English Edition (6 MB pdf) - Saudi Aramco

3. CASE 3 - Actual Well Path RSM: Drilled on one of the
wells on the current UBCTD project using rib steered
technology to TD at 14,215 ft MD.
Figures 3 to 6 show graphically the difference between the
three cases above for the same well and illustrates how well
path undulation and tortuosity affects available WOB for
CTDD applications. Inclination (deg) and DLS (deg/100 ft)
are plotted in Figs. 3 to 5 as a function of MD. Figure 6
shows maximum available WOB for each case and is also
plotted as a function of MD.
Computer aided simulation has been used and proven the
value of using RSM technology. The Tubing Forces
Simulations Results (Torque & Drag) were then generated
considering identical assumptions, where only the well path
was a variable for the three case studies.
Fig. 3. CASE 1 - Well profile survey severity planned well path with oriented
bent motor.
Fig. 4. CASE 2 - Well profile survey severity planned well path with RSM.
Fig. 6. Maximum available WOB.
As shown in Fig. 6, using rib steered technology adds a
significant advantage to the drilling of the laterals: While in
CASE 1 the maximum WOB achievable before lock-up is 925
lbf, the same planned lateral – CASE 2 using the RSM – has a
maximum available WOB of 2,640 lbf at the same MD of the
planned well. An increase of 185% of available weight was
transferred to the bit merely due to reduced well path
tortuosity. The actual well path drilled with RSM – CASE 3 –
has the available and measured WOB at TD in the range of
1,990 lbf at TD. This is 25% lower than expected of RSM
performance, but 115% higher than when using an oriented
bent motor.
Similarly, maximum available pickup weights on the BHA
at TD increase substantially when using the RSM BHA. The
use of rib steered technology allowed for roughly an 87%
higher additional pickup off bottom when comparing CASE 1
vs. CASE 2. Maximum Allowable Pull for the three cases
discussed was 6,780 lbf, 19,520 lbf and 13,150 lbf,
respectively.
Transcripting the results of available WOB into increased
reach, the analysis shows that the well path in CASE 2 can be
extrapolated to the depth of approximately 16,250 ft MD
(additional 2,035 ft) while the actual results of the per -
formance of RSM while drilling show that the actual leg could
have been drilled up to 15,300 ft MD, if requested. TD on the
actual leg was called due to reasons other than running out of
available WOB.
The results above not only demonstrate that wells drilled
using the RSM, which reproduces a well path with low
tortuosity, will be a lower risk from the surface/downhole
weights point of view, but they can be traded off by extended
reach possibilities, enhancing even more of the future of
CTDD applications.
CONCLUSION
Fig. 5. CASE 3 - Well profile survey severity actual well path drilled with RSM.
Since the first introduction of rib steered technology to the
field in 2006, the RSM tool, throughout its field test campaign
has successfully proven its value to the CTDD and UBCTD
operations by constantly increasing lateral reach and
14 SUMMER 2010 SAUDI ARAMCO JOURNAL OF TECHNOLOGY