Case Histories

International Snubbing Case Histories

International Snubbing Case History #1

Objective:
Snub out existing 244mm straddle packers assembly and snub in new straddle packers to isolate gas zone using a 177mm snubbing BOP stack.

Well Information:
Sour 7mPa 3200 meter multi zone oil / gas well.

Procedure: Snub out 88.9mm slick string. Snub in BHA consisting of 177mm retrieving tool, 88.9mm pup, circulating plug, x/o, 114mm joint, x/o and 88.9mm tubing. Latch onto straddle packers, release packers and snub out of hole till 114mm tubing joint. Land 177mm tubing hanger. Change over handling equipment to 2.06mm. Snub in retrieving toll and retrieve slip stop and circulating plug 2 20 meters from surface. Snub in 63.5mm inflatable packer and 26 joints and set inflatable in lower BHA. Snub out 2.06mm tubing. Change handling equipment over to 114mm. Stage out tubing hanger, 114mm tubing joint and upper packer. Land tubing hanger. Change over handling equipment to 73mm and snub in bridge plug and 16 joints, set bridge plug above inflatable packer and snub out 73mm tubing. Change over handling equipment to 114mm. Stage out tubing hanger, snub out remaining 13 joints of 114mm tubing, packer, flow sub w / ball catcher. Snub in new straddle packer assembly and 234 joints of 114mm tubing, space out and set packers. Come packer assembly with on/off and fill hole, latch back onto packers and pressure test. Come off on/off and pull 2 joints. Land tubing hanger and rig out

Time on location: 22 days

International Snubbing Case History

International Snubbing Case History #2

Objective: Snub out and replace 114.3mm packer.

Well Information: 3200kPa horizontal oil well, 4500 meters. 88.9mm upper string and 73mm lower string.

Procedure: Set bridge plug in lower 73mm tubing string just above BHA. Rig up snubbing unit and snub out 88.9mm tubing string. Land tubing hanger, add 5 meters of spacer spool and change over handling equipment to 73mm. Snub out hanger and remaining 73mm tubing string and BHA. Make up BHA and snub in along with 73mm tubing, land tubing hanger. Change over handling equipment to 88.9mm, snub out tubing hanger and snub in 88.9mm tubing to required depth, set packer, land tubing hanger and rig out snubbing unit.

Time on location: 6 days

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International Snubbing Case History #3

Objective: Drilling rig drilled into over pressurized zone, requiring snubbing unit to snub out drill string, and snub in liner.

Well information: 3800, 7-10 mPa, depending on well kill fluid density. Could not kill well.

Procedure: Prepped unit for job, install 3 ½ handling equipment. Rig in riser spools, rig up snubbing unit, screw into hang off sub, conduct pressure test. Snub in to bottom, circulate, set tubing bridge plug due to floats not holding. Snub out 3 ½ drill pipe, 4 ¾ drill collars, heavyweight, jars, and BHA. Snub in BHA, and 4 ½ liner to bottom. Tag obstruction around 3400m, pull same back out, snub in tools and 3 ½ drill pipe, perform tasks, snub out same and snub in 4 ½ liner, set, and rig out snubbing equipment.

Time on location: 30 days (standby while waiting on auxiliary equipment)

Case History for International Snubbing #3

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International Snubbing Case History #4

Objective: Drilling rig drilled into over pressurized zone, requiring snubbing unit to snub out drill string, and snub in liner.

Well information: 3800, 7-10 mPa, depending on well kill fluid density. Could not kill well.

Procedure: Prepped unit for job, install 3 ½ handling equipment. Rig in riser spools, rig up snubbing unit, screw into hang off sub, conduct pressure test. Snub in to bottom, circulate, set tubing bridge plug due to floats not holding. Snub out 3 ½ drill pipe, 4 ¾ drill collars, heavyweight, jars, and BHA. Snub in BHA, and 4 ½ liner to bottom. Tag obstruction around 3400m, pull same back out, snub in tools and 3 ½ drill pipe, perform tasks, snub out same and snub in 4 ½ liner, set, and rig out snubbing equipment.

Time on location: 30 days (standby while waiting on auxiliary equipment)

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International Snubbing Case History #5

Objective: Snub in completion string after pin point frac.

Well Information: 2800 meters, 11,300kPa and 3 zones.

Procedure: Rig up 5K Class 3 BOP stack and self-contained snubbing unit on a 10K 4 1/16” valve. Snub in BHA consisting of seal assembly, 2 hydraulic set packers, assorted nipples and sliding sleeves and blast joints along with premium chrome tubing. Sting into permanent packer, space out and set hydraulic set packers. Rig out snubbing unit.

