of the crude oil after waxing under different conditions .

Claims (10)

1. A deep-water wellbore wax analysis test device, including: test straight pipe string, oil tank, controllable constant temperature water bath box, recovery tank; characterized in that: the test straight-through pipe string provides a wax deposition environment, and the oil tank provides a preset Crude oil, the recovery tank recovers the crude oil after waxing. The crude oil enters the test straight-through column from the oil tank to form wax, and then enters the recovery tank for recovery. The controllable constant temperature water bath adjusts the external temperature during the waxing process. 2. The deep-water wellbore wax analysis and test device according to claim 1, characterized in that: the test straight tube string is placed upright and closed at the upper and lower ends, the lower end is an oil inlet, and the upper end is an oil outlet, which can be Simulate the wellbore in a deep water environment to provide a wax deposition environment; the oil tank is connected to the oil inlet of the test straight pipe string through the first delivery pipeline, and the direction from the oil tank to the oil inlet of the test straight pipe string is set in sequence on the first delivery pipeline. Equipped with the first peristaltic pump, the first control valve, the back pressure valve, the second control valve, and the first mass flow meter; the oil tank is filled with crude oil with preset configuration, the oil tank is equipped with a heating device, and the oil tank is equipped with first temperature sensor. 3. The deep-water wellbore wax deposition analysis and testing device according to claim 1-2, characterized in that: the oil outlet of the test straight tube string is connected to the top of the recovery tank through the second delivery pipeline, and the outlet of the test straight tube string is connected to the top of the recovery tank. The second mass flow meter and the third control valve are installed on the second delivery pipeline in the direction from the oil port to the top of the recovery tank; the bottom end of the recovery tank is connected to the back pressure valve on the first delivery pipeline and the second Between the two control valves, a centrifugal pump, a fourth control valve, a buffer tank, a second peristaltic pump, and a fifth control valve are sequentially arranged on the third delivery pipeline in the direction from the recovery tank to the first delivery pipeline. 4. The deep-water wellbore wax analysis and testing device according to claim 1-3, characterized in that: the test straight tube string is provided with a visualization window, a first sampling port, a second sampling port, a third sampling port, and a second sampling port. Four sampling ports, the visualization window is resistant to high temperature and high pressure. The first sampling port, the second sampling port, the third sampling port, and the fourth sampling port are installed equidistantly on the test straight tube string from bottom to top, and the test straight tube string is divided into equal parts. Three sections; the second temperature sensor, the third temperature sensor, the fourth temperature sensor, and the fifth temperature sensor are installed equidistantly on the test straight tube string from bottom to top, and are connected with the first sampling port, the second sampling port, and the third sampling port respectively. The test port and the fourth sampling port are aligned and level, and the test straight tube string is divided into three sections; the first differential pressure sensor, the second differential pressure sensor, and the third differential pressure sensor are respectively installed between the four temperature sensors from bottom to top. Between, measure the differential pressure of the pipe string, wherein the first differential pressure sensor is installed between the second temperature sensor and the third temperature sensor, the second differential pressure sensor is installed between the third temperature sensor and the fourth temperature sensor, and the third differential pressure sensor The sensor is installed between the fourth temperature sensor and the fifth temperature sensor. 5. The deep-water wellbore wax deposition analysis and test device according to claims 1-4, characterized in that: an annular insulation layer is set outside the test straight pipe string, and the top of the insulation annular layer passes through the fifth delivery pipeline and the controllable constant temperature water bath The bottom end of the thermal insulation annular layer is connected with the controllable constant temperature water bath box through the fourth delivery pipeline, and the third peristaltic pump is installed on the fourth delivery pipeline. 6. A method for analyzing and testing wax deposition in a deep-water wellbore, using the device for analyzing and testing wax deposition in a deep-water wellbore according to any one of claims 1-5, the specific steps are as follows: (1) Simulate the phenomenon of wax deposition on the inner wall of deep water wellbore Turn on the controllable constant temperature water bath, set the specified temperature, and when the temperature is stable, turn on the third peristaltic pump to form a cold water circulation in the annulus between the thermal insulation annulus and the test straight tube string, simulating the deep water environment; Turn on the heating device, preheat the prepared crude oil in the oil tank, observe the reading of the first temperature sensor on the oil tank until the test preset value is reached; open the first control valve and the second control valve, and turn on the first peristaltic pump , set the test preset pressure, use the back pressure valve to control the actual pressure of the flowing fluid, inject crude oil into the test straight tube string, and use the computer data processing system to record the reading of the first mass flow meter; Open the third control valve, and when the second mass flowmeter begins to read, use the computer data processing system to record and test the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the fifth temperature sensor, the first The readings of the differential pressure sensor, the second differential pressure sensor, the third differential pressure sensor and the second mass flow meter, and at the same time through the visual window, observe and record the occurrence of wax deposition in the test straight tube string until the wax deposition effect reaches the test expected; According to the test requirements, open the first sampling port, the second sampling port, the third sampling port and the fourth sampling port, and take the crude oil samples corresponding to each section in the test straight tube column to measure the real-time composition and rheological changes; (2) Recovery of crude oil after waxing in the wellbore Turn off the heating device and the first peristaltic pump, close the first control valve and the third control valve; open the fifth control valve, turn on the second peristaltic pump, introduce the crude