RU2267595C1 - Method for drilling mud cleaning of particulate mechanical impurities in suction tube of mud pump - Google Patents

Abstract

FIELD: oil production industry, particularly drilling mud cleaning during oil and gas well drilling.

SUBSTANCE: method for drilling mud cleaning in suction tube provided with pump and mud pit involves installing composite acoustic noise transducer made of quarter-wave resonators in suction tube of mud pump; converting low-frequency noise generated by mud pump in ultrasound; forming ultrasonic standing waves in suction tube over length equal to composite acoustic noise transducer length; applying standing ultrasound wave action in suction pipe on mechanical impurity coagulation and precipitating thereof in mud pit.

EFFECT: increased cleaning efficiency.

5 dwg, 1 ex

Description

The invention relates to the oil industry, in particular to a method for cleaning drilling fluid from cuttings.

Known methods for cleaning drilling fluid. For example, two types of equipment are used to clean drilling fluids from drill cuttings: equipment for mechanical cleaning and equipment for separating the fractions of the solid phase of solutions in terms of size and specific gravity using centrifugal forces.

Mechanical cleaning is carried out using sieves, ensures the removal of particles from the solution, the size of which is determined by the size of the sieve cells. However, with very small cell sizes, a viscous liquid cannot penetrate through them. Under the action of centrifugal forces, practically particles of any size can be removed from the liquid. Therefore, such a cleaning can be called thin, in contrast to a rough mechanical cleaning [1].

The disadvantage of these methods is the placement of complex technical devices in the production line.

The closest way to the technical essence of cleaning the drilling fluid from particles of mechanical impurities (fractions of the solid phase of solutions) can be attributed to the well-known phenomenon - acoustic coagulation in the fluid - if this phenomenon is applied to drilling technology, in particular for cleaning the drilling fluid from mechanical particles (solid fractions phase of solutions) on the suction pipe of the mud pump [2].

In this case, additional cleaning of the drilling fluid (fractions of the solid phase of the solutions) will be made, but from the barn tank.

The disadvantage of this method (in the case of using modern methods of exciting ultrasound in pipes) is the difficulty of using ultrasonic vibrations, for example, when using the magnetostrictive method (or other methods) - you need electricity, cable, and an ultrasonic frequency generator.

The objective of the invention is to ensure the cleaning of the drilling fluid (fractions of the solid phase of the solutions) from the barn in the suction pipe of the mud pump.

The technical result - the cleaning of the drilling fluid (fractions of the solid phase of the solutions) from the barn tank - is achieved by the fact that the method of cleaning the drilling mud from particles of mechanical impurities in a suction pipe equipped with a pump and a barn tank, providing for the following operations: a) installation of a composite acoustic transducer from quarter-wave resonators coaxially with the suction pipe of the mud pump; b) - the conversion of low-frequency noise of the mud pump into ultrasound; c) - the formation in the suction pipe at a length equal to the length of the composite acoustic noise converter from quarter-wave resonators of ultrasonic standing waves; d) - the creation of the action of standing waves of ultrasound in the suction pipe on the process of coagulation of particles of mechanical impurities, followed by their deposition in a barn tank.

Comparative analysis with the prototype shows that in the claimed method of cleaning drilling mud (fractions of the solid phase of the solutions) from the barn tank, ultrasonic vibrations are used that are converted from the low-frequency noise of the mud pump. The emitter of ultrasonic vibrations is a composite acoustic noise converter from quarter-wave resonators, which is placed coaxially with the suction pipe of the mud pump.

Thus, the present invention meets the criterion of "Novelty."

Comparison of the claimed solution with other technical solutions shows that acoustic coagulation of solid particles in a liquid is known [2]. However, it is not known that ultrasound can be created using a composite acoustic noise converter from quarter-wave resonators when the mud pump operates in ultrasound, with the creation of standing waves, coagulation of particles of mechanical impurities and their deposition in a barn tank.

Thus, the present invention meets the criterion of "Inventive step".

The main provisions of the physical nature of the method for cleaning the drilling fluid in the suction pipe of the mud pump from particles of mechanical impurities.