Time on location: 34 hours over 3 days

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International Snubbing Case History #6

Objective: Snub in tandem packer completion string with seal assembly.

Well Information: 12,400 kPa, 3100 meters, 3 zones gas well.

Procedure: Snub in chrome tubing with tandem packer, seal assembly and expansion joint. Sting into permanent packer, space out using expansion joint, set hydraulic set packers and land tubing hanger. Rig out rig assist snubbing unit.

Time on location: 20 hours over 2 days.

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International Snubbing Case History #7

Objective: Retrieve parted production tubing and install re-completion

Well Information: 38 mPa, 2% H2S content, 50% condensate, 3300 meter gas well

Background: Previous attempts to fish parted tubing were unsuccessful and parted tubing string was hampering production.

Procedure: Rig in well intervention pump and kill well using lubricate and bleed method. Remove wellhead and rig in 200K self-contained snubbing jack. Pressure test primary and stripping BOP stack.
Production tubing was parted at surface. Snub in with impression block and tag fish top at 280 meters, snub out of hole. Round trip scraper and then set WR plug with tubing and snub out. Rig out snubbing equipment and change out well head. Rig up snubbing unit and pressure test BOP stack. Run in and latch WR plug and snub out of hole. Run in with overshot on tubing and latch unto parted tubing. Not able to break tubing string free. Decision made to cut tubing. Wait on e-line to clear customs. Rig in e-line, run in hole and free point and cut tubing string. Pull out of hole with e-line and rig out e-line. Snub out with 1100 meters of tubing. Snub in with overshot but unable to latch back onto fish. Snub out and snub back in with spear, latch onto fish, jar tubing free and snub out with a 9 meter section of tubing. Run in numerous times with assorted fishing tools but were only able to recover small pieces of tubing previously damaged from fishing efforts several years prior. Snub in hole with mill and dress fish top, snub out of hole. Snub in with overshot and retrieve another 1100 meters of tubing. Top 25 joints of fish were collapsed and the next 100 joints were corkscrewed. Remaining tubing string was now in open hole and we were unable to latch back on. Decision was made to produce well AS IS, so we made a scraper run and snub in a production string. Rig out equipment.

Snubbing crew in Albania

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International Freeze and Hot Tap Case Histories

International Freeze and Hot Tap Case History #1

Objective: Hot tap Lower Master Valve to provide access to Tubing in order to freeze well and replace faulty valve.

Well Information: Sweet Gas Well Drilled in 1993. CSG is full of inhibited fluid with packer set 2334 meters from surface. Estimated SITP = 4000 kPA

Procedure: Perform JHA and Safety meeting with all personnel. Take measurements and ensure hot tap equipment is suitable for task. (Enough stroke to get through valve and can still retract back enough to get behind safety valve. Confirm valve is holding pressure. Remove all wellhead equipment above faulty valve. Install x/o flange onto valve, 2 9/16 x 2”, c/w 2 9/16”x 2” threaded nipple. Install 2” x 5K ball valve. Fill valve up with fluid. Install hot tap drill. Rig in pressure pump and pressure test all connections and drill to 21 MPA. Estimated SITP is 4 MPA. Bleed pressure back, maintaining 10 MPA. Start drilling through valve monitoring pressure above valve at all times. Pressure dropped to approximately 4.3MPA.Continue drilling until ¾” hole has been reamed clean, and the bit can pass through un hindered without rotating. Retract bit into drill housing and close 2” ball valve. Bleed off drill and remove. Hook up flow back line and flow tubing to ensure good access. Remove flow back line. Build Ice cribbing around surface casing and inject freeze gel into surface and production casings as well as tubing. Add dry ice and wait allotted time for gel to freeze. Pressure test freeze plug on the tubing side and when verified plug is holding, remove faulty master valve and install new valve and the rest of the well head components. Pressure test well head against freeze plug. Remove ice from well and let thaw.

Time on Location: 24 hours

Remote Freeze in Australia

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International Freeze and Hot Tap Case History #2

Objective: Hot tap and mill out a damaged gate valve 90% closed and freewheeling.

Well Information: 4,200kpa sweet gas well on an offshore platform with damaged gate valve not allowing access into tubing. Top gate valve functioning.

