CN109856175B - Method for measuring nuclear magnetic resonance oil-water two-phase flow parameters - Google Patents

Method for measuring nuclear magnetic resonance oil-water two-phase flow parameters Download PDF

Info

Publication number
CN109856175B
CN109856175B CN201910049656.5A CN201910049656A CN109856175B CN 109856175 B CN109856175 B CN 109856175B CN 201910049656 A CN201910049656 A CN 201910049656A CN 109856175 B CN109856175 B CN 109856175B
Authority
CN
China
Prior art keywords
water
oil
magnetic resonance
nuclear magnetic
phase flow
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201910049656.5A
Other languages
Chinese (zh)
Other versions
CN109856175A (en
Inventor
李利品
党博
王小鑫
党瑞荣
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xian Shiyou University
Original Assignee
Xian Shiyou University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xian Shiyou University filed Critical Xian Shiyou University
Priority to CN201910049656.5A priority Critical patent/CN109856175B/en
Publication of CN109856175A publication Critical patent/CN109856175A/en
Application granted granted Critical
Publication of CN109856175B publication Critical patent/CN109856175B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/30—Assessment of water resources

Landscapes

  • Magnetic Resonance Imaging Apparatus (AREA)

Abstract

A nuclear magnetic resonance oil-water two-phase flow parameter measuring method optimizes the parameters of a nuclear magnetic resonance system by analyzing magnetization vectors under different flow rates and different water contents and FID signals received by nuclear magnetic resonance, finally determines the magnetization length and the detection coil length, and carries out optimization design on the parameters of the nuclear magnetic resonance system on the basis of fully considering the influence of the interaction of the oil-water two-phase flow parameters; then, by analyzing the characteristics of the nuclear magnetic resonance receiving signals under different flow rates and different water contents and carrying out normalization processing on the nuclear magnetic resonance receiving signals of the oil-water two-phase flow, a measurement calculation model of the water content is established, and the measurement precision is improved; finally, the correlation of parameters such as different flow velocities, different water contents and the like is considered, a measurement and calculation model of the average flow velocity is established, the measurement of the average flow velocity of the oil-water two-phase flow is realized, and the oil-water two-phase flow parameters are more accurately measured.

