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Society of Petroleum Engineers Distinguished Lecturer Program

2. Assessing and Applying Petroleum Engineering Data
From the 2010 Macondo Blowout
J.A. (John) Turley
Marathon Oil Company—Retired
Society of Petroleum Engineers Distinguished Lecturer Program
©JA Turley

3. MACONDO—THE PLAN
Drill an Exploration Well in the Gulf of Mexico (Mississippi Canyon Block 252)
Spud October 2009
Depth: Approximately 20,000 ft (6,100 m)
Water: Approximately 5,000 ft (1,525 m)
Target: Geological structure (called Macondo)
Target Depth: Below 17,000 ft (5,200 m)
©JA Turley

4. Drilled another 1000 ft and discovered . . .
9-7/8 liner near
17,000 ft
Drilled another 1000 ft and discovered . . .
. . . A high-pressure stringer that needed
heavy mud (14.2-ppg)
. . . A number of lost circulation zones
. . . About 200 ft of pay from 18,000 to 18,200 ft
. . . Total depth 18,360 ft
©JA Turley

5. After evaluating discovery:
Completed well with
single string of
9-7/8 x 7 in.
production casing
Float collar installed
near 18,155 ft
Used Class-H lead cement, plus nitrified cement,
plus Class-H cement in
180-ft shoe track
Rat hole, 56 ft of mud
©JA Turley

6. AFTER THE CASING AND CEMENT JOB, TEMPORARY ABANDONMENT WOULD INCLUDE:
Prepare well for testing and the rig for abandonment
Positive and negative pressure tests— remediate as necessary
Install Lockdown Seal Ring
Set and test cement plug
Displace riser with seawater
Pull BOPs and Riser
Release Rig 1 2 3 4 5 6 7
©JA Turley

7. AFTER THE CASING AND CEMENT JOB, TEMPORARY ABANDONMENT WOULD INCLUDE:
Prepare well for testing and the rig for abandonment
Positive and negative pressure tests— remediate as necessary
Install Lockdown Seal Ring
Set and test cement plug
Displace riser with seawater 1 2 3 4 5
THE WELL BLEW OUT
©JA Turley

8. gravity segregation with rat-hole mud
Float collar: (1) possible mechanical damage, and (2) pump rate of 4-bpm fell short of 6-bpm required for conversion
Shoe-track and
annular cement
likely compromised by
gravity segregation with rat-hole mud
These early STATIC LEAK problems were invisible to personnel on the rig
©JA Turley

9. * BOP = Blowout preventer
April 20: Rig, Riser, and BOP* are in place. Entire well is full of necessary heavy mud
April 21: Rig, Riser, and BOP are gone. At least 5,000 ft of heavy mud replaced by seawater
Negative Pressure Test (NPT) is a simulation designed to ensure heavy mud from riser can be replaced by seawater
* BOP = Blowout preventer
©JA Turley

10. Minimum acceptable NPT is at 5,000 ft;
i.e., through 5,000-ft kill line,
(shown in blue)
Alternative NPT through drillpipe (DP) at 8,367 ft. This NPT (called NPT-1) was elected for Macondo.
Note cement plug
©JA Turley

11. Bleed DPP to zero for 30 minutes
Negative-pressure test (NPT-1) with seawater to 8,367 ft developed 2,400-psi backpressure
Time
BOP
closed
DPP
2,400 psi
Pressure at Surface
Bleed DPP to zero for 30 minutes
After closing BOP, bled trapped pressure to zero (to create 1,400-psi
underbalance)
BHP
13,500 psi
But pressures observed during bleed-off were declared anomalous, and NPT-1 was aborted. Testing reverted to kill line—called NPT-2
12,500-psi
reservoir
Pressure at TD
1,400-psi
underbalance 11
©JA Turley

12. Bleed kill line to zero for 30 minutes
NPT-2 with seawater in kill line would have developed 1,450-psi backpressure
Time
BOP
closed
DPP
1,450 psi
Pressure at Surface
Bleed kill line to zero for 30 minutes
Bleeding the trapped pressure to zero would have created 450-psi underbalance
BHP
13,500 psi
When the kill-line pressure for NPT-2 was bled to zero for minutes, the well was declared secure.
12,500-psi
reservoir
Pressure at TD
450-psi
underbalance 12
©JA Turley

13. and from NPT-2 (blue), which showed well to be secure
BP Internal Investigation
8 September 2010—Page 88
Mudlogging chart shows pressure data from NPT-1 (green), which was aborted,
and from NPT-2 (blue), which showed well to be secure
NPT-1
NPT-2
©JA Turley

14. Inflow data (leak plus dynamic flow)
Pressure build-up curve (well flowing into closed wellbore)
Pressure spikes (casing hanger lifting in csg head )
SIDPP* 1,400 psi (measure of underbalance) 1
NPT-1 4 2 3 2 1 3 4
*SIDPP: Shut-in Drillpipe Pressure
©JA Turley
London SPE 24/11/15

15. Missing 450-psi kill-line kick
Injectivity profile, pumping seawater down wellbore (at ~450 psi), through LCM, into formation
Shut-in kill line for 30 minutes at zero-psi, as measure of wellbore security 5
NPT-2 6 5 7 6 7
©JA Turley
London SPE 24/11/15

