CN102183675A - Polyacrylamide aqueous solution fluid ultra low flow velocity measuring method and polyacrylamide aqueous solution viscosity measuring method using same - Google Patents

Abstract

A method for measuring the ultra-low flow rate of polyacrylamide aqueous solution fluid and a method for measuring the viscosity of polyacrylamide aqueous solution by using the method belong to the technical field of polymer parameter measurement. It solves the problem that the existing technology cannot realize the measurement of the ultra-low flow rate of the polyacrylamide aqueous solution, and cannot obtain its actual flow rate and viscosity in the underground oil field core. Scheme 1: Connect the lower end of the polyacrylamide aqueous solution reservoir to the inlet of the glass capillary, and connect the outlet of the glass capillary to the solution collection bottle, use a microscope to observe the solution in the glass capillary, and record the time it takes for a tiny particle to flow through the observation section of the glass capillary , to calculate the flow velocity; Scheme 2 is based on Scheme 1, then calculate the inlet pressure drop when the polyacrylamide aqueous solution flows into the glass capillary, and finally calculate the viscosity of the polyacrylamide aqueous solution. The invention is used for measuring the ultra-low flow velocity of the liquid and further obtaining the viscosity of the ultra-low flow velocity liquid.

Description

Method for measuring ultra-low flow rate of polyacrylamide aqueous solution fluid and method for measuring viscosity of polyacrylamide aqueous solution using this method

technical field

The invention relates to a method for measuring the ultra-low flow rate of polyacrylamide aqueous solution fluid and a method for measuring the viscosity of polyacrylamide aqueous solution by using the method, belonging to the technical field of polymer parameter measurement.

Background technique

At present, tertiary oil recovery technology is widely used in oil extraction technology, among which polymer flooding technology effectively improves oil recovery. Oilfields that use polymer flooding need to carry out oilfield numerical simulation research, such as: the relationship between the viscosity and concentration of polymers, the rheology of polymer solutions in porous media and the optimization of design parameters, etc. The most important parameters are Viscosity of polymer solutions in porous media.

The polymer used in oil field flooding is usually polyacrylamide aqueous solution. The viscosity of polyacrylamide aqueous solution needs to be calculated according to the flow velocity. The flow velocity range of polyacrylamide aqueous solution in the underground oilfield core is 1-5m/d, which is equivalent to At 0.012-0.057mm/s, the flow rate is very low. The current instrument used to measure the flow rate of the lower liquid is the Doppler laser current meter, which measures the flow rate range of only 0.1mm/s-1000m/s, which is consistent with the actual polyacrylamide aqueous solution in the core of the underground oil field. The difference in flow rate is very large, and it is obviously impossible to obtain the viscosity of polyacrylamide aqueous solution.

Contents of the invention

The purpose of the present invention is to solve the problem that the existing technology cannot realize the measurement of the ultra-low flow rate of polyacrylamide aqueous solution, and the measurement of its actual flow rate in the underground oil field core, and thus its viscosity cannot be obtained. A method for measuring the ultra-low flow rate of polyacrylamide aqueous solution fluid and a method for measuring the viscosity of polyacrylamide aqueous solution by using the method.

The first technical scheme of the present invention is:

The method of measuring the ultra-low flow rate of the polyacrylamide aqueous solution fluid, the lower end of the polyacrylamide aqueous solution storage tank is connected with the inlet of the micron-sized glass capillary through a rubber tube, the glass capillary is placed horizontally, and the lower end of the polyacrylamide aqueous solution storage tank is high on the tube center line of the glass capillary; the outlet of the glass capillary is connected to the inlet of the solution collection bottle, and the glass capillary and the solution collection bottle are placed in the incubator;

Use a microscope to observe the solution in the glass capillary, and select a section of the glass capillary whose length is S in the field of view of the microscope as the observation section. The measurement process is:

Step 1: Inject the polyacrylamide aqueous solution into the polyacrylamide aqueous solution storage tank;

Step 2: Observe the observation section of the glass capillary through a microscope, and record the time t it takes for a tiny particle in the polyacrylamide aqueous solution to flow through the observation section through a stopwatch, and then calculate the flow velocity u of the tiny particle:

u=S/t,

The flow velocity u of the tiny particles is the flow velocity of the polyacrylamide aqueous solution.