Description

Method for measuring nuclear magnetic resonance oil-water two-phase flow parameters
Technical Field
The invention relates to the technical field of oil-water two-phase flow parameter measurement, in particular to a method for measuring oil-water two-phase flow parameters by nuclear magnetic resonance.
Background
In the process of oil exploitation, the produced liquid is mostly oil-water two-phase flow or oil-gas-water multiphase flow, and due to the fact that the dynamic information of the produced liquid of the oil-gas well is not comprehensively grasped, early water breakthrough in the exploitation process is usually caused, the whole oil-gas well is forced to be closed, the problems of shortening of the service life of the oil-gas well, reduction of yield and the like are caused, and the economic benefit of the oil industry is seriously influenced. Therefore, the method for measuring and calculating the parameters of the research oil-gas-water multiphase flow or the oil-water two-phase flow has very important significance for the optimized exploitation of the oil-gas well, the effective protection of the reservoir and the improvement of the recovery ratio.
Due to the variability and complexity of the two-phase or multiphase flow patterns, the measurement difficulties are much greater than for single-phase flows. The commonly used measurement methods are mainly: electrical methods, fiber optic methods, ultrasound methods, tomography methods, nuclear magnetic resonance methods, and the like. The nuclear magnetic resonance method utilizes transition and relaxation of atomic energy levels to realize multiphase flow measurement, the mass change of microscopic atomic energy levels is excited, the effect which is difficult to realize by a classical measurement method is achieved, the measurement result is not influenced by macroscopic physical characteristics, and the method has obvious superiority in the aspects of complex and variable multiphase flow and two-phase flow measurement. In nmr multiphase flow measurement, the flow rate and the phase fraction (or water content) are important parameters of multiphase flow, and they affect each other and have complexity and diversity in the development of multiphase flow or two-phase flow. If the analysis of the influence of two-phase flow or multi-phase flow parameters (flow rate, phase content, etc.) on the nuclear magnetic resonance measurement signal is not detailed or sufficient, the measurement and calculation model of the average flow rate and the phase content established in the nuclear magnetic resonance two-phase flow measurement has larger errors. In the existing documents, solutions such as a time-averaged scanning mode or a sufficiently long sampling period are mostly adopted to improve the accuracy of multiphase flow parameter measurement, however, the solutions generally require a long measurement time, and thus have great limitations in actual online measurement.
Disclosure of Invention
In order to solve the problems and defects in the prior art, the invention aims to provide a nuclear magnetic resonance oil-water two-phase flow parameter measuring method, which constructs an accurate nuclear magnetic resonance two-phase flow water content and average flow velocity calculation model by optimizing nuclear magnetic resonance system parameters and analyzing the characteristics of nuclear magnetic resonance FID signals at different flow velocities and different water contents.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for measuring nuclear magnetic resonance oil-water two-phase flow parameters is characterized by comprising the following steps:
the first step is as follows: the method comprises the following specific steps of:
(1) arranging a sensor A and a sensor B on a pipeline to be measured, respectively outputting measured NMR signals to NMR processing software by the two sensors, and establishing a relation between a magnetization intensity vector and a magnetization length according to data obtained by processing, wherein the expression is as follows:
Figure GDA0003368145790000021
wherein, M/M0Is a normalized magnetization vector, LMIs the magnetization length, v is the average flow velocity of the oil-water two-phase flow, T1The longitudinal relaxation time of the oil-water two-phase flow is related to the component proportion of the two-phase flow;
(2) analyzing the magnetization intensity vector M/M of the oil-water two-phase flow under different average flow velocities v and different water contents according to the relational expression established by the formula 10The change rule along with the magnetization length;
(3) by analyzing the magnetization intensity vector M/M under different average flow velocities and different water contents0Finding the magnetization vector M/M0The corresponding magnetization length when approaching the maximum value of 1, thereby determining a magnetization length parameter;
(4) establishing a relation between a nuclear magnetic resonance receiving signal FID and the detection coil length, wherein the expression is as follows:
Figure GDA0003368145790000031
wherein M isi0＝SiHI，i,，SiIs the saturation of the i-th component in the oil-water two-phase flow, HI，iIs the hydrogen index, L, of the i-th component in the oil-water two-phase flowDIs the detection coil length, T is the sampling time, c is the correction factor, T1,iIs the longitudinal relaxation time, T, of the i-th component2,iIs the transverse relaxation time of the ith component;
(5) analyzing nuclear magnetic resonance receiving signals FID under different average flow velocities v and different water contents according to a relational expression established by a formula 2;
(6) obtaining nuclear magnetic resonance under different average flow velocities v and different water contentsIntegration of the received signal FID to obtain SA_mixtureThen each FID signal corresponds to a value, and the solution expression is as follows:
Figure GDA0003368145790000032
(7) establishing S under different average flow velocity v and different water content according to formula 3A_mixtureThe rule changing with the detection coil length;
(8) by analysis of SA_mixtureFinding out S according to the rule of detecting coil length changeA_mixtureDetermining the length parameter of the corresponding detection coil when the detection coil tends to be stable;
the second step is that: the establishment of the water content calculation model specifically comprises the following steps:
(1) firstly, inputting a nuclear magnetic resonance receiving signal FID of pure water and oil-water two-phase flow;
