appendix l drill pipe in the bop - transocean · aa-3 dropped and landed on top of the upper...

Appendix L Drill Pipe in the BOP



The location of the drill pipe in the Deepwater Horizon BOP stack at the time of the incident has been established. It has been confirmed by comparing the measured height between the five ram preventers and the two annular preventers in the BOP stack to the measured length of recovered drill pipe sections, and by the distinctive markings or damage to the drill pipe.

When the recovered drill pipe lengths and locations were examined they confirmed that, at the time of the incident:

• The flow-washed drill pipe tool joint was in the upper annular;• The upper and middle variable bore pipe rams were closed; and• The blind shear rams cut the drill pipe.1

The sections of drill pipe recovered from the Deepwater Horizon BOP stack and the recovered marine riser section from above the BOP stack were photographed, cleaned, inspected, re-photographed, and the lengths measured by the Det Norske Veritas (DNV) at the NASA Michoud Assembly Facility (Michoud) in New Orleans.2 The sections were then laid out and placed in order for comparison.3 See Figure 6 and Table 1.

A. Drill Pipe Section “AA”: Upper Annular to Blind Shear Rams

Drill pipe section AA consists of three pieces of drill pipe that were located in the BOP stack between the upper annular and the blind shear rams. These three drill pipe sections are identified below as “AA-1,” “AA-2” and “AA-3.” The total measured length of these drill pipe sections is 234 in. The dimension from the bottom of the upper annular element to the middle of the blind shear rams in the BOP stack is 234 in., confirming the tool joint was partially in the upper annular when the drill pipe was cut by the blind shear rams. Refer to A and AA in Figure 6 and Table 1.

The top of drill pipe (section AA) includes the flow-washed tool joint that was eroded in the upper annular. The bottom of section AA was cut by the blind shear rams. The bottom of section AA was found resting upon the top of the upper annular element indicating it was ejected upward through the upper annular by the well flow. This section of drill pipe was fixed in place in the marine riser where the riser folded over and “kinked” as the Deepwater Horizon sank 36 hours after the first explosion. Refer to Figures 1 and 2.

During the intervention operations, on June 2, 2010, a band saw cut partially through the riser before becoming stuck. The lower portion of drill pipe section AA was cut by the saw creating AA-3. Sections AA-1 and AA-2 remained as one piece, captured in the riser kink.

Subsequently, on June 3, 2010, a subsea shearing device (scissor) cut the riser and drill pipe creating sections AA-1 and AA-2. See Figures 2, 3, and 4 below.

Drill Pipe Section AA-1: Tool Joint Connection Shoulder (at Flow-wash End) to the Riser Scissor Cut

Section AA-1 is 111.5 in. long from the tool joint connection shoulder to the sheared bottom.A It was captured in the riser “kink” and then removed from the recovered riser at Michoud on Jan. 20, 2011.4 See Figures 1, 2 and 3.5

Drill Pipe section AA-2: Riser Scissor Cut to Saw Cut Section

Section AA-2 is 7.5 in. long and was created when the scissor cut through the drill pipe above the saw cut. When cut, section AA-2 dropped and landed on top of the upper annular element. It was recovered later from above the upper annular element in the BOP stack onboard the Q4000 on Sept. 6, 2010.6 Section AA-2 has a shear-cut top and a saw-cut bottom.7

A When the drill pipe was removed from the recovered riser section at Michoud in January 2011, it was found that section AA-1 had broken in two parts at the riser “kink” approximately 30 in. from the bottom where the riser was sheared. The measured length of 111.5 in. includes both parts of section AA-1 recovered from the riser section.


Drill Pipe Section AA-3: Section Recovered From Above the Upper Annular in the LMRP

Section AA-3 is 109 in. long and was created when the band saw cut through the drill pipe. When cut, section AA-3 dropped and landed on top of the upper annular element. It was recovered later from above the upper annular in the BOP stack on board the Q4000 on Sept. 6, 2010.8 Section AA-3 has a saw-cut top and a sheared and deformed bottom.9

Dimension XX: Start of the Flow-wash Damage to the Tool Joint Connection Shoulder

Dimension XX is the distance above the AA-1 tool joint connection shoulder to where the flow-wash damage starts on section EE-3. This distance is 6 in. above the tool joint connection shoulder. This distance is the length of drill pipe between the bottom of the upper annular and the center of the blind shear rams. See Figure 1.

