RU2519496C1 - Method of oil and oil product in-process quality control - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: Proton Magnetic Resonance (PMR) spin-echo signals are excited in a sample placed in static magnetic field by series of radio frequency impulses, spin-echo amplitudes are registered in reference and measure samples, at that components of studied mixtures - water and oil (or oil product) - are taken as reference samples, and effective times of spin-spin relaxation in reference and measure samples are measured by initial segments of envelope echo signals in interval, which is selected in a specific way. The sample is added with a mixture component conditioning the value of PMR signal of a component with the lowest content, after which water and oil concentration is determined following relative mathematical expressions. Besides, integral parameters of disperse distribution of water drops from times of spin-lattice relaxation of water are additionally determined by a specific formula.

EFFECT: ensuring possibility of determination of water drop disperse distribution integral parameters.

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Description

The invention relates to methods for determining the technological parameters of a water-oil mixture by non-destructive testing based on proton magnetic resonance (PMR), is intended for determination in technical emulsions - well fluid (SCF), crude oil (CH), oil bitumen, oil sludge, waste oil, and t .P. - concentrations of water, oil (oil products), dispersion of water droplets and can be used in places of oil production and preparation for oil refineries (oil refineries), at oil depots, terminals, ships and drilling platforms, at thermal power plants and boiler houses that use boiler fuel and fuel emulsions.

State of the art

In the technological processes for the extraction of oil (bitumen) well fluid (SCF), currently, given the complexity and laboriousness of the recording operations of the SCF and crude oil (CH), the frequency of water concentration measurements is used once a day according to GOST 2477 for the combined sample (in the absence of moisture meter).

This affects the accuracy of the analyzes, especially when monitoring several (6-24) wells at a group metering unit, during production with production sharing, as well as during breakthroughs of produced water in the well, when the parameters can change dramatically for a short time.

In connection with the introduction of GOST 8.615 - 2005, according to which continuous monitoring of these parameters is required, there is a need to develop an operational method for monitoring mixtures - SKZh, SN, emulsions, and also commercial oil (petroleum bitumen) for the concentration of water and oil.

Since in the preparation of oil (petroleum bitumen), the dispersed size distribution of water droplets is important for the selection of the demulsification process, there is also a need to determine the dispersion parameters (determined according to GOST 18995.2, ASTM D 1218, 1747).

The incompleteness of oil purification from water to the level of oil of group I for oil refineries (this is less than 0.5% of water) is associated with the practical lack of methods for rapid express control of the parameters of SCF and SN. In the SKZh, the concentration of water can reach 95-98.

Measurement of water concentration in SKZh, SN and emulsions is necessary, since oil, mixed twice with water upon leaving the well and during desalination, forms stable emulsions that cannot be removed by sludge, which are most stable at a water concentration of 5-20%.

This increases the cost of oil transportation and gives the most significant unfavorable for cost correction when calculating the net mass of oil by gross weight. Water control is absolutely inevitable in the preparation of oil. According to GOST R 51858-2002, oil after its preparation for refineries and transportation through pipelines should contain no more than: 0.5 ÷ 1 wt.% Water. The measurement accuracy is regulated by GOST 2477 and corresponds to the table on the convergence of two measurement results by one performer and reproducibility of two results in two laboratories (both parameters with a 95% confidence probability):

Table 1 Sample volume, cm ³ Convergence, cm ³ Reproducibility, cm ³ <1 ≤0.1 ≤0.1 > 1 0.1 or 2% of the average volume - 1 ÷ 10 0.1 or 2% of the average volume 0.2 or 10% of the average volume > 10 0.1 or 2% of the average volume 5% of the average result

In connection with the increase in the production of highly watered oils with water concentrations of 90% and above, there was an acute problem of developing an instrumental operational method for measuring water concentrations in oil in the range of 0-100%. The used VEN-3M or automatic UVTN analyzers are based on microwave methods and have large errors in the field of phase inversion of emulsions (65-80% of water in oil. There is also a method of measuring the moisture content of oil and oil products based on measuring the density ρ _{e of an} oil-water emulsion, ρ _in water and ρ _n oil [Samigullin F.M., Idiyatullin Z.Sh. Development of a flow-weight densitometer-oil moisture meter / Research report No. 81010557. NPO Neftepromavtomatika. Kazan. 1983. 65 pp.]:

$${\rho }_{\mathrm{uh}}={\left[\left(\mathrm{one\; hundred}-0.1W\right)/{\rho }_n+0.01W/{\rho }_{\mathrm{at}}\right]}^{-\mathrm{one}}\left(\mathrm{one}\right)$$

However, this method requires operational control of density.