1. The presence of constant low-frequency noise in the suction pipe of the mud pump.

2. The source of low-frequency noise is the operation of the mud pump.

3. Converting the low-frequency noise of the mud pump in the suction pipe to ultrasound.

4. The conversion of low-frequency noise in the suction pipe is carried out by a composite acoustic noise converter from quarter-wave resonators.

5. The formation of ultrasonic standing waves in the suction pipe of the mud pump at a length equal to the length of the composite acoustic noise transducer from quarter-wave resonators integrated coaxially to the suction pipe.

6. Using the phenomenon of the physical process of acoustic coagulation of particles of mechanical impurities (fractions of the solid phase of solutions) by a standing wave, followed by the deposition of particles in a barn tank.

We show the possibility of using acoustic coagulation in a mechanical impurity fluid by ultrasonic standing waves in the suction pipe of a mud pump.

1. Waves and vibrational velocity.

The wave equation describing the elastic perturbation has the form / 2 /.

A particular solution to equation (1) is

where a is the displacement of a particle of the medium relative to the resting position; A is the bias amplitude; Ω - = angular frequency; t is time.

Expression (2) describes a plane harmonic wave of frequency f = ω / 2π propagating in the positive direction of the x axis.

Differentiating (2) with respect to t, we obtain for the particle velocity of the medium - the so-called vibrational velocity

Therefore, the amplitude of the vibrational velocity

The value of U determines the maximum speed with which particles move in the process of oscillation.

According to expression (4), the particle velocity fluctuates between this quantity and zero.

2. The interference of waves. Standing waves.

Phenomena associated with the simultaneous existence of several oscillations at some point in the medium are called interference.

Interference phenomena play an important role in the emission of sound.

A particularly important role is played by interference in the propagation of two identical waves in opposite directions. Oscillations propagating in the positive and negative directions along the x axis can be written as

Applying the addition theorem, we obtain for the resulting standing wave the expression

from which it directly follows that at the points Cos (2πx / λ) vanishes, the displacement a is identically equal to zero; this occurs when x is an odd number λ / 4. In the middle between these points are the points at which Cos (2πх / λ) is maximal in absolute value; here, the amplitude of the displacement in the standing wave is twice the amplitude in the initial traveling waves.

We find the expression for the vibrational velocity in a standing wave, differentiating the expression

Thus, the nodes and antinodes of the vibrational velocity are located at the same points as the nodes and antinodes of the bias.

3. Pressure in a standing wave.

We now turn to the question of the distribution of pressure in a standing wave. In a wave propagating in the direction of the x-axis forces, the pressure p is proportional to the change in displacement along x, i.e. d a / dx. Differentiating expression (7) with respect to x, we obtain

Thus, in a standing wave and sound pressure contains nodes and antinodes; however, the location of the pressure nodes coincides with the position of the displacement antinodes and vice versa. The pressure amplitude in the antinodes is twice the amplitude in the initial traveling waves [2].

4. Acoustic coagulation.

It has long been known that under the influence of sound vibrations between particles oscillating in a sound field, attractive and repulsive forces can arise. For spherical particles, this process was experimentally and theoretically investigated by Koenig [3] in connection with the work of Bjerkness [4]. Particularly, the occurrence of dust figures in Kundt tubes is based on this phenomenon.

Brandt and Freund [5] and Brand and Gideman [6] showed that under the action of ultrasonic waves in aerosols, coagulation and sedimentation of particles instantly occur.

Brandt and Freund studied the details of the process of settling particles by microphotography under illumination using the dark field method.

Based on these experiments, Brandt and Gideman distinguish two stages of coagulation. At the beginning, the particles take part in the oscillatory process and follow the motion of the fluid between the antinodes and the vibration nodes. Moreover, as a result of collisions and under the action of forces of mutual attraction, they stick together and increase in size. In the second stage, the increased particles no longer follow sound vibrations, but make random motions, and as a result of new mutual collisions and collisions with smaller particles, their sizes continue to increase, and then precipitate.

