Impulse Generator IPG800 and Borehole Source BIS-SH-DS

Operation and Maintenance Manual Jan 2017 page 1

Geotomographie GmbH, Am Tonnenberg 18, 56567 Neuwied (Germany) Tel.: +49 2631 778135 email: [email protected]

Impulse Generator IPG800 and Borehole Source BIS-SH-DS

Operating and Maintenance Instructions



Content Page PreCautions 3 1. Impulse Generator IPG800 4

2. Remote Control Unit (RCU) 8

3. Downhole Source BIS-SH-DS 11

3.1 Surface connectors 11

3.2 BIS-SH Probe 12

4. Operation and Maintenance Instructions 14

4.1 Connect batteries to IPG800 14

4.2 Connect Remote Control Unit to IPG800 14

4.3 Connect probe to IPG800 14

4.4 Placing the BIS probe into the borehole 15

4.5 Setting the IPG800 in operation 16

4.6 Finish operating the IPG800 16

4.7 FAQs 17



Precautions for

Operating Seismic Sparker and other HV- Sources Like other seismic sources as explosives, air guns or weight dropping systems, operating of an electrical spark or other high-voltage impulse sources requires several precautions. The most important precautions are:

1. Do not connect or disconnect high-voltage connectors whilst impulse generator

is in operation or switched ON. Switch OFF impulse generator before disconnecting cables or connectors.

2. No handling of surface cable, downhole source or borehole cable while impulse generator is in operation. 3. Impulse generator operation only by authorised personnel. 4. Do not expose impulse generator or connectors to water or dust. 5. Do not block air ventilation. 6. In case of any malfunction or emergency switch OFF impulse generator by

pressing the red OFF button at generator or at remote control. 7. Do not open impulse generator or remote control. Maintenance has to be

carried out by authorised personnel. On un-authorized opening of the impulse generator warranty will expire immediately.

Moreover observe the following: • Check cables for power supply, high-voltage surface and borehole cable and all connectors in relation with faultless conditions before and after every field survey. • Do not open the impulse generator during the device is connected with mains or other power sources. • Any repair or maintenance works has to be carried out only by authorised personnel. • The surface HV-connector (quick connector) should be dry to avoid a flash over inside the connector. Take care that no water e.g. rain can get into connectors. • In case of an electrical interruption between impulse generator and downhole source, resp. if an impulse is released without a spark action, the cable can be charged with high voltage like a small condenser. This charge has to be discharged by switching OFF the impulse generator. Check this by observing the HV-meter. Wait until the voltmeter at impulse generator shows a voltage of 0 Volt ! • In case of a malfunction the high voltage charge will be discharged slowly (in about 10 to 15 minutes) via a discharging resistor. Wait until the voltmeter at impulse generator shows a voltage of 0 Volt !



1. Impulse Generator IPG800 The impulse generator IPG800 is used to supply the seismic probe with energy. The IPG800 runs from 2 x 12V car batteries (not supplied). Fig. 1 shows the impulse generator IPG800. Following accessories for operation of the IPG800 are delivered: 1. IPG800 in PELI box 2. Battery connecting cables and interconnecting cables 3. Manual

Fig. 1: Impulse generator IPG800 The IPG800 supplies energy of 1000J at 800V to the downhole probe BIS-SH-DS by means of a short electrical pulse. This is performed by an electromechanical switch which discharges condensers inside the IPG800. The electromechanical switch is made of Wolfram metal for a long working life. Impulses can be released by choosing three different cycles (1, 5 or 10) via a turning knob located on the front panel. Connection between downhole probe and IPG800 generator is accomplished by attaching two special HV-connector into the output contacts located at the right side of the IPG800 box.



Connection between 12V batteries and IPG800 generator is accomplished by attaching batteries to the input contacts located at the left side of the IPG800 box. To prevent electromagnetic interference the generator should be operated in a certain distance to the seismic recorder.

The impulse generator must be protected from any wetness, e.g. rain and dust !

Fig. 2: Front side view

4

12

3

5

6

7

8

9

10

Function:

1 : ON/OFF (on OFF = System shut down)

2 : Battery Control (charge on yellow/red)

3 : Shooting Timer (1 = Single Shot release, 5 = approx. five shooting cycles, 10 = approx. ten shooting cycles)

4 : Emergency OFF Button (system shut down)

5 : Voltage Charging Display

6 : Impulse Counter

7 : Battery Slot 9V for trigger circuit

8 : Trigger ON/OFF (ON = green LED lights)

9 : Trigger Test Button (on test red LED flashes)

10 : General Instructions



Fig. 3: Left side view - Battery connecting side

Function:

1 : MINUS Pole Battery 1 (black)

2 : PLUS Pole Battery 2 (red)

3 : Connector to Remote Unit

4 : Air inlet (do not block)

Fig. 4: Battery Connection Scheme

Two 12V batteries have to be connected to the IPG800 as displayed on the left picture (connection at IPG800 could be reversed in earlier versions).