(2) the received signal FID of pure water is integrated according to the following formula to obtain a quantized value SA_water；
Figure GDA0003368145790000041
(3) Performing integral operation on the received signal FID of the oil-water two-phase flow according to a formula 3 to obtain a quantized value SA_mixture；
(4) Calculating SA_mixtureAnd SA_waterTo find SNThe formula is as follows:
Figure GDA0003368145790000042
(5) analyzing FID signal characteristics under different flow velocities and different water contents, and establishing water contents WH and SNThe specific calculation model is as follows:
WH＝-1.8343SN 6+7.2239SN 5-11.7927SN 4+10.4519SN 3-5.6919SN 2+2.6557SN-0.0126 (equation 6)
(6) According to the formula 3-6, after receiving the oil-water two-phase flow nuclear magnetic resonance signal FID, calculating the corresponding water content;
the third step: the average flow velocity of the oil-water two-phase flow is determined as follows:
(1) nuclear magnetic resonance received signal S input to sensor aA(n) nuclear magnetic resonance reception signal S of sensor BB(n)；
(2) Calculating the signal SA(n) and SB(n) the correlation coefficient is calculated as follows:
Figure GDA0003368145790000043
(3) s calculated according to equation 7A(n) and SB(n) correlation coefficient [ rho ] (tau) to find the transit time tRI.e. the time corresponding to the maximum value of the correlation coefficient;
(4) analyzing the average flow velocity characteristics under different flow velocities and different water contents, and establishing the distance between the average flow velocity v and the sensor A, B and the transit time tRThe average flow velocity calculation model is as follows:
Figure GDA0003368145790000051
wherein L isMDIs the distance between the sensors A, B.
(5) According to the formula 7 and the formula 8, after receiving the nuclear magnetic resonance signals of the oil-water two-phase flow sensors A and B, the average flow velocity corresponding to the oil-water two-phase flow can be calculated.
The sensor A and the sensor B are arranged on the same pipeline, the sensor A is positioned at the upstream, and the distance L between the sensor B and the sensor A is LMD＝0.3m。
The invention relates to a nuclear magnetic resonance oil-water two-phase flow parameter measuring and calculating method, which comprises three steps, wherein in the first step, the parameters of a nuclear magnetic resonance system are optimized by analyzing magnetization intensity vectors under different flow rates and different water contents and FID signals received by nuclear magnetic resonance, the magnetization length and the detection coil length are finally determined, and the parameters of the nuclear magnetic resonance system are optimally designed on the basis of fully considering the influence of the interaction of oil-water two-phase flow parameters; secondly, by analyzing the characteristics of the nuclear magnetic resonance receiving signals at different flow rates and different water contents and carrying out normalization processing on the nuclear magnetic resonance receiving signals of the oil-water two-phase flow, a measurement calculation model of the water content is established, and the measurement precision is improved; and thirdly, on the basis of fully considering the influence of parameters such as different flow rates, different water contents and the like on the signals received by the sensor A and the sensor B, establishing a measurement and calculation model of the average flow rate through the correlation of the signals received by the nuclear magnetic resonance sensor A and the sensor B which are arranged on the same pipeline, and realizing the measurement of the average flow rate of the oil-water two-phase flow. According to the nuclear magnetic resonance oil-water two-phase flow parameter measuring and calculating method, by optimizing parameters of a nuclear magnetic resonance system and analyzing FID signal characteristics under different flow rates and different water contents, a more accurate nuclear magnetic resonance two-phase flow water content and average flow rate calculation model is constructed, and more accurate measurement of oil-water two-phase flow parameters is realized.
Drawings
FIG. 1 is a schematic diagram of a nuclear magnetic resonance oil-water two-phase flow measuring system in an embodiment of the invention.
FIG. 2 is a flow chart of a nuclear magnetic resonance oil-water two-phase flow parameter measuring method in an embodiment of the invention.
FIG. 3 is the variation rule of magnetization vector of oil-water two-phase flow with magnetization length under different average flow rates in the present invention; the speed of fig. 3a is 0.1, the speed of fig. 3b is 0.3, the speed of fig. 3c is 0.6, and the speed of fig. 3d is 1.0.
FIG. 4 shows the variation of magnetization vector of oil-water two-phase flow with magnetization length, in which the water content in FIG. 4a is 10% and the water content in FIG. 4b is 30%.
FIG. 5 is a FID signal characteristic analysis when the water content and the flow rate of the oil-water two-phase flow change, FIG. 5a is a FID signal when the water content is 10%, 30%, 50%, 70% (oil speed 0.1m/s, water speed 12m/s), FIG. 5b is a FID signal when the water content is 10% (oil speed 0.1m/s, water speed 12m/s), 30% (oil speed 0.06m/s, water speed 8m/s), 50% (oil speed 0.09m/s, water speed 5m/s), 70% (oil speed 0.09m/s, water speed 3m/s), FIG. 5c is a FID signal when the water content is 70% (oil speed 0.1m/s, water speed 12m/s), 50% (oil speed 0.06m/s, water speed 8m/s), 30% (oil speed 0.09m/s, water speed 5m/s), 10% (oil speed 0.09m/s, water speed 3 m/s).
FIG. 6 shows the change rule of the quantized value of the FID signal with the detection coil length under different average flow rates of the oil-water two-phase flow of the present invention, wherein the speed in FIG. 6a is 0.1, the speed in FIG. 6b is 0.3, the speed in FIG. 6c is 0.6, and the speed in FIG. 6d is 1.0.
FIG. 7 shows the change rule of the quantified value of the FID signal of the oil-water two-phase flow along with the length of the detection coil, wherein FIG. 7a shows that the water content is 10%, and FIG. 7b shows that the water content is 10%.
FIG. 8 is a model of the relationship between water cut and quantized FID signals.
FIG. 9 shows FID signals at different flow rates of the oil phase and the water phase, FIG. 9a shows FID signals at oil flow rates of 0.2m/s, 0.6m/s, 1.0m/s, and 1.4m/s (water content of 20% and water flow rate of 9m/s), and FIG. 9b shows FID signals at water flow rates of 3.0m/s, 5.0m/s, 7.0m/s, and 9.0m/s (water content of 20% and oil phase flow rate of 0.08 m/s).