B. Drill Pipe Section BB: Blind Shear Rams to the Casing Shear Rams

The length of the drill pipe section recovered from below the blind shear rams resting on the casing shear rams is 42 in. and identified as drill pipe section BB.10 This section was later removed from the BOP on board the Q4000 on Sept. 6, 2010.11 The distance between the center of the blind shear rams to the center of the casing shear rams in the BOP is 43.5 in. See Figure 6 and Table 1. This confirms drill pipe section BB was cut by the blind shear rams and the casing shear rams.

C. Drill Pipe Section CC: Casing Shear Rams to the Lower Pipe Rams (Test Rams)

The length of the drill pipe section recovered from below the casing shear rams and above the test rams is 142 in. and identified as drill pipe section CC. This section was removed from the BOP at Michoud on Dec. 16, 2010.12 The dimension from the center of the casing shear rams to the center of the lower test rams in the BOP is 142 in., confirming the drill pipe was cut by the casing shear rams and was positioned in the upper variable bore rams, middle variable bore rams and test rams. See Figure 6 and Table 1. The bottom of section CC ends at the center of the lower test rams, where it was washed away. There are clear and obvious flow-wash areas on section CC where the upper variable bore rams and middle variable bore rams were closed on the drill pipe.13

D. Drill Pipe Dimension DD: Upper Annular to the Lower Pipe Rams (Test Rams)

Dimension DD is 418 in., representing the total length of drill pipe sections AA, BB, and CC, as shown in Table 1. The dimension from the bottom of the upper annular element to the center of the lower test rams in the BOP is 420 in. See Figure 6 and Table 1. This confirms the location of the drill pipe at the time of the incident.

E. Drill Pipe Section EE: Drill Pipe Tool Joint in the Recovered Riser to Drill Pipe Section A Tool Joint

The measured length of the drill pipe sections for dimension EE is 551 in. This represents the total length of drill pipe sections EE-1, EE-2, and EE-3, as shown in Table 1. The nominal length of a joint of 5.5-in. S-135 drill pipe is 552 in. (46 ft.) with a variance of plus or minus 6 in.B See Figure 6 and Table 1. The location of the tool joints that were fixed in place by the riser kink confirms the location of the drill pipe inside the BOP at the time of the incident.

B S-135 is a designation of the material strength and properties of drill pipe.


Section EE was captured in the marine riser in a kink above the BOP when the riser folded over as the Deepwater Horizon sank 36 hours after the first explosion. On June 3, 2010, a scissor tool was used to cut the riser and drill pipe.14 As a result, EE-1 was created above the scissor cut, and EE-2 was created below the scissor cut.

Drill Pipe Section EE-1: Upper Section of Drill Pipe Recovered from the Riser Joint Above the BOP Stack

Drill pipe section EE-1 is 388 in. long and is continuous from top to bottom with both ends scissor cut. See Figures 2 and 3. Section EE-1 is measured from the drill pipe tool joint connection shoulder, located in the upper end of the riser, to the bottom scissor-cut end. Section EE-1 was removed from the recovered riser section at Michoud on Jan. 20, 2011.15 Section EE-1 has a tool joint connection on top, a scissor cut on bottom, is bent 30 in from the bottom at the riser kink, and is bent (“corkscrewed”) and flattened in the section above the riser kink.16

Drill Pipe Section EE-2: Section of Drill Pipe Recovered from Inside the Deepwater Horizon BOP Upper Annular BOP

Section EE-2 is 136 in. long and is bent in a long sweeping bend. It has a scissor-cut top and a flow-washed and deformed bottom that aligns with the flow-washed top of drill pipe section A.17 See Figures 1, 2 and 5.

Drill pipe sections AA-1 and EE-2 were created when the Deepwater Horizon lost power and started to drift off location, parting the drill pipe at its weakened section. Approximately 30 minutes later, the travelling block fell, dropping approximately 5,000 ft. of drill pipe onto the partially closed annular element.18 The bottom of the drill pipe, section EE-2, landed on top of the upper annular element.

When the riser flange was removed from the top of the BOP stack on July 11, 2010, section EE-2 was visible with hydrocarbon flow coming out of the top.19 During drill pipe fishing operations, the upper section of the BOP stack was inspected with a bore-scope camera on Aug. 26, 2010. The upper annular element was closed and section EE-2 was in the opening of the element.20 An attempt was made to recover section EE-2 from the top of the BOP stack. When the fishing tool touched the top of section EE-2, it dropped down through the upper annular element, stopping at the scissor-cut top where the pipe is flattened and wider.21 Section EE-2 was later recovered out of the Deepwater Horizon upper annular element at Michoud on Nov. 24, 2010.