For commercial and team accounting (at humidity <60%) in the oil fields, a method for measuring well fluid moisture is used, based on measuring dielectric constant, for example, with a digital CVV-2C analyzer, and the AQUASYST WMC 5250Z system (Endress + Hausser Ltd., Manchester) on the same principle.

The disadvantage of this method is: a limited measurement range, since in oil-water emulsions in the range of water concentrations of 60-75% phase inversion is observed, which does not allow using it for analysis of crude oil with a water concentration above 50%.

The microwave method of measuring humidity by AGAR Corporation (Houston, Texas), implemented in the AGAR OW-101 analyzer, is based on the absorption of electromagnetic energy at a frequency of 4 MHz. The range of measurements on the brochure is 0-100%. But the continuity of the measurement range of 0-100% is achieved by computer “stitching” the calibration curve in the field of phase inversion.

However, studies have shown that in the field of "crosslinking" the error reaches 30%.

Thus, there are practically no analyzers of the concentration of water in oil over the entire range of 0-100%, not to mention analyzers of the well fluid containing the gas component.

The latest development - the VSN-1 moisture meter is designed to automatically calculate the humidity, volume of anhydrous oil, the percentage of free water in the volume of oil produced for a given period of time. In it, the calculator works in conjunction with a digital dielcometric moisture meter and a turbine flowmeter of the “Turboquant” or “Nord-E-3M” type.

However, the volumetric flow rate should be at least 2.5 l / s.

Such measurement conditions are a limitation of its applicability, being the exception rather than the rule. The measurement time depends on the time of the measurement interval.

The concentration of water in SKZh and SN can be determined by the method of pulsed PMR according to the method similar to that described in the application for invention No. 95117256, IPC G01N 24/08, 10.10.1997 "Method for measuring the moisture content of oil and oil products", authors Kashaev RS, Temnikov A.N., Idiyatullin Z.S. according to the formula:

$$W={\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_{2\mathrm{at}}\left({\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}-T_{2n}\right)\mathrm{one\; hundred}\%/{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\left({\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_{2\mathrm{at}}-T_{2n}\right)\left(2\right)$$

However, the method has a limited measurement range due to insufficient accuracy at low concentrations of water or oil (petroleum bitumen).

The dispersed distribution of water droplets in CH must be determined to select the type and quantity of demulsifiers and operating modes of ELOU. To date, there are no clear requirements for the method for determining the dispersion of emulsions, i.e. size distribution of water droplets in oil.

, максимальный диаметр D_max, соответствующий максимуму распределения.The most complete dispersion information can be obtained from the histograms of the dispersed distribution, i.e. on a curve characterizing the number of drops of a certain diameter. According to the dispersion distribution, the integral dispersion parameters can be determined, the main of which are the arithmetic mean diameter of the droplets D _ca = ∑N _i D _i / ∑N _i , the average volumetric-surface diameter D _vs = ∑N _i $$D_i^3/{\displaystyle \sum N_{\mathrm{<figure-callout\; id="2"\; label="i\; D\; i"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">i\; </figure-callout>}}{D}_i^{}{}_2^{}}$$

, the maximum diameter D _max corresponding to the maximum distribution.

Until now, the dispersion of oil-water emulsions is determined by the microscopic method by applying it to a microscope slide and counting the number of particles of approximately equal diameters. The method is time-consuming and lengthy, but it is the only control. The combination of the microscopic method with the design of an enlarged picture of the emulsion droplet on the display and the automation of the droplet counting using the Biotran II device achieves an accuracy of ± 24% [Prospect of Coulter Biotran IF].

