American Oil and Gas Reporter - August 2015 - 53

Sliding

SDP

ADP

Well 1

Well 2

Well 3

Well 4

ROP (ft/hr)

18.1

27.1

24.7

52.5

WOB* (klbs)

25.0

22.4

14.8

30.0

Well 1

Well 2

Well 3

Well 4

ROP (ft/hr)

132.9

153.9

133.3

130.0

WOB* (klbs)

16.4

16.9

16.1

20.8

*Surface WOB

*Surface WOB

FIGURE 5
Tension/Compression Curve while Sliding at 17,130 feet
For Wells 1 (SDP) and 2 (ADP)
-50.00

2,000.00

4,000.00

0.00

Tension (klb/ft)
50.00

100.00

150.00

-50.00

1 Level
2 Level
3 Level
4 Level

2,000.00

6,000.00

6,000.00

8,000.00

8,000.00

10,000.00

12,000.00

14,000.00

16,000.00

0.00

Tension (klb/ft)
50.00

100.00

150.00

1 Level
2 Level
3 Level
4 Level

4,000.00

Depth (ft)

Based on these observations and simulations, one can conclude that drilling
performance during the sliding phases
was better with ADP, with more efficient
weight transfer to the bit producing a
higher ROP (Table 2). Indeed, ROP was
about 50 percent greater in well 2 than in
well 1. In addition, ROP in rotary mode
was 16 percent higher in well 2 than in
well 1.
Figure 5 shows the evolution of tension/compression along both the SDP
and ADP strings while drilling in sliding
mode at the same bit depth of 17,130
feet. The hook load at surface was quite
similar, despite a larger WOB on the
ADP string than on the SDP string. In
addition, the helical buckling limit was
not exceeded on ADP, and a buckling
severity index of 3.0 was reached locally
in both wells in the curve, meaning that
bending stress and/or contact side forces
were significant enough to prevent good
weight transfer to the bit.
Figure 6 shows a 3-D view of the
ADP string while sliding at 17,130 feet.
Note the contact side forces (red arrows)
on ADP tool joints and wear bands, and
the low bending stress on the pipe compared with the curve section.
The Eagle Ford test results demonstrate
that the ADP string delivered better ROP
performance thanks mainly to reduced
torque and drag, eliminating up to two
days of rig time in drilling the curve and
lateral sections. In fact, comparing the
three wells drilled with ADP with offset
wells in the same field drilled with rotary
steerable systems, it appears that using
ADP with a steerable mud motor provides
similar performance in terms of drilling
days versus depth.
r

Actual ROP and Measured Surface WOB while Drilling
Curve and Lateral Sections

Rotary

Improved Performance

TABLE 2

Depth (ft)

WOB measured while sliding was about
22,400 pounds, overestimating the real
WOB transmitted to the bit.
Torque and drag simulations for the
SDP string showed low weight on the bit
compared with ADP, especially at the
end of the lateral section with only about
5,000 pounds of WOB. The calculated
hook load is very sensitive to the coefficient of friction. A difference of 0.1 in
the coefficient of friction can produce a
difference in the hook load of more than
30,000 pounds at surface.

10,000.00

12,000.00

14,000.00

16,000.00

FIGURE 6
3-D View of ADP String while Sliding at 17,130 Feet
(Bending Stress and Contact Side Force)

Coming In September
Special Report:
Tubulars Technology

AUGUST 2015 53
American Oil and Gas Reporter - August 2015

Table of Contents for the Digital Edition of American Oil and Gas Reporter - August 2015
