The implementation of the wire line logging programme at the well site is carried out by specialist contractors under the supervision of the Drilling Supervisor, although these responsibilities can be delegated to the Rig Drilling Engineer or the Well Site Geologist. The responsibilities of the well site personnel are identified below.

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If a radioactive logging tool sticks in the hole, the following guidelines must be adhered to:

• Do not continue work the tool because this may result in accidentally breaking the weak link.
• The Drilling Supervisor shall provide the Operations Engineer and provide him with all relevant information regarding the position of fish, allowable tension of weak point and cable, etc. The Operations Engineer must inform Head of Operations who shall approve the Fishing Programme which is to be written by the Operations Engineer. The Drilling Supervisor shall ensure that the Logging Engineer informs his management.
• Hold a pre-job safety meeting and emphasise to all personnel the requirement to keep clear of the rig floor during recovery.
• Proceed with strip over operations.
• Circulate bottoms up and have the logging contractor monitor the mud returns with a Gamma Ray tool placed in the return line. Ensure no personnel other than Logging Contractor's to be near mud pits or returns lines.
• Ensure that with the tool engaged in the overshot, circulation remains possible using the circulating sub if necessary.
• Unless authorised otherwise by the Head of Operations reverse stripping shall be carried out as a precaution against dropping the tool.

Recovery of Radioactive Sources

• Until a radioactive source has been fished out of the hole and is back in its carrying shield, try to keep the maximum distance between the source and personnel.
• Keep the number of personnel on the rig floor to an absolute minimum.
• The Driller should pull the tool containing the source as far as possible above the rig floor (minimum 50 ft).
• The rig crew should then cover the hole and leave the rig floor.
• The Driller should leave the rig floor until the Logging Engineer indicates that they are ready to disengage the fish and put the source into the shield.
• The shield should be placed near the spot where the source is to be released from the tool. Care should be taken to handle the source housing at points of minimum radiation, using the source handling tools.
• If the source cannot be removed from the tool, a wrap around shield should be attached to the tool and then taken to the logging base

Abandonment of a Source in the Hole

• Only the Head of Operations can authorise the abandonment of a tool down hole. If the hole is straight, a 1 000 ft cement plug shall be set on top of the tool prior to any other activity taking place. When well is handed over all details of radioactive source abandoned in hole has to be recorded in the handover sheet and metal plate marker installed on wellhead/Xmas tree.
• Ensure governmental legislation is followed

More fatalities occur during free point indication/ backoff than during any other wire-line operation except perforating.

In Free Point Indication/ Backoff  (FPI/ BO) operations, the travelling block is required for working the drill pipe and consequently the upper sheave has to be installed in the certified, permanent upper sheave support in the Drilling Mast. Precautions such as safety slings and shackle pin locking devices etc. shall be incorporated.

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Stuck logging tools are one of the non-productive time incidents experienced in well operations. Before logging, the Drilling Supervisor shall verify that the hole is in good condition and the well is not live. He shall also record the logging weak-point tension, cable tension limit and tool weight in mud. The Logging Contractor's stretch chart shall be available to verify the pull.

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This articles describes the mains guidelines and quality checks to be performed for successful logging operations

1. Preparation prior to logging operations:

• All wireline logging tools shall be checked and tested prior to rigging up.
• Logging operations shall commence when the hole conditions are stable. A check trip shall be required before running the formation pressure/sampling tool if there were hole problems during the previous run.
• The mud specifications shall meet the program specifications. The overbalance shall be at least 200 psi.
• Fishing equipment shall be available at the well site for all logging tools. All dimensions, lengths and connections of all the tools shall be recorded.
• For formation pressure/sampling logging a plot of expected pressures shall be prepared.

2. logging operations guidelines.

• The hole shall be circulated through the trip tank during logging operations. The hole shall be kept full throughout, and the trip tank volume shall be recorded every 15 minutes. The trend shall be monitored whilst running in and pulling out.
• The wireline logging depths shall be set to zero at surface and checked when pulling out to surface. Additional checks shall be made at casing depths and at TD.
• If a tool hangs up while running in and the section has not been logged before, log out of the well. If one of the detectors of a combination tool does not function properly, log the remaining detectors which have not been recorded before. When anticipating poor hole conditions, always log in as well as out of the hole to secure data.
• If a section has to be repeated, a 500 ft section shall be made on each logging run, and a 200 ft overlap with previous logging runs shall be made. The repeat section shall be made across an interval of interest.
• When running a calliper tool in a section where the top of the logged interval is below the casing shoe a 1 000 ft section over the shoe shall be run to check shoe depth and calliper gauge.
• Mud shall be sampled from both the pits and flowline immediately before the end of circulation prior to a logging job for analysis and resistivity measurement. This shall be repeated after check trips if resistivity tools are to be run.
• Check trips to bottom shall be required to ensure the hole and mud conditions.
• The weak-point tension limit and cable tension limit shall be checked and tool weight in mud calculated before entering open hole. Normal logging tension shall be checked every 1 000 ft in open hole. This is especially important in deviated holes where drag can be significant.

3. quality control guidelines

• The depth correlation of all the curves on the log must be checked with each other.
• The repeat section must be checked with the main log for agreement. The curves must be examined to see if they have sensible values. They shall be compared with logs in nearby wells, which must always be available on the rig.
• The correct logging speed must be verified. The speed can be determined from the breaks in the lines at the edges of the log which occur every minute. For example, if the distance is 60 ft, the logging speed was 60 ft/min. For resistivity logs the standard logging speed is 60 ft. Statistical nuclear tools require a speed of 30 ft/min. The acceptable range is +/- 10 %. Confirm this with the Logging Contractor in advance.
• Verification shall be made that there is 200 ft overlap between successive logging runs.
• The depth discrepancies between successive logging runs must be less than 2 ft.
• For the Cement Bond Log, a 300 ft section of the free pipe reading during logging must always be recorded (if uncemented sections exist).

4. Formation Pressure Tests guidelines

• When taking pressures the tool shall initially be set for two minutes only. If the pressure does not build up properly the tool shall be unseated and another attempt made.
• Plot both the formation pressure and mud pressures as they are taken. Inconsistencies in the mud gradient shall be checked immediately (a smooth mud gradient shall be regarded as a quality check).

5. Highly Deviated Wells guidelines

• Before entering open hole the normal logging tension shall be recorded. It shall be higher than that of a vertical hole and large stretch corrections shall be required.
• Checks shall be made to ensure that the tool is moving down the well as the wireline is being run into the hole.
• Short tool combinations are easier to get down the hole particularly in areas of high dogleg.
• For high deviations or particularly difficult holes, consideration shall be given to other techniques, eg., drillpipe (TLC) or coiled tubing (E-line) conveyed logging tools or the use of logging while drilling tools (LWD).

