CN103674147A - On-line measuring device and method for double-flowmeter crude oil water content - Google Patents

Abstract

The invention relates to an on-line measuring device and a measuring method for the water content of crude oil with double flowmeters. The invention includes a flange, a filter, an exhaust valve, a pressure reducing and stabilizing valve, a first horizontal pipeline, a volume flow meter, a second horizontal pipeline and an elbow. The inlet of the filter is connected to the pipe through the flange, the outlet of the filter is connected to the inlet of the exhaust valve, the outlet of the exhaust valve is connected to the inlet of the pressure reducing and stabilizing valve, and the outlet of the reducing and stabilizing valve is connected to the outlet of the first horizontal pipeline. One end is connected, the other end of the first horizontal pipe is connected with the inlet of the volume flowmeter, the outlet of the volume flowmeter is connected with one end of the second horizontal pipe, and the other end of the second horizontal pipe is connected with the elbow. The invention measures the fluid flow at the horizontal pipe through the volume flowmeter, and the elbow flowmeter measures the fluid flow at the elbow, with high accuracy and reliability, good stability and low cost, and reduces errors caused by manual measurement.

Description

On-line measurement device and method for water content of crude oil with dual flow meters

technical field

The invention relates to the field of crude oil measurement, in particular to an online measuring device and method for measuring the water content of crude oil with double flow meters.

Background technique

The water content of crude oil directly affects the extraction, dehydration, gathering and transportation, metering, sales, refining, etc. of crude oil. Therefore, it is required to detect the water content of crude oil in the process of crude oil production, storage and transportation in oilfields. The on-line detection of water content in crude oil is of great significance for determining the oil well water and oil producing layers, estimating crude oil production, and predicting the development life of oil wells. At the same time, accurate and timely online detection data of water content in crude oil can reflect the working status of the oil well, and play an important role in reducing energy consumption, reducing costs, and realizing automatic oilfield management for the management department.

my country has successively developed a variety of different forms of crude oil water content testers. Although they have achieved certain results after being put into use in oil fields, their stability, accuracy, real-time performance, reliability and cost are still limited due to technological and technical reasons. , it is difficult to adapt to the actual production requirements of high water-cut oilfields in my country. Contents of the invention

The technical problem to be solved by the present invention is to overcome the above-mentioned defects in the prior art and provide an online measuring device and method for measuring the water content of crude oil with dual flowmeters with high measurement accuracy, high reliability, good stability and low cost .

The on-line measurement device for the water content of crude oil with double flow meters includes flanges, filters, exhaust valves, pressure reducing and stabilizing valves, first horizontal pipes, volumetric flow meters, second horizontal pipes and elbows.

The inlet of the filter is connected to the pipe through the flange, the outlet of the filter is connected to the inlet of the exhaust valve, the outlet of the exhaust valve is connected to the inlet of the pressure reducing and stabilizing valve, and the outlet of the reducing and stabilizing valve is connected to the outlet of the first horizontal pipeline. One end is connected, the other end of the first horizontal pipe is connected with the inlet of the volume flowmeter, the outlet of the volume flowmeter is connected with one end of the second horizontal pipe, and the other end of the second horizontal pipe is connected with the elbow.

An elbow flowmeter is installed at the elbow, a pressure transmitter is installed on the first horizontal pipeline between the pressure reducing and stabilizing valve and the volume flowmeter, and a pressure transmitter is installed on the first horizontal pipeline between the volume flowmeter and the elbow. A temperature transmitter is installed on the second horizontal pipeline.

Furthermore, the elbow flowmeter is a differential pressure flowmeter, and the elbow is a 90° elbow attached to the elbow flowmeter.

The online measurement method of the water content of crude oil with dual flow meters comprises the following steps:

1) After the fluid flows through the filter and the exhaust valve respectively, a fluid with a full pipe and less impurities is obtained, and then flows through a pressure reducing and stabilizing valve to obtain a fluid with a stable pressure. The fluid flows through the first horizontal pipe into the volume flowmeter, and then It flows through the second horizontal pipe and enters the elbow flow meter.

2) Measure the flow value q _v of the fluid in the two horizontal pipes by the volume flowmeter, and measure the pressure difference Δp at the elbow by the elbow flowmeter, so as to obtain the water content q _{v water} in the oil-water mixed medium:

其中α是实际流速分布与强制旋流的差别而采用的系数，R为弯管半径，D为管道直径，ρ_油为原油的密度，ρ_水为水的密度，q_v为体积流量计测量两个水平管道中流体的流量值。

Among them, α is the coefficient used for the difference between the actual flow velocity distribution and the forced swirling flow, R is the radius of the elbow, D is the diameter of the pipe, _ρoil is the density of crude oil, _ρwater is the density of water, and _qv is the volumetric flowmeter measuring two The flow rate of the fluid in a horizontal pipe.

3) Use the temperature transmitter and pressure transmitter to collect the temperature data and pressure data of the fluid in real time, and then compensate the flow value.