5. Coagulation of particles of a mechanical impurity in a standing wave.

Let an impurity particle with a radius R and a density ρ be located in a fluid with a dynamic viscosity η oscillating with an amplitude U _W and a frequency f.

According to Stokes’s law [2], the friction force acting on a particle

where Av is the velocity difference between particles of a mechanical impurity and a liquid.

According to formula (10), the velocity of liquid particles

The motion of a particle of a mechanical impurity is described by the differential equation

or

The general solution to this equation has the form [2]

The non-periodic term represents the transient. It can be neglected, since coagulation occurs after a time when the transition process no longer has any effect.

Thus, the vibration amplitude of a particle of a mechanical impurity is equal to

The degree of particle participation in the sound vibrations of the medium (the so-called drag coefficient) in the case of a standing sound wave is determined by the relation

The ratio of the amplitudes X _mp / U _w will be the smaller, the larger the radius of the particle and the higher the frequency.

Thus, for the degree of participation of a particle of a mechanical impurity in fluid oscillations, the value R ² f is decisive.

If we take the value of X _MP / U _W = 0.8 beyond the boundary to which particles of mechanical impurity are still carried away by sound vibrations, then from the relation

we get

The value of Z determines the degree of participation of particles of mechanical impurity in the oscillations of the liquid.

Thus, relation (18) allows one to calculate the frequencies necessary to create standing waves in order to coagulate particles of a mechanical impurity in front of the pump and then precipitate them.

According to the above provisions of the physical essence, acoustic coagulation of particles of a mechanical impurity is achieved.

Figure 1 shows the technological layout of a composite acoustic noise converter of quarter-wave resonators on the suction pipe of a mud pump lowered into a barn tank; figure 2 shows the location of ultrasonic standing waves (for example, a composite acoustic noise Converter, consisting of three quarter-wave resonators) in the suction pipe of the mud pump; figure 3 shows the distribution of pressure in an ultrasonic standing wave and the movement of particles of mechanical impurities from the antinode to the node; figure 4 shows the distribution of the vibrational velocity in an ultrasonic standing wave and the beginning of coagulation of particles of mechanical impurity in the antinode of the vibrational velocity; figure 5 shows the deposition of particles of mechanical impurities from antinodes of vibrational velocity in a barn tank after the process of acoustic coagulation.

Figure 1 shows: 1 - a mud pump, 2 - a suction pipe of a mud pump, 3 - a composite acoustic noise converter from quarter-wave resonators coaxially integrated on a suction pipe of a mud pump, 4 - a barn container into which particles of solids are deposited after acoustic coagulation 5 - drilling fluid.

Figure 2 shows: 2 - the suction pipe of the mud pump, 3 composite acoustic noise converter from quarter-wave resonators coaxially integrated into the suction pipe of the mud pump, 5 - drilling fluid, 6 - distribution of vibrational velocity in a standing wave in the suction pipe 2, 7 - pressure distribution in the wave in the suction pipe 2.

Figure 3 shows: 2 - the suction pipe of the mud pump, 5 - mud, 8 - particles of mechanical impurities in the mud 5, 9 - pressure unit in a standing wave, 10 - antinode pressure in a standing wave, 11 - particle movement 8 mechanical impurities in the drilling fluid to the pressure node of the standing wave.

Figure 4 shows: 2 - the suction pipe of the mud pump, 5 - mud, 8 - particles of mechanical impurity in the initial stage of acoustic coagulation in the antinode of vibrational velocity in a standing wave, 12 - antinode of vibrational velocity in a standing wave, 13 - node vibrational velocity in a standing wave.

Figure 5 shows: 2 - the suction pipe of the mud pump, 5 - mud, 14 - particles of mechanical impurities after the process of acoustic coagulation, 15 - deposition of particles of mechanical impurities in a barn tank.

An example implementation of the method.

First operation. A composite acoustic noise converter of quarter-wave resonators 3 [7] (FIG. 1) is aligned coaxially with the suction pipe 2 (FIG. 1).