By instrumental methods, the dispersion of water in an emulsion is determined by:

- a laboratory analyzer VNIISPTKneft, based on the sedimentation of water droplets using a centrifuge and determining the moisture content of oil by the dielcometric method. The range of measurements of the diameter of the droplets is 0.1-100 μm, the content of the dispersed phase is up to 60% (vol.), OPP 50%. Analysis time - at least 15 minutes;

- a laboratory automatic analyzer with microprocessor control Kratel SA Partogrash FMP (Switzerland, 1983), used for the analysis of biological cells and based on the scattering of laser radiation. The measurement range of the diameters is 2-200 μm, the content of the dispersed phase is up to 10 ⁵ particles in 100 cm ³ . The measurement accuracy is ± 2 μm for particles ⌀> 20 μm and the standard basic error of 2.3% for ⌀ <10 μm.

образцах по начальным участкам огибающих эхо-сигналов в интервале t=2Nτ, который выбирают из формулы:The closest technical solution to the claimed invention is a method for the operational control of the quality of oil and oil products (application RU 2007124097, IPC G01N 24/08, 12/27/2008), including excitation in a sample placed in a constant magnetic field of spin-echo signals of proton magnetic resonance ( PMR) by a series of radio-frequency pulses, registration of the spin-echo amplitudes in the reference and measured samples, moreover, the components of the mixture under study — water and oil (or oil product) —are taken as the effective samples relaxation in the reference pin (T _2c, T _2O) and measured $$\left({\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\right)$$

samples on the initial sections of the envelope of the echo signals in the interval t = 2Nτ, which is selected from the formula:

t = k1 (T _2Hmax + k2),

where N is the number of pulses in a series of radio-frequency pulses, τ is the interval between pulses, T _2Hmax is the maximum measured spin-spin relaxation time, k1, k2 are constant coefficients, and the component of the mixture is added to the sample, which determines the magnitude of the PMR signal with the lowest content and the concentration of water is determined by the formula:

$$W=\left(T_{2B}{T}_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2B}-W^{*}{T}_{2H}{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\right)/{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\left(T_{2B}-T_{2H}\right)\mathrm{one\; hundred}\%$$

;where W * is the fraction of added water from the sample volume, which should not exceed the value $$W^{*}=\left({\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_{2\mathrm{AT}}{T}_{2N}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2B}\right)/\left(T_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\right)$$

;

oil concentration is determined by the formula:

, $$O=\left(T_{2B}{T}_{2H}-T_2^{*}{T}_{2H}-O^{*}{T}_{2B}{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\right)/{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\left(T_{2B}-T_{2H}\right)\mathrm{one\; hundred}\%$$

,

.where O * - the proportion of added oil, which should not exceed the value $$O^{*}=\left(T_{2B}{T}_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2H}\right)/\left(T_{2\mathrm{<figure-callout\; id="2"\; label="B\; T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">B\; </figure-callout>}}{T}_{}^{}{}_2^{*}\right)$$

.

The disadvantage of this method is the limited technological capabilities that do not allow to determine the integral parameters of the dispersed distribution of water droplets.

The objective of the present invention is to expand technological capabilities by providing the ability to determine the integral parameters of the dispersed distribution of water droplets.

образцах по начальным участкам огибающих эхо-сигналов в интервале t=2Nτ, который выбирают из формулы:The technical result is achieved by the fact that in a method for the operational control of the quality of oil and oil products, including excitation in a sample placed in a constant magnetic field, spin-echo proton magnetic resonance (PMR) signals by a series of radio-frequency pulses, registration of spin-echo amplitudes in the reference and measured samples moreover, the components of the test mixture — water and oil (or oil product) —are taken as reference samples, the measurement of effective spin-spin relaxation times in the reference (T _2B , T _2O ) and measured $$\left({\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\right)$$

samples on the initial sections of the envelope of the echo signals in the interval t = 2Nτ, which is selected from the formula:

t = k1 (T _2Hmax + k2),

where N is the number of pulses in a series of radio-frequency pulses, τ is the interval between pulses, T _2Hmax is the maximum measured spin-spin relaxation time, k1, k2 are constant coefficients, and the component of the mixture is added to the sample, which determines the magnitude of the PMR signal with the lowest content and the concentration of water is determined by the formula:

, $$W=\left(T_{2B}{T}_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2B}-W^{*}{T}_{2\mathrm{<figure-callout\; id="2"\; label="H\; T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">H\; </figure-callout>}}{T}_{}^{}{}_2^{*}\right)/{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\left(T_{2B}-T_{2H}\right)\mathrm{one\; hundred}\%$$