Compared with the prior art, the present invention has the following characteristics: the volumetric flowmeter measures the fluid flow at the horizontal pipe, and the elbow flowmeter measures the fluid flow at the elbow, with high accuracy and reliability, good stability and low cost. The error caused by manual measurement is reduced, and the problem of water content measurement in crude oil in medium and high water content areas is effectively solved; the use of temperature transmitters and pressure transmitters can also effectively reduce errors.

Description of drawings

Fig. 1 is a structural schematic diagram of an on-line measurement device for water content of crude oil with dual flowmeters of the present invention.

In Fig. 1: 1. flange, 2. filter, 3. exhaust valve, 4. pressure reducing and stabilizing valve, 5. pressure transmitter, 6. first horizontal pipeline, 7. volumetric flowmeter, 8. Second horizontal pipeline, 9, temperature transmitter, 10, elbow flow meter, 11, elbow.

Detailed ways

Referring to Fig. 1, the on-line measurement device for the water content of crude oil with dual flowmeters includes a filter 2, an exhaust valve 3, a pressure reducing and stabilizing valve 4, a first horizontal pipeline 6, a volumetric flowmeter 7, The second horizontal pipeline 8 and the elbow 11, that is, the original external pipeline is connected to the inlet of the filter 2 through the flange 1, the outlet of the filter 2 is connected to the inlet of the exhaust valve 3, and the outlet of the exhaust valve 3 is connected to the decompression stabilizer. The inlet of the pressure reducing valve 4 is connected, the outlet of the pressure reducing and stabilizing valve 4 is connected with one end of the first horizontal pipeline 6, the other end of the first horizontal pipeline 6 is connected with the inlet of the volume flowmeter 7, and the outlet of the volume flowmeter 7 is connected with the first horizontal pipeline 6. One end of the two horizontal pipes 8 is connected, and the other end of the second horizontal pipe 8 is connected with the elbow 11, and the elbow flowmeter 10 is installed at the elbow 11, and the first between the pressure reducing and stabilizing valve and the volume flowmeter 7 A pressure transmitter 5 is installed on the horizontal pipeline 6 , and a temperature transmitter 9 is installed on the second horizontal pipeline 8 between the volume flowmeter 7 and the elbow 11 .

The elbow flowmeter in this embodiment is a differential pressure flowmeter, and the elbow is a 90° elbow attached to the elbow flowmeter.

The fluid flow is measured at the horizontal pipeline by the volume flowmeter 7, and the fluid flow is measured at the elbow by the elbow flowmeter 10, which has high accuracy and reliability, good stability, low cost, and reduces errors caused by manual measurement.

The online measurement method of the water content of crude oil with dual flow meters comprises the following steps:

1) After the fluid flows through the filter and the exhaust valve respectively, a fluid with a full pipe and less impurities is obtained, and then flows through a pressure reducing and stabilizing valve to obtain a fluid with a stable pressure. The fluid flows through the first horizontal pipe into the volume flowmeter, and then It flows through the second horizontal pipe and enters the elbow flow meter.

2) The flow value of the fluid in the two horizontal pipes is measured by the volume flowmeter, and the flow value of the fluid at the elbow is measured by the elbow flowmeter; when the liquid flows through the volume flowmeter, the volume flowmeter will obtain a volume of the liquid flowing through it. value, denote this volume as q _v . Since the liquid has been processed by the filter, exhaust valve and pressure reducing and stabilizing valve in the system, and finally a stable fluid is obtained, it can be considered that the flow rate obtained by the elbow flowmeter can be considered assuming that the average density of the fluid is known. The value q _v0 is equal to the flow value q _v obtained by the volume flowmeter, that is:

q _v0 =q _v

Elbow flowmeter is a kind of differential pressure flowmeter. When the fluid flows along the curved channel of the elbow, the fluid generates centrifugal force due to the action of angular acceleration, which increases the pressure on the outer wall of the elbow, thereby forming a pressure difference _Δp between the inner and outer walls of the elbow . It can be shown that the square root of this pressure difference is proportional to flow. As long as the pressure difference is measured, the flow value can be obtained.

According to the forced swirl flow theory, the flow formula of the fluid volume flow through the 90° elbow can be obtained as:

${\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}\sqrt{\frac{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="R"\; filenames="HDA0000442888440000011.png"\; state="\{\{state\}\}">R</figure-callout></span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; D.</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; D.</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}}$

为流量系数，α是以考虑实际流速分布与强制旋流的差别而采用的系数，其数值一般取决于取压口的位置。本实施例中，由于弯管流量计的采购仪器，所以α为定值。In the formula,

is the flow coefficient, and α is a coefficient adopted in consideration of the difference between the actual flow velocity distribution and the forced swirling flow, and its value generally depends on the position of the pressure tap. In this embodiment, α is a fixed value due to the purchased instrument of the elbow flowmeter.

