The Deepwater HorizonBlowout and Oil SpillBlowout and Oil Spill

T A&M U i itTexas A&M UniversityPETE Graduate Seminar

September 28, 2010

1Sources: Congressional testimony, Internet (theoildrum.com), Newspapers (WSJ), Magazines, TV, DOE, BP

Dynamically positioned

Size: 396 ft by 256 ft

Cost: US$ 560 million

2

The Deepwater Horizon semisubmersible in transitThe USS Cole – Yemen - Oct. 2000

The Deepwater Horizonp

5th G ti D t Ri5th Generation Deepwater Rig

Capable of operating in 10,000 ft of water

15,000 psi BOP Stack

Built in 2001

BP operating cost~ $1,000,000 per day

3

The BlowoutOn April 20, 2010, large quantities of hydrocarbons escaped from BP’s Macondo #1 well in the Gulf ofescaped from BP s Macondo #1 well in the Gulf of Mexico.

Multiple explosions and a fire resulted. 11 lives were lost and 17 others were injured.

The fire, continued for 36 hours until the rig sank.

Hydrocarbons continued to flow for 87 days causing millions of barrels of oil to spill into the Gulf.p

4

5The Deepwater Horizon on fire – April 21, 2010

Ri k ORig sank On April 22, 2010

View one oJune 20, 2010

6

Rotary drilling BASICS

In the openholeIn the openhole section

(no casing)

pmud > ppore

dand

pmud < pfracture} OPENHOLE

( p = pressure)} OPENHOLE SECTION

Well Casing

What is casing? Casingg

Steel pipe placed inside the wellbore

Wh i / t?

Cementinside the wellbore

Why run casing/cement?

• To prevent the hole from caving inTo prevent the hole from caving in

• To prevent vertical migration of fluids outside the casing

8

Halliburton d drecommended

21 centralizers

BP installed 6!!

9

Centralizer

Bow Spring type

10

11BP did not run a cement bond log

Casing Design OptionsRIG

DRILLINGRISER

STEP 1 STEP 2STEP 1 STEP 2

DRILLINGRISER

WELLHEAD

BOP STEP 1 STEP 2STEP 1 STEP 2

BOPWELLHEAD

12The Long String The Liner and Tieback

13

The Drilling Riser

14

Subsea BOP Stack Subsea BOP System

Operatedby

PressurizedPressurizedHydraulic

Fluid

1512’x12’x80’700,000 pounds

16

Ram Blowout Preventer

SHEAR / BLINDRAM ASSEMBLYRAM ASSEMBLY

17Ram Blowout Preventer - cont’d

ShearShear Rams

DrillPipe Only

Two Pipes?

18

Hydraulic fluid?

What Happened?

9 7/8”

SEAL

LEAK?

9 /8CASING

7” CASING

19

CEMENT

Circulate Bottoms up - N2 - Gas

What Happened?

SEAL? SEAL was set, but not locked down

LEAK?

9 7/8” CASINGPositive Pressure Test - OK

Negative pressure tests - ??

7” CASING

Negative pressure tests - ??

No Cement Plug was setPrior to displacing7 CASING Prior to displacing

mud with water

No Float Valve in Casing Shoe?

20

CEMENT THE WELL KICKED –BIG TIME

What is a KICK ?

An unscheduled entry

of formation fluidsof formation fluids

into the wellbore

What happens if a kick

is not caught early

and is not controlled properly?

21

What happens if a kickWhat happens if a kick is not controlled?

BLOWOUT !!!BLOWOUT !!!

22

The Macondo Well D t R dData Record

(last two hours)

FOUR independent kick indicators

• Mud flow into and out of the well

• Mud volume in the surface pits

• Hook load

• Bottom-hole pressureBottom hole pressure

Data recorded on the rig and ti l t t H t

23

continuously sent to Houston

Oil and Gas Flows

G

120,000,000 scf/dayOil Oil

Gasmethane +

Methane Dissolves

Hydrates Bio – degradation

Solubility ?

yd atesDissolve

Oil and Gas Methane

RISER

Dispersants Hydrate Formation

24

GAS: 90,000 bbl/dayBOP OIL: 40,000 bbl/day

Containment dome

~ 40’ height~ 40 height~ 100,000 pounds

Gas Hydrates

IncreasedIncreased Buoyancy

Pl iPlugging

Gas!