FIG. 10 is a model of the average flow rate of the two-phase oil-water flow.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
The invention relates to a nuclear magnetic resonance oil-water two-phase flow parameter measuring and calculating method, which comprises three steps, wherein in the first step, the parameters of a nuclear magnetic resonance system are optimized by analyzing magnetization intensity vectors under different flow rates and different water contents and FID signals received by nuclear magnetic resonance, the magnetization length and the detection coil length are finally determined, and the parameters of the nuclear magnetic resonance system are optimally designed on the basis of fully considering the influence of the interaction of oil-water two-phase flow parameters; secondly, by analyzing the characteristics of the nuclear magnetic resonance receiving signals at different flow rates and different water contents and carrying out normalization processing on the nuclear magnetic resonance receiving signals of the oil-water two-phase flow, a measurement calculation model of the water content is established, and the measurement precision is improved; and thirdly, on the basis of fully considering the influence of parameters such as different flow rates, different water contents and the like on the signals received by the sensor A and the sensor B, establishing a measurement and calculation model of the average flow rate through the correlation of the signals received by the nuclear magnetic resonance sensor A and the sensor B which are arranged on the same pipeline, and realizing the measurement of the average flow rate of the oil-water two-phase flow. According to the nuclear magnetic resonance oil-water two-phase flow parameter measuring and calculating method, by optimizing parameters of a nuclear magnetic resonance system and analyzing FID signal characteristics under different flow rates and different water contents, a more accurate nuclear magnetic resonance two-phase flow water content and average flow rate calculation model is constructed, and more accurate measurement of oil-water two-phase flow parameters is realized.
With reference to fig. 1, a schematic diagram of a nuclear magnetic resonance oil-water two-phase flow measurement system in an embodiment of the present invention illustrates the components of the nuclear magnetic resonance measurement system. The NMR measurement system includes sensor a, sensor B, RF circuit A, RF circuit B, and NMR processing software. Wherein sensor A and sensor B all install the outside at the measuring oil water pipeline, and sensor A is located the upper reaches, and sensor B is apart from sensor A by LMDSensor a and sensor B each output the measured NMR signal to NMR processing software via RF circuit A, RF, circuit B, 0.3 m. The sensor A and the sensor B are both composed of a permanent magnet with magnetism of N and S and a detection coil wound inside the permanent magnet. The permanent magnet with N and S magnetism generates strong and stable magnetic field for magnetizing two-phase fluid flowing through the magnetic field in the pipeline; the detection coil in sensor A is used for transmitting RF pulse signals and receiving Nuclear Magnetic Resonance (NMR) signals, and the detection coil in sensor B is only used for receiving the NMR signals; the RF circuit A is used for generating an RF transmitting pulse signal and preprocessing an NMR signal received by the sensor A, and the like, and the RF circuit B is used for preprocessing an NMR signal received by the sensor B, and the like; the NMR processing software is used for processing, analyzing and outputting measurement results and the like of the NMR signals received by the sensor a and the sensor B after the preprocessing. The nuclear magnetic resonance measurement system can be directly connected in an oil-water pipeline (as shown in figure 1), and two-phase flow measurement experiment conditions with different oil-water phase content and different flow rates are constructed by adjusting the flow rates of a valve 1, a valve 2 and a curved rod pump. Wherein the flowmeter 1 and the flow rateThe meters 2 are all single-phase flow meters and are used for measuring the flow of oil or water in the pipeline. The oil tank is used for holding oil for the experiment, and the profit jar is used for holding experiment water and the oily product of recovery, and the blender in the pipeline is used for realizing the two-phase mixture of profit.
When the oil-water two-phase fluid to be measured passes through the nuclear magnetic resonance measuring system, the fluid flowing through the sensor A is firstly magnetized by the permanent magnet, and the direction of hydrogen atoms in the fluid is the same as the magnetic field direction of the permanent magnet. Meanwhile, radio frequency pulses are emitted to a detection coil in the sensor A through the RF circuit A, the transition of hydrogen atoms is excited, and the nuclear magnetic resonance of oil and water in the pipeline is realized. The NMR received signal is first detected at sensor a and, after a delay, reaches sensor B. Thus, parametric measurement and calculation of the oil-water two-phase flow can be achieved by analyzing the received NMR signals.
With reference to fig. 2, the present invention comprises the following steps in detail:
the first step is as follows: the method comprises the following specific steps of:
(1) arranging a sensor A and a sensor B on a to-be-measured calculation and measurement pipeline, respectively outputting measured NMR signals to NMR processing software by the two sensors, and firstly establishing a relation between a magnetization intensity vector and a magnetization length according to data obtained by processing, wherein the expression is as follows:
Figure GDA0003368145790000081
wherein, M/M0Is a normalized magnetization vector, LmIs the magnetization length, v is the average flow velocity of the oil-water two-phase flow, T1The longitudinal relaxation time (related to the component ratio of the two-phase flow) of the oil-water two-phase flow.
(2) Analyzing different average flow velocity v and different water content (influence parameter T) according to the relational expression established by the formula 11) Magnetization intensity vector M/M of oil-water two-phase flow0The change rule along with the magnetization length;
