RU2755939C1 - Method for sampling multiphase liquid from a pipeline and a device for sampling multiphase liquid from a pipeline - Google Patents

Abstract

FIELD: pipeline liquid sampling.SUBSTANCE: invention relates to the technology and technique of sampling a multiphase liquid from a pipeline and can find application in the oil production and other industries. The method for sampling a multiphase liquid from the pipeline (2) by a sampling element (1) includes preliminary mixing of the flow by means of a complex hydrodynamic effect on the flow of tear-off, jet and pulsating vortex flows using a sampling device. The device for sampling multiphase liquid from the pipeline (2) contains a mixer for mixing the flow and a sampling element (1) installed in series in the pipeline (2) with the orientation of the inlet opening towards the flow. The mixer is made of a sequentially arranged perforated pipe (3) and a cylindrical body (4) coaxially with the pipeline, the inner cavity of which is formed by three sequentially arranged sections: an inlet annular diffuser section (I), a middle cylindrical section (II), on the inner surface of which tear-off spherical recesses (8) are made along the entire length in a corridor or staggered order, and an outlet section (III) made smooth with a transition to the inner diameter of the pipeline (2). At the same time, throttling holes are additionally made in the inlet section of the cylindrical body.EFFECT: invention increases the representativeness of the sampled multiphase liquid from the pipeline and the accuracy of determining its composition, as well as increases the resource of reliable operation of the mixer and the sampling element.4 cl, 4 dwg

Description

The invention relates to a technology and technique for sampling a multiphase fluid from a pipeline and can be used in oil production and other industries.

When developing a productive oil reservoir, oil, water and associated gas are present in the well production, as well as chloride salts and various fine mechanical impurities in the solid phase (solid hydrocarbons, mineral particles, etc.). The composition of the produced multiphase fluid for each well is unique and requires constant monitoring, since the concentration of each component can change over time, which, in turn, disturbs the stability of the physical properties and the flow regime of the oil-water-gas flow.

There is a known method of sampling a liquid from a pipeline, in which a sampling element is placed in a pipeline from one sampling tube with a bent end, which is located on the pipeline axis with an inlet towards the flow; sampling is carried out in proportion to the flow rate of the pipeline, at which the sampling rate is at least half and not more than twice the average flow rate of the pipeline: (see Method of sampling liquid from the pipeline. / GOST 2517-85. p. 2.13.1.3. 2.13.1.7 ).

A device for implementing this method is known, including a sampling element in the form of one sampling tube with a bent end, which is installed on the axis of the pipeline with an inlet facing the flow (see Device for sampling liquid from a pipeline. / GOST 2517-85, p. 2.13.1.7 , fig. 14).

In the presence of free gas in the liquid flow, the known technology and sampling techniques do not provide a high sample representativeness.

A known method of intensifying convective heat exchange in heat exchangers of power plants using the action of self-organizing large-scale vortex structures arising under the influence of the relief of the heat exchange surface, on which the detachable spherical recesses are made, and pulsating tornado vortices formed inside these recesses, when flowing around them with a coolant ( "Intensification of heat transfer by spherical grooves under the influence of disturbing factors" / AV Shchukin, AP Kozlov, RS Agachev, Ya.P. Chudnovsky; edited by Academician V.E. Alemasov. Kazan: Izd- in Kazan State Technical University, 2003. - 143 pp. In addition, as a result of the turbulence of the coolant flow in the detachable spherical recesses, the intensity of their pollution decreases as noted in the work // Handbook on heat exchangers: In 2 vol. T. 2 / P. 74. Translated from English under the editorship of OG Martynenko et al. - M .: Energoatomizdat, 1987. - 352 p.

This method of intensification is used on external and internal flat heat exchange surfaces, as well as on external tubular heat exchange surfaces. This method is not used on internal heat exchange surfaces of circular cross-section due to the technological complexity of manufacturing tear-off spherical recesses inside pipes of a sufficiently long length.