Drill Pipe Section EE-3: Tool Joint Connection Shoulder to Top of Flow-washed Drill Pipe

Drill pipe section EE-3 measures 17.5–20.5 in. and is connected to the top of drill pipe section AA at the tool joint.22 For comparison, the height of a Cameron DL Annular element is 18 in., confirming the annular was closed on this section of pipe and tool joint. Section EE-3 was removed from the recovered riser section at Michoud on Jan. 20, 2011. See Figures 1 and 2.

F. Dimension XX - Start of the Flow-wash Damage to the Tool Joint Connection Shoulder

Dimension XX is part of drill pipe section EE-3 and is referenced to identify the distance from the tool joint connection to where the flow-wash damage starts, 6 in. above the tool joint connection shoulder. See Figure 1.


Section EE-3 = 17.5 in. to 20.5 in. to the start of

flow wash to end

Dimension XX 6 in. from tool joint connection to

start of flow

Broken section from riser link

Tool joint connection

Section AA-1

Section EE-1

Figure 1 Drill Pipe Section AA-1 and Section EE-3

Figure 2 Drill Pipe in the Recovered Riser Section at the Kink End with the Drill Pipe Sections EE-1, AA-1 (with EE-3 Attached)


Section AA-1

Section EE-1

Saw cut

Shear cut

Tensile break

Location of rupture

Figure 3 Sheared Section of the Recovered Riser at the Lower Kink End with the Drill Pipe Sections EE-1 and AA-1

Figure 7 Failed End of Drill Pipe – Top of Section EE-3 Showing Location of the Rupture and the Tensile Break

Figure 4 Riser Flange from Above the Deepwater Horizon BOP with the Partial Saw Cut and the Final Shear Cut


Figure 6 DWH BOP with the Drill Pipe in the Position at the Time of the Incident

EE

AA

BB

CC

DDD

A

E

B

C


Table 1

# Description Length (inches)

A Bottom of upper annular element to the center of the blind shear ram 234

XX Start of the flow-wash damage to the tool joint connection break 6

AA-1 Tool joint connection break at flow-wash end to the riser shear cut 111.5

AA-2 Riser shear cut to saw cut section 7.5

AA-3 Section recovered from inside the upper annular in the Deepwater Horizon LMRP 109

AA Total length of drill pipe section 234 B Center of the blind shear ram to center of casing shear ram 43.5

BB Section recovered from below the BSR and above the CSR 42 C Center of the casing shear ram to the center of the lower test rams 142

CC Section recovered from below the CSR that extends to the lower test rams 142 D Bottom of upper annular element to the center of the lower test rams 420

XX Tool joint connection to the start of the flow-wash damage on the tool joint 6

AA-1 Upper tool Joint connection break at flow-wash end to riser shear cut 111.5

AA-2 Riser shear cut to saw cut section 7.5

AA-3 Section recovered from inside the upper annular in the Deepwater Horizon LMRP 109

BB Section recovered from below the BSR and above the CSR 42

CC Section recovered from below the CSR that extends to the lower test rams 142

DD Total length of drill pipe section (AA + BB + CC) 418 E Nominal length of the Deepwater Horizon S-135 Drill Pipe = (+/- 6 inches) 552

EE-1 Upper section recovered from the riser joint above the BOP 388

EE-2 Section recovered from inside the upper annular in the Deepwater Horizon LMRP 136

EE-3 Flow-washed tool joint connection to failed end 27

EE Total length of upper drill pipe section 551


1. DNV, Forensic Examination of Deepwater Horizon Blowout Preventer, March 20, 2011.

2. Ibid.

3. Ibid.

4. Riser Drill Pipe Dimension Sketch, Sept. 15, 2010, Revised by Geoff Boughton, Dec. 4, 2010.

5. DNV Metallurgical Examination and testing of Drill Pipe, Feb. 3, 2011.

6. Ibid.



9. The inspection of this section indicates it was sheared by the blind shear rams. DNV, Forensic Examination of Deepwater Horizon Blowout Preventer, March 20, 2011.



12. Ibid.


14. Transocean operations report from BP ERC, June 3, 2010.

15. DNV, Forensic Examination of Deepwater Horizon Blowout Preventer, March 20, 2011; DNV Metallurgical Examination and Testing of Drill Pipe, Feb. 3, 2011.


17. Ibid.

18. Ibid.


20. Ibid.

21. Ibid.

22. Ibid.

appendix l drill pipe in the bop - transocean · aa-3 dropped and landed on top of the upper...

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