Viscosity reduction and acoustic treatment

Known physical effects often require practical confirmation so that psychologically we can accept them. The same applies to the effect of acoustic effects on the change in viscosity of liquids. In the course of laboratory studies, we obtained a decrease in the viscosity of oil emulsion (oil + formation water) due to the destruction of its rheological structure and homogenisation.

Laboratory investigations were carried out in three phases, evaluation:

• of the original viscosity;
• influence of acoustic treatment on the load of an oil emulsion pump before and after treatment;
• reduction of oil emulsion viscosity after acoustic treatment and time of initial viscosity recovery.

A glass vessel with a 4 mm outlet opening was used for viscosity estimation. The volume of samples to be taken is 100 ml. The oil emulsion flow time was estimated based on the flow rate of 75 ml sample. All samples were kept in a room with a temperature of 22 C. When the sample was heated during acoustic treatment, it was cooled down to 22 C, after which the viscosity was measured.

The test bench is represented by an ultrasonic reactor (rod radiator with a magnetostrictor in a cylindrical vessel) and a UZG-5 generator. The coolant circulation is provided by a circulation pump.

1 STEP. Measurement of the flow rate of the initial oil emulsion sample from the viscometer. The temperature of the emulsion is 22 C.

Sample	Measurement	Volume, ml	Temperature, C	Expiration time, sec
original emulsion	1	75	22	92
	2	75	22	94
	3	75	22	92
	4	75	22	98

The viscosity of the initial oil emulsion sample was estimated. The average flow rate was 94 seconds at the initial sample temperature of 22C (absolute error +/-2 seconds, relative error 2%).

2 STEP. Circulation pump load evaluation tests at initial viscosity and after ultrasonic treatment.

The aim is to evaluate the load on the circulation pump at initial viscosity and after acoustic treatment while maintaining the temperature of the treated sample.

The temperature of the original and treated samples is 22C. The sample volume for acoustic treatment is 800 ml.

Measurement of the pump load while circulating the original sample.

Measurement	U, В	J, А	Temp, C	Power, W
1	24	2,76	22	66
2	24	2,8	22	67
3	24	2,87	22	69
4	24	2,84	22	68

Average value of current J=2.817 A, power 68 W. Absolute error +/- 0.0375 A, relative error 1.3%.

Measurement of pump load while circulating the ultrasonically treated sample for 60 seconds.

Measurement	U, В	J, А	Temp, C	Power, W
1	24	1,7	22	41
2	24	1,73	22	42
3	24	1,76	22	42
4	24	1,8	22	43

Average current J=1.747A, power 42W. Absolute error +/- 0.0325 A, relative error 1.2%.

The effect on the load of an oil emulsion pump was found, with acoustic treatment for 60 seconds reducing the load by 38%.

3 STEP. Conducting tests to evaluate viscosity as a function of acoustic exposure while maintaining a constant temperature. Estimation of viscosity recovery time.

The aim is to establish the dependence of oil emulsion viscosity change on acoustic impact and to estimate the time of viscosity recovery (relaxation).

The temperature of the original and treated samples is 22C. The sample volume for acoustic treatment is 800 ml.

Measurement of the viscosity (flow time) of the oil emulsion after 60 seconds of acoustic treatment.

Time after RCD, hour	0	1	2	3	4	5
Initial viscosity at T=22C	94	94	94	94	94	94

Acoustic treatment 60 seconds, T=22C

Measurement 1. Expiration time, sec	65	69		75	84	97
Measurement 2. Expiration time, sec	67	71	64	73	82	93
Measurement 3. Expiration time, sec			70
Average value, sec	66	70	67	74	83	95

Absolute error +/- 2 sec, relative error 2%.

Acoustic treatment 300 seconds, T=22C

Measurement 1. Expiration time, sec	62	65	65	93	93
Measurement 2. Expiration time, sec	68	64	64	91	91
Measurement 3. Expiration time, sec		68	68
Average value, sec	65	66	66	92	92

Absolute error +/- 2 seconds, relative error 3%.

The 3 stage tests found a 30% reduction in viscosity after treatment for 60 and 300 seconds. The decrease in viscosity is purely due to acoustic effects, as all measurements were made at the same temperature. Viscosity recovery begins after 2 hours of settling, with the longer acoustic treatment not producing a greater reduction in viscosity and showing a faster recovery to the initial state. Also in the course of the experiment it was found out that the stability of the emulsion is maintained for about 10-12 hours.

Key Findings:

1. During the tests, the effect of heating the oil emulsion by acoustic influence was excluded. Energy losses for heating will give an additional effect due to heat transfer to the oil emulsion.
2. After treatment, a stable emulsion was obtained with the condition maintained up to 10-12 hours, with viscosity lower by 30% with recovery within 5 hours.
3. A 38% load reduction on the transfer pump was obtained, the effect was achieved without heating the oil emulsion.
4. When processing oil emulsion in weak acoustic obtained a faster separation of water and oil.
5. A transmitter with an acoustic power of 1kW was used There are more powerful loudspeakers that can be used in industrial settings.
6. Additional tests with acoustic treatment with exposure times of less than 1 minute, at higher frequencies and with more powerful acoustic radiators should be carried out.