25

I ti T bInsertion TubeRISER INSERTION TUBE

26

The Top Kill

Acknowledgements.tifg

27

Top Hat

Acknowledgements.tifg

28

The New BOP that stopped the flowTotal Height = 30 ft ppgWeight = 165,000 lbs

29

Relief WellsThe ultimate solution!

Well #1 - Started May 2Reach near bottom inReach near bottom in

late July

Well #2Well #2Started May 22

Expert in charge had killed 40 blowouts!

30

(40 out of 40)

D th J l 5

31

Depth on July 5:17,725 ft

Possible Problems

Did not Circulate bottoms up prior to pumping cement

Installed 6 Centralizers on the Casing instead of 21

Used Long Casing String instead of Liner and Tieback

Did not Run Cement Bond Log

Did not Secure Seal at top of Casing

Performed questionable Negative Pressure Tests

Removed mud from the hole before setting cement plug

Did not pay close attention to KICK Indicators

Did not make sure BOP was thoroughly tested as needed

32

US OIL - Supply and Demand

20 millionbarrels/day

Imports Onshore

USProduction Deep Water

33

ProductionShallow Water

The BP Macondo Well:

Oil production ~ 40,000 barrels/day (rough estimate)

about 0.6% of total US oil production

Gas Production 120 000 000 standard cubicGas Production ~ 120,000,000 standard cubic feet of gas per day

The average US oil well produces ~ 10 barrels of oil per day. y

This is why we drill offshore in deep water!

34

This is why we drill offshore in deep water!

Saudi Arabia ~5,000 b/d

Oil Flow Rate

Estimated or Calculated flow rate:Estimated or Calculated flow rate:

From 1,000 barrels/day to 60,000 barrels/day

Captured and Measured flow rate:

/ /From 0 barrels/day to 25,000 barrels/day

Pl d C t C itPlanned Capture Capacity:

From 60,000 to 80,000 barrels/day

35Actual Oil Production Rate?

Calculating Flow Rate

Flow Velocity = 4 ft/sec

Flow Area (20” dia) ~ 2.2 sq. ft

Flow Rate = 8.8 cu.ft / sec ~ = 130,000 bbl / day

Assume gas/oil ratio (GOR) = 3,000 scf / bbl

S fl 150 t h ( pV = znRT )Seafloor pressure ~ = 150 atmospheres

GOR at seafloor = 3,000/150 * 0.68 * 500/530

= 13 cu.ft / bbl = 2.3 bbl of gas / bbl of oil

( pV = znRT )

g

Oil flow rate = 40 000 bbl/dayOil flow rate 40,000 bbl/day

Gas flow rate = 90,000 b/d (seafloor)

Now What?

On July 15 the well was closed in by closing the y y gvalves on the new BOP that was sitting on top of the old one.

On September 18, the relief well was used to finally plug the well by pumping lots of cement around the bottom of the well – the so-called “Bottom Kill.” Well declared dead on Sept. 19.

What is being done to prevent a similar occurrence in the future?

37

What is being done?

Learn as much as possible from the MacondoLearn as much as possible from the Macondo incident, determine what really did happen, and apply the lessons learnt to prevent future problems of this kind.

Four (five) major oil companies formed a consortium to develop better understanding, better methods, and

$equipment that is always ready and available. ($ 1 B!)

Not to be left out: Our government split the MMS into three separate units; pledged to provide more oversight, applied a DRILLING MORATORIUM !!

38

AcknowledgmentsAcknowledgments

Dr Alex Dessler Professor EmeritusDr. Alex Dessler - Professor Emeritus, atmospheric physics and astronomy, Rice U.

Dr. Ann Jochens - lawyer and oceanographer

They were very helpful in selecting and organizing the slides Without their help thisorganizing the slides. Without their help this presentation could have taken twice as long.

39

Any Questions?yDeepwater Horizon

Top HatRelief Wells

Th lti tThe ultimate solution!

Two wells

40