D.N. 10023765 Rev.2 Spartek Systems Page | 1

SCBT User Guide

Spartek Systems Spartek SCBT/Warrior Help File

This manual intends to give the users instructions on how to run Spartek SCBT on Warrior. It is a quick guide and not a comprehensive manual.

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SCBT User Guide

Overview

The reason for using the Segmented Cement Bond Tool (SCBT) is to ensure hydraulic seal in the well by confirming a good cement bond between the casing and the formation. It is also to confirm sufficient hydraulic isolation between producing and non-producing zones over the production interval. The cement bond log aims to confirm good cement to formation bond, good casing to cement bond and also that the quality of cement in place is good enough to offer the essential hydraulic isolation. SCBT tools measure decreasing acoustic energy as it passes from the tool through casing and cement into the formation. Perfect Cement Bond Scenario, Fig 1:

Good Compressive Strength Cement quality Good Cement to Formation Bond Good Cement to Casing Bond

Fig 1.

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SCBT User Guide

Potential for problems: It is essential for a good cement job to ensure well integrity for the life of the well. Operators are increasingly under pressure to safeguard against potential leak problems caused by fluid migration to surface. Fluid migration can occur due to channelling problems, where fluid follows the path where no cement is present. Standard Cement Bond log tools are not well equipped in identifying channels in the cement but the Spartek Radial SCBT tools offer a circumferential cement map of the casing to cement bond which enables improved identification of channels contamination and cement free areas. Cement Channelling, Fig 2. usually occurs when drilling or circulating mud has not adequately been removed during the clean-up process prior to the cementing operation. This can lead to pockets of cement free areas. Channelling can also occur due to issues when the cement is curing when water or gas can migrate into the cemented areas causing cement free pockets. More recently with an increasing amount of highly deviated wells, there can be issues where the cement falls to the low side of the well leaving little or no cement on the high side. It is also very important to ensure sufficient zonal isolation. Zonal isolation between reservoirs is vital to ensure there is no communication between producing zones. We want to avoid gas and water introduction to Oil wells and water production into gas wells. Poor isolation can allow produced water to flow into a load paying zone causing production of water to surface and increasing the potential for casing corrosion. Hydraulic isolation is the most important factor when it comes to cementing a well. The lack of hydraulic isolation is most commonly due to a low cement compressive strength. This low compressive strength is caused when uncured cement pressure drops to formation pressure. This can happen when the well hydrostatic pressure becomes isolated from the curing cement below. More often this is caused by premature curing of cement further up the hole. When the cement drops to formation pressure it allows the ingress of formation fluids and this can contaminates the cement making it permeable and therefore weakened.

Fig 2.

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SCBT User Guide

Theory of Operation:

The Spartek SCBT transmits an acoustic signal from its transmitter. This signal can permeate back to the tool receivers a number of ways:

Through the tool Through the wellbore fluid Through the casing, cement and formation.

The signal detected at the receiver is a combination of these signals and is the foundation of the log interpretation. The SCBT evaluates the cement bond quality and integrity to both pipe and formation by providing the measurements of the cement bond amplitude (CBL) through near receiver (3-ft crystal) casing cement bond, and variable density log (VDL) through far receiver (5-ft Crystal) formation cement bond. The Spartek SCBT also provides a 2ft radial receiver for the detection of channels, each of the 8 radial segments covering 45 sections of the pipe and provides a higher resolution. (The superior acoustic isolation of the SBT, well below 2% of tool-mode noise, makes the tool less susceptible to road noise yielding faster, efficient runs. Additionally, a slotted housing design for increased rigidity allows for better tool centralization, which is key to successful channel detection, and provides better logs in highly deviated wells.)

Tool Calibration

Calibration of the tools is performed when the tools are manufactured and the calibrations are set to industry recognised parameters. In years gone by downhole calibration of CBL tools were common place but more recently those running bond logs have found it increasingly difficult to find cement free sections of casing where free-pipe calibrations are performed. It is for this reason that the Spartek SCBT does not require any kind of downhole calibration and indeed we recommend that no downhole calibration be performed on the tools as the readings logged will alter the tool settings and render the internal calibrations unuseable. Note- SDS Warrior systems and the Spartek SCBT tools are set up so that 1V=123ms for 5 casing.

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SCBT User Guide

Tool Set up

Prior to logging you must carry out a few checks.

Clean and Grease all exposed O-rings, and replace if necessary. Check the piston position as shown in the pictures below. If the piston is covering the

positioning hole at room temperature it means that the tool requires an oil service. Refer to tool service section.

Check all screws and bolts are tightened to the proper torque settings as listed

below.