The second technical scheme of the inventive method is:

The method of measuring the viscosity of the polyacrylamide aqueous solution is to connect the lower end of the polyacrylamide aqueous solution storage tank with the inlet of the micron-sized glass capillary and the liquid level gauge through the rubber tube, the glass capillary is placed horizontally, and the polyacrylamide aqueous solution storage tank The lower end is higher than the tube center line of the glass capillary, the lower end of the liquid level gauge is on the same level as the lower end of the polyacrylamide aqueous solution storage tank, the outlet of the glass capillary is connected to the inlet of the solution collection bottle, and the glass capillary and the solution collection bottle are placed in a constant temperature inside the box;

Use a microscope to observe the solution in the glass capillary, and select a section of the glass capillary whose length is S in the field of view of the microscope as the observation section. The measurement process is:

Step 1: Inject the polyacrylamide aqueous solution into the polyacrylamide aqueous solution storage tank;

Step 2: Observe the observation section of the glass capillary through a microscope, and record the time t it takes for a tiny particle in the polyacrylamide aqueous solution to flow through the observation section through a stopwatch, and then calculate the flow velocity u of the tiny particle:

u=S/t,

The flow velocity u of the tiny particles is the flow velocity of the polyacrylamide aqueous solution;

Step 3: Calculate the inlet pressure drop P when the polyacrylamide aqueous solution flows into the glass capillary;

Step 4: Calculate and obtain the viscosity μ of the polyacrylamide aqueous solution.

The advantage of the present invention is that: the method of the present invention adopts micron-sized glass capillary as the physical model of porous medium to simulate the rock core of the downhole oil field, and combines them with conventional physical instruments to realize the ultra-thin polyacrylamide aqueous solution fluid. The measurement of low flow velocity solves the problem that the Doppler laser flow meter cannot measure ultra-low flow velocity. It is simple, easy, inexpensive and highly accurate.

The method of the present invention obtains the viscosity of the polyacrylamide aqueous solution by measuring the flow velocity of tiny particles in the polyacrylamide aqueous solution, and then calculating, the realization method is simple, the speed measurement range that can be achieved is 0.01mm/s-0.1mm/s, and the estimated value of the precision is The content is 0.5%, which can meet the requirement of measuring the flow velocity of the polyacrylamide aqueous solution in the core of the underground oil field.

Description of drawings

Fig. 1 is the flowchart of the method described in Embodiment 2;

Fig. 2 is a schematic diagram of the device used in the method described in Embodiment 2.

Detailed ways

Specific embodiment one: this embodiment is described in conjunction with Fig. 2, the measuring method of the ultra-low flow rate of polyacrylamide aqueous solution fluid described in this embodiment, the lower end of polyacrylamide aqueous solution reservoir 1 is passed through rubber hose and micron-sized glass The inlet of the capillary 2 is connected, the glass capillary 2 is placed horizontally, and the lower end of the polyacrylamide aqueous solution storage tank 1 is higher than the tube center line of the glass capillary 2; the outlet of the glass capillary 2 is connected to the inlet of the solution collection bottle 3, and the glass capillary 2 Place in the incubator 4 with the solution collection bottle 3;

Use a microscope to observe the solution in the glass capillary 2, and select a section of the glass capillary 2 whose length is S in the field of view of the microscope as the observation section, and the measurement process is:

Step 1: Inject the polyacrylamide aqueous solution into the polyacrylamide aqueous solution storage tank 1;

Step 2: Observe the observation section of the glass capillary 2 through a microscope, and record the time t it takes for a tiny particle in the polyacrylamide aqueous solution to flow through the observation section through a stopwatch, and then calculate the flow velocity u of the tiny particle:

u=S/t,

The flow velocity u of the tiny particles is the flow velocity of the polyacrylamide aqueous solution.

Embodiment 2: This embodiment is a further description of Embodiment 1. A tiny particle in the polyacrylamide aqueous solution is a tiny particle at the center of the glass capillary 2 . Others are the same as the first embodiment.

The tiny particles at the tube center of the glass capillary 2 have the fastest flow speed and are easy to find among numerous particles.