6. Horizontal Wells guidelines

• Horizontal wells shall be logged either with LWD or TLC techniques.
• The use of drilling jars are not recommended because of the risk of logging tool damage. It shall not be possible to run jars or HWDP because of ID restrictions for an extended length. This requires enough regular drillpipe at the well site to replace the HWDP’s, drill collars, jars, etc.
• The running in speed shall not exceed that used when running a packer on drillpipe. Below the kick-off point, the tools shall tend to lie on the low side of the hole and not be subject to so much bouncing as higher up. Obstructions downhole (eg., liner tops) shall be passed with caution. Break circulation at regular intervals (ie., every 10 stands).
• A down log shall be taken while running in. The Logging Contractor procedures shall recommend that the tools do not tag the bottom of the hole but stay a minimum 20ft above drillers depth. Depth control shall be checked with the drillpipe during in-run and out-run.
• Continuous communication is required between Driller and the wireline unit to ensuring the pulling speed and cable spooling speed are matched, and to minimise reaction time if the tool begins to stick. Minimise downward movement when setting slips, because the calliper will be in the open position.
• The cable shall not be slacked off to avoid the risk of damaging it at the side entry sub.
• A cable head tension/compression meter readout shall be made available to the Driller on the rig floor.
• The string to be spaced out to have latch point in cased hole.
• If circulating sub cannot be latched increase cable running speed and check for latching from logging unit.

Prior to any fishing operations ensure that all personnel involved are aware of their duties by means of a pre-operation safety meeting.

Dressing the Tools

Take a new grapple, grapple control and guide and assemble the overshot. Ensure that the correct type and size of grapple is used.

Preparing the Cable

The following procedures should be adhered to when preparing the cable for the cut and thread method:

1. Pull the cable to 2000 lbs above normal tension to remove any slack.

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The following equipment should be available for stripping over a logging cable:

• Loggers fishing kit (to be supplied by Logging Contractor).
• Additional tension meter with cable tension readout for the Driller.
• 90 m of ¼" rope to control the run of cable going over the top sheave.
• 30 m of ½" rope to hold the lower sheave straight.
• Intercom between Driller and Logging Contractor winch operator. 

1. Preparation

1. To prepare the overshot; Inspect, lubricate and dress the overshot contained on the loggers fishing kit. (The single wicker grapple specified for epoxy or rubber covered heads has one cutting edge, and the grapple for steel heads or bodies has several smaller cutting edges). Check the top end to ensure that the 2 3/16" bushing is in place. This holds the 2 1/4" hexagonal adapter of the lower rope socket, if the cable is dropped at the surface.

2. To prepare the cable for cutting;  Set the cable tension at 1-2 MT above normal hanging weight. Secure the cable clamp (T-bar) to the cable, just above the rotary table; (check that the correct sized bushing is used). Lower the cable until the cable clamp is supported by the rotary table. (Continue slacking off the cable, then cut it at a point 1 1/2 - 2 m from the cable clamp, and secure the ends.

3. To re-rig the derrick; Position the lower sheave to that it does not interfere with drill floor operations, and hang the upper sheave from one of the main derrick (water-table) beams, well above the drill  pipe stand, in such a position that it does not interfere with the travelling block.

4. To prepare the cut and thread assembly;  Fit rope sockets to both ends of the logging cable. It is preferred and safer to fit standard rope sockets, (slip type rope sockets, although they are quickly   fitted have been known to fail). Make up the remainder of the assembly, i.e. spearhead, spearhead overshot, swivel, and sub. Sinker bars may be added to the catcher assembly to provide the necessary weight.

Having rigged the derrick, assembled the rope socket and spearhead overshot to the winch end of the cable, and assembled the rope socket and spearhead to the well end of the cable, carry out a full  test. Latch the spearhead overshot to the spearhead while the cable clamp remains on the cable. Mark the cable adjacent to each rope socket with tape and test the cable with 2.5 MT tension for 1 minute. The well-end of the cable should be passed through the (fishing) overshot before the hex-  adapter is replaced.

5.To thread the cable through the drill pipe; In addition to the regular drilling crew, there should be:

• An experienced winch operator.
• One man at the rotary to engage and release the spear overshot.
• A logging engineer on the drill floor to observe the operation.

2. Going In The Hole

The following is a step by step procedure of running in while stripping over the logging cable.

1. Pick up the first stand of drill pipe and install x-over subs as required.

2. Draw the spearhead overshot up to the derrick man, who can then thread it through the first stand of drill pipe. If the sinker bars make the assembly too stiff to pass the travelling block, the assembly should be fed into each stand before it is picked up.

3. Attach the spearhead overshot to the spearhead and make-up the fishing overshot with chain tongs onto the bottom of the first stand.

4. With tension in the cable, check the operation of the remote tension indicator, then remover the cable clamp.

5. Complete the make-up of the fishing assembly with the rig tongs.

6. Run the first stand into the hole:

• maintain a depth tally,
• maintain the cable tension to 1.0 MT,
• pay close attention to the tension indicator.

7. Install the "C" plate, and slack-off the cable until it is supported by the "C" plate.

• the winch operator should flag his cable to ensure that he can easily return to this exact spot for each stand of drill pipe.

8. Release the spearhead overshot, thread it through the next stand, and re-connect it to the spearhead.

9. Pull tension in the cable and remove the "C" plate. Make up the second stand onto the first and repeat the whole process for each stand. Run in slowly and carefully (according to the points listed in Item 6), thus avoiding the following primary hazards:

• the cable being dropped,
• broken armour wire balling up ahead of the overshot,
• the impact of the overshot on a bridge cutting the cable,
• the cable (if it is not removed from a keyseat) double-backing around the overshot.

Note:  Do not rotate the pipe in the hole.

10.When approaching the depth of the fish, it is good practice to clean out the fishing tool by circulating. Circulation at a bridge, at the fish, or during engagement of the fish is accomplished by hanging the cable spearhead on a bushing in a special circulating sub.

• a) With the spearhead hanging on the "C" plate, thread the circulating sub and adapter sub over  the spearhead overshot. Latch the spearhead overshot onto the spearhead, lift the cable and remove the "C" plate.
• b) Make-up the subs onto the drill-pipe. Place the special bushing over the cable and into the circulating sub. Lower the cable until the rope socket rests on the bushing. Unlatch the spearhead overshot.
• c) Make up the kelly onto the circulating sub, using the appropriate cross-overs.