A device is known for implementing this method in the form of a shell-and-tube heat exchanger, inside which pipes of the HRS Group Corporation (Spain) are installed for the movement of the coolant, on the outer surface of which depressions are made in a checkerboard pattern in the form of detachable spherical recesses to intensify heat transfer (see the monograph "Physical foundations and industrial application of heat transfer intensification: heat transfer intensification "/ IA Popov, Kh.M. Makhyanov, VM Gureev; under the general editorship of Yu.F. Gortyshov. - Kazan: Center for Innovative Technologies, 2009. - 560 with). It has been experimentally established that the efficiency of convective heat transfer is increased when the tear-off recesses are staggered on the outer surface of the pipe by a factor of 2.1 at moderate hydraulic losses (see the work of Munyabin K.L. The efficiency of heat transfer intensification by spherical depressions and protrusions // Thermophysics and Aeromechanics. 2003 . No. 2. S. 235-247). The main distinguishing feature of tear-off cuts is their relative depth h / d> 0.2, where h is the maximum depth of the cut, d = 4F / P is the hydraulic diameter of the cut in the plan. Here F is the area of the cut in the plan, and P is its perimeter. When a turbulent flow of a coolant flows around a detached spherical recess, a self-organizing large-scale vortex structure is formed in it, which appears sequentially in one or another epicenter of the recess and exits it in the form of a tornado onto the heat exchange surface, increasing heat transfer.

In shell-and-tube heat exchangers, which make up up to 80% of the total number of devices for this purpose, the known method for intensifying heat transfer inside pipes by forming pulsating tornado-like vortices in detachable spherical recesses is not used due to the complexity of making recesses on the inner surface of sufficiently long pipes. Since in this case, the use of more modern technologies is required, for example, additive technologies or investment casting technologies that differ from traditional ones (knurling, indentation), which increases the cost of the production process.

A known method of sampling liquid from a pipeline (see RF Patent No. 2215277, IPC G01N 1/10, publ. 27.10.2003, bull. No. 30) is the closest in technical essence to the claimed invention and taken as a prototype, in which placement is carried out in sampling pipeline and sampling is carried out; before sampling, the mixing of the flow in the cross-section of the pipeline is combined with the mixing of the flow along the pipeline. In the process of mixing the multiphase flow in the cross section of the pipeline, it is possible to ensure a uniform distribution of associated gas and reduce its concentration, at the same time, under the influence of mass forces, settling of solid particles on the pipeline walls occurs in the form of a sediment of solid particles, which disrupts the hydrodynamics of the flow and reduces the intensity of its mixing, reduces the accuracy sampling and ensuring its representativeness.

Known device for sampling liquid from the pipeline (see RF Patent No. 2215277, IPC G01N 1/10, publ. 27.10.2003, bull. No. 30) for the implementation of this method, the closest in technical essence to the claimed invention and taken as a prototype containing a sampling element installed on the pipeline with the orientation of the inlet towards the flow; a mixer is installed on the pipeline in front of the sampling element, made of a perforated pipe located coaxially with the pipeline, made docked with a block of transversely tapering and expanding sections. The use of a perforated pipe with rather small holes in the mixer, a system of converging-diffuser channels formed inside the block of transversely narrowing and expanding sections, solves the problem of uniform distribution of associated gas and a decrease in its concentration at the inlet to the sampling element.

However, in a mixer of this design, there are areas where, in a turbulent flow regime, precipitation of solid particles is formed, which violates the hydrodynamics of the multiphase flow and reduces the efficiency of the mixing process. These sections include: a section of the annular cavity between the pipeline and the perforated pipe at the point where it joins with a block of transversely tapering and expanding sections; the joints of the transversely narrowing and expanding sections inside the block, which is part of the mixer.

In the presence of various small mechanical impurities in the solid phase in the liquid flow, the known technology and sampling technique do not provide a high sample representativeness and do not eliminate the tendency to clog the mixer hydrodynamic path.

The technical problem to be solved by the present invention is to increase the representativeness of the sample when it is taken by the sampling element and the elimination of contamination in the form of precipitation of solid particles on the working surfaces of the pipeline.

The technical result, which the present invention is aimed at, is to increase the intensity of mixing of the components that make up the multiphase liquid and the accuracy of determining its composition during continuous hydrodynamic cleaning of the pipeline working surface from contamination during sampling.

