3d bhr information syllabus

8/3/2019 3D BHR Information Syllabus

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T&A Survey B.V. Dynamostraat 481014 BK Amsterdam, The NetherlandsT/F: +31 20 6651368/[email protected] - www.ta-survey.nlU.S. agent: [email protected] - T: +1 720 261 4775

Product Information

System Configuration

Applications

Survey Data Sheets

Operational Information

33DD BBOOR R EEHHOOLLEE R R AADDAAR R



3D Borehole Radar 2

Contents

3D Borehole Radar: A Breakthrough in Ground Penetrating Radar Survey ..................... 3

System Configuration ............................................................................................. 4

Application: Reservoir Characterization .................................................................... 6

Application: Mining Industry ................................................................................... 7

Application: Geothermal Energy Detection ................................................................ 8

Application: Geotechnical Survey ............................................................................. 9

Application: Determination of Jet Grout Column Diameter ........................................ 10

Application: Tunnel Track Exploration ..................................................................... 11

Application: Detection of Unexploded Ordnance (UXO) ............................................. 12Data Sheet 1: Water Test Case ............................................................................. 13

Data Sheet 2: Soil Test Case ................................................................................. 15

Data Sheet 3: Sheet Piling Wall ............................................................................. 17

Data Sheet 4: Object Classification ........................................................................ 18

Operational Information ....................................................................................... 19



3D Borehole Radar 3

3D Borehole Radar: A Breakthrough in Ground

Penetrating Radar SurveyThe 3D Borehole Radar (3D BHR) is a geophysical technique for high-resolution 3D

mapping of borehole surroundings. It’ s a breakthrough technology with very high

accuracy as it allows, for the first time, radar survey at great depths and in difficult

circumstances. Applied in a single borehole, the 3D BHR combines all the advantages of

ground penetrating radar tools in one:

Directional information: 3D positioning of detected objects.

High-resolution data: exact positioning of detected objects.

Penetration range up to 15 meters.

T&A is responsible for the design, engineering, operating and processing software and

testing. Subcontractors TNO-FEL (Physical Electronic Laboratory) and NLR (Dutch

National Aerospace Laboratory) developed and built the mechanical and electronic

components of the down hole tool.

How does it work?

The 3D BHR emits radar waves into the subsurface by means of a transmitter antenna,

situated in the borehole. When a wave meets a contrast in material parameters (an

object or geological boundary), part of it is reflected and received by the receiver

antenna, situated in the same borehole. A continuous 3D image of the subsurface is

obtained by rotating the antenna system and moving the 3D Borehole Radar vertically in

the borehole.

Applications of the 3D

Borehole Radar:

• Oil and gas reservoir

characterization• Mining• Geothermal energy

detection• Geotechnical survey • Determination of jet

grout column diameter • Tunnel track

exploration• Object detection



3D Borehole Radar 4

System Configuration

The 3D Borehole Radar system is pulled or pushed

through a non-metallic cased and water-filled borehole.

It consists of four main parts:

1. Positioning unit

The positioning unit contains a control unit, a motor to

rotate the radar unit and several sensors to determine

the position of the system in the borehole. The sensors

consist of magnetometers, accelerometers, FOG

gyroscopes sensors and an angle encoder. This unit is

the outer shell of the complete 3D BHR system as it has

a specially designed housing for the enclosed radar

unit, protecting it from mechanical and environmentalborehole conditions.

2. Radar unit

The radar unit is

enclosed and rotates inside the 3D BHR system. It

contains two directional antennas. The reflectors behind

the antennas provide the directional sensitivity and the

energy bundling of the antenna.

The control unit, transmitter electronics and receiver

electronics are also situated in the radar unit. The

recorded analogue data is digitized down hole by a veryfast A/D converter.

3. Cable

The 3D BHR is connected to the surface by a cable which

supplies power and allows high-speed data transmission.

At the surface, the data is stored and can then be

processed to provide a 3D image of the borehole

surroundings.