11.When the overshot is a short distance from the fish, the fish may come free. If this occurs  circulation may be used to clean the overshot and then the logging tool can be pulled into the grapple. The fish may, however, be covered by formation solids, requiring the overshot to be circulated down onto the fishing neck. In this case the overshot must reach the fish with sufficient       tension still in the logging cable to prevent it going slack and looping over the rope socket.

The original tension at surface, including the weight of the logging tool, is known. Also, the elongation (stretch) per 3000 m of standard logging cable sizes with respect to tool weight, can be determined from charts supplied by the Logging Contractor. Thus the fish can be engaged as follows:

• a) Pull on the logging cable with the original logging tension and check the elevation of the spear point.
• b) From the Logging Contractor's chart, find the cable stretch due to the weight of the logging tool in mud.
• c) The elevation minus the stretch gives the elevation of the spear point for neutral tension in the cable at the logging tool. Space out the string with pup joints so that the spear point will not be below this elevation when the overshot engages the fish.

Note:   This procedure cannot be used on floating rigs because of the heave and tide  movements of the rig in relation to the logging tool. In this case, lower the string without circulating over the fish while maintaining a close-to-maximum pull on the logging cable.

If circulating over the fish, continue pumping while lowering the pipe and engaging the fish. An increase in both pump pressure and cable tension should be noted as the tool head enters the overshot. Stop circulating.

12.After proving, by motion of the pipe and its effect on the cable tension, that the fish is engaged, the  cable weak-point may be broken by:

• installing the cable clamp,
• latching the elevators around the cable, (under the cable clamp) and,
• pulling slowly until the weakpoint breaks.

13.Cut the cable to remove the rope sockets, then tie the two ends together with a reef knot. Tape the loose ends onto the logging cable to prevent them hanging up as they pass over the sheaves.

14.Spool the cable onto the winch, then pull the fish out of the hole. Do not rotate because the fish may disengage from the overshot.

3. Problems While Stripping Over The Cable

1. If the spearhead rope socket fails, then a broken cable is left in the hole.

2. If the spearhead with rope socket and cable is accidentally dropped into the pipe, run the thread through overshot with the largest applicable guide down the pipe and attempt to engage the spear. If this fails, the drill pipe can be pulled because the bushing in the fishing overshot will catch the hexagon adapter on the spearhead.

3. When cable tension increases sharply, the cable may be stuck in a keyseat and doubled back outside the overshot. Picking up the pipe should cause a small decrease in tension. Increase the cable tension and the guide should free the cable ahead of the advancing overshot.

4. When cable tension increases moderately fast, a broken armour cable may be balling up at the overshot.

5. If the cable tension increase is gradual, as is normal for a deviated well, the elevation of the spear point will be lower. If the spear point becomes lower than the top of the pipe during running in, a  short length of spacer bar may be introduced between the rope socket and spear head.

6. If a bridge is encountered, it should be removed by circulating.

7. During stripping over operations on floating rigs, the sheave arrangement is not compensated for heave and tide movements. Hence the winch operator has to take extra care to avoid breaking the  weak point prematurely.

4. Logging Tool Stuck In A Cased Hole

In deviated wells (greater than 25 deg) it is almost invariably safer to strip over the cable in order to recover both tool and cable.

In vertical wells it is also preferable to strip over, although in certain circumstances (after consultation with Base) the following fishing procedure may be applied;

1. Secure the cable clamp to the cable just above the rotary table.

2. Re-arrange the sheaves as per item (b) 3.

3. Latch the elevators around the cable, (under the cable clamp), and pull slowly until the weak point breaks.

4. With the logging cable in tension, remove the cable clamp and spool the cable onto the logging unit winch.

5. Rig down wireline and fish for the stuck tool using conventional methods. On retrieval, ensure that the complete tool has been recovered.

5. Fishing Through Tubing

When a tool becomes stuck either in or below tubing, in most cases the only remedy is to pull the tubing to recover the fish.

Reverse circulating to recover the fish may be feasible. Fishing with slick line (piano-wire) could be considered, although this technique can only be successful if the tool is free, (e.g. if it has dropped off the end of the logging cable). Although jarring is possible, fishing for stuck tools using slick-line will almost invariably aggravate the problem.

The Reverse Cut and Thread Method is recommended in case a logging tool containing a radioactive source is stuck and has to be fished.

After this point the procedure deviates from the Cut and Thread Method.

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3. Rig-Up and Survey Quality Control

The checks for rigging up for logging and running the survey are important to achieve a good quality of the surveys to be run. The wireline contractor shall have detailed procedures developed for this purpose. These shall cover activities and services like:

-   Placement and installation of wire-line unit(s).

-   Rigging up of wire-line sheaves.

-   Handling and storage of explosives and radioactive material, and precautions in this respect.

-   Surface preparations, assembly and function testing of logging tools.

-   Running in hole.

-   On bottom checks and considerations.

-   Measures to prevent getting stuck.

-   Surveying.

-   Post Survey activities.

-   Cutting Side Wall Samples.

-   Running and Setting of Packers.

-   Running directional Survey Tools.

-   Reporting.

4. Safety

Good communications are important in order to maintain safety during electric wire-line logging. The following procedures should be observed with regard to the safety of personnel and equipment:

1. The chain connecting the lower sheave shall be securely anchored and the sheave adjusted to  the centre of the well.

2. Keep well clear of the logging cable. If it is stretched tight in the hole and is over tensioned, the cable may break suddenly. If the cable is loose on the deck, it may be that the tool is hung up in the hole and too much cable has been unspooled.

-       Never step over the cable, always walk around it!

3. Check the cable armour regularly for unravelling armour strands. This applies particularly to operations through a stuffing box.

4. Avoid the drill floor area during logging operations.

5. Do not stand close to the lower sheave, in case the tie-down chain breaks or comes undone due to high tension in the cable.

6. Tag a reminder on the BOP control panel to ensure the cable is not cut by inadvertent closure during wire-line operations.

7. Do not perform overhead lifts across or near the cable during wire-line operations.

When the wire-line operations involves the use of explosives and radioactive sources, all operations shall be conducted in accordance with the safety procedures. Only authorised and qualified personnel shall be on the drill floor during these operations, and clear signs and barriers should be placed to show such operations are in progress. The requirement regarding radio silence shall be observed as appropriate.

5. Preparation for Logging

1. Carry out a test transmission to check if the equipment is operational.

2. Ensure that logs of any adjacent or nearby well are available for comparison and correlation.

3. Check the logging programme with the contractor to confirm the running order of the tools. Do not run a tool requiring a radioactive source as first in hole, until bottom hole conditions are known. Run the surveys in decreasing order of importance in case the hole condition deteriorates.