The technical result is achieved by the fact that in the method of sampling a multiphase liquid from a pipeline by a sampling element from a premixed flow, the new is that the mixing process is carried out by means of a complex hydrodynamic effect on the flow of separated, jet and pulsating vortex flows.

Thus, the simultaneous complex hydrodynamic effect on the flow of various types of flows allows, before sampling, not only to ensure a uniform distribution of gas in the flow, reduce its concentration and reduce dispersion per unit volume of the flow, but also prevents the deposition of solid particles on the working surface of the pipeline as a result of its continuous hydrodynamic cleaning. This contributes to the proportional sampling and obtaining its higher representativeness in comparison with the prototype method.

To achieve the technical result when implementing the proposed method, a device for sampling a multiphase liquid from a pipeline is used, which contains a sampling element installed on the pipeline with an orientation of the inlet towards the flow, a mixer for mixing the flow is coaxially installed in front of the sampling element in the pipeline, which includes a series of perforated pipe and cylindrical body, new is that the inner cavity of the cylindrical body in the direction of fluid flow is formed by three successive sections, an inlet section made in the form of a smooth annular diffuser concentrically located relative to the mixer axis, a middle cylindrical section, along the entire length of the inner surface of which in tear-off spherical recesses are made in corridor order, and the outlet section is made smooth with a transition to the inner diameter of the pipeline.

The opening angle of the smooth annular diffuser in the inlet section of the cylindrical body of the mixer is θ _d = 60 ... 80 °.

, а относительный шаг в осевом и окружном направлениях между выемками составляет

.The relative depth of the detachable spherical recesses on the inner surface of the middle section of the cylindrical mixer body is

, and the relative pitch in the axial and circumferential directions between the grooves is

...

Tear-off spherical recesses on the inner surface of the middle section of the cylindrical body of the mixer are staggered.

The essence of the invention is illustrated by the drawing.

FIG. 1 shows a longitudinal section of a pipeline with a liquid sampling device installed therein.

FIG. 2 shows a cross-section AA of the inlet section of the cylindrical mixer body.

FIG. 3 shows a cross-section BB of the middle section of the cylindrical body of the mixer and an enlarged view of Position IV in this section.

FIG. 4 shows a longitudinal section of a mixer, on the inner surface of the middle cylindrical section of which tear-off spherical recesses are made in a checkerboard pattern.

Where:

1 - sampling element installed vertically with an inlet facing the flow;

2 - pipeline;

3 - perforated pipe;

4 - cylindrical body of the mixer;

5 - holes in the perforated pipe;

6 - annular diffuser;

7 - axial throttling holes;

8 - detachable spherical recesses;

9 - sampling valve;

d is the diameter of the spherical tear-off grooves;

d ₁ - the diameter of the holes in the perforated pipe;

d ₂ - the diameter of the axial throttling holes;

D is the inner diameter of the cylindrical body of the mixer;

h is the depth of the tear-off spherical notch;

t _a is the step between the detachable spherical grooves in the axial direction;

t _u is the step between the detachable spherical grooves in the circumferential direction;

θ _d - opening angle of the annular diffuser;

I - inlet section of the cylindrical body of the mixer;

II - middle section of the cylindrical body of the mixer;

III - outlet section of the cylindrical body of the mixer;

IV - position on section А-А of the cylindrical mixer body;

– направление движения потока многофазной жидкости.

- direction of flow of multiphase fluid.

The method of sampling liquid from the pipeline is carried out as follows. In the pipeline 2 (see Fig. 1), through which the multiphase liquid is pumped, a mixer for mixing it and a sampling element 1 is installed in series. The mixer is made of successively arranged perforated pipe 3 with holes 5 and a cylindrical body 4 docked together. Part of the flow of the multiphase liquid, getting inside the perforated pipe 3, enters the annular diffuser 6, made in the inlet section I of the cylindrical body 4, and provides mixing of the flow in the longitudinal direction inside the mixer. In this case, the separated flows arising on the smooth walls of the annular diffuser 6 (see the work of Idelchik I.E. Handbook on hydraulic resistance / Edited by M.O.Steinberg. - 3rd ed., Revised and supplemented by M. : Mashinostroenie, 1992. - 672 p.), Increase turbulization and the intensity of mixing flow in the longitudinal direction. The efficiency of flow mixing increases with a turbulent flow around the inner walls of the middle section II of the cylindrical body 4, on which the detachable spherical recesses 8 are made. in the transverse direction and clean the grooves from small fractions of contaminants, as shown in the work // Handbook of heat exchangers: In 2 volumes. Vol. 2 / P. 74. Per. from English ed. O.G. Martynenko and others - M .: Energoatomizdat, 1987 .-- 352 p.