4. Software

The 3D BHR is supplied with custom designed operating

and processing software, called Dafos, which can also be

used by other geophysical equipment containing multiple

sensors.

Accessories

Depending on the application, the following accessories

are required to operate the 3D BHR:

Tripod

Winch

Surface equipment (DC power supply, computerand housing)

15.9 cm

A specially designed connection between the positioning unit and radar unit allows high-speed data

communication and power supply during rotation.



3D Borehole Radar 5

Technical Specifications

Length 4.2 meters

Diameter 16 centimeters

Weight 250 kgSource signal impulse (up to 850 V)

Centre frequency 100 MHz

Sample frequency 600 MHz

Bandwidth 100 MHz

Dynamic range between

transmitter/receiver

120 dB

Avg. penetration 5 – 15 meters

Avg. angle accuracy 1– 30 degrees

Avg. axial accuracy 1 – 30 centimeters

Conductivity range 20 mS/m @ 100MHz and lowerAntenna set-up bistatic (two antennas)

Antenna type shielded dipole (directional)

Temperature rage 0 C - 60 C

Max. pressure 15 bar (150 meters in vertical water-

filled borehole)

Avg. power consumption 60 Watts

Material RVS 316 (non-magnetic) and

composite materials

T&A operates on a policy of continuous product improvement. Future series of the 3D

BHR will be smaller and possess extended temperature and pressure ranges.

Versions

The 3D BHR is available in different versions, from a full-service modular geophysical tool

to a stand-alone radar module.

3D BHR Omni To be used in cased boreholes (in every position)

Parts: positioning and radar unit, housing and cable

Length: 4.2 meters, Weight: 250 kg

Extras: centralizers for open boreholes3D BHR Vertical Only to be used in vertical boreholes.

Parts: Integrated positioning and radar unit (more robust)


Parts: 1 (integrated rotor/stator and cable)

3D BHR Probe A system of a separate radar unit (with embedded software)

To be integrated in other equipment




3D Borehole Radar 6

Application: Reservoir Characterization

The 3D Borehole Radar technology is a

promising addition to existing loggingtechniques in oil and gas exploration

and production.

Main applications

• Logging tool: In an exploration environment, the 3D BHR can be used as an ElectricPropagation Tool to detect the electrical properties of the formation.

• Geosteering: In thin pay zones, where it is crucial to follow a specific drilling path,the 3D BHR can provide the information to steer the drill bit. The distance to the topand bottom of the reservoir can also be measured.

• Monitoring: In production phases, where water or steam drives are used, the 3DBHR is well suited to monitor the movement of the steam/water front in 3D.

Penetration rangeThe penetration range of the 3D Borehole Radar system in reservoirs is 5 to 10 meters,

based on average reservoir properties (see table). Penetration range increases with

increasing resistivity. In ideal situations, a penetration range of 15 meters can be

obtained.

Reservoir Permittivity Resistivity [Ohm-m]

Oil-bearing 10 50

Water-bearing 20 2

T = 120º C and p = 300,000 hPa

Main advantages

• A more complete picture of the reservoir. The 3D BHR can detect the position

of the oil-water contact zone in reservoirs because, between the two layers,the electromagnetic impedance contrast is higher than the contrast in acoustic

impedance.• A detailed 3D image of the borehole surroundings is achieved by using high

frequency, high resolution electro-magnetic waves resulting in unprecedented penetration depth.

• Only one borehole is needed in SAGD. In the drilling stage, 3D BHR providesan accurate relative position of the two wells from only one borehole, without needing access to the producer well.



3D Borehole Radar 7

Application: Mining Industry

The mining industry is all about knowing what's going on in the underground. Without

subsurface testing, it is impossible to locate an ore body, to define exploitable reserves

or to design a mine plan.