4. Provide the logging contractor with the following data:

a)      Well description, location and drill floor elevation, BOP and Wellhead depths.

b)     Bit and casing sizes, total depth and casing shoe depths, any anomalies in the string.

c)      Mud type, weight, viscosity, water loss and pH.

d)     The logging programme, including;

-           all logs which are required,

-           intervals to be logged, and where repeat sections are to be recorded,

-           which logs are to be taped, and when transmission should be carried out, as applicable.

e)      Downhole conditions relevant to the logging operations; e.g. deviation, tight spots, dog legs, pressure and gas zones, fill experienced on previous trips, etc.

f)      The duration of the last circulation of the hole and the time when circulation stopped prior to pulling out of the hole for logging.

5. Provide a mud sample 1 litre, mud filtrate 10 cc. and mud cake (at least 3/16 in (6 mm) thick to be representative). The mud sample should be taken from the flow line during circulation just prior to logging. Ensure the measurements are made on the sample as soon as possible.

6. Sidewall Samples

Sidewall samples are taken to provide either palaeotological or petrophysical information. The samples are obtained using a tool on a wireline. Because sidewall sampling involves the use of explosives, the following procedures shall be strictly adhered to:

1. All operations shall be conducted in accordance with the safety procedures given above on the use and handling of explosives. Only authorised and qualified personnel shall be on the drill floor during these operations, and clear signs and barriers should be placed to show such operations are in progress. The requirement regarding radio silence shall be observed as appropriate.

2. Check distance from the measure point of correlation tool (S.P. or Gamma Ray) to the bottom shot. Make the appropriate correction before taking the first sample and adjust as the firing proceeds.

3. Ensure the powder load for each shot has been correctly loaded.

4. Ensure that:

a)      The correct size gun is used.

b)     The correct length fasteners are used.

c)      High temperature powder is used when necessary above 140 C, bottom hole temperature.

5. Make the depth correlation log (GR) at the normal gamma ray logging speed of 500 m/hr and   determine the correct depth. Check carefully for creep i.e. the movement of sample taken after the winch has stopped. If the creep is 0.5 m or less, stop at correct firing depth to shoot sample. If creep exceeds 0.5 m, it is permissible to shoot "on the run": in this case, note on the report form that this technique has been used, and in particular report any samples suspected of being shot off   depth.

6. After successfully firing each shot, try to "work" the core free. If all attempts at freeing a core fail, the retaining wires can be broken by dropping the sample taker rapidly and snapping them off.

7. Move up and down slowly 3000 m/hr with the samples. For unconsolidated samples lower speeds should be used e.g. 1200 m/hr.

8. Watch the tension very carefully when entering and ascending through casing.

9. Untangle the retaining wires. Remove one bullet at a time from the gun, starting at the bottom of the gun (Sample no.1). Place the bullets in the correct compartment of the box, (supplied by the Logging Contractor) and continue to remove the other bullets. Once all the bullets have been removed, press each core into a sample bottle one at a time noting the recovery. Record also when bullets are lost or empty. This sample removal/identification should be supervised by the Logging     Engineer and a Company Drilling or Petroleum Engineering representative, to ensure that depth identification of the samples is correct.

10.Ensure that all relevant data i.e. Company name, well number, sample depth, sample number is given on the sample container. Mark the sample number on the container lid.

The sidewall samples shall be described on the Sidewall Sample Report.

These descriptions shall be sent immediately to Base and the samples despatched on the first available helicopter.

7. Running and Setting Packers

Because the running and setting of packers involves the use of explosives, the following procedures shall be strictly adhered to:

1. All operations shall be conducted in accordance with the safety procedures on the use and handling of explosives. Only authorised and qualified personnel shall be on the drill floor during these operations, and clear signs and barriers should be placed to show such operations are in progress. The requirements regarding radio silence shall be observed as appropriate.

2. Keep the packer under cover in a safe place until required.

3. Run the junk catcher until hole is clean. If necessary, make a check trip with a bit and scraper   followed by a further junk catcher run.

4. Inspect the packer carefully (particularly the slips and rubber) and witness the preparation of the packer prior to running in hole. Ensure the correct size packer is used.

5. Avoid running the packers into or through perforated intervals because deformed casing or burred holes may jam the packer or damage the seal rubbers. Do not exceed a running speed of 3000 m/hr. Keep the tension under constant observation, as the plug is a tight fit and may easily hang up on any obstructions.

6. Use a CCL for depth control, and never attempt to set a plug within 1 m of a collar. The normal practice is to check depths when pulling up, to avoid problems with loops or slack cable. However, in large casing sizes, the centralising action of the packer may keep the CCL away from the hole sides so the collars are difficult to locate. In this case it is often possible to see the collars when moving down - when moving upwards subsequently to setting depth, make allowance for hysteresis in the tool movement.

7. Make a CCL log across the setting depth to ensure correlation with GR/CCL survey.

8. Record at a distance of two or three casing collars below setting depth, then stop at required depth.

9. Set packer. Observe the tension change or cable vibration. Up to three distinct tension kicks may be observed when setting a packer. Allow at least one minute after firing for the packer to fully set   before carefully pulling back the setting tool. For large packers, a longer time may be required.

10.Move the CCL across the scale, record two casing collars above setting depth. Pull up slowly to ensure the tool has disengaged from the packer.

11.After setting a bridge plug, lower the setting tool on to the plug, record the pick-up point and two collars above. This procedure should not be followed with production packers (cement retainers) in case the tool latches on to the packer and cannot be freed.

Note:The pick up point may appear deeper due to reduced cable stretch as the weight of the plug will no longer be applied to the cable.

12.Ensure the plug has set correctly, but do not exceed 3000 m/hr when pulling out. If the plug has NOT set, pull out much more slowly, particularly if there are indications that only one set of slips may have operated.

13.Keep unnecessary personnel off rig floor while gas pressure is released from the setting tool.

14.Check the setting tool carefully to ensure that its operation was normal, i.e. the release stud has sheared, and there is no damage to the release sleeve. If there is any doubt that the packer has set correctly, run slim-hole CCL (1 11/16") to determine packer depth.

8. Formation Testing

Basically there are six stages to formation testing operations:

-   Surface preparation

-   Running in the hole

-   Pretests

-   Sampling

-   Transfer of samples

-   Reporting of results

and the procedures and guidelines for each are given in the article on production testing.

9. Pipe Conveyed Logging

9.1 Pipe Conveyed Logging/ Logging Through Drillpipe

-   Two systems are available for use:

1. Push Down Systems TLC/PCL. These systems use regular open hole logging tools run down hole on 3 1/2" or 5 1/2" Drillpipe (Schlumberger/Western Atlas).

