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 

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 KPAProcedure: 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

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 ( some standby while waiting on auxiliary equipment)

Objective: Mill out gate to 3 1/8 diameter on top master valve that is seized closed and free wheeling 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 wellProcedure: 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