and (3) analyzing the change rule of the magnetization vector of the oil-water two-phase flow along with the magnetization length under different average flow velocities and different water contents by combining with a graph 3. In FIG. 3, the water contents were 10%, 30%, 50% and 70%, respectively, and the average flow rates were 0.1m/s, 0.3m/s, 0.6m/s and 1.0m/s, respectively. As can be seen from fig. 3, at the same water content and average flow velocity, the magnetization vector gradually increases and stabilizes as the magnetization length increases. At the same average flow rate, the magnetization length to reach full magnetization becomes longer as the water content increases. Further, as the average flow velocity increases, the rising speed of the magnetization vector becomes slow, and the length for achieving a good magnetization effect becomes long.
(3) By analyzing the magnetization intensity vector M/M under different average flow velocities and different water contents0Finding the magnetization vector M/M0The corresponding magnetization length when approaching the maximum value of 1, thereby determining a magnetization length parameter;
and (5) analyzing the change rule of the magnetization intensity vector under different flow rates and different water contents by combining with the graph 4, and determining the magnetization length parameter. FIG. 4 shows the change of magnetization vector of two-phase oil-water flow with magnetization length at average velocities of 0.1m/s, 0.3m/s, 0.5m/s, and 1.0m/s, respectively (water contents of 10% and 30%, respectively). At the same flow velocity and water content, the magnetization vector gradually increases as the magnetization length increases. When the magnetization reaches a certain length, the magnetization vector tends to be stable. At the same water content, the magnetization vector tends to decrease with increasing average flow velocity. Thus, parameters of the NMR measurement system are optimized by analyzing the magnetization vector as a function of magnetization length at different water cut and flow rates. As can be seen from fig. 3 and 4, at a low average flow velocity, when the magnetization length is in the range of 0.8 to 1.0m, the magnetization vector changes little and tends to be stable, so that the optimal magnetization length is finally determined to be 0.8 m.
(4) Establishing a relation between a nuclear magnetic resonance receiving signal FID and the detection coil length, wherein the expression is as follows:
Figure GDA0003368145790000101
wherein M isi0＝SiHI，i,，SiIs the second in oil-water two-phase flowSaturation of i Components, HI，iIs the hydrogen index, L, of the i-th component in the oil-water two-phase flowDIs the detection coil length, T is the sampling time, c is the correction factor, T1,iIs the longitudinal relaxation time, T, of the i-th component2,iIs the transverse relaxation time of the ith component.
(5) Analyzing different average flow velocity v and different water content (influence parameter T) according to the relational expression established by the formula 21,iAnd T2,i) Receiving a signal FID by nuclear magnetic resonance;
FIG. 5 analyzes the characteristics of the FID signal when the water content and the flow rate of the oil-water two-phase flow change, and establishes the relationship between the FID signal and the two-phase flow parameters. FID signals with water content of 10% -70% (oil speed 0.1m/s, water speed 12m/s) are shown in FIG. 5 (a). When the water content is 10% to 70%, the attenuation characteristics of the FID signal are different. At the same flow rate, the FID signal decays faster and for a shorter time as the water cut increases. However, when the NMR two-phase flow rate and water cut change, it will no longer follow this law. FIGS. 5(b) and (c) show the FID signals in the range of 10% -70% water content, 0.06-0.09m/s oil velocity, 3-12m/s water velocity. In the later period of attenuation, some cross points exist between FID signals with different speeds, and the water content and the FID signals gradually decline. In fig. 5(c), when the oil velocity is low, the FID signal does not have a clearly consistent direction of change with the increase in water content and water velocity. Showing the interaction of the flow velocity and the water content of the oil-water two-phase flow to the FID signal of the nuclear magnetic resonance.
(6) Obtaining S by integrating nuclear magnetic resonance received signals FID under different average flow velocities v and different water contentsA_mixtureThen each FID signal corresponds to a value, and the solution expression is as follows:
Figure GDA0003368145790000102
when the magnetization length is determined, the quantized value of the FID signal can be expressed as a function of the detection coil length and two-phase flow parameters (moisture content and average velocity) for optimizing the detection coil length.
(7) Is established according to equation 3S at the same average flow velocity v and different water contentsA_mixtureThe rule changing with the detection coil length;
and analyzing the change rule of the quantized value of the FID signal along with the detection coil length under different flow rates and different water contents by combining with the graph 6. Fig. 6 shows the variation of the quantized value of the FID signal (formula 3) with the length of the detection coil for different average flow rates of the oil-water two-phase flow. In FIG. 6, the water contents were 10%, 30%, 50% and 70%, respectively, and the average flow rates were 0.1m/s, 0.3m/s, 0.6m/s and 1.0m/s, respectively. In fig. 6(a), (b) and (c), the quantized value of the FID signal gradually increases and stabilizes as the detection coil length increases, at the same water content and flow rate. At the same flow rate, the quantified value of the FID signal increases with increasing water cut. In fig. 6(d), as the detection coil length increases, the quantized value of the FID signal continues to increase when the water content is 30%, 50%, and 70%, respectively. Further, at an average flow velocity of 1.0m/s, there was no clear upward tendency in the quantized value of the FID signal. At the same flow rate and water cut, the quantized value of the FID signal gradually increases as the detection coil length increases. The quantized value of the FID signal tends to stabilize when the detector coil reaches a certain length. At the same water cut, the quantified value of the FID signal decreases with increasing flow rate.
(8) By analysis of SA_mixtureFinding out S according to the rule of detecting coil length changeA_mixtureAnd (4) determining the corresponding detection coil length when the detection coil length tends to be stable.
