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Unformatted text preview: average RPM also increase from
140 rpm for the first bit, to 155 rpm for the second bit. Average torque remains almost the same for both bits. HSI reduces
from 2.1 hp/ in.2 at the first bit, up to 0.8 hp/in.2 at the second bit.
On the second bit, the mechanical energy component is progressively increased by raising the WOB and RPM. The
hydraulic energy component, on the other hand, is continually reduced as the well goes deeper, by the reduction on HSI. The
second bit is limited by the fact that the maximum standpipe pressure is reached at the end of the first bit run. The friction
losses generated by circulating a 16.5 lb/gal mud trough the 3-1/2 in. pipe dramatically affects the second bit performance.
Field Case No. 3: DSE with Surface and Downhole Data
On this well, the 6 in. section is drilled at balance (no overbalance pressure) with oil base mud across shale-sand intercalated
beds. Downhole gages are run to monitor the drilling parameters and understand the well behavior in order to i...
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- Spring '13