Snubbing, Oilfield Equipment :: Snubco Group : Well Services : Case Histories

Case History 1

Objective: Sand cleanoutsWell Information: 8000kPa, Sweet gas and 1500 metersProcedure: Performed 67 cleanouts through out the whole project. Rig in coil unit. Pressure test. Run in the hole and cleanout sand from perforations to plug back. Out of the 67 wells completed only 2 wells required further cleanouts due to sand entering the well from the perforations.

Time on location: 4 hours per well.

Case History 2

Objective: Spot acidWell Information: 300kPa, sweet gas, 1700mProcedure: Rig up and pressure test CT unit. Run in the hole pumping nitrogen. Stop at 1600 meters. Pump acid to end of tubing and start pulling out of hole. Flush coil with 3% KCL. Pull up to 300 meters and start to pump nitrogen to purge coil. POOH. Rig out unit.

Time on location: 6.5 hours

Case History 3

Objective: Chemical washWell Information: 0kPa, heavy crude, 1700 meters horizontalProcedure: Rig up and pressure test. RIH while pumping 3% KCL fluid. Clean out sand in horizontal section. Pump chemical to end of tubing. POOH till kick off point. Repeat wash over same section of well 3 times. POOH and purge coil. Bleed off and rig out.

Time on location: 8.5 hours

Case History 4

Objective: Sand cleanout using mill and motorWell Information: 8700kPa, sweet gas well, 2170 metersProcedure: Rig up CT unit with mill and drilling motor. Pressure test and function test. RIH> Tag sand top and mill thru to plug back using commingled fluid. Insure returns are clean and fluid is lifted from well. POOH and rig out.

Time on location: 13 hours

Case History 5

Objective: Land velocity stringWell information: 9200kPa, sweet gas, 2100 metersProcedure: Rig up CT unit with spooler and pressure test. RIH and land at predetermined depth. Isolate well bore pressure and cut and land coil. Rig out.

Time on location: 9.5 hours

Case History 6

Case History 7

Objective: Pump nitrogen blanketWell information:Procedure: Rig up nitrogen unit and pressure test. Pump hole volume into well to hold down H2S. Rig out unit.Time on location: 1.5 hours

Case History 8

Objective: Unload fluid from wellWell information: Procedure: Rig up nitrogen and cool down. Pressure test surface equipment to 32mPa. Pump nitrogen and unload well. Rig out unit.

Time on location: 10.5 hours

Case History 9

Objective: Unload well bore fluidWell information:Procedure: Rig in nitrogen pumper and cool down. Pressure test surface equipment. Pump down tubing and unload fluid up casing, stop pumping. Flow well for 3 hours. Rig out unit.

Time on location: 5.5 hours

Case History 10

Objective: Pressure up well to run wireline logWell information: Cavern wellProcedure: Rig up pumper and pressure test to 21mPa. Pump 1000 SCM down casing. Pump 500 SCM down tubing. Rig in wireline and begin logging. Pump nitrogen at predetermined depths while logging. Rig out wireline. Rig out pumper.

Time on location: 13 days

Case History 11

Objective: Coil cleanoutWell information: Procedure: Rig in CT unit and nitrogen pumper. Pressure test surface equipment and coil to 14mPa. RIH with coil to predetermined depth and begin to pump nitrogen. Cleanout fluid from wellbore. POOH and rig out equipment.

Time on location: 6 hours

Case History 12

Objective: Pressure up wellWell information: Procedure: Rig in nitrogen pumper and cool down. Pressure test surface equipment to 17mPa. Pump nitrogen into well until well bore pressure is 15mPa. Rig out unit.

Time on location: 1 hour

Case History 13

Objective: Pump nitrogen blankets on 2 wellsWell information: 5% H2S Procedure: Rig up pumper and cool down. Pressure test surface equipment to 24mPa. Pump 100 SCM for a blanket. Rig out and complete pumping operations on next well.

Time on location: 4 hours total to pump on both wells

.Case History 14

Objective: Purge pipeline with pigWell information: 5400 meters of 139mm pipe lineProcedure: Rig in nitrogen pumper and cool down. Pressure test surface equipment to 14mPa. Start pumping down pipeline at 30 SCM. Decrease rate to hold pipeline pressure at 10mPa. Pig would not move. Operator checked pipeline files and determined there were 2 pigs from a previous operation still in pipeline. Pressure was increased behind first pig to 11.5mPa and then shut in. Pressure slowly pushed all 3 pigs to end of pipeline to catcher.

Time on location: 13 hours. Pigs into catcher after 72 hours

Case History 15

Objective: Utilize Mayperf drilling tool to perforate multiple zones in a well.Well information:Procedure: Rig up and deploy Mayperf drilling tool utilizing 33 meters of lubricator. A total of 5 sets of perforations were opened up using the Mayperf drilling tool and 50.8mm coil tubing.Time on location: 30 hours over 3 days

Case History 16

Objective: Recover 3600m braided wireline / perforating BHA, and tractorWell Information: 14mpa WHP, sweet gas, 4000m with 1400m horizontal section, 114mm casing to PBTD, perforating tool stuck at 3600m, wireline had parted at surface and fell down hole.Procedure: MIRU 50.8mm coil tubing unit with injector extension hoses to accommodate 22m of lubricator required for tool recovery. Rig Injector, lubricator, and coil tubing BOP on to wireline BOP, and pressure test. Run in hole with “spear” fishing assembly to hook wireline and bring to surface. Once back at surface, secure wireline with BOPs, and strip off coil lubricator to expose wireline. Feed wireline through packoff, and strip additional cable through packoff using crane, causing cable to shear off cable head down hole. Once enough cable has been exposed, secure to wireline truck and spool on to drum. Repeat procedure as required until all wireline has been removed from well. Once wireline is out of well, rig on with coil and “overshot” fishing assembly and using jars, dislodge and recover perforating tool string and tractor.Results – Job completed successfully. Total trips in hole 7 – 5 to recover wireline, 1 impression block run, and 1 run to recover tool string. Job spanned 3 days utilizing 24 hour operations. After fishing operations were concluded, the remaining plugs were set, and perforations shot without further incident using Snubco coil tubing.

Case History 17

Objective – Remove scale buildup on tubulars – 2 wells on same pad

Well Information – 7-10mpa WHP, Sweet gas, 4200m with 1100m horizontal section, 114mm casing to PBTD. Casing was plugged, and a camera run indicated that scale buildup was the problem.

Procedure – MIRU 50.8mm coil tubing with 70mpa BOP. Rig up and pressure test. Run in hole pumping water until obstruction is tagged. Once depths and string weight have been confirmed, alternate slugs of 15% HCL acid and water, and work coil to bottom. Once at bottom, perform acid wash to heel, then cleanout run back to bottom and unload well with nitrogen.

Results – PBTD reached on both wells in 48 hours utilizing 24 hour crews.