Torque Values for Machine screws Nominal Screw size Seating torque (lbs. in.) Axial Holding Power (lbs.)

Nc.0 0.5 50 Nc.1 1.5 65 Nc.2 1.5 85 Nc.3 5 120 Nc.4 5 160 Nc.5 9 200 Nc.6 9 250 Nc.8 20 385

No.10 33 540 1/4 in. 87 1,000

5/16 in. 165 1,500 3/8 in. 290 2,000

7/16 in. 430 2,500 1/2 in. 620 3,000

9/16 in. 620 3,500 5/8 in. 1,225 4,000 3/4 in. 2,125 5,000 7/8 in. 5,000 6,000 1 in. 7,000 7,000

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SCBT User Guide

Ensure the transmitter and receiver cans are free from dents. Ensure the upper and lower electrical connectors are clean, undamaged and there is

no shortage between the pins and ground.

Centralisation

Tool centralisation is vital in ensuring that the tool remains centralised at all times during the logging operation. At least two centralisers must be used in wells with deviation up to 30 and three centralisers used in wells with deviation greater than 30. The centralisation is to ensure that the transmitter and receivers are as close to pipe centre as possible. The Spartek SCBT offers two types of centraliser for each size of tool*:

1. SS9228 Roller Centralizer (2.75 dia) 2. SS9229 Roller Centralizer (in-line) (2.75dia) 3. SS9238 Roller Centralizer (3.50 dia) 4. SS9239 Roller Centralizer (in-line) (3.50 dia)

*The 2.75 SCBT can also be supplied with the SS9208 Bowspring Centraliser.

Spartek advises the use of inline centralisers on deviations greater than 30.

The top and bottom centraliser both have Industry standard GO connection field joints. The bottom centraliser connection can combine with all standard pulse tools.

The inline centraliser has its own multi-pin field joint design.

The SCBT tools have built-in Casing Collar Locators (CCL) and Gamma Rays (GR) in the telemetry section above the transmitter/receiver section.

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SCBT User Guide

Install the middle (inline) centraliser (if required) to the Sonde section at the transmitter side and tighten with C-spanners (pin wrenches).

Install the electronics section to the other end of the middle centraliser and tighten as above.

Install one centraliser to each end of the tool and tighten as above.

Note: If the middle centraliser is not being used, install the electronic section directly to the Sonde section as shown below.

Attach the cable head and tighten. The SCBT top connection is industry standard GO thread pin.

Set up the logging system and prepare to RIH.

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SCBT User Guide

Logging System & Service Set up

The SCBT is at present only available to be run on the Warrior logging system. Both Warrior versions 7 and the latest version 8 are supported. Future developments of the service will allow the tool to be run on Sparteks own high speed telemetry system enabling memory logging options. Below is a block diagram showing the basic set up required for running the Spartek SCBT with the SDS Warrior logging system and the panel pin out connectors for running depth, encoder and tension cables. SDS Warrior Logging System

Depth, Encoder & Tension outputs

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SCBT User Guide

Logging System Information

The SDS Warrior panel is attached to the line cable output (UHF connector) at the top right hand corner at the rear of the panel. This is in turn connected to the collector (slip rings). The logging cable is then attached to the tool via a standard PL logging head to the GO connection at the top of the toolstring.

There are 110V and 220V panel options so the correct type must be used for your region power supply.

Operating System- Windows 2000, XP, Vista, and Windows 7 32 Bit are supported. Warrior logging panel- Standard Cased Hole STIP panels are supported. No specific telemetry interface card is required in recent panels (2005 or later). If

using an older SDS Warrior panel Spartek can provide a Warrior Line Interface Card P.N. 10019163. This interface card is where the telemetry interface is controlled.

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SCBT User Guide

Load software and Configuration

1. Open the Warrior Control Panel from the Warrior services folder.

2. Select the licenses tab from the selection at the top of the panel and make sure the Warrior software code license is present. If it is not, input the required number.

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SCBT User Guide

3. Close the control panel and open Warrior Utilities then click on the Services Editor. From the Active tool list scroll down and select the DSS Bond Tool service. This holds all of the service information such as the Device type, Sensors and tools.

4. If the service is not available from the drop down box list then it will need to be

imported. You can do this by clicking on the Add tab on the top line.

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SCBT User Guide

5. When the Add tab is opened it will take you to the Warrior Config file where the DSS Tool service can be chosen from a list of several. The reason for this is that there are numerous services available through SDS Warrior from different companies using that logging system. All of the services cannot be listed at any one time and must be chosen to suit the individual user.

6. When the Service has been selected you can save the service and exit the Services Editor.

7. The Tool service has now been selected and the Acquisition tab can be selected.

This opens the logging system control box.