Geophysical tools used in the oil industry

(such as 3D seismic techniques) have been

adapted and applied in mining industry,

resulting in great benefits for the exploration

of mines. However useful these tools may be,

none of them can compete with the 3D

Borehole Radar’s capacity to reveal a high-

resolution contrast between different

materials in the underground.

Main applications

The 3D Borehole Radar (3D BHR) provides a

useful addition to existing geophysicaltechniques in recognizing geology for mining. Itcan be applied in both exploration andproduction phases.

In an exploration environment, the 3D BoreholeRadar can be applied in horizontal and vertical

drillings into e.g. coal, ore and salt bodies.

Depending on the resistivity of the formation,

the signals penetrate up to 20 meters aroundthe borehole. It can be used for detecting:

• Lateral and vertical inhomogeneities

• Cavities • Faults • Fracture zones: length, dip and distance

Other possible applications are:

• Locating an ore body

• Defining exploitable reserves • Designing a mine plan • Detecting pot holes

Main advantages

In an exploration environment:

• High-resolution data:transitions can be detected with great accuracy.

• Directional data: a 3D image

of geological situation around the borehole is obtained

• High penetration range up to20 meters.

In a production environment:

• monitoring and locating potential mining problems.

• finding zones of potential danger due to caving and

shock bumps.• finding hazardous structures

like water bearing fissures

ahead of planned minedevelopment.



3D Borehole Radar 8

Application: Geothermal Energy Detection

Due to increasing scarcity in oil and gas resources, energy

costs are rising and so is the demand for alternative

resources. Deep geothermal energy is an alternative

energy source with great advantages, which could become

more and more important.

Geothermal Energy is generated by pumping up deep

groundwater from a depth of 1.5 to 4.0 kilometers with a

temperature of 70 to 100 degrees Celsius, in order to heat

houses and/or horticulture greenhouses. After releasing its

heat, the groundwater is pumped back into the

groundwater reservoir. This energy source is almost

inexhaustible.

Mapping deep groundwater reservoirs

In order for a geothermal project to be successful, it is

important to study the geological structure and

stratigraphy of the subsurface of the planned location. The

research target of a geological study is to map deep

groundwater reservoirs. The results of the study include a

detailed description of, for example, the geometry and

other properties of the reservoir. The completed study is

comprised with other drillings, wire line logs and cores.

Main applications

The groundwater reservoir needs to be estimated very accurately prior to making the

decision whether a geothermal system can be successfully and economically exploited.

Additional information, next to the wire line logs, can be obtained by 3D Borehole radar

measurements. 3D Borehole Radar data can be used to delineate the location and

dimensions of the reservoir and

to determine the presence of

impermeable cap rock on top of

the groundwater reservoir. Faults

and fractures can be detected,

including dip measurements.

Main advantages

• 3D BHR can be applied in vertical and horizontal drillings into the formationto detect transitions between different rock types and to detect and delineate

cavities, faults and fractures.• 3D BHR provides 3D positioning of

interesting features.• 3D BHR provides high accuracy data.• 3D BHR provides a high penetration

range compared to other geophysical survey methods.



3D Borehole Radar 9

Application: Geotechnical Survey

Measurement of underground structures (concrete piles, sheet piles and foundations) are

important in order to verify their exact location and dimensions and to check possible

damage or degradation. After many years, the

exact location of structures is often unknown

and needs to be determined again.

Measurement of underground structures with

conventional surface measurement techniques

are operationally difficult and tend to be

unreliable for several reasons:

• The structures are positioned too deep for

conventional measuring.• The current surface techniques prevents

conducting overburden.

• The current techniques do not provide

enough resolution.

• The existing above ground structures

makes measuring difficult.

Steered Drilling

Steered drilling is a new technique for laying underground cables. As an alternative to

digging trenches, it is a cost-effective method that causes fewer disturbances to the

environment. As the number of cables and other objects in the shallow subsurface

increases, there is more need for exploration of the drilling path. As an alternative to

measurements from the surface, the high-resolution directional borehole radar can be

integrated in the drilling process to explore the drilling path in advance.

