PL238514B1 - Method and measurement system of mass flow in drilling fluid and other two-phase systems - Google Patents

Abstract

A method of measuring mass flow in drilling mud and other two-phase systems containing a sensor, measurement transducers, and an analyzer, consisting in measuring in two sets of electrodes (4) and (5), using two measurement transducers (6) and (7), is the capacity analyzed in the analyzer (8), and then, after taking into account the density of the liquid (1) and gas (2), the distance (10) and the cross-sectional area of the body (9), the mass flow of the two-phase system is calculated. The mass flow measurement system in drilling mud and other two-phase systems, including a sensor, measurement transducers and an analyzer, is built in the form of two sets of electrodes (4) and (5) used to measure capacitance placed on the outer surface of the sensor body (9) or inside the body. sensor (9) at a distance (10), and inside the sensor body (9) in the direction (3) a liquid (1) flows, which together with gas bubbles (2) creates a two-phase system, with sets of electrodes (4) and (5 ) are connected to the analyzer (8) using measuring transducers (6) and (7).

Description

Description of the invention

The subject of the invention is a mass measurement system in drilling mud and other two-phase systems.

There is a known solution of flow meters with a variable cross-section, popularly known as rotameters. They measure the flow of gas flowing into the free space. The result of the measurement is read from the scale, determining the position of the float lifted by the flowing fluid. This result is related to standardized temperature and atmospheric pressure. In order to determine the gas mass flow rate, it is necessary to take into account the temperature and barometric pressure during the measurement. Moreover, it is difficult to digitize the result. Rotameters with a measuring range meeting the criterion of "low gas flow" are expensive and rare.

Flow meters based on the Coriolis acceleration effect to produce a force proportional to the mass flow rate are also known. These flowmeters generally induce pulsating elastic strains proportional to the Coriolis force caused by the fluid flow which are then measured by strain gauges, capacitive or inductive sensors. However, they are mainly intended for mass flow measurements of liquids and do not meet the above-mentioned criterion for measuring "low gas flow".

There are also known manometric (pressure) flow meters based on the measurement of the pressure drop on the weiring element. Usually, orifices, nozzles, etc. are used as damming elements. The disadvantage of most known solutions of manometric flow meters is their non-linear characteristics. Moreover, in order to determine the gas mass flow rate, the gas temperature and pressure should be taken into account in addition to the pressure drop across the damming element. The result is the inconvenience of having to perform calculations that take into account the results of partial measurements and the temperature dependence of the flowmeter characteristics. The complexity of the calculations increases with the requirements for the accuracy of the final measurement result.

From the Polish patent specification PL 168889 B1 there is known an oscillometric mass flow meter with direct Coriolis force measurement, comprising at least one tube with a fluid channel connected to a vibration excitation system and rigidly fixed in the yoke. This yoke is a balance beam mounted preferably elastically in relation to the stationary rigid base body at the point of rotation of the balance sheet located in the axis of symmetry of the entire mechanical system. One side of the force sensor is attached to the yoke and the other side of the sensor is attached to the stationary body of the base.

On the other hand, from the Polish patent specification PL 215527 B1 there is known a capillary mass flow meter shown in Fig. 1, especially for small gas flows, based on the measurement of the pressure drop on the capillary damming element.

Moreover, from the Polish patent specification PL 198147 B1 there is known an apparatus comprising a mass flow meter arranged in the flow path of a substance stream for generating first signals to measure the mass flow velocity of a substance stream, the mass flow meter being a Coriolis mass flow meter and comprising a densimeter. Preferably, the interpreter / controller comprises a circuitry for receiving the first signals from the Coriolis flow meter and for determining a representative flow density of the substance based on these signals. Preferably, the interpreter / controller comprises circuitry for determining the enthalpy of substance flow based on the densimeter signal.

The essence of the invention is the mass flow measurement system in drilling mud and other two-phase systems, containing a sensor, measuring transducers, an analyzer, which is constructed in the form of two sets of electrodes for measuring capacitance located on the outer surface of the sensor body, or inside the sensor body at a distance, and inside a liquid flows in the direction of the sensor body, which together with the gas bubbles form a two-phase system, where the electrode assemblies are connected to the analyzer by means of measuring transducers.

The measuring transducer system is built on the basis of a capacitive-digital converter system.

The advantage of the method of the invention is that it is cheap to implement, does not interfere with the flow of the two-phase system in any way, and has an accuracy sufficient for industrial applications.

The advantage of the system according to the invention is that it is simple in structure, cheap and reliable in operation, and resistant to external disturbances.

PL 238 514 B1

The subject of the invention is shown in the drawing in the form of a block diagram of a system for measuring mass flow in two-phase systems.

The invention is illustrated by the following non-limiting embodiment.

The mass flow meter shown in Fig. 1 is constructed in the form of two sets of electrodes (4) and (5) placed on the outer surface of the sensor body (9) at a distance (10). Inside the sensor body (9), a liquid (1) flows in the direction (3), which together with gas bubbles (2) form a two-phase system. In the first set of electrodes (4), the capacitance is measured by means of the first transducer (6), which changes with the change of the percentage of liquid (1) and gas (2) in a two-phase system.

Similarly, in the second set of electrodes (5) placed at a strictly defined distance (10) in the direction of the liquid flow (3), by means of the second measuring transducer (7), the capacity is also measured, changing with the change of the percentage of liquid (1) and gas content. (2) in a two-phase system. The results of capacitance measurements from the measuring transducers (6) and (7) are recorded and analyzed in the analyzer (8). As a result of operations carried out on an ongoing basis in the analyzer (8), we obtain two time courses of capacitance from the electrode systems (4) and (5), which are subject to correlation, thanks to which we obtain the time in which the two-phase system needs to travel the distance (10) between electrode assemblies (4) and (5). This allows for the calculation of the flow velocity of the two-phase system, and after taking into account the cross-sectional area of the sensor body (9), for the calculation of the volumetric flow of the two-phase system. Since the measurement of capacitance in the electrode systems (4) and (5) at the same time shows the percentage of the phases, we can use this to calculate the volumetric flow of each of the phases. The independently performed density measurement of each of the phases allows the calculation of the mass flow of both the two-phase system and the mass flow of liquid (1) and gas (2) through the sensor body (9).

Designation index

- flowing liquid

- gas bubbles contained in the liquid

- the direction of movement of the fluid

- the first set of measuring electrodes

- the second set of measuring electrodes

- the first measuring transducer

- second measuring transducer

- analyzer

- sensor body

- the distance between the electrode assemblies

Claims (2)

Patent claims 1. Mass flow measurement system in drilling mud and other two-phase systems, including a sensor, measuring transducers, and analyzer, characterized by the fact that it is constructed in the form of two sets of electrodes (4) and (5) for measuring the capacitance located on the outer surface of the sensor body ( 9), or inside the sensor body (9) at a distance (10), and inside the sensor body (9) in the direction (3) a liquid (1) flows, which together with gas bubbles (2) form a two-phase system, the electrode assemblies (4) and (5) are connected to the analyzer (8) by means of measuring transducers (6) and (7). The system according to claim 2, characterized in that the measuring transducer system is built on the basis of a capacitive-digital converter system.