2. Pump Down Systems. These systems pumps down slim hole logging tools (2 3/4" or 1 11/16") through drillpipe ( Western Altas).

The two systems are usable in any well where wireline run logging tools are unable to pass, such as bad hole section/wash out or where hole deviation is too high.

The preplanning of a TLC/PCL operation require planning of tool combination, selection of and organisation of special tools based on well data.

Drilling jar will be run if required .Special precautions shall be taken when a drilling jar is run.

Check that Logging service contractor is only using only zone 0 equipment and maintain the certification of same .

Be aware of that only GR; BHC and Induction Log are available for Pump Down Systems 2) (PDS) when using 3 1/2" DP.

A Side Entry Sub (SES) should be placed in the drillstring  but is only recommended with 9 5/8" casing or larger. The system available for 7" casing , with the 1" ID of the accompanying SES will not permit the passage of any back off tools. The Western Atlas 3 1/2" IF SES has an ID of 1.81" through which back off tools can pass .

When the Side Entry Sub on the bottom of the drillstring reaches the casing shoe it guides the multi conductor cable from the inside of the drillstring into the drillstring/ casing annulus.

Note that the  SES should not be run past  a point of  more than 30 inclination and not placed in a position where it will squash the cables against the low side of the hole.

General outline of procedures

The TLC/PCL system is a technique which can be used in highly deviated holes or holes with deteriorating conditions, where it is not possible to log on conventional wireline. The logging tools are run on drillpipe and the wireline cable is attached with a wet-connector on top of the tools. The cable is run through a Side Entry Sub (SES) to allow continuos logging and circulation.

Preparations prior to logging

-   Prior to and during the job, safety meetings should be held with each crew to highlight the operational steps

-   All drillpipe and the jar should be drifted (size to be checked with the contractor)

-   Two sets of wet connectors are to be supplied by the logging contractor.

-   Install the jar at approximately 200m above the wet connector. See that the jar stroke is completely extended ( if the jar is fired, run in hole and function test tools)

-   Make up any additional stands of drillpipe required to reach the bottom the logging interval.

-   Install intercom/ communication head sets and tension compression monitor near driller.

-   Have the logging unit positioned such that direct eye contact with drill floor is possible.

-   Cable cutter s on drill floor

Running tools into bottom of logging interval

1. Make up logging tools in rotary table .Test function of wet connector and logging tools ( check wet connection vertically in the rotary table, not horizontally on the floor). Before fully torquing up the IF connection of the latch assembly, put on the one single of drillpipe above to prevent sideways movement.

2. RIH 200m drillpipe.

3. Install jar.

4. RIH string slowly till tools are approximately 20-30m from top of  logging interval.

Note: CONTRACTOR PERSONNEL SHOULD BE ON DRILLFLOOR CONTINUOUSLY FROM THIS TIME ON.

5. Insert female part of wet connector in the Side  Entry Sub. RIH wireline cable a few hundred metres until it can run on its own weight.

6. RIH the Side Entry Sub on 1 joint of drillpipe (below BOP's) ,make up Right Hand Kelly Cock (RHKC) and circulation head (use DP-screen). the packoff seal of the side entry sub more effective when wet.

7. RIH wireline cable to approximately 50m above wet connector . Use snugger sheave (pull over sheave ) to pull cable back from drillpipe. Record cable tension.

8. Circulate for 10-15 minutes.

9. RIH wireline cable to wet connector  and latch on .(Depending on the depth, angle, etc. pump down while latching, contractor to advise )

10.If positive indication of latch :

- indication from line check (communication with tool)

- test logging tools

- make sure  pumps are off again before coming up

If not latched, pull out approximately 50m and try again . Circulate and try to find right pumping pressure and cable speed (contractor to advise).

11.POOH Side Entry Sub(SES)above table . Pull on cable to recorded cable weight . Slack off one (1) m  and put on clamp.

12.RIH tools to bottom of logging interval .Record weight of string up and down.

-       While running in , log down (contractor to advice on running speed).

-       Communication between driller and winch man is vital.

-       Watch for cable damage by slips and tongs

-       Contractor to advice on maximum compression allowed.

Logging

During calibration in open hole keep string moving to avoid  differential sticking.

Start logging up . After every stand set slips (minimise downward movement because caliper/ pad is open). Winchman to give slack after slips are set . Again: communication between winchman and driller is vital.

With the side entry sub back on surface, disconnect clamp and POOH with cable until  approximately  50m  below entry sub . Ensure the RHKC is installed on top (swabbing ).

Rig down sheaves and POOH logging tools

Hole problems

In case of stuck pipe: try to work string free, circulate . Use the jar only as a last resort .If unsuccessful, pull cable to side entry sub .

In case of well flow: retrieve cable if possible, otherwise cut cable above rotary and close BOP.

9.2 Recovery of Logging Cables under Pressure

General

Recovering unweighted logging cable by pulling through the lubricator while under well pressure is generally acceptable .

Adding sinker bars or weight above the weak point will hamper normal operations (not recommended).

Procedures

The operation carries out a higher than normal risk and requires specific procedures and extra precautions. The following points must be emphasised when recovering  the cables under pressure:

1. A safety meeting must be held with all staff involved to discuss the produce to be followed .

2. All personnel not essential to the operation are to be cleared from the wellhead rig floor area.

3. Ensure that proper means of communication between the operator at the lubricator and the winchman are available and in use .

4. Line up and test kill equipment before attempting to recover the cable . Also check grease injection equipment before commencing .

5. Lower top logging sheave as much as is practical to reduce free length of cable above the lubricator.

6. Do not use lubricator BOP rams to apply friction to the cable, apply sufficient grease injection pessure on the flow tube injection head to counteract/ control well pressure and reduce cable speed.

For more detailed information reference is made to the Integrated Service Contract manuals which will be available.

10. Stuck Tools

1. Keep the wire-line tension under constant review and in particular ensure that normal tension is known within 0.5 kN (100 lbs) at logging depth.

2. At the first sign of a sticking tool, alert the winch operator/engineer. Precise procedure to be followed subsequently depends upon a rapid assessment of the most probable sticking  mechanism. The four most probable causes of tool sticking are:

a)      Key-seated cable. This is caused by severe dog-legs, or as a result of the cable wearing a slot in the formation during a long logging operation.

b)     Key-seated tool head. This can happen in the vicinity of dog-legs, or in oval or key-hole shaped holes.

c)      Bridged hole. Often a result of shale collapse.

d)     Differential Sticking. This may occur when logging porous, permeable intervals in depleted reservoir zones, or intervals at much lower pressure than the mud column.

