Ultra-sonic Water Well CleaningRegenering af boringer med highpower ultralyd

VandCenter SydMads Clausen Institute, SDU

Funded by Vandsektorens Teknologiudviklingsfond (Project: 7300)

Robert Brehm, Mads Clausen Instituttet, Syddansk UniversitetPeer Locher, VandCenter Syd

Ultra-sonic Water Well CleaningRegenering af boringer med highpower ultralyd

1. Project Introduction

2. Involved Technology and Equipment

3. Experimental Setups, Models and Results

4. Improvements

5. Current Progress and Summary

Project Introduction

Project partner: VandCenter Syd, Mads Clausen Institute (SDU), InFluxFunded by: Vandsektorens TeknologiudviklingsfondTimeframe: Jan. 2012 Dec. 2012Budget: ~2.0 Million DKK

Projektpartnerne udvikler et ultralydsbaseret, miljvenligt og energieffektivt vrktj til rensning og regenerering af grundvandsboringer. Boringen bliver dermed mere effektiv og regenerering foretages i n, tidsbesparende arbejdsgang.

This work investigates the usage of high power ultra-sonic push-pull transducers to rehabilitate water wells in contrast to conservative well rehabilitation methods. We compare the effectiveness of the ultrasonic cleaning method with state-of-art conventional cleaning methods such as brushes and chemical acids. In addition the task is to study the effectiveness and level of cleaning for different filter gravel granularities and geology compounds around water wells.

Water Well AgingWells clogg over time and thereby the efficiency of the well declines.

Physical and chemical processes cause the hydraulic conductivity of the wells filter pipe and gravel pack to decline which results in a higher draw-down at the same discharge rate or with a loss in the discharge rate.

- Gravel coatings consists mainly of iron and manganese

- The pore volume fills up with fine sands and silt

- Incrustations in the formation

An aged WellBefore and after mechanical cleaning

Use of known Ultrasonic Cleaning Technology

Resonator rod induce longitudinal pulses in the resonator at the points of attachment.

Transducers inside each end cap produce cyclic positive and negative pressure waves.

The positive pressure wave acts as a pushing force and the negative pressure wave acts as a pulling force (hence "Push-pull").

The pushing and pulling action causes the rod to resonate at the frequency of operation.

As a result, near perfect, omni-directional radiation of sound waves is achieved.

Push-Pull Transducer

Micro-motion:Micro-motion as resonance causes rubbing of the filter gravel stones at each other. Coatings will be rubbed off if not completely hardened.

Oscillation:The gravel stones will start volume oscillating and coatings are spelled off.

Fluidise thixotropics:The ultrasonic energy is used to fluidise thixotropiccements, cut and break molecular lattice of gels, slime, colloidal substances

Ultrasonic Cleaning Effects

The test well (tank) cleaning setup

~50mm

~400mm

Valve (slider)

Fine mesh

Tubewith gravel

Water reservoir

Measurement of the flow rate by letting a fixed volume of water flow through a fixed volume of gravel sample. Different samples and a reference clean sample have been tested. (Darcy test)

Determination of cleaning efficiency

Proof-of-Concept Experiments Results

1 2 367,62 50,6 53,28 53,97 51,34 48,71

64,1 66,43 51,81 45,03 47,16 51,12 55,1568,18 55,19 58,57 46,6 44,29 57,69

67,47 68,91 48,66 58,81 40,87 54,03 52,2865,97 65,09 50,32 54,28 53,47 54,5 56,3566,5 69,35 51,19 55 54,28 52,18 44,6567,91 68,09 52,72 50,6 44,25 44,29 55,0970,75 59,94 50,19 56,59 43,19 50,78 54,06

Mean 67,1166667 66,70125 51,335 54,02 47,97375 50,31625 50,996875Std. 2,22489251 3,05282276 1,966250965 4,540981643 5,287394545 3,951668499 4,914188094

Flow l/min 0,89 0,90 1,17 1,11 1,25 1,19 1,18

Dirty Gravel Sieved Cleaned BOT(10cm away)

Cleaned TOP(10cm away)

Cleaned BOT(1520cm away)

Cleaned TOP(1520cm away)

CLEANREFERENCE

Recent results in water well model

Verification of results with real core samples from a polluted well inside a tank.

75cm core sample from a sonic drill borehole cleaned by the ultrasonic push-pull transducer

Time in seconds for 1liter to pass through a fixed volume of gravel.

Quantitative verification using a high range turbidity sensor andqualitative visual verification of the cleaning effect using an underwater camera.

Gravel pack

Inner well tube

Ultrasonic Probe

Camera

In-Situ testing and verification at a real well.

Turbidity and Video inspection results.

80 90 100 110 120 130

-10

-5

0

5

10

15

20

Time in minutes

relativ

e Tu

rbidity

in T

u un

its

data 1

Filter tube barrier (signal loss ~70%)

Mathematical modeling of sound propagation inside the well.

Measurement of sound propagation inside the tank model using hydrophones:

Compared to the model wave lenght maxima/minima every:

Loss reduction by improving the accoustic bridge by means of direct contact between the transducer and the filter tube. Transducer

Filter tube

Active Transducer Areas

Filter Tube

Improvements to compensate for the intensity loss

Before improvement

After improvement

Consisting of:

- Further testing to improve the sound intensity outside the filter

- New design of the ultra-sonic device

-Turbidity measurements of discharged water

-Hydrophone intensity measurement at different distances from the well

-Camera inspection during treatment

Currently ongoing

Ultralyd test ved V3E i Odense

Sonic Drill kerneboringer omkring en ldre vandvrksboring.

6 kerneboringer til 18 meters dybde.Med udtagelse af fulde kerneprver fra 4,5 til 18 m.u.t.

Kerneboring til dokumentation af tilklogning af boring

Sonic Drill Core sampling

Kerneprver fra formationen

Special thanks to:

For providing the most accurate in-situ MultiSense TuX High-Range Turbidity Sensorfor the In-Situ turbidity measurements.

For funding the project

For providing the project with purpose built specialized test equipment.

For further information or discussions please contact:

Peer Locher, tlf.: 61 63 23 71, pl@vandcenter.dk, mobil 40 80 84 62VandCenter Syd asVandvrksvej 7, 5000 Odense Cwww.vandcenter.dk

Robert Brehm MCI, Mads Clausen Instituttet, 6400 Snderborg, tlf.: 65501612, brehm@mci.sdu.dkwww.sdu.dk/mci

Or visit:

http://vtu-fonden.dk/projektzonenProject: 7300

-> http://vtu-fonden.dk/projektzonen/projekter/2011/7300.aspx