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Unformatted text preview: t has almost no wear
shows that most likely bit balling was affecting the bits performance. Cutting-structure balling was observed on the pulled
bit, reinforcing the previous conclusion. It is also believed that bottom balling was present while drilling this section because
of the progressive reduction of ROP.
Field Case No. 2: Friction Limited
On this well, the 6-1/2 in. section is drilled with a 16.5 lb/gal oil base mud across shale-sand intercalated beds. 3-1/2 in. drill
pipe is used to drill the section. One bit is used to drill from 9,120 ft to 12,800 ft where the maximum temperature for the
downhole tools is reached. The maximum standpipe pressure was also reached at this particular depth (12,800 ft) forcing a
progressive reduction on the flow rate as the drilling progresses. A new-similar bit is run to drill from 12,800 ft to the well SPE 116667 5 depth total depth (TD) at 14,900 ft. The total flow area (TFA) of the new bit is increased from 0.26 in.2 to 0.31 in.2 to make
sure the minimum flow rate can be reached at TD. The chan...
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This note was uploaded on 01/31/2014 for the course MOGE 9114 taught by Professor Thomod during the Spring '13 term at Memorial University.
- Spring '13