Procedure: Assemble hot tap equipment and function. Bleed off gas pressure above top valve and remove wireline flange install hot tap equipment pressure test. Equalize pressure and open top operating gate valve hot tap a ¾ inch hole in bottom valve pull above top valve close bleed off well gas remove drill bit. Install mill and reconnect flange equalize with well gas and open top valve mill out damaged bottom valve pull above top valve and close bleed off well gas and remove mill. Install reamer to open bore to 3 1/8 reconnect flanges and equalize with well gas and open top valve ream bottom gate valve to full drift. Pull above top valve and bleed off well gas remove reamer. Install wire brush reconnect flange equalize with well gas open top valve clean tubing hanger threads with wire brush pull up above top valve and close. Bleed off well gas and remove hot tap equipment.

Time on off shore platform: 33hrs over three days

Rigging in Drill on Platform

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International Freeze and Hot Tap Case History #3

Objective: Mill out gate to 3 1/8 diameters on top master valve that is seized closed and freewheeling to accommodate wireline tools and installation of back pressure valve in tubing hanger. Bottom master valve previously milled out.

Well Information: 3 mPa water injection well

Well Procedure: Assemble hot tap equipment, start power pack and check all functions. Confirm no pressure above damaged valve, remove wireline cap and install crossover-work valve-Bop and hot tap equipment. Pressure test all components and connections to 7 mPa. Bleed pressure back to 5 mPa drill ¾ inch pilot hole. Retract drill above work valve, close, bleed off pressure, and change out bit to 3 inch cone mill. Rig up new assembly, equalize above work valve and open valve. Advance mill to gate, record measurements and confirm depth is correct. Commence milling, noting time for advancement gained. After advancing 2 inches through 2 ½ inch gate advancement slowed considerably. Retract cone mill above work valve, close valve and bleed off. Change out cone mill to 2 7/8 outside-in aggressive mill. Rig up hot tap equipment, equalize above work valve and open valve. Advance drill to gate, check measurements and resume milling. Monitor torque and distance travelled, double check measurements to confirm through gate. Retract mill above working valve, close valve and bleed off. Change out mill to 3 1/8 reamer re-install hot tap equipment, equalize and open work valve. Ream out gate valve, retract above work valve, close and bleed off. Change out reamer to wire brush, re-install equipment, equalize above work valve and open. Advance brush to threads in tubing hanger, check measurements and clean threads in hanger. Retract brush above work valve and close valve, bleed off and rig out hot tap equipment. Hand over well to wireline.

Time on location: 27 hours over three days

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International Freeze and Hot Tap Case History #4

Objective: To gain entry into 3.5” tubing to set wireline tools. Hot tap and mill out lower gate valve.

Well Information: 19 mpa sweet gas. Swab valve functioning and holding pressure. Valve type – Cameron with 3” thick solid gate, material unknown. Pin stem free wheeling and gate in fully closed position.

Procedure: Obtain all proper permits. Unpack and precheck equipment and position on deck platform. Ensure swab valve is closed. Bleed off any pressure between swab valve and well cap. Remove well cap. Install 10,000-5,000 crossover spool. Install BOP’s. Rig up hot tap drill. Pressure test equipment. Ensure all is in proper working order. Double check measurements. Bore 1” pilot hole through gate. POOH. Changeover bit to 3.25” mill. Bore through gate. POOH. Changeover to 4” mill. Bore through gate. POOH. Close swab valve. Bleed off pressure. Rig out hot tap equipment and spools. Rig up wireline. Run in with gauge ring to confirm hole. MILLING TIME: 37 hours over several days.

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International Freeze and Hot Tap Case History #5

Objective: To install access port to remedial SSSV control line inside the tubing. A coupling installed inside of the hanger connected the port we drilled to the control line.

Well info: Dual string completed sweet gas well with both tubing strings online and flowing. Tubing string to be worked on was isolated with tubing blanking plug.

Procedure: In flow testing performed on well head prior to cold tapping to ensure isolation of new annulus once tubing hanger is drilled. Identify and isolate lock down screw to allow access to required tubing string. Bleed off pressure above tubing blanking plug to be accessed with hot tap. Remove existing lock down screw and packing, install new packing and modified lock down screw. Pressure test new lock down screw and packing. Rig in hot tapping equipment and pressure test. Pressure up tubing string to ensure cuttings from drilling process are kept out of tubing string. Drill hole thru tubing hanger and access tubing string. Retract drill bit and close needle valve on lock down screw. Bleed off pressure in drill and rig out hot tapping equipment. Turn well over to production staff.

Time on platform: 4 hours

Inernational Freeze and Hot Tap Case History 5 Photo

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