RU2265122C2 - Oil well output measuring device - Google Patents

Abstract

FIELD: measuring equipment, particularly to locate fluid leaks, intrusions, or movements.

SUBSTANCE: device has multithrow product switch having a number of inlets corresponding to a number of oil wells and two outlets. One outlet is used to direct product obtained from one well to measure output thereof. Another one is connected to common oil field manifold. Product output is determined by means of flow meters, which measure flows of liquid and gas and installed in each pipeline correspondingly at vertical reservoir outlet from top and bottom thereof. Product is supplied into reservoir through side tangential connection pipe arranged in cylindrical reservoir part at transition part which connects cylindrical and conical reservoir parts. Sensor, which determines presence of liquid droplets in gas flow and throttle valve are located between reservoir and gas flow meter. The sensor operates the throttle valve through controller.

EFFECT: increased accuracy of gas-and-liquid components of product obtained from the well and simplified operation.

2 cl, 11 dwg

Description

The invention relates to flow measuring equipment, mainly to devices for primary accounting of production of wells at oil production facilities.

Well-known metering units [1] for the initial registration of production of wells covering a geographically certain area of an oil field, which, according to a number of technological and other conditions, are combined into separate groups in the infield system for collecting, transporting and preparing oil. Structurally, they consist of a multi-position fluid switch, a separation volumetric vessel with instrumentation (I&C), automation (A) and control elements, contain an industrial microcontroller (or computing unit) communicated by communication lines with I&C elements, as well as a piping system, locking and safety devices (taps, valves, gate valves, etc.).

These units operate in a cyclic mode of filling-emptying a measured separation tank using the energy of a controlled medium (well production), summing up the production volume for a certain specified time (or number of cycles) of measurement for all - in turn, according to the program - for wells in the group.

Common shortcomings of existing devices for this purpose are both the complexity and material, metal consumption of manufacturing, and a fairly wide range of requirements for installation, commissioning, operation and repair in the presence of many mechanical and hydraulic, and electrical components and elements. However, the most significant drawback is precisely the cyclical operation of the flow meters and the inconvenience and errors of its measurement associated with this, due to the presence of a mechanical system of levers for controlling the “filling - emptying” of the measuring tank through the float level gauge, as well as the need for periodic cleaning of the hydraulic cavities of the installation from all kinds of deposits (pollution), which requires a complete shutdown of the latter.

The closest technical solution, that is, the prototype of the proposed device, is a device containing, according to [2], a vertical reservoir with a lateral tangential body of the reservoir with a nozzle for supplying well products to it, with an upper nozzle and a pipeline with a flow meter for venting associated gas, with lower pipe and pipe with a flow meter for draining the liquid, with sensors for state and position parameters (for example, pressure, temperature, phase separation sensors, etc.) and in the cavity of the tank, a controller (the so-called control and calculation unit) with a multichannel, according to the number of sensors, input for introducing electric information signals of these sensors into it and control outputs, as well as (presumably) a multi-position fluid switch with inputs according to the number of connected wells and two exits, one of which is hydraulically connected by a pipeline to the reservoir through the lateral tangential body of the reservoir of the nozzle, the second of the exits of the fluid switch hydraulically, by pipelines, respectively communicated with the upper and lower nozzles of the reservoir and with the prefabricated manifold of the oil field, and the lower part of the reservoir is conically tapering toward the nozzle for draining the fluid.

The device is fully functional, but mainly in measurements of flow rates with low and medium productivity of wells (up to 100 tons per day) with a slight release of dissolved associated gas (note that the intensity of the gas separation process depends on both the initial gas content of the oil and the pressure drop in the reservoir and, of course, from water cut in well production). The process of measuring (or more accurately calculating) the flow rate entirely depends on the efficiency of the tank, equipped with a number of structural elements inside, the position of the products in the tank and the quality of the preparation of the computing base in the controller, and the presence of additional structural elements in the tank significantly complicates the design and increases water loss. It is also worth pointing out that in a measured tank at rest or in a weak flow regime, well production is a rather complex and unstable system of liquids and gas in time along its height, namely (from top to bottom): associated (free) gas - oil and gas foam - anhydrous oil - oil-water emulsion - water-oil emulsion - produced water, and depending on the temperature, on the physicochemical properties of the components of this system and on a number of other factors, the volume they occupy (the thickness of each layer) is absolutely produced flax and complicated for instrument control, and lack of quality control items gas separation increases measurement error output FLOW METER. It follows that the main disadvantages of the known prototype device are insufficient consumer properties with a rather complex and expensive manufacturing, tuning, operation and repair (cleaning) technology, requiring the work of highly qualified personnel.

The purpose of creating the proposed technical solution is to increase the consumer properties of the known design by a more acceptable (for the primary accounting of well production) layout and improvement.

This goal is achieved by the fact that, according to the description of the prototype device, containing a vertical tank with a lateral, tangential housing of the tank pipe for supplying well products to it, with an upper pipe and pipe with a flow meter for discharge of associated gas from it, with a lower pipe and pipe with a flow meter for draining the liquid, with sensors of the parameters of the state and position of the products in the cavity of the tank, a controller with a multi-channel, by the number of sensors, input for introduction into it the electrical information signals of these sensors and control outputs, as well as (presumably) a multi-position fluid (product) switch with inlets by the number of connected wells and two outlets, one of which is hydraulically connected by a pipeline to the reservoir through the side, tangential body of the nozzle reservoir , the second of the fluid switch exits hydraulically, by a pipeline, respectively connected with the upper and lower nozzles of the tank and with the collector of the oil industry slu, gas and liquid flow meters, each installed on a pipeline corresponding to it, and the lower part of the tank made tapered to the drain pipe, a sensor for the presence of liquid in the gas and a throttling valve controlled by this sensor through the controller are installed on the gas outlet pipe and the lateral tangential branch pipe is installed on the tank body at the transition to its lower conical part. Additional distinctive features of the proposed device is that the ratio of the height H _{to the} conical part of the tank to its diameter D is taken from the ratio of H _to /D=1.5 ... 2.0, the height N _{c of the} cylindrical part of the tank is taken equal to its diameter D.

The required technical result is ensured by the presence of the essential features (characterizing the proposed design of the device for measuring oil production rate) of the above distinctive features, and the non-detection of equivalent technical solutions with the same properties in the patent and technical information sources assumes the claimed object meets the criteria of "invention".

In figures 1-2 presents a diagram of the device as a whole, in figures 3-4 shows the preferred shape of the vertical tank, and figure 5 ("a" - "g") shows other possible forms of the same tank.

The device consists of (figure 1) a vertical reservoir 1 with three nozzles: lateral tangential 2 for supplying well products to the reservoir, upper 3 for discharge of released free associated gas, lower 4 for draining the fluid. It also contains a switch 5 wells multi-way (the so-called PSM), which is a multi-position switch fluid. This switch has several inputs according to the number of wells connected to the proposed device and two outputs, one of which is hydraulically connected by a pipe 6 to the tangential side pipe 2, and the other output by a pipe 7 is hydraulically connected respectively to the gas outlet pipe 8 from the tank through the pipe 3 and with the pipeline 9 for draining the liquid from the tank through the pipe 4, while the switch 5 provides through the pipeline 6 the supply to the tank of the product only one of the group (connected to it) Vazhin, and the products of the remaining wells from the group through pipeline 7 are sent to the prefabricated reservoir of the oil field. To ensure the operation of the device in stand-alone (automatic) mode, it contains an industrial controller 10 with a multi-channel (for informational electrical signals of sensors) input and control outputs, one of the last line 11 is connected to the electric drive (a separate position not shown) of the multi-position switch 5 and provides the latter with a standard , according to the program of the controller, sequentially connecting any oil well (from the group) to measure the flow rate. To control and regulate the process of separation of the production of wells into liquid and gas phases in the tank 1, a sensor 12 for the presence of droplet liquid in the gas and an electrically controlled throttling valve 13 are installed on the gas pipeline 8, and the sensor 12 is connected to the input of the controller 10 and the controller is connected to the throttling line 14 valve 13; in addition, directly to measure the productivity (flow rate) of wells in pipelines 8 and 9 of the device, a gas flow meter-counter 15 and a liquid flow meter-16 are installed, respectively. The vertical tank 1 is made cylindrical (as shown in figures 1 and 3) with a diameter D with a tapered tapering lower part of the size (height) N _to , and structurally this size is 1.5 ... 2.0 of the diameter D of the tank, and the size H _{c of the} cylindrical part of the latter is equal to its diameter. The side pipe 2 for tangential to the cavity of the product supply tank is placed (installed) on the cylindrical part of the latter above its transition into a tapered tapering lower part, as shown in figure 1.

This form and the ratio of the size of the tank are the most technologically preferable and established experimentally, however, other forms of its execution are possible (some of them are shown in figure 5, see variations from "a" to "g"); in this case, the basic requirements for the specific design of the tank should be the necessary volume to ensure the calculated kinetic energy of the hydraulic flywheel, which is several orders of magnitude greater than the pulses of hydraulic energy from the well production unevenly entering the tank, and the technologically justified location of the supply and outlet pipes on this tank.

We also note that for greater adaptability of the device to operating conditions, it can be equipped with additional pressure sensors of the same type (the sensors in figure 1 are not shown, but points A, B and C indicate the places of their installation on the pipes 2, 3 and 4 of the tank, and their communication with the controller 10 is indicated by dashed lines). For specific dimensions of the vertical tank and the lateral tangential pipe (knowing the flow rate), it is easy to calculate the linear velocity of the product into the tank and (taking into account the viscosity of the product) the peripheral and angular velocities of the rotating fluid, and according to information from pressure sensors on the pipes 2, 3 and 4 of the tank determine the additional amount of gas emitted (to the free gas already present in the incoming product) in the tank and compare the value obtained by calculation with the readings of the gas flow meter. For information, we note that the initial gas content (the so-called gas factor) of oil under the conditions of occurrence of the reservoir is constant and when the pressure (during the extraction of products to the surface) decreases from the reservoir to the pressure at the inlet to the lateral tangential branch 2 (point A) the reservoir, the amount of free gas is known by the so-called "degassing curve", which is usually performed in the coordinates "pressure - amount of free gas", therefore, it is not difficult to receive second accuracy for practical purposes and to determine the degree of water production, given that the associated gas is practically insoluble in highly mineralized produced water.

