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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 www.spe.org/dl ©JA Turley

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

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

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

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

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

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

* 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

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

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

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 30 minutes, the well was declared secure. 12,500-psi reservoir Pressure at TD 450-psi underbalance 12 ©JA Turley

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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-167970-MS Book: THE SIMPLE TRUTH: BP’s Macondo Blowout ©JA Turley

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