The second operation. The composite acoustic noise transducer is lowered from the quarter-wave resonators 3 (Fig. 1) together with the suction pipe 2 (Fig. 1) into the barn tank 4 (Fig. 1) with drilling mud 5 (Fig. 1).

The third operation. Turn on the mud pump 1 (figure 1).

The fourth operation. A low-frequency noise spectrum is created in the suction pipe 2 (FIG. 2) with the mud pump 1 turned on (FIG. 1).

Fifth operation. Create a composite acoustic noise converter from the quarter-wave resonators 3 (figure 2) ultrasonic waves in the suction pipe 2 (figure 2) from the low-frequency noise of the operation of the mud pump 1 (figure 1).

Sixth operation. Standing waves 6 and 7 (FIG. 2) are created from ultrasound along a length of a portion equal to the length of a composite acoustic noise transducer from quarter-wave resonators 3 (FIG. 2).

Seventh operation. Acoustic coagulation is performed (at the first stage) in ultrasonic standing waves 6 and 7 (Fig. 2) by moving 11 (Fig. 3) particles of mechanical impurity 8 (Fig. 3) from the antinode of pressure 10 (Fig. 3) to node 9 ( figure 3) pressure waves generated in the suction pipe 2 (figure 3) of the mud pump 1 (figure 1).

The eighth operation. Acoustic coagulation (the second stage) is continued at the antinode 12 (Fig. 4) of the vibrational velocity of the standing wave by further convergence of the particles 8 (Fig. 4) of the mechanical impurity and their enlargement.

Tenth operation. Deposition 15 (FIG. 5) of coagulated particles 14 (FIG. 5) of a mechanical impurity from antinodes 12 (FIG. 4) of the vibrational velocity of a standing wave under its own weight into a barn container 4 (FIG. 1) is deposited.

Field tests carried out at the Tarasovskoye field of the Purpeyskoye UBR of Purneftegaz on 1 bush, at wells No. 1, 2, 4 and 66 with composite acoustic noise transducers from quarter-wave resonators showed the efficiency of the proposed method for cleaning drilling mud from particles of mechanical impurities.

The source of information

1. Handbook of a drilling engineer. T.1./ Mishchevich V.I., Sidorov N.A. - M .: Nedra, 1973. - S.369-374].

2. Bergman L. Ultrasound and its application in science and technology. IL - M .: IL, 1957. - S.23-25, 489-491, 495-497. [PROTOTYPE].

3. König W., Hydrodynamisch-akustische Untersuchungen, Ann. d. Phys. (3), 42.353, 549 (1891).

4. Bjerknes C.A. Remarques historiques sur la theori du mouvement d'un ou de plusieurs corps, de formes constantes ou variables, dans un fluide incompfessible; sur les forces apparentes, qui en resultent et sur les experiences qui s'y rattachent, Compt. Rent., 84, 1222, 1309, 1375, 1446, 1493 (1867).

5. Brandt., Über das Verhalten von Schwebstofen in schwingen Gasen bei Schall- und Ultraschallfrequenzen, Kolloid / Zs., 76, 272 (1936).

6. Brandt O., Hiedenmann E., Über das Verhalten von Aerosolen im akustischen Feld, Kolloid. Zs., 75, 129 (1936).

7. The fight against noise in production: Handbook, / E.Ya. Yudin, L. A. Borisov, I. V. Gorenshtein and others; Under the total. ed. E.Ya. Yudina - M .: Mechanical Engineering, 1985. P.305-307.

Claims (1)

A method for cleaning drilling fluid from particles of mechanical impurities in a suction pipe equipped with a pump and a barn tank, which includes the following operations: a) installing a composite acoustic noise converter from quarter-wave resonators on the suction pipe of the mud pump; b) the conversion of the low-frequency noise of the mud pump into ultrasound; c) the formation in the suction pipe at a length equal to the length of the composite acoustic noise transducer from quarter-wave resonators, ultrasonic standing waves; e) the effect of standing waves of ultrasound in the suction pipe on the process of coagulation of particles of mechanical impurity, followed by their deposition in a barn tank.

Images