And determining the optimized detection coil length by combining the change rule of the quantized value of the FID signal with the detection coil length under different flow rates and different water contents in the graph 7. As can be seen from fig. 7, for low average flow velocity, the change in the quantization value of the FID signal is small when the detection coil length is in the range of 0.6-1.0m, ultimately determining an optimized detector coil length of 0.6 m.
The second step is that: the establishment of the water content calculation model specifically comprises the following steps:
(1) firstly, inputting a nuclear magnetic resonance receiving signal FID of pure water and oil-water two-phase flow;
(2) for pureThe received signal FID of water is integrated according to the following formula to obtain a quantized value SA_water；
Figure GDA0003368145790000121
(3) Performing integral operation on the received signal FID of the oil-water two-phase flow according to a formula (3) to obtain a quantized value SA_mixture；
(4) Calculating SA_mixtureAnd SA_waterTo find SNThe formula is as follows:
Figure GDA0003368145790000122
(5) analyzing FID signal characteristics under different flow velocities and different water contents, and establishing water contents WH and SNThe specific calculation model is as follows:
WH＝-1.8343SN 6+7.2239SN 5-11.7927SN 4+10.4519SN 3-5.6919SN 2+2.6557SN-0.0126 (equation 6)
And (5) analyzing the establishment of a water content measurement model by combining with the graph 8. 100 sets of FID signals of nuclear magnetic resonance are collected within the ranges of 10% -100% of water content, 0.01-0.1 m/s of oil speed and 3-12m/s of water speed, and the quantized FID signals are normalized according to formulas 3-5. Quantitative value S of water content WH of oil-water two-phase flow and FID signal of oil-water mixtureNAnd (4) establishing a water content calculation model. Fitting moisture content WH and S by polynomialNAnd (4) establishing a water content measurement calculation model. A large number of experiments show that the fitting effect of the sixth-order polynomial is best. FIG. 8 shows the water content WH and the FID signal quantization value SNThe relationship, the calculation model is equation 6. In the nuclear magnetic resonance two-phase flow measurement, according to the built FID data measurement model (formula 3-formula 6), the water content of the oil-water two-phase flow is obtained, and the average relative error of 100 groups of FID signals is 0.43%.
(6) According to the formula 3-6, after receiving the oil-water two-phase flow nuclear magnetic resonance signal FID, the corresponding water content can be calculated.
The third step: the average flow velocity of the oil-water two-phase flow is determined as follows:
(1) nuclear magnetic resonance received signal S input to sensor aA(n) nuclear magnetic resonance reception signal S of sensor BB(n)；
(2) Calculating the signal SA(n) and SB(n) the correlation coefficient is calculated as follows:
Figure GDA0003368145790000131
(3) s calculated according to equation 7A(n) and SB(n) correlation coefficient [ rho ] (tau) to find the transit time tR(time corresponding to maximum value of correlation coefficient);
(4) analyzing the average flow velocity characteristics under different flow velocities and different water contents, and establishing the distance between the average flow velocity v and the sensor A, B and the transit time tRThe average flow velocity calculation model is as follows:
Figure GDA0003368145790000132
wherein L isMDIs the distance between the sensors A, B.
FID signal characteristics at different oil phase flow rates or water phase flow rates were analyzed in conjunction with fig. 9. When determining parameters of the nuclear magnetic resonance system, the FID signal is a function of the phase velocity and phase content of the oil-water two-phase flow. On the basis of researching a water content measurement model, the influence of the oil-water phase separation speed on the FID signal is analyzed. When the water content was 20% and the water flow rate was 9m/s, FID signals were obtained at different oil phase flow rates, assuming oil flow rates of 0.2, 0.6, 1.0 and 1.4m/s, respectively, as shown in FIG. 9 (a). FID signals of different oil phase flow rates have different times and decay rates. Further, as the oil phase flow rate increases, the amplitude of the FID signal significantly decreases, and thus the FID signal at different oil phase flow rates can be determined. When the water content was 20% and the flow rate of the oil phase was 0.08m/s, FID signals were obtained at different flow rates of the aqueous phase, as shown in FIG. 9(b), assuming that the flow rates of the aqueous phase were 3.0, 5.0, 7.0 and 9.0m/s, respectively. As the flow rate of the aqueous phase increases, the decay rate of the FID signal becomes faster and the decay time becomes shorter, which has the same rule as that of fig. 9 (a). As the flow rate of the aqueous phase increases, the amplitude of the FID signal decreases and the decay rate increases. When the water content is constant, either the water phase flow rate or the oil phase flow rate is increased, which causes an increase in the average flow rate of the two-phase flow. That is, the average flow rate is the same for both the water phase and the oil phase. Thus, fig. 9(a) and (b) can be interpreted as the FID signal showing the characteristics of a shorter decay time and a faster decrease in amplitude with an increase in average velocity.
And analyzing an oil-water two-phase flow average flow velocity calculation model by combining the graph 10. 80 pairs of FID signals of nuclear magnetic resonance are acquired from the sensor A and the sensor B, the water content ranges from 0% to 100%, the water phase flow velocity ranges from 1m/s to 12m/s, the oil phase flow velocity ranges from 0.02 m/s to 2m/s, and the transit time t of the oil-water two-phase flow can be obtained according to a formula (7)R. The average speed v of the oil-water two-phase flow can be determined by the distance L between the sensor A and the sensor BMD(in this system LMD0.3m) and a transit time tRThe results show that the average flow velocity and L of the two-phase flowMD/tRThe linear relationship is satisfied as shown in fig. 10. Therefore, the average flow velocity of the nmr two-phase flow is modeled as a linear relationship as described in equation (8).
(5) According to the formula 7 and the formula 8, after receiving the nuclear magnetic resonance signals of the oil-water two-phase flow sensors A and B, the average flow velocity corresponding to the oil-water two-phase flow can be calculated.