Specific embodiment three: the present embodiment is described below in conjunction with Fig. 1 and Fig. 2,

The method for measuring the viscosity of the polyacrylamide aqueous solution described in this embodiment using the method for measuring the ultra-low flow rate of the polyacrylamide aqueous solution fluid described in Embodiment 1 is to pass the lower end of the polyacrylamide aqueous solution storage tank 1 through the rubber tube and simultaneously contact with the micron level The inlet of the glass capillary 2 communicates with the liquid level gauge 5, the glass capillary 2 is placed horizontally, and the lower end of the polyacrylamide aqueous solution storage tank 1 is higher than the tube center line of the glass capillary 2, and the lower end of the liquid level gauge 5 is connected to the polypropylene The lower end of the amide aqueous solution reservoir 1 is located on the same horizontal line, the outlet of the glass capillary 2 is connected to the inlet of the solution collection bottle 3, and the glass capillary 2 and the solution collection bottle 3 are placed in the incubator 4;

Use a microscope to observe the solution in the glass capillary 2, and select a section of the glass capillary 2 whose length is S in the field of view of the microscope as the observation section, and the measurement process is:

Step 1: Inject the polyacrylamide aqueous solution into the polyacrylamide aqueous solution storage tank 1;

Step 2: Observe the observation section of the glass capillary 2 through a microscope, and record the time t it takes for a tiny particle in the polyacrylamide aqueous solution to flow through the observation section through a stopwatch, and then calculate the flow velocity u of the tiny particle:

u=S/t,

The flow velocity u of the tiny particles is the flow velocity of the polyacrylamide aqueous solution;

Step 3: Calculate the inlet pressure drop P when the polyacrylamide aqueous solution flows into the glass capillary 2;

Step 4: Calculate and obtain the viscosity μ of the polyacrylamide aqueous solution.

The micron-scale glass capillary 2 described in this embodiment is used to simulate the porous medium in the underground oil field, and the lower end of the polyacrylamide aqueous solution storage tank 1 is higher than the tube centerline of the glass capillary 2 in order to produce liquid pressure drop, and the microscope can Observe the flow state of tiny particles in the polyacrylamide aqueous solution in the glass capillary 2. The incubator 4 keeps the glass capillary 2 in a constant temperature state, so that the density of the solution in the glass capillary 2 remains stable.

working principle:

The polyacrylamide aqueous solution in the polyacrylamide aqueous solution storage tank 1 will flow in the glass capillary 2 under the action of the pressure drop generated by the liquid level gauge 5, because the tiny particles in the polyacrylamide aqueous solution flow together with the liquid, and the tiny The particles can be observed through a microscope, so the flow velocity of the tiny particles is taken as the flow velocity of the polyacrylamide aqueous solution. This method makes the acquisition of viscosity μ easier and easier to implement.

Embodiment 4: This embodiment is a further description of Embodiment 3. A tiny particle in the polyacrylamide aqueous solution is a tiny particle at the center of the glass capillary 2 . Others are the same as the third embodiment.

The tiny particles at the tube center of the glass capillary 2 have the fastest flow speed and are easy to find among numerous particles.

Embodiment 5: This embodiment is a further description of Embodiment 3 or 4.

The method for calculating the inlet pressure drop P when the polyacrylamide aqueous solution flows into the glass capillary 2 described in step 3 is:

The height difference h between the initial liquid level height in the polyacrylamide aqueous solution storage tank 1 and the tube centerline of the glass capillary 2 is measured by an altimeter, then the pressure drop P of the polyacrylamide aqueous solution is:

P = ρgh,

In the formula, ρ is the density of the polyacrylamide aqueous solution, and g is the acceleration due to gravity.

Others are the same as the third or fourth embodiment.

In this embodiment, the height difference h can be obtained by measuring the initial height of the liquid level of the polyacrylamide aqueous solution and the height of the centerline of the glass capillary 2 respectively by the liquid level gauge 5 and then making a difference.

Specific implementation mode six: this implementation mode is a further description of implementation mode five,

The method for calculating the viscosity μ of polyacrylamide aqueous solution described in step 4 is:

First calculate the shear rate of the polyacrylamide aqueous solution

$\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; ,</span>$

In the formula, d is the inner diameter of the glass capillary 2;

Then calculate the shear stress τ of the polyacrylamide aqueous solution:

τ=Pd/4L,

In the formula, L is the total length of the glass capillary 2;

和剪切应力τ计算粘度μ：According to the shear rate

and the shear stress τ to calculate the viscosity μ:

$\mathrm{<span\; class="notranslate">\; \&mu;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&tau;</span>}<span\; class="notranslate">\; /</span>\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}<span\; class="notranslate">\; .</span>$