Red to +

Black to - Do not connect in a different way. It is recommended to use car batteries with at least 35Ah.

Note: The connectors to IPG800 are of push-pull type. To get them out one has to push in

first and then out.



Fig. 5: Right side view (Source connecting side)

1

2

Function:

1 : Air Outlet (do not block)

2 : Source Connector



2. Remote Control Unit (RCU) The remote control unit fulfils following functions: 1. Converting the impulse reference signal in a trigger signal to start the seismic recorder. 2. Start/Stop of shot release 3. Immediately interruption of impulse operation by pressing EMERGENCY OFF Following accessory for operation of the RCU is provided: 1. Remote Control with 20m cable on drum

Fig. 6: Remote Control Unit RCU The remote control unit is connected to the IPG800 by a single cable. Only if Remote Control is connected to the IPG800 the system can be operated. The RCU provides two different trigger. One is a TTL trigger directly provided by the IPG800 and the other is same but directed via an OPTO-Coupler. The second option is necessary in case there is too much electrical noise and seismic traces getting distorted. The OPTO-Coupler is powered by a 9V battery. For most seismograph no triggering via OPTO-coupler is needed. Anyhow, please make example records to see what the best option is.

Attention: Rental units might have the OPTO-coupler option only. In this case no trigger is released if the trigger is not switched on (=LED lights) at the RCU.



Fig. 7: Front view

1

3

2

4

5

6

Function:

1 : Start Shot release

2 : Stop Shot release

3 : Emergency OFF Button (system shut down)

4 : Trigger output to seismograph (red = +, black = -)

5 : Battery Slot 9V for OPTO-Coupling trigger circuit

6 : Trigger Select (Optocoupling = LED is green, standard trigger = no LED)

The trigger signal is a raising edge TTL (positive pulse).

Note: The triggering through opto-coupling is not needed for most seismographs. It is just an

option. Try first if your seismograph triggers without the opto-coupling switched ON. For this you can just press the red Trigger Test Button at IPG800.



Fig. 8: Complete assembly of IPG800 and Remote Control Unit



3. Downhole Source BIS-SH-DS Based on an outer diameter of about 65 mm the probe BIS-SH can be used for SH-wave surveys in boreholes having a minimum diameter of 75 mm and up to 4 inch without extension. The borehole source consists of following parts: 1. BIS-SH source with borehole rotary string on drum, standard length 30 m 2. Valve and pressure gauge adapter 3. Air pump 3.1 Surface connectors The borehole rotary string ends in a white plastic cylinder typically directly mounted on the drum. This end terminator splits of the HV cable and the air connection (to inflate the BIS-SH packer). A special adapter with gauge and valve can be connected to the air-in connector. It’s a push-pull connection at the gauge-valve adapter. An air pump is provided to inflate the packer for clamping the source to the borehole wall. Also here it’s a push-pull connection. Once air pressure is applied to inflate the packer close the valve and disconnect the air pump. Without disconnecting air cannot being released.

Keep the push-pull connectors always clean !

The HV cable itself splits off after a few meters into two HV Connectors (to be connected to the IPG800). For older BIS-SH-DS probes they are connected to the IPG800 via the quick surface connector. The HV-cable terminates into surface connector. Fig. 9: Surface end connector

Function:

1 : Surface Connector

2 : Push-Pull connection at

valve-gauge adapter

3 : Pressure gauge

4 : Valve

5 : Connector to air pump



3.2 BIS-SH Probe The BIS probe consist of the probe head, two half sleeves, the rubber protected and sealed active probe part, an air clamping device and the probe end part (see picture below).

Fig. 10: BIS-SH probe The probe head splits between the HV-cable and the air supply. Further, the probe head is connected to the rotary pipe string. Always make sure the connection is very tight ! Further, make sure the probe active part (shooting direction) is in alignment with the rotary string marking.

Fig. 11: Rotary String Marking (points towards shooting direction)



The two half sleeves connect the probe head to the active probe part. To maintain cable connection (cleaning) and to connect/disconnect air hose one may open one side for operation.

Fig. 12: Half-Sleeves with HV cable and pressure hose connector The air clamping part can easily be removed by unscrewing from the active part to change the airbladder.

Fig. 13: Unscrew to replace air bladder The active part of the source contains a seismic source working after the eddy current principle. A high duty rubber tube (3 mm wall thickness) protects the HV part from water and dust. The probe can run in a borehole on its own cable only. The probe can work in water filled and dry boreholes !

Due to the high-voltage the active probe part heats up. Temperature raises fast up to 100°C. Make sure that no overheating happens (for example: after a 30 .. 50 shots in continuous mode without stopping). Mainly, this is observed in dry boreholes where cooling is not optimal as in water filled boreholes.