Claims (1)

1. A method for measuring nuclear magnetic resonance oil-water two-phase flow parameters is characterized by comprising the following steps:
the first step is as follows: the method comprises the following specific steps of:
(1) arranging a sensor A and a sensor B on a pipeline to be measured, respectively outputting measured NMR signals to NMR processing software by the two sensors, and establishing a relation between a magnetization intensity vector and a magnetization length according to data obtained by processing, wherein the expression is as follows:
Figure FDA0003368145780000011
wherein, M/M0Is a normalized magnetization vector, LMIs the magnetization length, v is the average flow velocity of the oil-water two-phase flow, T1The longitudinal relaxation time of the oil-water two-phase flow is related to the component proportion of the two-phase flow;
(2) analyzing the magnetization intensity vector M/M of the oil-water two-phase flow under different average flow velocities v and different water contents according to the relational expression established by the formula 10The change rule along with the magnetization length;
(3) by analyzing the magnetization intensity vector M/M under different average flow velocities and different water contents0Finding the magnetization vector M/M0The corresponding magnetization length when approaching the maximum value of 1, thereby determining a magnetization length parameter;
(4) establishing a relation between a nuclear magnetic resonance receiving signal FID and the detection coil length, wherein the expression is as follows:
Figure FDA0003368145780000012
wherein M isi0＝SiHI，i，SiIs the saturation of the i-th component in the oil-water two-phase flow, HI，iIs the hydrogen index, L, of the i-th component in the oil-water two-phase flowDIs the detection coil length, T is the sampling time, c is the correction factor, T1,iIs the longitudinal relaxation time, T, of the i-th component2,iIs the transverse relaxation time of the ith component;
(5) analyzing nuclear magnetic resonance receiving signals FID under different average flow velocities v and different water contents according to a relational expression established by a formula 2;
(6) obtaining S by integrating nuclear magnetic resonance received signals FID under different average flow velocities v and different water contentsA_mixtureThen each FID signal corresponds to a value, solving for the expressionThe formula is as follows:
Figure FDA0003368145780000021
(7) establishing S under different average flow velocity v and different water content according to formula 3A_mixtureThe rule changing with the detection coil length;
(8) by analysis of SA_mixtureFinding out S according to the rule of detecting coil length changeA_mixtureDetermining the length parameter of the corresponding detection coil when the detection coil tends to be stable;
the second step is that: the establishment of the water content calculation model specifically comprises the following steps:
(1) firstly, inputting a nuclear magnetic resonance receiving signal FID of pure water and oil-water two-phase flow;
(2) the received signal FID of pure water is integrated according to the following formula to obtain a quantized value SA_water；
Figure FDA0003368145780000022
(3) Performing integral operation on the received signal FID of the oil-water two-phase flow according to a formula 3 to obtain a quantized value SA_mixture；
(4) Calculating SA_mixtureAnd SA_waterTo find SNThe formula is as follows:
Figure FDA0003368145780000023
(5) analyzing FID signal characteristics under different flow velocities and different water contents, and establishing water contents WH and SNThe specific calculation model is as follows:
WH＝-1.8343SN 6+7.2239SN 5-11.7927SN 4+10.4519SN 3-5.6919SN 2+2.6557SN-0.0126 (equation 6)
(6) According to the formula 3-6, after receiving the oil-water two-phase flow nuclear magnetic resonance signal FID, calculating the corresponding water content;
the third step: the average flow velocity of the oil-water two-phase flow is determined as follows:
(1) nuclear magnetic resonance received signal S input to sensor aA(n) nuclear magnetic resonance reception signal S of sensor BB(n)；
(2) Calculating the signal SA(n) and SB(n) the correlation coefficient is calculated as follows:
Figure FDA0003368145780000031
(3) s calculated according to equation 7A(n) and SB(n) correlation coefficient [ rho ] (tau) to find the transit time tRI.e. the time corresponding to the maximum value of the correlation coefficient;
(4) analyzing the average flow velocity characteristics under different flow velocities and different water contents, and establishing the distance between the average flow velocity v and the sensor A, B and the transit time tRThe average flow velocity calculation model is as follows:
Figure FDA0003368145780000032
wherein L isMDIs the distance between the sensors A, B;
(5) according to a formula 7 and a formula 8, after receiving the nuclear magnetic resonance signals of the oil-water two-phase flow sensors A and B, calculating the average flow velocity corresponding to the oil-water two-phase flow;
the sensor A and the sensor B are arranged on the same pipeline, the sensor A is positioned at the upstream, and the distance L between the sensor B and the sensor A is LMD＝0.3m。
CN201910049656.5A 2019-01-18 2019-01-18 Method for measuring nuclear magnetic resonance oil-water two-phase flow parameters Active CN109856175B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910049656.5A CN109856175B (en) 2019-01-18 2019-01-18 Method for measuring nuclear magnetic resonance oil-water two-phase flow parameters