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SCBT User Guide

8. Change the Tool Interface Panel Configuration by clicking on Edit/Device Configuration/SDSTIP. Change the Aux settings highlighted below to Gain to 0.05, Q to 0.33 & Fc to 2000. These are the optimum settings for the SCBT telemetry signals.

9. Next click on Edit/Variables. This displays the variable (parameter) editor window, enabling depth dependant parameters associated with the selected service to be zoned and values to be set.

Check the proper Casing OD under CASEOD. If you are delivering a Bond Index Curve, enter the Minimum and Maximum Amplitudes and any other variables that may be required. Then push the Accept button.

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SCBT User Guide

10. Select File & Select Dataset. This will allow you to populate the parameters for naming and tracking your log data, calibrations and presentations. The Field name, Well name and run data should all be entered. Alternatively you can choose to Reopen an existing database file and all data will continue to be stored in that database file. Proper naming of the database and subsequent directories is strongly advised as in time you should have multiple database files.

11. Now select the logging service to be used by clicking on Service and double clicking the desired service title- DSS Bond Tool.

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SCBT User Guide

12. When the service is selected the tool string window will automatically pop up. You can alter the tool string as required.

13. A number of other windows will also pop up onto the screen. The Warrior Logging System and Depth windows are always present. The Tel Threshold, Panel Controls and WVFS7 Signal boxes are specific to the Bond tool service.

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SCBT User Guide

14. At this point power can be sent to the tool by clicking on Action-Power Control. This will open the Power Control box where you tick the Enable box. This action opens the Warrior panel power output to allow the user to send power to the logging tool. The Keep this box check box can be ticked if you wish to have the Power Control box on the desktop throughout the operation. If left unchecked the Power Control box will disappear.

15. Set the line power to positive. Power can now be sent to the tool by turning the power control dial to the optimum 110V. This should see current draw of approx. 75mA. The Spartek SCBT will work within a wide range of voltages from 90V to 150V but 110V is the recommended.

16. The SCBT will start to emit Transmitter ticking noises. If it does not then there may be an issue with the set up or cable head etc. Check all connections to the tool, collector etc. and re-try.

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SCBT User Guide

17. With the tool powered up you can now adjust the TEL Threshold as shown below. On the window the left arrow adjusts the positive threshold and the right arrow the negative threshold. Adjust the positive (+) and negative (-) thresholds to approximately 50%. Adjust the Panel Control AUX Slider to adjust the height of the digital signal until the pulses are just below saturation point.

18. Select Monitor/Devices/DSP (SDSDSP). Below are the approximate values for the 3 1/8 tool.

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SCBT User Guide

19. Select Monitor Outputs from the Acquisition window. An output window appears that will allow you to monitor signals such as GR, CCL, TEMP etc.

Opposite shows the Monitored outputs of the tool at surface. The screenshot below shows the Monitored outputs when the tool was in the Calibration tank.

Opposite are the approximate values for the 3 1/8 tool. These values are close to what the tool will normally read. Monitor the outputs for stable readings and adjust the positive threshold in the TEL Threshold window up or down to stabilise the readings.

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SCBT User Guide

20. As previously mentioned, the Spartek SCBT does not require any wellsite calibration and any attempt to do so will render the tools internal calibration unusable. If the tool is ascertained to be functioning properly it can be RIH.

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SCBT User Guide

Tool response & checks The Tool Cycle timing can be checked by attaching a scope to the SDS Warrior panel.

Above is the Cycle timing showing the Complete Tool Cycle and Positive and Negative Trigger Width and associated timing. The photographs below show this on the scope.

One complete cycle Double cycle

Additional checks

The average of the Radial output AMPAVG should be similar to the average of the 3ft output.

Between the Near & Far receivers the difference in output should be 114ms +/- 2ms. Between the Near receiver and Radial receivers the difference should be 57ms +/-

1ms.

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SCBT User Guide

Travel Times and Expected 3ft Amplitudes

Outputs and Channel allocation

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SCBT User Guide

Log output, LQC and Interpretation

This actual SCBT log excerpt shows the top of cement. There are ruler straight casing signals up to 600m (as long as the tool is centred and the casing signals are in evidence the casing signal bands will always be straight). There then follows a good bond section between 600m and 613m. The amplitude is low and there are wavy chevrons in the VDL map column. There are also no casing signals showing on the VDL map.

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SCBT User Guide

Log Quality issues There are factors that affect the quality of the log and/or the capability of the tools to perform as expected. These factors could be environmental or user associated. Centralization: Correct tool centralization is critical to ensure a good CBL. Eccentering of the tool can create lower amplitude readings indicating a good bond but if the tool is eccentered this reading will prove to be false. The effects of eccentering relating to false signal travel times are shown below.

