Location: Indonesia

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The Challenge

The well need to be  sidetracked  from  945/8″  csg.  window using a 8 1/2″ bit.  Two problematic  sections  have  to be  penetrated.  Parigi  (dolomite  &  sand)  and  Pre-Parigi (limestone) are two thick formations for sloughing shale, losses, tight hole, bit  balling  and  stuck  pipe  across  limestone  stringers  associated  with  these  two formations. At the nearest (previous) well had to pump more than 20 cement plugs to combat loss of circulation in these notorious sections.

The Action

The  8½”  hole  was  drilled  from  9⅝”  casing  window  at  2,583  ft.  FRACSEAL  was maintained at 648 ppb in the 9.1 ppg Low pH Desco active mud. Drilling at 2960 ft had initial loss at 10-20 bph. FRACSEAL concentration was increased to 7.5 ppb and seepage  losses  reduced  and  hole  was  static  and  stable  until  drilling  at  3,400 ft. Sometimes sudden high losses were detected, then displaced hole with FRACSEAL pill containing 30 ppb FRACSEAL and 10 ppb CaCO3 Medium while keeping 6H8 ppb in the active mud.

The Result

None  cement  plugs  needed  for  stopping  losses  in  this  well.  Had  a  relative  smooth drilling of the long section of 8½” hole up to to 7″ liner point at 8,450 Y (MD). The 7″ liner was run and set without any problem.