Main advantages

• The radar is brought down to the locationof the object in the subsurface.

• No overburden effects.• Much higher resolution with the acquired

images.

• No site constraints with surface structuresas boreholes can be drilled at any angle or even horizontally.



3D Borehole Radar 10

Application: Determination of Jet Grout Column Diameter

Measuring jet grout columns

Concrete foundations are used for an increasing number of underground infrastructure

projects. Various jet grout injections consolidate the soil and decrease the risks of

subsidence from large surface structures.

Jet grout columns vary in diameter, depending upon the injection pressure and the soil

conditions. The diameter is an important property that should be quantified, especially

when several grout columns are connected to form an underground concrete floor.

Until now, no proven or tested techniques existed to calculate the diameter of

injected columns. Until now, it has been almost impossible to conclude whether the

jetgrout foundations provide enough stability, especially in underpinning applications.

Main applications

By integrating the 3D Borehole

Radar technology into the

injection lance, the diameter of

the column can be determined

on site. The boundary between

grout column and hosting

medium is a sharp edge and,

therefore, a good

reflector for incident radar

waves.

There are two ways to apply the 3D BHR in the jet grouting process. In both cases, the

diameter can be measured very precisely because of the resolution of the 3D Borehole

Radar method:

Integrating the 3D BHR in the jet grouting system. During construction of

the column, the radar is located just below the injection point and the grout

column diameter is measured from within the column. The injection pressure can

be adjusted while the column is being made.

Drilling a borehole near the grout

column allows the 3D BHR to measure the

distance from this borehole to the edge of

the column.

Main advantages

The diameter of a jet grout

column can be measured

very precisely, because of the resolution of the 3DBorehole Radar method.




Application: Tunnel Track Exploration

It is essential that any tunnel project starts with a comprehensive investigation of ground

conditions. In addition, encountering unforeseen ground conditions, objects or anomalies

can be costly in terms of time and materials. The 3D Borehole Radar technique

continuously gathers detailed information about obstacles and geological transition

zones.

Main applications

The 3D BHR is positioned in a

horizontal borehole with a diameter

of about 20 centimeters, and drilled

along the planned trajectory. It

measures the complete surroundings

of the borehole. Rotating 360°, itgathers and processes data from all

angles with special proprietary

software. After processing, the raw

ground penetrating radar data is

combined with simultaneously

collected positioning data, providing

meaningful operating data.

T&A is the first geophysical survey company to successfully integrate radar electronics

into a geophysical tool. It is capable of surveying the surrounding soil construction and

simultaneously determining the exact position of objects from within one borehole.

Main advantages

• Better analysis: The complete tunnel track can be explored in advance,

identifying the exact location of fault zones.• More efficient use of TBM’s: As more relevant information is available

during drilling, it allows for more precise decision-making.• Substantial technical and financial risks can be avoided.• Enhanced safety during tunnel construction.




Application: Detection of Unexploded Ordnance (UXO)

Unexploded ordnance, such as aircraft bombs and

artillery shells from for example World War II still

can be found in the subsurface throughout Europe.

These explosives are especially dangerous when

touched or moved during digging, dredging or piling

activities.

Detection from the surface is often not feasible,

since the explosives are buried too deep. When a

bomb dropped from an airplane doesn't explode

touching the surface, it penetrates the upper soft

peat and clay layer and stops at the first stable

sand layer. In the Netherlands, this layer can belocated at a depth of more than 10 meters below

the surface. Due to resolution problems, detection

from the surface is not an option in these cases.

Measurements from a borehole are needed to solve

the problem. Traditionally, these measurements are

done using a magnetometer.

The main drawbacks of the magnetometer method are:

Limited penetration range of 1 to 2 meters.

The measurements contain no directional information.

