Well spudding-in and lowering of a marine riser casing 

A pilot borehole of 660,4 mmin diameter is drilled by boring chisel L111 “Varel” to the depth of 129 m. A marine riser 508 mmcasing is lowered to the depth of 121,1 m, a torque ring for the hanger is Mud Line 339,7 mm. The 508 mmcasing is composed from pipes of K-55 steel grade with wall thickness of 12,7 mm. The casing is cemented within interval from the casing shoe to the sea level by cement solution with density of 1,9 g/cm³. The hardener injection rate of CaCl2 is 5%. The used amount of dry cement is 31,5 t.

 Drilling of 129-640 m interval and lowering of 245 mm casing

The interval is drilled by the boring chisel 311,2 ERAMPSFJ4 in one run. For drilling it is used a polyglycol solution, in the packaging it is included D-305 mmsender with 2хК14 noses (with two damped). While drilling and operation of lowering and raising not sizeable slackings off and torqueings of 3-6 t. are observed. By GIS-data the casing borehole is close to the nominal bore. The casing lowering has not any difficulties.

A casing of339,7 mmwith wall thickness of10,92 mmis lowered into the well to the depth of34,7 mfrom the rotary table. The seat for the hanger Mud Line 245 is on the depth of  34,01 m from the rotary table.