The procedure to be followed in the first three above cases (a, b AND c) is:

1. When an overpull of 2.2 kN (500 lbs) is reached, stop the winch, lower the cable until tension is 2.2 kN (500 lbs) below normal.

2. If the stuck tool has powered arms, close the sonde arms.

3. Reduce the tension to 4.4 kN (1000 lbs) below normal.

4. Observe whether the tool is still moving (in this case down).

5. If the tool is still moving, attempt to work the tool above the obstruction. While the tool will still move down the hole, do not apply an overpull more than 2.2 kN (500 lbs).

6. If the tool is NOT moving down, release tension further, to 6.7 kN (1500 lbs) or 8.9 kN (2000 lbs) below normal. Do NOT allow slack cable at the surface. Wait 5 minutes.

Note:    Do not exceed this limit without the approval of Base.

This procedure ensures that excessive pull is not applied in the initial stages, as this can jam the head, pads or cable into a key seat which can only be released by fishing. If the hole is bridged over, it is much better to be able to keep the tool moving below the bridge and attempt to work it through the obstruction than to lock it irrevocably into place with the first sharp pull.

When logging with a pad tool in porous and permeable sections of depleted reservoirs, differential sticking can be a problem. In this case, adherence to the above procedure may lead to unnecessary problems. If differential sticking is probable, follow the alternative procedure:

1. At the first sign of sticking, continue to increase pull to normal logging tension plus two thirds of nominal weak point strength.

Note:    Do not exceed this limit without the approval of the Base.

2. At 8.9 kN (2000 lbs) overpull, start to close the sonde arms.

3. If the tool comes free, re-open arms and continue logging.

4. If the tool does not pull free, reduce tension and work the cable up and down as in the first procedure.

If the tool is stuck, continue attempts to free it until the decision is made to cut the cable and strip over to the fish. The weak point must NEVER be broken when a tool is stuck in open hole EXCEPT when:

-       the cable has been stripped over and the head of the tool is securely engaged in the overshot, or

-       a decision has been made at Base either to abandon the tool, or to pull off and fish without overstripping.

Investigate the probable sticking mechanism by applying a stretch test, i.e. measuring the cable extension generated by 0.9 kN (200 lbs) increments of pull up to 8.9 kN (2000 lbs) above normal logging tension. Remember that, in deviated holes, friction at the dog-leg may give a false impression of key-seated cable.

Note: The incorporation of a down-hole tool head tension indicator in the tool string is being introduced on certain advanced telemetry tools. This device should improve the knowledge of down-hole conditions immeasurably, and may assist in avoidance of stuck tools, as well as   aiding in safe descent into highly deviated wells.

This article describe the requirements for radioactive sources and explosives (permit to work, transporation, handling and storage).

1. Radioactive Sources

Permit to Work

All operations involving the use of radioactive sources must be performed under the Permit to Work system.

Storage

The radioactive sources must be stored in clearly marked approved storage containers (locked and keys with Drilling Supervisor) on each rig inside their appropriate shields. The storage containers must be fixed by welding, bolting or chains and must be located as far as is practical from regularly occupied working areas. The gamma radiation level at the surface of the container must be no more than 7.5 u Sv per hour. The 7.5 - 2.5 u Sv/hr area around the container shall be marked a “no-stay area”. Barrier stands/signs shall be erected to mark the extent of the controlled area.

Transportation

Sources must be transported in the special storage boxes under police escort. Transportation shall be limited as much as possible. A controlled area shall be established on the transport vessel or vehicle.

Handling

The Logging Engineer, or his designated operator under the Company written instruction, are the only persons permitted to handle radioactive sources at all times. The drilling crew are not permitted to help during this operation. Sources should be returned to the storage container immediately after use.

2. Explosives

Permit to Work

All operations involving the use of explosives must be performed under the Permit to Work system.

Storage

There must be two clearly labelled storage boxes available for primary and secondary explosives respectively. Explosives should only be taken outor transported immediately before use. Explosives storage boxes should be placed on jettison platforms offshore or at easy dump positions.

Handling

The Logging Engineer is the only person who is allowed to arm or disarm any tool using explosives. The red “safety key” must be removed from the logging cab before any arming or disarming operation. The only people permitted on the drill floor when explosive tools are on surface are the Logging Crew, Drilling Supervisor and the Driller. Radio silence is to be maintained during arming/disarming the tools and when tools are less than 500’ from surface in hole.

Pipe conveyed logging (PCL) logging is performed when conventional wireline operations are not feasible, such as in high angle/horizontal wells.

 If there is doubt as to whether wireline logging will be successful, consideration should be given to mobilising PCL equipment on standby, although the standby cost should be balanced against the likelihood of its required use. Above 70^o inclination (PCL) logging shall be used.

Job Preparation

A successful operation requires obtaining vital well site information before the job.

Basic information that needs to be acquired includes:

casing depth size and weight

liner top (if applicable)

hole size and TD

directional data

mud weight and temperature, mud type, mud additives (nut plug etc.)

drillpipe size, grade, tool connections, ID’s

include drillpipe connections ie., 4.1/2in x H 4.1/2 IF, as well as drillpipe size, 4.1/2in, 5in, etc. so that the internal diameter of the drillpipe is known

use of a top drive on the rig, iron roughnecks or other effect mechanical apparatus that effect the PCL operation should be checked.

Bit Size and Drillpipe

Another major area to be concerned with is small bit size (6in) and small drillpipe, commonly 3.1/2in IF Cable Side Entry Sub.

If 3.1/2in IF drillpipe is run all the way to the surface and a split drillstring is not used, it will require using a small 3.1/2in IF Cable Side Entry Sub

It will not be possible to run jars or heavy weight drillpipes since there are restrictions of 2.1/4in for an extended length.

This will require the rig to have enough regular drillpipe (grade E or 3 ½” tubing - Xover to be available) on location to replace the heavyweights, drill collars, jars, etc. and only normal drillpipe should be run below the Cable Side Entry Sub .

Heavyweight can be shifted in the derrick in order to be run on top of Cable Side Entry Sub

Cable Side Entry Sub shall not be run in open hole.

If a rig is using a tapered drillstring, (ie., 3.1/2in bottom, 4.1/2in on top) the internal diameter of the crossover subs should be checked to make sure they are at least 2.40in ID. It is possible to get through an ID of 2.1/4in but only if it is a short section like a crossover. Any 2.1/4in ID’s need to be physically checked for clearance using a pump-down wet cement head (PWCH) (female connector) or rabbit of the same length.

Tool Checks and Calibrations

The Logging Contractor Engineer shall perform all tool and auxiliary equipment checks and calibration.