,

;where W * is the fraction of added water from the sample volume, which should not exceed the value $$W^{*}=\left({\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_{2\mathrm{AT}}{T}_{2N}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2B}\right)/\left(T_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\right)$$

;

oil concentration is determined by the formula:

, $$O=\left(T_{2B}{T}_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2H}-O^{*}{T}_{2\mathrm{<figure-callout\; id="2"\; label="B\; T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">B\; </figure-callout>}}{T}_{}^{}{}_2^{*}\right)/{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\left(T_{2B}-T_{2H}\right)\mathrm{one\; hundred}\%$$

,

, согласно заявляемому изобретению дополнительно определяют интегральные параметры дисперсного распределения P_i капель воды из времен спин-решеточной релаксации воды T_1B по формулам:where O * - the proportion of added oil, which should not exceed the value $$O^{*}=\left(T_{2B}{T}_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2H}\right)/\left(T_{2\mathrm{<figure-callout\; id="2"\; label="B\; T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">B\; </figure-callout>}}{T}_{}^{}{}_2^{*}\right)$$

, according to the claimed invention, the integral parameters of the dispersed distribution P _i of water drops from the times of spin-lattice relaxation of water T _{1B are} additionally determined by the formulas:

P _i = k _mi + k _ni exp (k _li T _1B ),

where k _mi , k _ni , k _li are constant coefficients of the i-th measured parameter.

The invention is illustrated by graphs, in which Fig. 1 shows the linearization of the dependence of the water concentration W _PMR according to the PMR on the real values of W (%) of the water concentration in the samples of water emulsions in oil, Fig. 2 shows the dependence of the dispersed distribution of water droplets for the arithmetic mean diameter D _CA (integral parameter dispersity D _CA) from the spin-lattice relaxation time T _1B, Figure 3 is a plot of the distribution of the particulate water droplets to the diameter D _max (integral parameter dispersity D _max) on the time spin -reshetochnoy relaxation T _1B, Figure 4 is a plot of the distribution of the particulate water drops to r _3/2 = D _3/2 / 2 (dispersion integral parameter r _3/2) of the spin-lattice relaxation time T _1B.

по начальным участкам огибающих эхо-сигналов в течение времени t для включения всех экспоненциальных компонентов в анализ.The determination of humidity by the proposed method by the method of pulsed PMR is carried out by measuring the times of spin-spin relaxation T _2B , T _2H and $${\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}$$

along the initial sections of the envelopes of the echo signals during time t to include all exponential components in the analysis.

The number of 180 ° N pulses in the KPMG measurement technique (Carra-Parcell-Maybum-Gill) [Meiboom S., Gill D. Rev. Sci. Instr., 29, 688 (1958); Carr H.Y., Purcell E.M., Phys. Rev., 94, 630 (1954)] is selected from the formula:

, $$N=\mathrm{<figure-callout\; id="3"\; label="k"\; filenames="00000025.png"\; state="\{\{state\}\}">k</figure-callout>}3\rho -k\mathrm{four}\left(3\right)$$

,

where ρ _H is the oil density in kg / m for the Romashkinskoye field k3 = 0.34, k4 = 284.

Figure 1 shows the linearization process of the dependence of W (%, PMR) on the real values of W (%) of the samples in water emulsions in oil by changing the number N. Curve a corresponds to the number of 180-degree pulses used in the KPMG method N = 10, straight line corresponds to N = 23.

The graph shows that the selection of the number of pulses linearizes the dependence, as a result of which conditions of the same slope (sensitivity) are created in the entire measurement range.

The graph also shows that the main reduced measurement error (OPP) falls within ± 4% (mass.).

When measuring small concentrations of water and oil (the signal from which has an amplitude at the noise level or disappears in the region of receiver paralysis), adding a certain amount of the measured component facilitates the separation of the envelope of the spin-echo signals into exponentials, and the effective relaxation time has a more accurate value due to the lower noise value . The concentration of water in oil in accordance with the claimed method is determined by the formula

$$W=\left(T_{2B}{T}_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2B}-W^{*}{T}_{2\mathrm{<figure-callout\; id="2"\; label="H\; T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">H\; </figure-callout>}}{T}_{}^{}{}_2^{*}\right)/{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\left(T_{2B}-T_{2H}\right)\mathrm{one\; hundred}\%,\left(\mathrm{four}\right)$$