Main applications

For 3D Borehole Radar measurements, a

borehole is drilled in a safe zone, just

outside the investigation area. When it's

determined that the area around this

borehole is safe, the next measurement is

done in an adjacent position closer to the

area of investigation. This way the whole

area is searched for deep explosives.

Unexploded bombs with a large metal

content show a strong electrical contrast

with the surrounding soil. Therefore, these

objects are very good reflectors of radar

waves.

Main advantages

High penetration range of 5-15 metres reduces the number of boreholes considerably. Even

with a penetration range of only 5 meters, the number of required boreholes is reduced by

a factor of 25 compared to themagnetometer method.

Very high location accuracy dueto the nature of the radar method and the directional radiation pattern that istransmitted by the 3D BHR.




Data Sheet 1: Water Test Case

Objective and circumstances

The first measurements in water were carried out to calibrate the

3D Borehole Radar. These measurements took place in a water

basin at the TNO Physics and Electronics Laboratory. An iron gas

cylinder was hung next to the 3D BHR at a distance of 1.5

meters from the 3D BHR, at a depth of 2 meters below water

level and at an angle of 270º.

Radiation pattern

The 3D BHR was positioned vertically in the water basin. This

way, the transmitted signal travels along a horizontal plane, as

shown in the figure below. The radar unit of the 3D BHR rotates,

so it is a directional device. This means that the signal that istransmitted has an angular movement in the horizontal plane. In

both vertical and angular (horizontal) direction, the signal is not

transmitted in a single direction but in a bundle of directions.

This bundle has a width of 10-15º in vertical direction and a

width of 70-90º in angular direction. The two bundles combined

form what we call a detection cone. The energy density of the

transmitted signal is strongest in the middle of the cone. Because

of this, in measured data, objects are visible within a certain

angle and depth range and not at one single angle/depth

position. Note also that, because a separate transmitting and

receiving antenna are used, the detection cone starts at a smallradial distance from the antennas.

Detection cone

Detected object

70-90°

Horizontal plane

Transmitting antenna

10-15°

Detection cone

Receiving antenna

Rays that hit thereceiver

Detected object

Side view Top view

Rays that miss thereceiver




Measurement results

The figure to the left shows a

vertical angle scan of the

gas cylinder measurement.All data in a vertical angle

scan have the same

measurement angle. The x-

axis represents the radial

distance from the 3D BHR

and the y-axis the depth

below water surface. The

radial distance is converted

from measurement time,

using the relative permittivity

of water.

The figure shows the reflection of the cylinder at a depth of 2 meters below water surface

and at a radial distance of 1.5 meters from the 3D BHR. In the vertical direction, one can

see the same hyperbolic reflection pattern that is characteristic for surface ground

penetrating radar. This is because, as the 3D BHR is lifted vertically and ‘passes’ the

object, the distance between the object and the 3D BHR first decreases and subsequently

increases.

The figure to the right shows ahorizontal depth scan of the

same measurement. All data in a

horizontal depth scan have the

same measurement depth, in this

case, 2 meters below the water

surface. The radial axis is the

radial distance from the 3D BHR

and the angular axis is the angle in

relation to the magnetic North.

The figure shows the reflection

from the cylinder at an angle of 270º with respect to magnetic

North and at a radial distance of

1.5 meters from the 3D BHR, a

prove of the excellent directionality

of the system.

In a horizontal depth scan, one doesn’t see a hyperbolic reflection pattern. This is

because, as the 3D BHR rotates and horizontally passes the object, the distance between

the object and the 3D BHR remains constant. What does change, however, is the

intensity of the radiated wave. It increases and subsequently decreases as the antenna

radiation beam horizontally passes the object. This results in the kind of ‘banana’ pattern

that can be seen in the figure. The object is located in the middle of this pattern.




Data Sheet 2: Soil Test Case


The water test case was repeated under the real circumstances of the subsoil. In this

test, the 3D Borehole Radar (3D BHR) was placed in one borehole and an iron cylinder of 10 cm. in diameter and 30 cm. in height was placed in another.