In the formula, _Δp is the pressure difference, which is a parameter directly measured by the elbow flowmeter, and the density ρ of the medium flowing in the pipeline is an unknown number, which needs to be deduced:

By (2) formula $q_{v0}=\mathrm{\&alpha;}\sqrt{\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA0000442888440000011.png"\; state="\{\{state\}\}">R</figure-callout>}}{2\mathrm{D.}}}\left(\frac{\mathrm{\&pi;}}{4}{\mathrm{D.}}^2\right)\sqrt{\frac{2\mathrm{\&Delta;P}}{\mathrm{\&rho;}}}=C\left(\frac{\mathrm{\&pi;}}{4}{\mathrm{D.}}^2\right)\sqrt{\frac{2\mathrm{\&Delta;P}}{\mathrm{\&rho;}}}---\left(3\right)$

Available: ${q_{v0}}^2=C^2{\left(\frac{\mathrm{\&pi;}}{4}{\mathrm{D.}}^2\right)}^2\frac{2\mathrm{\&Delta;p}}{\mathrm{\&rho;}}---\left(4\right)$

$\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; C</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; D.</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;p</span>}}{{{\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; V</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; K\&Delta;p</span>}}{{{\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

in $K=2C^2{\left(\frac{\mathrm{\&pi;}}{4}{\mathrm{D.}}^2\right)}^2$

Put (1) into (5), we can get:

$\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; K\&Delta;p</span>}}{{{\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

Among them, each parameter in K is known, so K can be regarded as a known quantity, _Δp is the pressure difference, measured by the elbow flowmeter, _qv is the measured volume, measured by the volume flowmeter, solid The density of the medium can be obtained, expressed by (6) formula.

When the measured fluid flows through the flowmeter, the total mass of the flowing medium is constant, so:

q _m = q _{m water} + q _{m oil} (7)

that is

ρq _v = ρ _water q _{v water} + ρ _oil q _{v oil} (8)

In the formula, q _m is the total mass of the medium, q _{m water} and q _{m oil} are the mass of water and oil respectively, q _{v water} and q _{v oil} are the volume of water and oil respectively.

The total volume flowing through the medium is also constant, that is:

q _v ＝q _{v water} +q _{v oil} (9)

Combining formula (8) and formula (9):

Get: (ρ- _ρoil )q _v = ( _ρwater - _ρoil )q _{v water} (11)

Right now:

q_v已测得，ρ_水和ρ_油均可差表得出，为已知数，所以将（6）式和C、K分别代入（12）式，可以得到管道中流过的油水混合介质中水的含量。in:

q _v has been measured, and both ρ _water and ρ _oil can be obtained from the differential table, which are known numbers, so substituting (6) and C and K into (12) respectively, the oil-water mixed medium flowing in the pipeline can be obtained water content.

This water content is expressed as:

3) Use the temperature transmitter and pressure transmitter to collect the temperature data and pressure data of the fluid in real time, and then compensate the flow value.

Claims (3)

1. An online measuring device for water content of crude oil with double flow meters, including flanges, filters, exhaust valves, pressure reducing and stabilizing valves, first horizontal pipes, volume flow meters, second horizontal pipes and elbows, characterized in that : The inlet of the filter is connected to the pipe through the flange, the outlet of the filter is connected to the inlet of the exhaust valve, the outlet of the exhaust valve is connected to the inlet of the pressure reducing and stabilizing valve, and the outlet of the reducing and stabilizing valve is connected to the outlet of the first horizontal pipeline. One end is connected, the other end of the first horizontal pipeline is connected to the inlet of the volume flowmeter, the outlet of the volume flowmeter is connected to one end of the second horizontal pipeline, and the other end of the second horizontal pipeline is connected to the elbow; An elbow flowmeter is installed at the elbow, a pressure transmitter is installed on the first horizontal pipeline between the pressure reducing and stabilizing valve and the volume flowmeter, and a pressure transmitter is installed on the first horizontal pipeline between the volume flowmeter and the elbow. A temperature transmitter is installed on the second horizontal pipeline. 2. The online measuring device according to claim 1, characterized in that: the elbow flowmeter is a differential pressure flowmeter, and the elbow is a 90° elbow attached to the elbow flowmeter. 3. utilize the device described in claim 2 to carry out the on-line measuring method of double flow meter crude oil water content, it is characterized in that comprising the steps: 1) After the fluid flows through the filter and the exhaust valve respectively, a fluid with a full pipe and less impurities is obtained, and then flows through a pressure reducing and stabilizing valve to obtain a fluid with a stable pressure. The fluid flows through the first horizontal pipe into the volume flowmeter, and then Flow through the second horizontal pipe and enter the elbow flowmeter; 2) The flow value q _v of the fluid in the two horizontal pipes is measured by the volumetric flowmeter, and the pressure difference Δ _p at the elbow is measured by the elbow flowmeter, so as to obtain the water content q _{v water} in the oil-water mixed medium:

Among them, α is the coefficient used for the difference between the actual flow velocity distribution and the forced swirling flow, R is the radius of the elbow, D is the diameter of the pipe, _ρoil is the density of crude oil, _ρwater is the density of water, and _qv is the volumetric flowmeter measuring two The flow rate of fluid in a horizontal pipe 3) Use the temperature transmitter and pressure transmitter to collect the temperature data and pressure data of the fluid in real time, and then compensate the flow value.

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