Journal of Canadian Petroleum Technology
Volume 49,
Number 10,
October 2010,
pp. 45-52
Summary
In this paper, a new drilling optimization procedure is presented that is
designed to improve the drilling efficiency with positive displacement motors
(PDMs) and PDC bits. This developed optimization method is based on predicting
rate of penetration (ROP) from PDM outputs for any PDC bit design. More
specifically, optimization is done for a hole section and optimum values of
weight on bit (WOB) and surface RPM are obtained for the section. For given
flow rates, estimated values of optimum WOB and surface RPM are used to
calculate the corresponding motor differential pressures and the foot by foot
ROP values. Also, the method is used to show how improper operational parameter
selection can affect total drilling time. A case study was done to consider
different PDMs with different lobe configurations and a set of fixed
operational parameters.
The presented method is verified by generating a confined rock strength log
based on drilling data for a previously drilled well in Alberta. This
foot-by-foot strength log is compared to a confined rock strength log generated
as a follow-up analysis by a commercially available drilling simulator package.
Also, a PDM differential pressure log is generated and compared to
field-recorded on-bottom differential pressure values.
The method's application is best demonstrated by simulating the drilling
operation of the Alberta well with three different PDMs. It is shown that
consideration of PDM performance/selection in the drilling planning phase will
help to perform a safe and cost-effective operation by preventing motor stalls
and maintaining highest average ROP for the section. It is also shown that by
optimizing WOB and surface RPM values for a constant mud flow rate and
predefined bit wear at total depth, a maximum average ROP for the section can
be reached for any PDM.
© 2010. Society of Petroleum Engineers
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History
- Original manuscript received:
1 April 2008
- Meeting paper published:
18 June 2008
- Revised manuscript received:
14 July 2010
- Manuscript approved:
13 August 2010
- Published online:
1 October 2010
- Version of record:
1 October 2010