Another part of the multiphase fluid flow through throttling holes 7, made in the inlet section I of the cylindrical body 4, enters the mixer in the form of an axial jet flow and allows not only cleaning the mixer sections at the junction of the perforated pipe 3 with the inlet section I of the cylindrical body 4, but also promotes flow acceleration in the near-wall boundary layer. This increases the intensity of vortex generation in the detachable spherical recesses 8 at the entrance to the middle section II of the cylindrical body 4 of the mixer and increases the mixing efficiency. Thus, the complex hydrodynamic effect of three phenomena: separated flows in an annular diffuser 6, axial jet flows through throttling holes 7 and the generation of pulsating self-organizing large-scale vortex structures in separation recesses 8 (pulsating vortex flows) can significantly increase the efficiency of mixing a multiphase fluid in a mixer continuous hydrodynamic cleaning. The outlet section III of the cylindrical body 4 of the mixer is connected to the pipeline 2. An efficiently mixed flow of multiphase liquid, flowing out from the outlet section III, enters the sampling element 1, with the help of which a sample is taken for its analysis with the valve 9 open.

The proposed invention allows for a more accurate quantitative and qualitative accounting of the multiphase fluid pumped through pipelines and extends the service life of the sampling element due to the hydrodynamic cleaning of the pipeline.

A device for implementing the proposed method for sampling a multiphase liquid from a pipeline works in the following way. The flow of a multiphase liquid (the direction of movement is shown by arrows in Fig. 1) through the pipeline 2 enters the mixer, made of a perforated pipe 3 coaxially with the pipeline with holes 5 with a diameter d ₁ and a cylindrical body 4 with an inner diameter D (Fig. 3), docked together. Part of the flow through the holes 5 enters the perforated pipe 3, from which it flows into the cylindrical housing 4 of the mixer, organizing the mixing of the flow in it in the longitudinal direction. The number of holes 5 and their diameter d _{1 are} determined individually depending on the operating conditions and the composition of the multiphase fluid. The inner diameter D of the cylindrical body 4 corresponds to the inner diameter of the pipeline through which the multiphase liquid is pumped.

The cylindrical body of the mixer 4 is made of three sequentially located sections (Fig. 1): the inlet section I, made in the form of a smooth annular diffuser 6, concentrically located relative to the mixer axis, the middle cylindrical section II, along the entire length of the inner surface of which tear-off spherical recesses 8 (Fig. 1 and 3), the diameter and depth of which were d and h, and the step between the recesses in the axial and circumferential directions is t _a and t _u, respectively, and the outlet section III, made smooth with the transition to the inner diameter of the pipeline 2.

Another part of the flow, passing through throttling holes 7 with a diameter d ₂ (Figs. 1 and 2), forms an axial jet flow in the near-wall layer above the spherical separation recesses 8 of the middle cylindrical section II. The diameter d ₂ and the number of holes 7 depend on the operating conditions and the composition of the multiphase fluid and are selected individually.

The flow of a multiphase fluid entering the cylindrical body 4 at its inlet I and middle II sections is simultaneously affected by three phenomena: flow separation from the walls of a smooth annular diffuser 6; axial jet flow in the wall layer of the middle cylindrical section II; pulsating self-organizing large-scale vortex structures arising in spherical separation grooves (pulsating vortex flows). If the first two phenomena increase the efficiency of mixing the flow in the longitudinal direction, then the third phenomenon - in the transverse direction. The complex hydrodynamic effect of these three phenomena contributes to a more uniform distribution of gas in the flow, a decrease in its concentration and a decrease in dispersion per unit volume of the flow of a multiphase liquid. In addition, the combined action of the second and third phenomena provides continuous hydrodynamic cleaning of the working sections of the mixer from sediment deposition of solid particles from the flow.