Roller centralizers are advised because Gemco style centralisers can cause excessive friction on the casing wall increasing the risk of erratic tool movement. Fast Formations: Acoustic signals from low porosity limestones and dolomites can reach the receiver ahead of the pipe signal. Amplitude is high but not as high as free pipe. A point to remember is that even if fast formations are suspected the arrival of the signal in any case suggests that cement to formation bond exists. Light cement: It is difficult to see a contrast between lightweight cement and wellbore fluid and cement evaluation relies on being able to see this contrast. Lightweight slurries are commonly used in areas where cementing weak formations is required. Microannulus: This is defined as very small annular gaps between the casing and cement. It can be caused by a number of factors including:

Excessive wellhead pressure being held for too long during pumping operations which causes the casing to expand. When the pressure is released the casing retracts causing a break between the casing and cement.

Mudcake deposits on the casing which does not allow correct bonding to the cement. Some pipe coatings make this bonding difficult too.

Temperatures can affect the cement curing process which can lead to microannulus issues.

The recommended scale range for the travel time is 100s. This increases the readability of changes in the travel time. Lithology will also affect the signal as fast formations causes the signal to exhibit a shorter travel time.

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SCBT User Guide

Interpretation examples Good Cement No Cement Amplitude low, VDL signals strong. Amplitude high, VDL signals straight.

Partial Cement Microannulus Amplitude low and moderate, Amplitude is moderate. VDL can show VDL shows both straight and curving curving formation signals and straight Signals. casing signals. No Cement Bond to Formation Cement Bond in Hard Formations Amplitude is low, VDL does not show Amplitude fluctuates between low casing or formation signals. Thin mud and high. Formation signals cover signals are visible. casing signals.

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SCBT User Guide

Evaluating Hydraulic isolation Bond Index The Bond Index (BI) is a figure that is derived from two values. BI= Attenuation rate in the zone of interest (db/ft) Attenuation rate in a well cemented zone (db/ft) The Bond Index cannot tell us if partially bonded intervals provide isolation or if channelling exists. If the BI results in 1.0 the bond is considered to be perfect with 100% cement coverage. If the BI is less than 1.0 the bond is not 100% perfect but there may still be sufficient hydraulic isolation which will mean that there will be no need for remedial cement operations. A BI 0.8 is an industry recognised figure to achieve sufficient hydraulic isolation. Below is a guide to the accepted cement intervals for each common size of pipe.

(Graph courtesy of SPWLA, Ref. 27) From the graph above it is easy to see that for 9 5/8 casing, a 15ft (4.57m) fully cemented interval with BI=0.8 or greater is required to declare hydraulic isolation. This figure does not guarantee isolation but it is a good indicator. These figures are however in stark contrast to figures recommended by the US Environmental Protection Agency who declares that 7 casing should have continuous good cement for 33ft and 9 5/8 casing should have 45ft of continuous good cement. The Oil operator will guide you to the required BI.

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SCBT User Guide

Oil Service Procedure

1. Unthread the 7/16 slot screw at the top end of the Sonde section.

Note:

Ensure this end is elevated and that you have some soaking up material available as you may have fluid escape due to the spring pressure. You can use a pin punch or screwdriver to stop the piston from moving down.

Keep the top end of the tool elevated throughout the entire servicing procedure.

2. Thread the oil filling adaptor into the filling hole. Note:

The filling station should contain DC-200 fluid 100 C.S.T.

3. Attach the hose from the filling station (vacuum chamber) to the filling adaptor as shown in the picture below.

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SCBT User Guide

Below is a typical filling station set up

4. Start by vacuuming the tool for at least 30 minutes (the piston should slide all the way down to the bottom of the slot and cover the positioning holes).

5. Start filling the tool with DC-200 fluid until the piston stops at the top end of the slot and leave it to settle for two minutes.

6. Repeat steps 4 & 5 at least three times until no bubbles appear in the filling station chamber.

7. Fill the tool with DC-200 fluid as in step 4.

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SCBT User Guide

8. Install a pin into the positioning hole and release the pressure from the chamber. The piston should slide back and be stopped by the pin punch.

9. Unthread the pressure hose and filling adaptor. 10. Thread the 7/16 seal screw. 11. Pull the pin punch from the positioning hole. 12. Loosen the 7/16 seal screw slowly until you see some fluid dripping from the filling

hole. 13. Thread the 7/16 seal screw back in. 14. Ensure the seal screw is tight. 15. Check that the piston is in the right position as shown below.

Note: The piston should not cover the positioning hole more than illustrated above.