;where W * is the fraction of added water from the sample volume, which should not exceed the value $$W^{*}=\left({\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_{2\mathrm{AT}}{T}_{2N}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2B}\right)/\left(T_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\right)$$

;

oil concentration is determined by the formula:

$$O=\left(T_{2B}{T}_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2H}-O^{*}{T}_{2\mathrm{<figure-callout\; id="2"\; label="B\; T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">B\; </figure-callout>}}{T}_{}^{}{}_2^{*}\right)/{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}\left(T_{2B}-T_{2H}\right)\mathrm{one\; hundred}\%,\left(5\right)$$

.where O * is the proportion of added oil (petroleum bitumen), which should not exceed the value $$O^{*}=\left(T_{2B}{T}_{2H}-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}{T}_{2H}\right)/\left(T_{2\mathrm{<figure-callout\; id="2"\; label="B\; T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">B\; </figure-callout>}}{T}_{}^{}{}_2^{*}\right)$$

.

Dispersed distribution of water droplets in an emulsion

The obtained dependence of the dispersed distribution of water droplets for the arithmetic mean diameter D _CA on the spin-lattice relaxation time T _1B is shown in Fig. 2, for D _max - in Fig. 3, for r _3/2 - in Fig. 4.

Thus, the integral dispersion parameters D _CA , D _max and r _3/2 = D _3/2 / 2 can be determined by pulsed PMR with regression coefficients R ² = 0.9513, R ² = 0.923, R ² = 0.9642 and R ² = 0.88374 by approximating equations:

$$D_{CA}=0.1645\cdot \exp \left(\mathrm{2,8493}\cdot T_{\mathrm{one}A}\right)\left(6\right)$$

$$D_{\max I}=0.3162\cdot \exp \left(\mathrm{1,3666}\cdot T_{\mathrm{one}A}\right)\left(7\right)$$

$${\mathrm{<figure-callout\; id="2"\; label="D\; max"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">D\; </figure-callout>}}_{\max }=\mathrm{1,1777}\cdot \exp \left(0.8447\cdot T_{\mathrm{one}A}\right)\left(8\right)$$

$${\mathrm{<figure-callout\; id="3"\; label="r"\; filenames="00000025.png"\; state="\{\{state\}\}">r</figure-callout>}}_{3/2}=\mathrm{2,3963}{\left(T_{\mathrm{one}A}\right)}^{\mathrm{4,2709}}\left(9\right)$$

The proposed method for the on-line monitoring of the quality of oil and oil products by pulsed PMR is implemented by our laboratory PMR relaxometer (resonance frequency 8 MHz) or portable PMR relaxometer NP-1 (resonance frequency 10.14 MHz), protected by utility model patent No. 67719, G01N 24 / 08 authors Idiyatullin Z.Sh., Kashaev RS, Temnikov AN, priority of June 25, 2007. The PMR NP-1 relaxometer has small dimensions and weight, autonomous power supply from the battery (or from the mains), can be transported in a case by one operator.

Examples of the implementation of the method of operational quality control of oil and oil products

The expressivity of the analysis lies in the method of pulsed PMR, which refers to methods with an internal standard, is non-contact and non-destructive and does not require sample preparation. The analysis time depends on the number of accumulations n, which increase the measurement accuracy by √n times, and on average is 2-3 minutes.

Example 1. The implementation of moisture measurement of water-oil emulsion samples of Almetyevsk oil with produced water when measured on a portable PMR relaxometer.

Three oils of different densities were used: heavy oil of NGDU Jalilneft with density ρ = 903 kg / m ³ , average oil of NGDU Leninogorskneft with density ρ = 870 kg / m ³ .

Light oil with a density ρ = 825 kg / m ³ was prepared from heavy oil by dilution with gasoline. From these “oils”, emulsion samples were prepared by emulsification in a mixer based on a gear pump (multiple pumping through a gear pump) of oil mixtures with water mass concentrations of 1, 3, 7, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, 97, 99%. Samples were poured in a volume of 15 ml into glass tubes with a diameter of ⌀ 30 mm and placed in a PMR relaxometer sensor located in the gap of a permanent magnet. The sample in the sensor was irradiated with a series of radio-frequency pulses according to the KPMG method with the following parameters: the start-up period of the series T = 8 sec, the interval between 180-degree pulses τ = 400 μs, the number of pulses N = 1000, the number of measurement accumulations n = 10. The start-up period was chosen from the condition that the period T should be (3-5) T _2B , that is, 3-5 times the maximum relaxation time. In our water, T _2B ≈ 2.5 sec. Samples of formation water and oil were placed in the PMR sensor. The envelope of the spin-echo signals was a relationship for produced water:

$$A=A_B\exp \left(-t/T_{2B}\right)\left(10\right)$$

and

$$A=A_H\exp \left(-t/T_{2H}\right)\left(\mathrm{eleven}\right)$$

эмульсии проведением средней линии начиная с первой амплитуды спин-эхо. По формуле (4) определялась концентрация воды в эмульсии. Результаты измерений влажности W (с добавками воды в количестве 20% масс. от веса образца для образцов W с 1 и 3% воды); без добавок для образцов с W=10-90% и с добавкой 20% масс нефти (для образцов с 95, 97 и 99% воды) представлены в таблице 1, из которой видно, что основная приведенная погрешность (ОПП), то есть отношение максимального отклонение параметра к диапазону измерений, не превышает 2,5% независимо от значений концентрации воды, что лучше показателя аналога. Время одного измерения составило: t^'=nT+t^”=10·8+40=120 сек, где t^” - суммарное время работы оператора на клавиатуре (время проведения средней линии для определения $$T_2^{*}$$

и расчета влажности по формуле (4) на ЭВМ).for oil. The envelope was logarithmized in a computer and by drawing a theoretical line from the beginning of the envelope, T _2B = 230 ms was determined for water, and for oil, by choosing the right linear portion of spin-echo signals and drawing a theoretical line, the maximum spin-spin relaxation time T _2Hmax = 112 ms to select the interval of t measurements. For the calculation, we used the values of the coefficients k1 = 34.5, k2 = 100, characteristic of the Romashkinskoye field. It was determined that N = t / 2τ = 9 - the number of pulses required to linearize the dependence of W _PMR (W,%) in the KPMG technique. The effective time T _{2H was} then determined by drawing a midline through the first amplitude of the spin echo. The effective relaxation times for the densities ρ = 825 kg / m ³ , ρ = 870 kg / m ³ and ρ = 903 kg / m ^{3 are} equal to T _2H = 256 ms, respectively; 112 ms and 17.2 ms. Then, emulsion samples with different concentrations of water in oils of different densities were placed in the PMR sensor and the effective relaxation time was determined $${\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}$$

emulsions by conducting a midline starting from the first amplitude of the spin echo. By the formula (4), the concentration of water in the emulsion was determined. The results of measurements of humidity W (with water additives in an amount of 20% by weight of the sample weight for samples W with 1 and 3% water); without additives for samples with W = 10-90% and with the addition of 20% of the mass of oil (for samples with 95, 97 and 99% water) are presented in table 1, which shows that the main reduced error (OPP), that is, the ratio the maximum deviation of the parameter to the measurement range does not exceed 2.5% regardless of the values of water concentration, which is better than the analogue indicator. The time of one measurement was: t ^' = nT + t ^” = 10 · 8 + 40 = 120 sec, where t ^” is the total time of the operator on the keyboard (the time of the middle line to determine $${\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="00000024.png,00000025.png"\; state="\{\{state\}\}">T</figure-callout>}}_2^{*}$$

and calculating humidity according to the formula (4) on a computer).