To achieve the optimal effect of the appearance of separated flows from the smooth walls of the annular diffuser, concentrically located relative to the mixer axis in the inlet section I, it is necessary that the opening angle of the annular diffuser should be θ _d = 60 ... 80 °.

, а относительный шаг в осевом и окружном направлениях между выемками составлял

. При этом расположение отрывных выемок в шахматном порядке (фиг. 4) повышает интенсивность процесса образования пульсирующих вихревых структур из-за увеличения количества отрывных выемок на внутренней поверхности участка II.To ensure a stable process of the emergence of pulsating self-organizing large-scale vortex structures in separated spherical grooves during turbulent flow, it is necessary that their relative depth on the inner surface of section II is

, and the relative pitch in the axial and circumferential directions between the notches was

... In this case, the arrangement of the tear-off recesses in a checkerboard pattern (Fig. 4) increases the intensity of the process of formation of pulsating vortex structures due to an increase in the number of tear-off recesses on the inner surface of section II.

The efficiently mixed flow enters the outlet III section of the mixer connected to the pipeline 2, in which the sampling element 1 is installed with the orientation of the inlet towards the flow. When valve 9 is open, a sample is taken for its subsequent analysis.

Modern technological methods of manufacturing parts of complex geometry, for example, additive technologies and investment casting technology, allow cylindrical mixers with tear-off recesses on their inner surface with in-line (Fig. 1) and staggered (Fig. 4) arrangement. An increase in the number of detachable grooves, as occurs with their staggered arrangement (Fig. 4), leads to an increase in the intensity of mixing of the flow inside the mixer in the transverse direction due to an increase in the number of pulsating self-organizing large-scale vortex structures generated by each groove.

The axial length of all three sections of the cylindrical mixer body is determined by the variable relief of its inner surface and the thickness of the pipeline walls.

Thus, the proposed invention will provide better mixing of the components of the multiphase liquid in the mixer installed in the pipeline in front of the sampling element. This will increase the representativeness of the multiphase fluid sample taken from the pipeline and the accuracy of determining its composition. Continuous hydrodynamic cleaning of the mixer working surface from contamination in the form of precipitation of solid particles from the flow will increase the resource of reliable operation of the mixer and sampling element.

Claims (4)

1. A device for sampling a multiphase liquid from a pipeline, containing a sampling element installed on the pipeline with the orientation of the inlet facing the flow, and a mixer installed coaxially in the pipeline in front of the sampling element for mixing the flow, including a series of perforated pipe and a cylindrical body, characterized in that, that the inner cavity of the cylindrical body in the direction of the flow of the multiphase fluid is formed by three sequentially located sections, the inlet section made in the form of a smooth annular diffuser concentrically located relative to the mixer axis, the middle cylindrical section, along the entire length of the inner surface of which, in a corridor or staggered manner, detachable spherical recesses, and an outlet section made smooth with a transition to the inner diameter of the pipeline, and in the inlet section of the cylindrical body, a throttling valve is additionally made shining holes. 2. The device according to claim 1, characterized in that the opening angle of the smooth annular diffuser in the inlet section of the cylindrical body of the mixer is θd = 60 ... 80 °. 3. The device according to claim 1, characterized in that the relative depth of the detachable spherical recesses on the inner surface of the middle section of the cylindrical body of the mixer is

, and the relative pitch in the axial and circumferential directions between the grooves is

, where h is the depth of the tear-off spherical notch; d is the diameter of the spherical tear-off grooves; t _a is the step between the detachable spherical grooves in the axial direction; t _u is the step between the detachable spherical grooves in the circumferential direction. 4. A method of sampling a multiphase liquid from a pipeline by a sampling element from a premixed flow, characterized in that the process of mixing the flow is carried out by means of a complex hydrodynamic effect on the flow of separated, jet and pulsating vortex flows by means of the device according to claim 1.

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