Re: Drilling Problems
by
Published on 03-25-2012 02:08 PM
Originally Posted by
a_elgamal
hey everyone, these are some drilling problems that I can't fiind a solution to:
1. Drilling 12.25" hole section to depth 10,450ft in gas well had pressure dropped 500 psi while drilling Sand interval and unexpected fast break, the rest of the section TD is 60ft and ROP still high.
2. Drilling 12.25" hole section to depth 16,500ft, bit type in hole was insert bit IADC617, total bit drilling hours 110hrs, Bit specification sheet mentioned the recommended working hours not exceed over 95hours, still in progress to complete section to Casing point to depth 16,550ft, Rop was 5 ft/hr and in the last 10 hrs Rop was 2.7 ft/hr.
3. While drilling deviated well with inclination 55 degrees using PDC bit had rate of penetration dropped from 20 ft/hr to 1.5ft/hr , hole size 12.25” and reached drilling depth 8,790ft (dog leg 4.5 /100ft) Torque off bottom=14,500 ft .lb ,Torque on bottom=14,510 ft.lb, …. Give what your indication about the slowdown in ROP and risk evalution to continue with consideration offshore rig (Cost/hr. =12,000 & Tripping time 1000ft/2.5hr).
Any help will be helpful...Thanks
For your problem 1....I suggest that if there is no well control problem (loss/gain)......you may continue drilling as there is very short interval remaining.
2. Bit was drilling with 5 ft/hr which has dropped to 2.7 ft/hr which shows that bit has got dull........with an avge rop of 2.7 ft/hr. you have to spend 18 more hours to reach TD........You have already used your bit for 15 extra hours.....so you must not take risk and POOH to change bit instead of using the same bit for 18 more hours (if ROP does not drop further).....
3. Answer to this question requires a lot of information.......e.g.
a) on bottom and off bottom torque before this problem occured.....
b) on bottom /off bottom pressure before and after the problem.....
c) either you are expecting any formation change at the depth you are drilling.
there may be many possible reasons for ROP drop.......such as
1. your bit has become dull due to an extremely hard formation encountered
2. as your hole angle is 55 degree.......means almost wors case of hole cleaning.....may be due to poor hole cleaning you can not drill further (on/off bottom torqe is almost same indicating this possibility)
3. your string may be twisted off.......pressure can give you some indication about this.
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