Table 1 The density of oil kg / m ³ True mass humidity of the prepared samples,% one 3 7 10 20 thirty 40 fifty 60 70 80 90 95 97 99 The humidity of the samples obtained by measurement according to the proposed method by PMR from the formula (4) 825 3.4 5.5 7.5 11.2 22.3 32.5 42.8 52.5 60.9 71.9 82.3 91.6 97.5 97.6 96.5 825 0.4 1.5 5.5 10.5 19.5 31.7 40.2 51.9 62.4 72.3 78.6 88.6 92.7 95.3 98.4 825 0 3.3 4.5 8.7 19.7 30.8 41.7 49.8 58.3 69.4 79.7 90.9 96.0 94.5 99.2 825 1.5 2.5 9.4 9.3 20.9 30.3 39.9 48.3 59.8 68.8 80.8 92.5 95.5 99.4 one hundred 870 2.8 0.5 4.3 8.9 18.4 29.1 38.9 52.4 61.3 70.4 81.5 89.4 95.0 97.5 one hundred 870 3.5 4.8 7.4 9.1 22.3 28.3 42.4 50.6 60.8 72.5 79.7 90.8 93.1 98.3 99.8 870 0 0.9 5.4 8.6 21.8 29.6 39.7 51.8 62.5 68.5 82.5 88.7 94.8 94.5 96.5 870 1.3 5.3 9.0 8.1 20.8 32.4 38.5 48.9 60.9 69.9 79.6 87.5 97.4 99.3 968 903 0.9 3.5 9.2 9.2 18.1 32.3 37.6 49.1 59.4 71.8 78.2 91.9 97.0 95.0 one hundred 903 1.8 2.0 7.3 10.6 19.5 30.8 41.8 52 60.3 70.9 82.3 92.5 96.2 96.5 99.5 903 2.1 5.0 4.9 11.5 21.3 29.6 40.5 51 58.8 72.5 80.8 90.8 93.0 99.2 983

The oil concentration was determined by the formula O = 100% -W.

Example 2. The implementation of the measurement of the dispersed distribution of water droplets in oil emulsions by the PMR method.

The dispersion distribution parameters D _ca , D _max and D _3/2 can be determined in accordance with formulas (6), (7), (8), (9). In particular, when determining D _ca in emulsions obtained at different speeds of the propeller stirrer (see the graph in FIG. 2), the results presented in Table 2 were obtained from the measurements of T _1B .

table 2 D _caM , μm (according to the microscopy method) 14.0 13.8 12.5 9.7 7.7 6.0 5,0 4.7 2.7 T ₁ sec 1,5 1,57 1,5 1.4 1.35 1.3 1.13 1.15 1,0 D _caPMR , MKM (according to the PMR method) 12.1 14.6 12.1 9.15 7.9 6.8 3.9 4.1 2,4 S, μm 1.9 0.8 0.4 0.55 0.2 0.8 1,1 0.6 0.3 S,% 12.6 5.3 0.3 3,7 1.3 5.3 7.3 4.0 2.0

That is, in the studied range D _ca = 0–15 μm, the maximum absolute error is 1.9 μm, and the maximum basic reduced error (SOP) S (%) = | D _caM -D _{ca NMR} | 100% / maxD _ca , where maxD _ca - the maximum measured value of D _ca is 12.6%.

When determining D _max (see the graph in figure 3) in the emulsions obtained by the gear stirrer according to the measurements of T _{1B, the} results were obtained, presented in table 3.

Table 3 D _maxM1 , μm (according to the method of microscopy) 2,8 2.7 2.6 2.0 / 2.0 1.9 1.8 1,5 0.8 T ₁ sec 1.8 1,62 1,5 1.4 / 1.3 1,1 1.05 0.9 0.87 D _{max PMR} , MKM (according to the PMR method) 3.05 2.7 2.46 2.25 / 2.1 1.7 1,6 1.35 1.3 S, μm 0.25 0 0.14 0.1-0.25 0.2 0.2 0.15 0.5 S,% 2,5 0 1.4 1-2,5 2.0 2.0 1,5 5,0

That is, in the studied range D _ca = 0 ÷ 10 μm, the maximum absolute error is 0.5 μm, and the maximum OPP is 5.0%. Repeatability - 1%.

When determining D _max (see the graph in figure 3) in the emulsions obtained by the propeller stirrer according to the measurements of T _{1B, the} results were obtained, presented in table 4.

Table 4 D _maxM2 , μm (according to the method of microscopy) 4,5 4.2 4.0 3.6 3.4 2,8 2.6 2.2 T ₁ sec 1,64 1.4 / 1.5 1.48 1.25 1.13 1,1 1.05 0.9 D _{max PMR} , MKM (according to the PMR method) 4.7 3.9 / 4.25 4.2 3,5 3,1 3.0 2.85 2,4 S, μm 0.2 0.05-0.3 0.2 0.1 0.3 0.2 0.15 0.2 S,% 2.0 0.5-3.0 2.0 1,0 3.0 2.0 1,5 2.0

That is, in the studied range D _ca = 0 ÷ 10 μm, the maximum absolute error is 0.3 μm, and the maximum OPP is 3.0%. Repeatability - 3.0%.