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910049656.5A CN109856175B (en) 2019-01-18 2019-01-18 Method for measuring nuclear magnetic resonance oil-water two-phase flow parameters

Publications (2)

Publication Number Publication Date
CN109856175A CN109856175A (en) 2019-06-07
CN109856175B true CN109856175B (en) 2022-02-18

Family

ID=66895324

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910049656.5A Active CN109856175B (en) 2019-01-18 2019-01-18 Method for measuring nuclear magnetic resonance oil-water two-phase flow parameters

Country Status (1)

Country Link
CN (1) CN109856175B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110579502B (en) * 2019-09-29 2023-03-28 西安石油大学 Sensor for nuclear magnetic resonance two-phase flow measurement
CN112949218B (en) * 2021-02-20 2021-09-03 东北石油大学 Method for evaluating separation effect of oil-water cyclone separator of ultra-high water-cut horizontal well
CN116412863A (en) * 2021-12-31 2023-07-11 中国石油天然气股份有限公司 Multiphase flow metering system and method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001036919A1 (en) * 1999-11-16 2001-05-25 Wollin Ventures, Inc. Magnetic resonance analyzing flow meter and flow measuring method
AU2011318468A1 (en) * 2010-10-19 2013-04-18 Baker Hughes Incorporated Multiphase flow measurement using Nuclear Magnetic Resonance
WO2016030059A2 (en) * 2014-08-29 2016-03-03 Krohne Ag Method for operating a nuclear magnetic resonance flow meter and nuclear magnetic resonance flow meter
CN108918573A (en) * 2018-08-23 2018-11-30 中国石油天然气股份有限公司 Oil-water two-phase flow constituent content measurement method and system

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6268727B1 (en) * 1997-06-24 2001-07-31 Southwest Research Institute Measurement of flow fractions flow velocities and flow rates of a multiphase fluid using ESR sensing
AR048373A1 (en) * 2004-07-08 2006-04-26 Spinlock Srl A DEVICE AND A METHOD FOR MEASURING DIRECTLY AND IN REAL TIME, THE PROPORTION AND FLOW OF THE DIFFERENT COMPONENTS THAT CONFORM A MULTICOMPONENT COMPLEX FLUID, A PRODUCTION LINE PROVISION FOR A MULTICOMPONENT COMPLEX FLUID THAT USES A SAID AND DEPOSITIVE METHOD
DE102014002392A1 (en) * 2013-08-21 2015-02-26 Krohne Ag Nuclear magnetic flowmeter and method of operating nuclear magnetic flowmeters

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001036919A1 (en) * 1999-11-16 2001-05-25 Wollin Ventures, Inc. Magnetic resonance analyzing flow meter and flow measuring method
AU2011318468A1 (en) * 2010-10-19 2013-04-18 Baker Hughes Incorporated Multiphase flow measurement using Nuclear Magnetic Resonance
WO2016030059A2 (en) * 2014-08-29 2016-03-03 Krohne Ag Method for operating a nuclear magnetic resonance flow meter and nuclear magnetic resonance flow meter
CN108918573A (en) * 2018-08-23 2018-11-30 中国石油天然气股份有限公司 Oil-water two-phase flow constituent content measurement method and system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Quantitative multiphase flow characterisation using an Earth"s field NMR flow meter;Keelan et al.;《Flow Measurement and Instrumentation》;20171012;第58卷;104-111 *
层析成像技术在多相流中的研究动态;李利品 等;《地球物理学进展》;20120430;第27卷(第2期);651-659 *

Also Published As

Publication number Publication date
CN109856175A (en) 2019-06-07

Similar Documents

Publication Publication Date Title
CN109856175B (en) Method for measuring nuclear magnetic resonance oil-water two-phase flow parameters
CN103279647B (en) A kind of method calculating Sandstone Gas Reservoir permeability based on pore character parameter
RU2666124C1 (en) Method of interpreting nmr signals to give multiphase fluid flow measurements for gas/liquid system
Arola et al. Use of nuclear magnetic resonance imaging as a viscometer for process monitoring
RU2004126712A (en) METHOD AND DEVICE FOR DETERMINING SPEED AND PROPERTIES OF A CURRENT LIQUID MEDIA USING MEASUREMENTS ON THE BASIS OF NMR
US9804108B2 (en) Multi-phase metering device for oilfield applications
CN202126492U (en) Digital fluxgraph
AU2017279558A1 (en) Nuclear magnetic flow meter and method for operation of nuclear magnet flow meters
CN107525553B (en) A kind of method and device of determining heterogeneous fluid composition flow rate
CN104864925A (en) Flowmeter With A Measuring Device Implementing A Tomographic Measuring Principle
CN104568024A (en) Vibration type flow meter characteristic signal extraction method
Shi et al. A proposed NMR solution for multi-phase flow fluid detection
CN103175986A (en) Method for measuring gas-phase flow rate and liquid-phase flow rates of oil-gas-water three-phase flow
CN102928026A (en) Method of obtaining integrated transient void fraction by utilizing local transient void fraction
CN104061970A (en) Electromagnetic flow signal detection method
US10371653B2 (en) Multi-phase metering device for oilfield applications
Sun Design and performance of the converging-diverging vortex flowmeter
CN209088048U (en) Antenna for nuclear magnetic resonance analysis of fluid instrument
CN109974793B (en) Signal processing method for measuring flow of gas-containing conductive liquid by electromagnetic vortex shedding flowmeter
RU74710U1 (en) DEVICE FOR MEASURING THE COMPOSITION AND CONSUMPTION OF MULTICOMPONENT LIQUIDS BY THE NUCLEAR MAGNETIC RESONANCE METHOD
CN102360024A (en) Paper pulp flow velocity and flow measuring method
CN106595782A (en) Stepped multiple-valued excited electromagnetic flowmeter
CN106404270B (en) Gas-liquid two-phase flow parameter measurement method based on Venturi tube differential pressure data
Liang et al. Research on Rheological Parameters Correction Method Based on Pipe Viscometer
CN112683347B (en) Fluid component flow measuring device and method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant