CN111397671A

CN111397671A - Open type liquid flowmeter for unsteady multiphase flow

Info

Publication number: CN111397671A
Application number: CN202010276601.0A
Authority: CN
Inventors: 杜宏宇
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-04-09
Filing date: 2020-04-09
Publication date: 2020-07-10

Abstract

The invention relates to liquid flow metering electronic equipment under a special fluid state condition, which is mainly used for on-site real-time metering of shale gas and coal bed gas fracturing flowback fluid in oil and gas industry. The shale gas and coal bed gas fracturing fluid flowback has the characteristics of possibility of containing impurities or carrying gas, wide and unstable flow range, non-full flowing state of a pipeline in low flow and the like, and an open type liquid flowmeter is designed by utilizing a hydraulic impact principle aiming at the characteristics so as to adapt to the requirement of the fracturing fluid flowback measurement. The structure of the flowmeter device designed by the invention is shown in the attached drawings; the principle is that the hydraulic impact force of the liquid of the backflow liquid at the outlet of the diversion pipeline is measured; the technical key points are that hydraulic impact force is ensured to be vertically downward through a steering pipeline, a measuring table provided with a pressure sensor is adopted for real-time measurement, the sampling frequency and the uniform algorithm of the sensor are required to be properly set, and the signal response curve is accurately corrected.

Description

Open type liquid flowmeter for unsteady multiphase flow

Technical Field

The invention relates to liquid flow metering electronic equipment under a special fluid state condition, which is mainly used for on-site real-time metering and data acquisition and transmission of shale gas and coal bed gas fracturing flowback fluid in oil and gas industry.

Background

Shale gas and coal bed gas fracturing fluid flowback characteristics include that ① may contain impurities such as sand grains and coal dust, gas carrying (gas-liquid two-phase flow) is possible when gas-water separation is insufficient, ② flow fluctuation is large and unstable, the flow is in a pipeline non-full flow state when the flow is low, ③ flow range is wide, the flowback initial stage flow is very large and can reach 20-30 m³In the interval of/hr, the flow rate at the later stage is very small, 0.01-0.1 m³The/hr interval.

At present, four methods are commonly used for measuring the liquid flow on site: volumetric flow meter, turbine flow meter, volumetric method and bucket test.

Volumetric water meters-volumetric water meters are the same type as household water meters, but small amounts of solid particles (such as coal dust, sand or fracturing gel) in the fluid tend to clog the meter, resulting in measurement misalignment; in addition, the water meter is not suitable for liquid metering under the condition of gas-liquid two-phase flow.

Turbine flowmeters, often mounted at the pump outlet, are also used in reservoirs or water treatment facilities where the readings are more accurate than volumetric flowmeters. The instrument consists of a turbine flow transmitter, a preamplifier and a display instrument, wherein fluid pushes a turbine rotor to rotate when passing through the turbine flow transmitter, and the rotating speed of the turbine rotor is in certain proportion to the liquid flow, so that the liquid flow can be calculated. The instrument is also not suitable for fluid states containing impurities, gas-liquid two-phase flow, low flow and the like.

Volumetric-method, in which liquid flow data is obtained by measuring the increase in volume of liquid (increase in cross-sectional area ×) in a pool or tank of water containing the liquid, is crude, inefficient, unsuitable for low flow measurements and environmentally sensitive (e.g., precipitation, evaporation).

Bucket test, namely, a graduated container or bucket is used for testing, the time required for the produced water to fill a bucket with a certain volume is measured, and then the measured time is converted into a stage flow, and the method has rough results and low efficiency; an automation device is also designed according to the principle, but the volume is larger (a liquid storage tank and a buffer tank) and the manufacturing cost is higher.

Therefore, the invention designs the open type liquid flowmeter by utilizing the hydraulic impact principle to adapt to the flowback metering requirement of the shale gas and coal bed gas fracturing fluid.

Disclosure of Invention

The flowmeter device is structurally shown in figure 1.

The principle is as follows: the 'hydraulic impact force' of the liquid at the vertical downward outlet of the diversion pipeline of the return liquid is measured.

The key technology is as follows: the steering pipeline (the outlet is vertically downward) and the hanger (the screen opening structure) are firmly and stably installed; the sampling frequency and the uniform algorithm of a measuring table (the 'electronic scale' principle) provided with the pressure sensor are properly set, and the signal response curve is accurately corrected; environmental conditions affect abatement.

Measuring range: can be divided into two stages, 0.01-2.0 m³A volume of 0.50 to 50 m/hr (about 3 to 600ml/s)³A/hr (about 0.15 to 1501/s).

Error: 0.01 to 2.0m³The/hr grade is not more than 5%, 0.50-50 m³The/hr rating is not more than 2%.

The advantages are that: the influence of impurities such as sand grains, coal dust and the like on measurement and equipment is small, the influence of small amount of gas mixture on the measurement is small, and an exhaust tee joint can be additionally arranged when necessary; the device can continuously and automatically measure, and can realize remote data transmission by additionally arranging a wireless communication module.

And others: the working environment temperature is-5 to 50 ℃; the data storage space can continuously record for more than 30 days, and can provide battery endurance for more than 30 days without an external power supply; the service life is 3-5 ten thousand hours.

Drawings

FIG. 1 is a schematic view of a flowmeter apparatus

① turning pipeline ② hanger ③ measuring desk ④ exhaust tee

FIG. 2 flow meter field installation schematic

① Cement pier ② fixing bolt

FIG. 3 is a schematic view of the structure of the measuring table

① conical disc ② pressure sensor and A/D conversion module ③ data acquisition, calculation, storage and communication module

Detailed Description

1. A diversion pipeline is additionally arranged at the outlet of the fluid pipeline firstly to ensure that the outlet is vertical downwards (the liquid impact is consistent with the gravity direction); it should be noted that when the flow rate is large, the steering pipeline is subjected to large hydraulic impact force, and can be fixed by adopting a proper mode (such as cement pier and bolt fixation) when necessary.

2. If the pipe flow contains gas obviously, an upward exhaust port (tee joint) can be additionally arranged; it is necessary to pay attention to the height of the exhaust pipeline to avoid liquid overflowing from the exhaust port, and if the liquid amount of the gas is large, a primary gas-liquid separator can be added before the diversion pipeline (out of the scope of the invention).

3. A hanger and a measuring table are fixedly arranged outside the outlet of the steering pipeline (hydraulic impact force is large when the flow is large, and a cement pier can be erected to support the measuring table); the hanger adopts a 15-degree outward-inclined bell-mouth-shaped stainless steel support and loose filter screen combined structure (the whole height is 30-50 cm, the height of the filter screen is 20-30 cm, gas discharge is facilitated, and gas impact force is not added to the measuring table), and the bottom of the hanger is connected with the measuring table to receive and measure hydraulic impact force.

4. The measuring table adopts the principle of an electronic scale, has a core structure of a 5-degree conical surface disc and a pressure sensor, and provides digital display (a display panel is required to be arranged on a hanger and connected with the measuring table through a lead) and a data output interface for measuring real-time flow and accumulated flow results; the conical disks facilitate rapid liquid spillage and moderate impact force reduction.

5. According to an indoor experiment, investigating the discrete and stable condition of a sensor signal, and reasonably setting the acquisition frequency (2-5 times/second) of the sensor signal and the average calculation of stage (1-5 seconds) data; and calculating a response correction curve according to response results of a plurality of flow points (5-8). The work content belongs to measurement and correction work, and the data input and the calculation program are all solidified in the measuring table and are corrected before being provided for field use.

6. The field measurement can be additionally provided with a wireless data communication module and a corresponding data communication program to realize remote automatic data acquisition (out of the scope of the invention).

Claims

1. An open-type liquid flowmeter suitable for unsteady and multiphase flow state features that the liquid flow is indirectly calculated by directly measuring the vertical downward hydraulic impact force of liquid.

2. The fluid flowmeter of claim 1, wherein said measurement of said "hydraulic impact force" is performed using a pressure sensor.