The Drilling Supervisor or Operations Engineer shall check tool dimensions and position of each logging tool. It is a requirement to run the AMS and the Drilling Supervisor should check that it has been modified to give a readout range from (-3000 lbs) compression to (+3000 lbs) tension.

Rig Up Considerations

The rig up procedures require a large degree of planning and co-ordination between the Logging Contractor and Drilling Contractor. Overall responsibility for safety rests with the Drilling Supervisor. The Drilling Supervisor shall make a forward plan and conduct an operations and safety meeting prior to rigup.

Initial Trip Downhole

After rig-up the tool string is ready to be run in the hole. The running in speed should not exceed that used when running a packer on drillpipe (one stand per 2 mins) or as recommended by the logging contractor.

Additional considerations are:

• the flexibility of the drillpipe.
• whether the travelling block is on rails or not.
• the kick-off point, (below this depth the tools will tend to lie on the low side of the hole and not be subject to so much bouncing as higher up)
• obstructions downhole, eg., liner tops, (these should be passed with caution)

Continue to RIH to the casing shoe (or top logging interval, if higher). Install the cable side entry sub.

The Drilling Contractor should also have checked there is sufficient stands of drillpipe in the derrick to get to the bottom of the logging interval to avoid stationary connection time in open hole.

Connecting Cable Side Entry Sub to the Drillpipe

The Logging Engineer shall advise the Driller on the correct procedures for this operation.

Running/Pump Down of PWCH and Cable

The Logging Engineer shall supervise running the pump-down wet connector head (PWCH) and cable in the hole. The drillpipe assembly shall clearly record all restrictions, which should be passed with caution.

If it is required to pump down the PWCH, the Logging Engineer shall advise the required pump rates

Preparing for Latching

The Logging Engineer shall supervise the operation and advise on the required pump rates. The outline procedure is to run the PWCH to within +/- 1 m of the male connector. At this point the (pumps are shut down if in use and) cable up weight is checked which also relieves torque build-up, together with distance to the (DWCM) male connector.

After this, the pumps are used to establish additional cable tension (prior to running the PWCH downhole at the required latch speed). Increased cable speed requires additional pump rate to maintain pressure (all to be advised by the Logging Engineer).

After latching, there will be a pressure increase of typically 200 - 300 psi. Pumping should continue until advised by the Wireline Engineer to stop. This is to insure a good mechanical latch.

Tool Latch Verification

The Logging Engineer shall check insulation of cable phases and confirm that there is a good electrical and mechanical latch prior to continuing with the programme.

Running In / Log- In

A slug of heavy mud is pumped either prior to running in or on bottom prior to logging out, to ensure the drillstring is pulled dry.

Continuous voice communication shall be maintained between the Driller and the logging unit, as this will minimise the reaction time required to stop the drillpipe, eg., if the tool string hits an obstruction. One logging contractor personnel with portable radio to stay on rig floor during the entire operation.

A down log should be taken while running in. The Logging Contractor procedures recommend that the tools do not tag the bottom of the hole but stay a minimum 20 ft above drillers depth. Depth control will be checked with the drillpipe which should be checked on in-run and out-run.

Log Out

Continuous communication is required between Driller and the logging unit to ensuring the pulling speed and cable spooling speed are matched, and to minimise reaction time if the tool begins to stick.

After Logging and Rig Down

Once the Cable Side Entry Sub  is within one stand of the drill floor the preparations to unlatch the female connector commence. The exact procedures will be advised by the Logging Engineer and include unlatching the PWCH up to rig down of the Cable Side Entry Sub .

Once the logging tool string is at surface the Logging Engineer shall supervise the rigging down, and report any observations, eg., tool damage, to the Drilling Supervisor immediately on completion.

Logging While Drilling (LWD)

Planning

Formation evaluation whist drilling (LWD) may be included in the Drilling Programme by the Operations Engineer for the following reasons:

• when accurate selection of casing points is required
• to assist in picking core points when justified in terms of time savings for circulating samples
• to guarantee obtaining some log information if hole conditions are very unstable
• to save time and cost against running wireline logs
• to assist in the early identification of hydrocarbons
• to assist in the detection of the on-set of overpressures.

A detailed technical and financial justification is required for using LWD.

Procedures and Reporting

When LWD is specified, full procedural requirements for the preparation and running of tools will be provided by the LWD Contractor. Reporting requirements will be detailed in the Drilling Programme by the Operations Engineer and Petrophysicts.Particular attention must be paid to the procedures for running and removal of nuclear sources.

The required equipment (Logging Contractor Fishing Kit) for both Cut and Thread and Reverse Cut and Thread methods are:

•  Bowen overshot kit series 105 (H-131931) with a multiple choice of grapples and guides
• cable hanger kit (H-133930) with different sizes and weights of sinkerbars and at least two cable hangers.
• Rope socket kit (H-133929)
• subs of 4.1/2in API IF for top end of the Overshot Top sub (B-20913) and both ends of the circulating sub (B-20914).
• remote tension meter
• Intercom set
• deployment bars
• 5 ft pup joint of sucker rod if the cable cut was made to low
• 300 ft of 1/4in rope to control the end of the cable going over the top sheave
• 100 ft of 1/2in rope to hold the lower sheave straight.

Acronyms for Baker Atlas logging tools.

Back-off                                               BO

Bridge Plug                                        BPS

Borehole Compensated Acoustilog

(Norm. Spacing)                               AC

Borehole Compensated Acoustilog

(Long Spacing)                                 ACL

Borehole Geometry Tool

(4 Arm Calliper)                                4CAL

Calliper                                              CAL

Cased Hole Formation Tester      CHFT

Cement Bond Log                           CBLV

Circumferential Borehole Imaging Log    CBIL

Check Shot Survey                          SLS

Compensated Densilog                CDL

Compensated Neutron                  CN

Diplog (Four-Arm High Resolution)         RDIP

Dual Laterolog                                 DLL

Electrical Log                                   EL

Flowmeter                                        CSF

Fluid Density                                         FDL

Formation Multi-tester                            FMT

Formation Tester Cased Hole                 FMTCH

Free Point Indicator                               FPI

Gamma Ray                                          GR

Natural Gamma Ray Spectrosc.             SPL

Induction - Electrical                              IEL

Junk Catcher                                         JB

Laterolog                                              LL

Microlog                                               ML

Microlaterolog                                       MLL

Neutron                                     NL

Photon Log                                           PHT

Proximity Log                                       PL

Pulsed Neutron (Lifetime Log)                NLL

Pulsed Neutron (Dual Detector)              DNLL

Radioactive Tracer                                 RT

Sidewall Samples                                  SWC

Sonic Log                                             AC

Sonic Long Spacing                              ACL

Sound (Sonan) Log                               SNL

Spinner Flolog                                      CSF

Temperature Log                                   TEMP

Thru-tubing Bridge Plug                         TPS

Ultrasonic Dip-Log                                U-DIP

Vertical Seismic Profiling                       VSP

This article provides cable and weak strength for Schlumberger and Baker Atlas

Logging Cables And Weak Points - Schlumberger

CABLE DIAMETER        WT/FT   BREAK. STRAIN

(INS.)                            (LBS)                (LBS)