The device operates as follows. A geographically integrated group of oil wells is connected to the multi-position switch 5 of the fluid (production), while the controller 10 is initially assigned a control program for the drive of the switch in order of setting a particular well for flow rate measurement. Further, the process of measuring the flow rates of all wells is similar to the existing technology, that is, the products of one of the group of wells through pipeline 6 enter the vertical tank 1 through the side pipe 2. Since this pipe is tangential to the tank body, the production of the well receives rotational movement along the wall in its cavity, moreover, the more intense, the higher the linear flow rate of the product through the pipe 2. After some time, the so-called dynamic equilibrium state of the components s production tank between the inlet (nozzle 2) and its output (branch pipe 3 and the gas conduit 4 for liquid), both meter-counter 15 and 16 begin to show substantially stable values of gas and liquid flow rates respectively. This is due to the fact that the well’s production even under the most adverse plug flow regime in the flow line of the well and at the moment it enters the flow rate measuring device, that is, into the reservoir, enters under a rotating mass of liquid and, due to a very significant difference in densities, is divided into liquid and gas phase. To the above, we note that the sensor 12 for the presence of liquid in the gas works in the device according to the well-known principle, that is, it generates a signal about the mismatch (decrease) in the transparency of the gas with a predetermined standard setting, informing the controller 10 that the entrained gas is carried out through the pipe 8 fine droplet liquid. According to this signal, the controller 10 controls the flow area of the throttle valve 13.

An example of a specific implementation.

Source data (conditionally):

- well flow rate (Q) - 100 m ³ / day, or

- 4.166 (6) m ³ / hour;

- 0,0694 m ³ / min;

- 0.0012 m ³ / s (1.2 liters / sec);

- diameter (D) of the tank - 0.4 m;

- height (H _i) of the cylindrical portion of the vessel is equal to D - 0,4 m;

- the height of the conical part of the tank (N _to ) = 1,5D = 0,6 m;

- the diameter of the channel of the tangential pipe (d _p ) - 0.02 m;

This implies:

- the cross section of the channel of the tangential pipe is 0,0003 m ² ;

- linear flow velocity at the entrance to the tank ≈ 4 m / s;

- the circumference of the cavity of the tank = 1,256 m;

- the speed of rotation of the liquid in the tank is 3.18 sec ^-1 or 191 rpm;

- the total volume of the cavity of the tank - 0,084 m ³ ;

- time for a complete change of fluid in the tank - 70 seconds;

- in 1 hour of monitoring the operation of the well, the volume of production in the tank will change (in transit) - 51.4 times.

This calculation is presented without correction for the viscosity of the product, since in fact the rate of rotation of the liquid in the tank will be slightly lower, but the effect of the "hydraulic flywheel" remains in any case, ensuring a uniform supply of products to the flow meters separately by phases.

As it turned out during the comparative and experimental work, the claimed device, as a combination of essential features (including distinctive ones), provides the required technical result when used, meets the criteria of "invention" in essence of the technical solution when comparing it with a modern (known) device - a prototype, launched into production, and with consumer properties of the latter, in connection with which it is proposed to be protected by the corresponding title of protection (patent) of the Russian Federation.

SOURCES OF INFORMATION

1. Oilfield equipment. Directory. M .: Nedra, 1990, p. 424-411.

2. RU 2191262 C1, IPC ⁷ E 21 B 47/10, priority 10/15/2001, prototype.

Claims (2)

1. A device for measuring the flow rate of oil wells, containing a vertical tank with a lateral tangential body of the tank pipe for supplying well products to it, with an upper pipe for removal of associated gas from it and a lower pipe for draining the fluid, with sensors of parameters of the state and position of production in the cavity reservoir, a controller with an input multi-channel for the number of sensors for introducing electrical information signals of these sensors and control outputs into it, as well as a multi-position switch a fluid (product) switch with inlets according to the number of connected wells and two exits, one of which is connected hydraulically by a pipeline to the reservoir by means of the lateral branch pipe of the latter, the second of the fluid switch outlets is hydraulically connected by a pipeline to the upper and lower reservoir nozzles and to the prefabricated oil reservoir , a gas flow meter and a liquid flow meter, each installed on its corresponding pipeline, the lower part of the tank is made tapered tapering to the drainage pipe, characterized in that the tangential to the reservoir side pipe for supplying products is installed on the tank body at its transition to the lower part of the conical shape, and between the tank and the gas flow meter, the sensor has a liquid in the gas and controlled by this sensor through the controller throttle valve. 2. A device for measuring the flow rate of oil wells according to claim 1, characterized in that the ratio of the height H _{to the} lower conical part of the tank to its diameter D in the upper cylindrical part is taken from the ratio N _to / D = 1.5-2.0, and the height N _{c of the} cylindrical upper part of the tank is taken equal to its diameter D.

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