For D _3/2 (see the graph in Fig. 4) by the PMR method in an oil emulsion with a density ρ _H = 874 kg / m ³ prepared in a gear mixer, its characteristics were obtained - D _3/2 , μm, determined by microscopy and PMR (analysis time - 100 s), absolute deviations S, μm and the main reduced errors relative to the limit of 10 μm S,%, in table 5.

Table 5 D _3/2 , microns (by microscopy) 3.70 3.84 4.2 5,6 T ₁ sec 1,03 1,08 1.44 1.80 D _3/2 , μm (according to the PMR method) 3,59 3.71 4,51 5.26 S, μm 0.11 0.13 0.31 0.34 S,% 1,1 1.3 3,1 3.4

The measurement errors of the parameters of the dispersed distribution fit into a standard deviation of less than 4%, the analysis time (for the PMR analyzer is 120 s) compared with the fastest Coulter LCM II analyzer, which determines only fixed sizes of the detected particles: 5, 15 and 25 μm (analysis time - 60-90 s) is reduced by 30-45 times. In this case, the parameters by the PMR method are not determined discretely, but continuously in the range of 0–25 μm studied by us (the range limit depends on the upper value of the determined relaxation time of water). The maximum value of the times of spin-lattice relaxation of water measured in this PMR analyzer is T _1B ≈ 2.7 s. Therefore, the measurement of D _{ca is} possible up to D _ca = 140 μm.

Compared with the analogue method, when determining the water concentration W, the measurement range is increased by 4%, the measurement time is reduced by 3 times.

Compared with the prototype method, the use of the proposed method for operational control of the quality of oil and oil products will allow to expand technological capabilities by providing the ability to determine the integral parameters of the dispersed distribution of water droplets. When determining the dispersion of droplets, the measurement range increases to 140 μm, the measurement error decreases by 1.5% and fit into the standard deviation of less than 4%, the measurement time is reduced by 30-45 times.

The proposed method can be implemented when measuring in flow mode on a flowing installation PMR for brigade accounting in the extraction and preparation of oil.

Claims (1)

A method for operational control of the quality of oil and oil products, including the excitation in a sample placed in a constant magnetic field of spin-echo proton magnetic resonance (PMR) signals by a series of radio-frequency pulses, registration of the spin-echo amplitudes in the reference and measured samples, and take as reference samples components of the mixture under study - water and oil (or oil product), measurement of effective spin-spin relaxation times in the reference (T _2B , T _2O ) and measured $$\left(T_2^{*}\right)$$

samples on the initial sections of the envelope of the echo signals in the interval t = 2Nτ, which is selected from the formula:
t = k1 (T _2Hmax + k2),
where N is the number of pulses in a series of radio-frequency pulses, τ is the interval between pulses, T _2Hmax is the maximum measured spin-spin relaxation time, k1, k2 are constant coefficients, and the component of the mixture is added to the sample, which determines the magnitude of the PMR signal with the lowest content and the concentration of water is determined by the formula:
$$W=\left(T_{2B}{T}_{2H}-T_2^{*}{T}_{2B}-W^{*}{T}_{2H}{T}_2^{*}\right)/T_2^{*}\left(T_{2B}-T_{2H}\right)\mathrm{one\; hundred}\%$$

,
where W * is the fraction of added water from the sample volume, which should not exceed the value $$W^{*}=\left(T_{2\mathrm{AT}}{T}_{2N}-T_2^{*}{T}_{2B}\right)/\left(T_{2H}-T_2^{*}\right)$$

;
oil concentration is determined by the formula:
$$O=\left(T_{2B}{T}_{2H}-T_2^{*}{T}_{2H}-O^{*}{T}_{2B}{T}_2^{*}\right)/T_2^{*}\left(T_{2B}-T_{2H}\right)\mathrm{one\; hundred}\%$$

,
where O * - the proportion of added oil, which should not exceed the value $$O^{*}=\left(T_{2B}{T}_{2H}-T_2^{*}{T}_{2H}\right)/\left(T_{2B}{T}_2^{*}\right)$$

characterized in that the integral parameters of the dispersed distribution P _i of water droplets from the times of spin-lattice relaxation of water T _{1B are} additionally determined by the formulas:
P _i = k _mi + k _ni exp (k _li T _1B ),
where k _mi , k _ni , k _li are constant coefficients of the i-th measured parameter.

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