The cylinder was placed at depth of 6

meters, at a radial distance of 9

meters and at an angle of 345 degrees

relating to the magnetic North from

the 3D BHR.

The soil was composed of

homogeneous sand and was water-

saturated to about half a meter below

the surface. Conductivity was low.

Measurement results

The figure below shows the measured raw data. No processing has been done yet. The

figure shows a vertical angle scan of the measurement data. All data in a vertical angle

scan have the same measurement angle. The x-axis is the radial distance from the 3D

BHR and the y-axis is the depth below surface. The radial distance is converted from

measurement time, using the relative permittivity of the soil.

The large amplitude at small distance, which corresponds with small amount of time, is

the direct wave. This is the signal that travels directly (without reflection) fromtransmitter to receiver antenna. The object cannot be seen in this unprocessed data.






cylinder after processing. The

direct wave has been

suppressed and the reflectionfrom the cylinder now appears

at a depth of 6 meters below

surface and at a radial distance

of 9 meters from the 3D BHR,

the exact position of the object!

The figure to the right shows a

horizontal depth scan of the same

measurement. All data in a

horizontal depth scan have the

same measurement depth, in this

case 6 meters below the surface.

The radial axis is the radial

distance from the 3D BHR and the

angular axis is the angle in relationto the magnetic North.

The figure shows the reflection

from the cylinder at an angle of

345 degrees and at a radial

distance of 9 meters from the 3D

BHR, again the exact position of

the object!

Although the bottle object has a diameter of only 10 centimeters, the object appears in

the data not only at an angle of 345 degrees, but over an angle range of about 300 to 30degrees. This is because the 3D BHR transmits a bundle of signals with a width of 70 to

90 degrees. The energy density of the transmitted signal is the strongest in the middle of

this bundle.

This test case proved the excellent performance of the 3D BHR with regard to

directionality and accuracy, not only under laboratory circumstances, but also in a real-

life case of a subsoil survey. It shows the system is able to detect the exact position of

an object placed at 9 meters from a single borehole, which is an unprecedented result in

ground penetrating radar survey.




Data Sheet 3: Sheet Piling Wall

Survey objective and circumstances

In this survey, the objective was to detect a sheet piling metal wall in the subsoil. The

measurements were carried out from a 15-metre deep, PVC-cased borehole. The local

subsoil consisted of peat material (from the surface until 6 meter depth) and below it

consisted of sand. The metal wall was located at 2.8 meters horizontally from the 3D

Borehole Radar (3D BHR) and had a depth of 10 meters. The subsoil water table was

very near to the surface. The conductivity of the water-saturated subsoil was rated fairly

high.

Measurement results

The figure to the right shows a


measurement. All data in thisa scan have the same

measurement angle. The x-

axis represents the radial

distance from the Borehole

and the y-axis the depth

below water surface. The

radial distance is converted

from measurement time, using

the relative permittivity of the

soil. The figure shows the

results after data processing.

One can see the reflection of

the metal wall up to a depth of

about 10 meters and at a

distance of 2.5 meters from

the 3D BHR.

The figure to the right shows a horizontal

depth scan of the same measurement. All

data in this scan has the samemeasurement depth, in this case 8 meters

below the surface. The radial axis is the

radial distance from the 3D BHR and the

angular axis is the angle in relation to the

magnetic North.

The figure shows the wave reflection from

the wall at an angle of 200 degrees and at

a radial distance of 2.5 meters from the 3D

BHR.




Data Sheet 4: Object Classification


The objective of the survey was to determine

whether objects encountered during drilling

could be World War II conventional explosives.

During drilling activities, an object was hit at 8

m depth, which caused the drill bar to break.

Because of the history of the area, the

presence of either explosives or a bunker in the

underground could not be excluded. To

minimize risks during further drilling activities,

a 3D BHR survey was carried out at the drill

hole location. The specific goal in this surveywas to determine the dimensions of the object and whether it was part of a larger structure

like a bunker.