Claims (6)

1. the measuring method of the ultralow flow velocity of a polyacrylamide solution fluid, it is characterized in that: the lower end of polyacrylamide solution being store pond (1) is connected by the inlet of sebific duct with micron-sized glass capillary (2), glass capillary (2) is horizontal positioned, and the lower end in polyacrylamide solution storage pond (1) is higher than the tube hub line of glass capillary (2); The outlet of glass capillary (2) connects the inlet of solution receiving flask (3), and glass capillary (2) and solution receiving flask (3) are placed in the constant temperature oven (4);

Adopt the solution in the microscopic examination glass capillary (2), and selected glass capillary (2) length is one section conduct observation section of S in the microscopical visual field, measuring process is:

Step 1: in polyacrylamide solution storage pond (1), inject polyacrylamide solution;

Step 2:, and, calculate the flowing velocity u that obtains described molecule then by the used time t of observation section that flows through of a molecule in the stopwatch record polyacrylamide solution by the observation section of microscopic examination glass capillary (2):

u＝S/t，

The flowing velocity u of molecule is the flowing velocity of polyacrylamide solution.

2. the measuring method of the ultralow flow velocity of polyacrylamide solution fluid according to claim 1 is characterized in that: a molecule in the described polyacrylamide solution is the molecule that is in the tube hub place of glass capillary (2).

3. one kind is adopted the measuring method of the ultralow flow velocity of the described polyacrylamide solution fluid of claim 1 to measure the polyacrylamide solution method of viscosity, it is characterized in that: the lower end of polyacrylamide solution being store pond (1) is connected with the inlet and the liquid level gauge (5) of micron-sized glass capillary (2) by sebific duct simultaneously, glass capillary (2) is horizontal positioned, and the lower end in polyacrylamide solution storage pond (1) is higher than the tube hub line of glass capillary (2), the lower end in the lower end of liquid level gauge (5) and polyacrylamide solution storage pond (1) is positioned on the same horizontal line, the outlet of glass capillary (2) connects the inlet of solution receiving flask (3), and glass capillary (2) and solution receiving flask (3) are placed in the constant temperature oven (4);

Adopt the solution in the microscopic examination glass capillary (2), and selected glass capillary (2) length is one section conduct observation section of S in the microscopical visual field, measuring process is:

Step 1: in polyacrylamide solution storage pond (1), inject polyacrylamide solution;

Step 2:, and, calculate the flowing velocity u that obtains described molecule then by the used time t of observation section that flows through of a molecule in the stopwatch record polyacrylamide solution by the observation section of microscopic examination glass capillary (2):

u＝S/t，

The flowing velocity u of molecule is the flowing velocity of polyacrylamide solution;

Step 3: P falls in the inlet pressure when calculating polyacrylamide solution inflow glass capillary (2);

Step 4: calculate the viscosity, mu that obtains polyacrylamide solution.

4. measurement polyacrylamide solution method of viscosity according to claim 3 is characterized in that: a molecule in the described polyacrylamide solution is the molecule that is in the tube hub place of glass capillary (2).

5. according to claim 3 or 4 described measurement polyacrylamide solution method of viscosity, it is characterized in that: the method that P falls in the inlet pressure when calculating polyacrylamide solution inflow glass capillary (2) described in the step 3 is:

The difference in height h of the initial liquid level that adopts altimeter to measure to obtain in the polyacrylamide solution storage pond (1) and the tube hub line of glass capillary (2), then the pressure of polyacrylamide solution falls P and is:

P＝ρgh，

ρ is that density, the g of polyacrylamide solution are acceleration of gravity in the formula.

6. measurement polyacrylamide solution method of viscosity according to claim 5 is characterized in that: the method for calculating the viscosity, mu that obtains polyacrylamide solution described in the step 4 is:

At first calculate the shear rate of polyacrylamide solution

$\stackrel{\&CenterDot;}{\mathrm{\&gamma;}}=4u/d,$

D is the internal diameter of glass capillary (2) in the formula;

Calculate the shear stress τ of polyacrylamide solution then:

τ＝Pd/4L，

L is the total length of glass capillary (2) in the formula;

According to shear rate Calculate viscosity, mu with shear stress τ:

$\mathrm{\&mu;}=\mathrm{\&tau;}/\stackrel{\&CenterDot;}{\mathrm{\&gamma;}}.$

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