4. Operation and Maintenance Instructions 4.1 Connect Batteries to IPG800 Two 12V batteries have to be connected to the IPG800 as displayed on the picture below. It is recommended to use car batteries with at least 35Ah each. Fig. 14: Battery Connection Scheme

Do not connect in a different way ! Connection at IPG800 could be reversed in earlier versions.

Red to Plus Black to Minus

4.2 Connect Remote Control Unit to IPG800 Connect Remote Control to 7-pin connector located at left side of the IPG (please refer to fig. 3). Make sure, emergency button is up. On emergency button down (=pressed) system will not work. 4.3 Connect Probe to IPG800 Un-spool BIS-SH to desired working depth. Figure 15 shows the HV socket at IPG800 and the connector at BIS-SH-DS. Fig. 15: Connectors at IPG800 for connecting the source



Push in and lock connector (see Figure 16).

Fig. 16: Connection established to IPG800 4.4 Placing the BIS probe into the borehole In order to determine the correct clamping air pressure put the source in uppermost borehole part (0,5m) and start applying pressure carefully. Due to the cable air volume pressure raises first slowly but later rapidly ! Inspect visually if the air bladder reaches the borehole wall (AP1-Air pressure 1). Determine AP1. Apply 1.2 .. max 1.5 bar overpressure to AP1 to have sufficient clamping pressure. In case of a damaged rubber tube any operation has to be stopped immediately. The rubber hose has to be exchanged. A separate instruction is given to maintain this part. Warning: In continuous operation or extensive SINGLE mode operation the temperature of the active probe part might raise to temperature which may damage the source or lead to a burn if touched without gloves. Wear gloves operating the source. Avoid overheating. The rotary pipe string does not need any special maintenance. Inspect regularly the cable mantle for mechanical damages as cuts.



4.5 Setting the IPG800 in operation To start working with the crosshole system please read the following instructions carefully. 1. Connect batteries to IPG800 as described under 4.1

Check battery state at “Battery Control” right off the ON switch at the IPG800 front panel if fully powered.

2. Connect Remote Control as described under 4.2 Check if “Emergency OFF” button is in UP position (=not pressed) Connect trigger to seismograph

3. Connect BIS-SH source to IPG800 as described under 4.3 and 4.4

4. Check at IPG800 if “Emergency OFF” button is in UP position (=not pressed) Switch ON the trigger at IP800

5. Press “ON” at IPG800 (the system should now start loading till 800V is reached).

6. Set “Shooting Timer” to desired position (1/5/10). The IPG800 is now ready to start cycling and can only be controlled by the Remote Control Unit.

7. Make sure everything is well connected and safe. The operator is responsible for handling the system and its safety. If source is at desired position and clamped you may start your survey by pressing the “START” button at the RCU (remote control unit). The source will start working.

8. Shot release is finished if the “Shooting Timer” has reached the end or by pressing the “STOP” button ate the RCU. Press “Start” again if you want to have a new cycle started.

9. Any operation can be finished at any time by pressing the “Emergency OFF” buttons at the IPG800 or at the RCU.

4.6 Finish operating the IPG800 If you want to finish the survey press the “OFF” button at the IPG800 or any of the two “Emergency buttons”. Disconnect batteries next followed by disconnecting the RCU. Finally disconnect trigger cable and disconnect source from IPG800.



4.7 FAQs (1) How to adjust the source ?

Please check the “General Instructions” displayed at the front panel of the IPG800 for instructions.

(2) Can I check if triggering works ?

You may test if your seismograph accepts a trigger by pressing the “Trigger Test” button at the IPG800. On release the LED flashes red. This will be same if a real shot is released. Observe how your seismograph is reacting.

(3) The seismograph is not triggering.

Please check if the trigger is ON at the IPG800. If yes, please check if the LED flashes red once a shot is released. If it flashes red IPG and source works fine. If it does not flash please check 9V battery at IPG800 and test again. If you trigger via OPTO-coupling please check 9V battery. If you do not use OPTO-coupling trigger please check sensitivity of your seismograph as well as the selected trigger slope (positive/negative). Further, please check the wires connecting RCU and seismograph if they are OK. Last but not least, check the RCU cable connecting the RCU and IPG800 if all wires have continuity. For this you have to open the RCU (shut down IPG800 first).

(4) Traveltimes are far too short (approx. 10ms). It looks like the shot is already released before the seismograph starts triggering. Please check the selected trigger slope (positive/negative) of your seismograph. Slope has to be positive.

(5) Everything is connected correctly but the system will not start charging up to 800V. Please check if both “Emergency OFF” button are released (UP position).

Impulse Generator IPG800 and Borehole Source BIS-SH-DS

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