16. While overbalanced, as head of mud in riser decreases, the pumping DPP
While overbalanced, as head of mud in riser decreases, the pumping DPP* decreases
While underbalanced, flowing O&G* pushes mud up wellbore into drillpipe annulus, which causes pumping DPP to increase
During sheen test, with pumps off, well continued to flow, evidenced by continually rising DPP
* DPP = drillpipe pressure
* O&G = oil and gas
©JA Turley

17. Flow filled 750-bbl* casing plus portion of 1,500 bbl in riser before O&G reached bubble-point depth
With gas below bubble point, rapid expansion blew O&G through rig floor & over the derrick.
Closed two BOPs (red), but drillpipe compromised by extreme flow rate and falling blocks, which allowed flow to continue
* bbl = barrels = 0.16m3
©JA Turley

18. Spilled almost 5MM bbls of oil into Gulf of Mexico
Tool joints and DP were uplifted into closed BOPs. Excess DP trapped between closed BOPs was buckled, which prevented closure of the blind shear rams
In minutes:
Explosions and fire
11 deaths
115 survivors evac’d rig
Rig sank 1-1/2 days later
Well flowed for 86 days
Spilled almost 5MM bbls of oil into Gulf of Mexico
©JA Turley

19. Factors evidenced by data that to the Cause of the Blowout
CONTRIBUTED
to the Cause of the Blowout
Rat Hole
Float Collar
Back-flowing well
Unseen forensic data
LCM in the BOP
Simultaneous operations
©JA Turley

20. Factors evidenced by data that
CAUSED
the Blowout 
Viable NPT results that confirmed a leak and the well’s flow potential when underbalanced
The lack of a primary cement-plug barrier before seawater displacement
Viable pump-pressure data that confirmed the well flowed for an hour prior to the blowout
Massive, unchecked well flow that ultimately debilitated proper functioning of the BOPs
©JA Turley

21. CONCLUSIONS:
Macondo Blowout Evidence is defined by basic petroleum-engineering concepts, training, and responsibilities.
Skilled application of such concepts, would have made a difference on Macondo.
Also helpful would have been industry initiatives like: Drilling Process Safety, Human Factors, Safety & Environmental Management Systems, Real-time Data, etc.
But . . .
©JA Turley

22. CONCLUSIONS:
Macondo Blowout Evidence is defined by basic petroleum-engineering concepts, training, and responsibilities.
Skilled application of such concepts, would have made a difference on Macondo.
Also helpful would have been industry initiatives like: Drilling Process Safety, Human Factors, Safety & Environmental Management Systems, Real-time Data, etc.
But How do we APPLY Macondo lessons to future wells?
©JA Turley

23. from rig-up to rig-down, is a sequence of processes . . .
A well, from mob to demob,
from rig-up to rig-down,
is a sequence of processes . . .
with steps to be executed
as per the Plan
but when something
INTERRUPTS any PROCESS,
whatever’s broken needs to be fixed 23
©JA Turley

24. Process Interruption Goal
Running casing
Testing BOPs
Installing a wellhead
Drilling to next casing point
Testing Casing
Interruption
Any unplanned/unexpected result
Goal
Figure out what’s wrong & Fix it 24
©JA Turley

25. Process Interruption Example—
Drilling Ahead
Alarm Screams
Stop Drilling
Well Control 25
©JA Turley

26. Process Interruption Example— the Process of Drilling
Drilling Ahead
Alarm Screams
Stop Drilling
Remediate the Problem
Critical Data
About what
Interrupted
the Process of Drilling
Washout?
Bit failure?
Well Control?
Pack-off?
Lost Circulation?
Other? 26
©JA Turley

27. PROCESS INTERRUPTION PROTOCOL must be . . . Stop the Process
If any process related to the well
is interrupted
The
PROCESS INTERRUPTION PROTOCOL
must be . . .
Stop the Process
Resolve the Interruptive Data
Remediate the Problem 27
©JA Turley

28. Process Interruption Protocol— Negative Pressure Test
Run drillpipe
Fill with seawater, close BOPs
Bleed trapped pressure to zero, hold 30 min
Interruption
Pressure wouldn’t bleed, and made 15 bbl
Protocol
Stop the Process, Resolve Interruptive Data (at the Yellow #1), Remediate the problem 28
©JA Turley

29. Inflow data (leak plus dynamic flow)
Pressure build-up curve (well flowing into closed wellbore)
Pressure spikes (wellhead lifting in casing head )
SIDPP* 1,400 psi (measure of underbalance) 1
NPT-1 4 2 3 2 1 3 4
*SIDPP: Shut-in Drillpipe Pressure

30. Macondo—A Lesson Learned:
PROCESS INTERRUPTION PROTOCOL—
STOP the Process
RESOLVE the Interruptive Data
REMEDIATE the Problem
Applicability:
Wells worldwide, any process, deep or shallow, onshore or offshore, design through abandonment
Goal
To minimize the chance of ever
losing control of another well. 30
©JA Turley

31. The end Fix the Problem Not the Blame
©JA Turley
London SPE 24/11/15

32. Assessing and Applying Petroleum Engineering Data
Q&A
Assessing and Applying
Petroleum Engineering Data
From the 2010 Macondo Blowout
By: J. A. (John) Turley
Only if we understand and care about the CAUSE of the 2010 Macondo blowout,
will we know why it should not have happened and why it should never happen again.
Website: JohnTurleyWriter.com
Technical paper —SPE MS
Book: THE SIMPLE TRUTH: BP’s Macondo Blowout
©JA Turley

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Society of Petroleum Engineers Distinguished Lecturer Program
©JA Turley