_______________________________________________

7 - 46    15/32"               0.330                16,000

7 - 46V  15/32"               0.330                16,700

1 - 22    7/32"                0.080                5,100

CABLE WEAK                       BREAKING STRAIN

POINTS                                                  (LBS)

______________________________________________

Strong                                      5,450 - 6,900

Standard                                   4,800 - 5,400

Deep Well                                 3,500 - 4,400

Note:    For cables that are not new, the breaking strain will be lower than the quoted values. Thus 50% of the new cable     breaking load is the maximum that may be pulled without consulting the Base.

Logging Cables And Weak Points - Atlas Wireline Services

CABLE DIAM.               WT/FT   BREAKING       MAX. REC.

(INS.)                            (LBS)    STRAIN(LBS)    PULL (LBS))

___________________________________________________________

Multi-conductor:

7H464G 15/32"(0.462)      0.343  17,000              11,340

7H314A  5/16"(0.323)       0.181  9,500               6,365

Mono-conductor:

1H220A  7/32"(0.223)       0.093  5,000              3,350

1H181A  3/16"(0.185)       0.064  3,600              2,400

CABLE WEAK   STRANDS         NOMINAL         NORMAL

POINTS                                    STRENGTH       LIMIT(LBS)

___________________________________________________________

Multi-conductor:

7H464G STUD      -                    6,000               3,800

7H314A STUD      -                    3,000                2,000

Mono-conductor:

1H220A CABLE    7                   1,323                  886

1H181A CABLE    6                   1,062                  711

___________________________________________________________

Note:    For cables that are not new, the breaking strain will be lower than the quoted values. Thus 50% of the new cable     breaking load is the maximum that may be pulled without consulting the Base.

This article discusses perforating casing with the use of wireline for:

• carrying out remedial casing cementing, by squeezing through perforations and
• for monitoring of (formation) pressures behind the casing.

1  Casing perforation

A meeting should be held prior to rigging up for perforation, with the following staff present:

• Logging Engineer/ Well Site Geologist
• Well Service Supervisor, as applicable
• Wireline Operations Supervisor
• Drilling Supervisor
• Well Site Drilling Engineer

The main purpose of the meeting is to:

• Clarify the reporting and communication lines.
• Discuss the operation.
• Discuss any special circumstances, e.g. weather conditions, hole condition, radio silence, timing, concurrent operations, etc.

In addition a pre-job discussion with the logging and drill crews should be held.

Before the gun is run in the hole, a dummy run is made, to check that the tubing/casing is free from obstructions. The dummy should have the same OD. as the perforating gun to be used. Logging run previously conducted without any obstructions encountered, may be regarded as a dummy run, which under such circumstances may be excluded, subject to discussion with Base.

If pressures are expected to be released during perforation, or if a permeable zone is perforated, a wireline BOP, lubricator and stuffing box shall be rigged up on a wireline riser nippled up on top of the BOP. With the cable head in the lubricator, pressure test the equipment to the required pressure.

Make sure that there are no stray voltages in the cable head, or voltage potential between rig and casing, and also that the wireline unit is properly earthed.

Measure the length of each gun and the distance between first shot and CCL/GR, when assembled.

During all handling of guns, nonessential personnel must be excluded from the work area.

When guns are armed all personnel shall keep out of the line of fire, until the gun is safely in the well.

2  Depth Correlation

Run casing collar locator (CCL) and gamma-ray (GR) logs over the entire interval to be perforated. Record log at perforation depth, and correlate with previously run gamma-ray logs on the reference logs. To ensure that the gun is at the correct depth before shooting, the depth calculations shall independently checked twice, prior to authorise the logging engineer to fire the guns.

During the detonation, observe for indications that gun has fired.

The mud level in the hole should be carefully observed for losses or gains throughout the logging run, and specifically prior to POH. The hole should be kept full at all times.

When the perforating assembly is retrieved, ensure that the gun is in the top of lubricator before closing the wire-line valve.

When the gun is laid out on catwalk it shall be checked for unfired charges.

Bore Hole Compensated Sonic              BHC

Bridge Plug Setting                                 BP

Calliper                                                  CAL

Calliper (Thru-Tubing)                           TTC

Cement Bond Logging                           CBL

Variable Density Logging                       CBL-VD

Cement Dump Bailer                              DB

Combination Production Logging           PCT

Compensated Neutron Log                    CNL

Customer Instrument Service                  CIS

Depth Determination                              DD

Dipmeter (High Resolution)                    HDT

Bore Hole Geometry Tool                      BGT

Dual Induction Laterolog                        DIL

Dual Laterolog (Simultaneous)               DLL

Explosive Service (Back-off)                 BO

Flowmeter-Continuous                           CFM

Flowmeter-Packer                                  FM

Formation Density Logging                    FDC

Formation Micro Scanner                       FMS

Free Point Indicator                               SIT

Full-Bore Spinner Flowmeter                  FBS

Gamma Ray                                          GR

General Purpose Inclinometry                 GPIT

Gradiomanometer                                  GM

Induction/Electrical Logging                   IES

Induction (Spherically Focused)             ISF

Junk Basket                                          JB

Laterolog                                              L

Lithology Density Log                           LDL

Long Spaced Sonic                               LSS

Micro Laterolog                                     MLL

Microlog Calliper                                   MLC

Micro Spherically focused Log               MSFL

Neutron Logging                                   NL

Production Packer and Retainer Setting  PPS

Proximity Log/Calliper/Microlog             PML

Repeat Formation Tester                        RFT

Seismic Reference Service                    WST

Side Wall Coring (Core Sampler Taker)   CST

Sonic Log                                             BHC

Stratigraphic High resolution Dipmeter    SHDT

Tubular Goods Jet Cutter                       TGC

Temperature

(High Resolution Thermometer)              HRT

Thru Tubing Bridge Plug                        TBT

Thru Tubing Dump Bailer                        TBT-DB

Tubing Gauge                                       TGR

Tubular Goods Jet Cutter                       TGC

Vertical Seismic Profiling                       VSP