oil in the test straight column into the buffer tank, and then turn on the fourth control valve. Valves and centrifugal pumps to guide the crude oil in the buffer tank into the recovery tank; (3) Calculation of wax deposition thickness, quality and deposition rate It is known that the initial pipe wall diameter of the test straight tube string is D ₀ ; under ideal conditions, flowing crude oil is a homogeneous medium; the initial reading of the differential pressure sensor is ΔP ₀ , and the differential pressure sensor includes the first differential pressure sensor and the second differential pressure sensor , The third differential pressure sensor, since the nature and flow velocity of the crude oil are the same, in the test straight tube string, the actual crude oil flow at the corresponding part of the differential pressure sensor satisfies the following formula: ${\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}^{\mathrm{<span\; class="notranslate">\; 5</span>}}}$ The pressure drop caused by the temperature change can then be calculated: ${\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&Delta;ZQ</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}^{\mathrm{<span\; class="notranslate">\; 5</span>}}}$ In the formula: ΔP ₀ ——the initial reading of the differential pressure sensor, ΔZ——The length of the fixed section corresponding to the differential pressure sensor, ΔP _T ——pressure drop caused by temperature change, ρ ₀ ——the density of crude oil, Q—crude oil flow rate, D ₀ ——the initial pipe wall diameter of the test straight pipe string, λ ₀ —— drag coefficient along the way; Since the temperature of the crude oil is constant, the pressure drop ΔP _T caused by the temperature change can be regarded as a fixed value. Assuming that when the wax deposition time is t, the reading of the differential pressure sensor is ΔP _t , then the pipe wall diameter of the test straight pipe string 1 at time t can be calculated by the following formula: ${\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; \&Delta;ZQ</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}^{\mathrm{<span\; class="notranslate">\; 5</span>}}}$ In the formula: ΔP _t - the reading of the differential pressure sensor at time t, ΔZ——The length of the fixed section corresponding to the differential pressure sensor, ΔP _T ——pressure drop caused by temperature change, ρ ₀ ——the density of crude oil, Q—crude oil flow rate, D _t ——test the diameter of the inner wall of the straight pipe string at time t, λ ₀ —— drag coefficient along the way; The wax thickness is: $\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}$ In the formula: ΔD——measure the thickness of the wax deposit on the inner wall of the straight pipe string at time t, D ₀ ——the initial pipe wall diameter of the test straight pipe string, D _t - the diameter of the inner wall of the straight pipe string tested at time t; From the ΔD-t corresponding relationship curve, the wax deposition rate on the inner wall of the test straight tube string can be calculated by the following formula: $\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; t</span>}}$ In the formula, v—wax deposition rate on the inner wall of the test straight pipe string 1; In the test straight column, the wax deposition point can be deduced by the following formula: ${\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}^{\mathrm{<span\; class="notranslate">\; 5</span>}}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;D</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 5</span>}}}$ In the formula: ΔP _t - the reading of the differential pressure sensor at time t, ΔZ——The length of the fixed section corresponding to the differential pressure sensor, ΔP _T ——pressure drop caused by temperature change, ρ ₀ ——the density of crude oil, Q—crude oil flow rate, D ₀ ——the initial inner wall diameter of the test straight pipe string, ΔD _t ——measure the wax deposition thickness inside the straight pipe string at time t, λ ₁ ——The drag coefficient along the way without wax deposition, λ ₂ —— drag coefficient along the way during wax deposition, Z _t - the position height of the waxing point at time t; By recording the readings of the mass flowmeter and the corresponding time in each link of the test process, the mass of wax deposition can be calculated by the following formula: m＝∫Q ₁ dt ₁ -∫Q ₂ dt ₁ -∫Q ₁ 'dt ₂ In the formula: m——Test the wax deposition quality on the inner wall of the straight pipe string 1, Q ₁ ——the reading of the first mass flow meter 601 during the test, Q ₂ ——the reading of the second mass flow meter 602 during the test, Q ₁ '——the reading of the first mass flow meter 601 during the recovery process, t ₁ ——the time used for the test, t ₂ ——The recovery time. 7. The deep-water wellbore wax analysis and test method according to claim 6, characterized in that: using the corresponding software in the computer data processing system, the image collected from the visualization window is enlarged, high-definition, and optimized for removing noise treatment to explore the microscopic mechanism involved in the wax formation phenomenon. 8. The deep-water wellbore wax analysis test method according to claim 6-7, characterized in that: the crude oil with different specified components and component ratios has been prepared, and the components include wax, colloid, asphaltenes, mud, Put sand and water into the oil tank and conduct a comparative test to explore the influence of different components and component ratios in crude oil on the waxing phenomenon. 9. The method for analyzing and testing wax deposition in deep-water wellbore according to claims 6-8, characterized in that: by adjusting the setting temperature of the heating device and the controllable constant temperature water bath box, and conducting a comparative test, the temperature difference between the inner and outer walls of different wellbores can be explored. The effect of wax formation. 10. The deep-water wellbore wax deposition analysis and testing method according to claims 6-9, characterized in that: by adjusting the set pressure of the back pressure valve and the first peristaltic pump, a comparative test can be conducted to explore the effect of crude oil pressure on the wax deposition phenomenon. Influence; By adjusting the setting pressure of the third peristaltic pump and conducting comparative tests, the influence of system pressure on wax deposition can be explored; By adjusting the set flow rate of the first peristaltic pump and conducting a comparative test, the influence of crude oil flow rate on wax deposition can be explored; By replacing the test straight pipe string with different materials and inner wall roughness, and conducting comparative tests, the influence of the wellbore pipe wall properties on the wax deposition phenomenon can be explored; By measuring the components and rheological parameters of the crude oil samples taken from the first sampling port, the second sampling port, the third sampling port, and the fourth sampling port, the real-time changes of the crude oil after waxing under different conditions were explored.