Measurement results

The results of the measurements indicated that the object was not part of a larger

structure. The survey also indicated that the object was located at a depth of 5 meters.

This conclusion was later confirmed by magnetometer measurements.


vertical cross-section of the

data at a single angle of 2.8º.

The absolute value of the

data is shown, the wave

pattern of the data has been

removed. The object is

represented by the yellow

color at 5 meters depth and

3.5 meters radial distance.

The red color at small radial

distances represents thedirect wave between

transmitter and receiver

antenna.




Operational Information

Equipment

The field crew needs a flat surface of about 40 m² near the

borehole to unpack and mount the equipment. Computers

and monitors need to be protected from rain and dirt, either

by a shelter or by a van. Setting up the equipment takes

approximately 60 minutes for two operators.

Auxiliary equipment

Auxiliary equipment needed to operate the 3D BHR:

Crane, rig or tripod

Winch

Power supply

Water supply

The mounted 3D BHR is 4.4 meters long, has a diameter

of 16 centimeters and weighs approximately 250

kilograms, so it needs to be lifted by a crane or, when

using a tripod, by an electrical winch. The crane or tripod

must be able to lift the 3D BHR approximately 5.0 meters

above borehole casing level. The cable speed of the crane

or winch must be reducible

to 1 meter per minute.

Boreholes

Boreholes can have a maximum depth of 30 meter and need

to be cased using PVC pipes or any other non-metallic (non-

conductive) material. Preferably, they have a inner diameter

of approximately 20 cm, with a minimum inner diameter of

19 cm and a maximum inner diameter of 24 cm. During

measurements, these holes need to be filled with fresh

water up to the edge of the casing.

If the groundwater table is low, for example, a few

meters below the surface, it is recommended to plug the

bottom end of the casing using a lid or clay in order to

avoid losing borehole water during measurements. A

fresh water supply is needed to maintain a stable water

reference level at all times.

Right: Water fill and depth reference.

Left: Wheel blocks at top and bottom will centralize the 3D BHR. An

inner diameter of 20 cm is ideal.




Connection

The cable can be connected

in multiple ways, using hooks

or pulleys as indicated in the

pictures. The inner diameterof the eye on top of the

upper wheel block is 34 mm.

Left: ribbon

Right: hook

Procedure

The 3D BHR is lowered into the borehole, followed by a heating up period of 15 minutes.After heating up, the 3D BHR is lifted slowly (1 meter per minute) while measuring.

When the 3D BHR is surfacing, the measurements are stopped.

Left:

Lowering

Middle:

Heating and

starting

Right:

Stopping

Power supply

230 V/50 Hz/200 W or 24 Vdc/8A

Objects on the site

Large objects at the surface of the site like steel pylons, metal plates, concrete walls willcause interference with the 3D BHR measurements. Please provide us all the information

to make sure that 3D BHR measurements can be performed under the given conditions.

The presence of power cables near a borehole should be avoided as much as possible.

Weather conditions

Weather conditions, except lightning, do not influence 3D BHR measurements. In the

case of lightning, measuring will stop until the weather improves.

The minimum temperature during operation is –5 °C as lower temperatures can damage

the water filled 3D BHR system.



Summary

Crane, rig or tripod cable length Approximately 30 meters of free cable length

Crane, rig or tripod weight

lifting

Approximately 250 kg

Crane, rig or tripod cable

pulling velocity

Approximately 1.0 meter/minute during measuring

Boreholes Maximum depth 30 meter, PVC cased (or similar)

inner diameter 20 cm, closed at bottom end in

certain situations

Connection Eye in top wheel block 34 mm inner diameter

Power supply 230 V/50 Hz/200 W or 24 Vdc/8A

Water supply Fresh water, quantity depending on geology, water

table height and site.

Object on the site Contact usPower cables nearby Contact us

Weather condition Minimum temperature –5 °C

3d bhr information syllabus

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