STUDY CASE “DEEPWATER HORIZON OIL SPILL”: REMOVING, RECOVERING

AND CLEANING UP.

Submitted by

Helena Patricia De la Hoz De la Hoz

In partial fulfillment of the requirements for

Lecture: Chemistry of Environmental systems (CHM 760)

Missouri State University

December 7th 2012

On April 20th

2010, British Petroleum’s (BP) Macondo well blew out. A series of

management failures caused what is today considered the biggest oil spill in the history. Nobody

was prepared to face the challenge of addressing this incident, nor the Government neither the

Oil industry. At 10:22 a.m. on April 22, the Deepwater Horizon well sank; right after this

incident happened many efforts were made to stop the leak. However it was not until July 14

that the well was sealed. The lack of tested technique to stop a deepwater blowout other than the

lengthy process of drilling a relief well is what led to a period of almost 3 months to stop the

leak. Within a week of the explosion, “BP embarked in what would become a massive effort to

generate containment options, either by adapting shallow-water technology to the deepwater

environment, or by designing entirely new devices”1.

Among other challenges, calculating the estimate of the flow rate of oil released was not

successfully achieved until May 27. On May 12, BP released a 30-second video of oil and gas

streaming from the end of the broken riser. This helped make a better assessment of oil flow.

After an estimation report of 50,000 barrels2 of oil per day was released to the public, several

other adjustments were done. Finally, later studies would conclude an estimate of 12,000 to

25,000 barrels a day.

The amount of oil released was a very important issue (although some of the response

team organizations did not think so). The use of dispersant and other response operations were

1 National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. Deep Water: The Gulf Oil Disaster and

the Future of Offshore Drilling. Report to the President, Washington, DC: U.S. Government Printing Office, 2011. p,

135.

2 Ibíd. p,147

based on a primary input of 5,000 barrels per day3. This could explain the insufficient collection

capacity showed during the response operation4.

The use of dispersants

For the incident response, a total amount of 1,843,786 gallons5 of dispersant where used.

1,072,514 gallons were applied to the surface and 771,272 gallons to the wellhead. In both

modes, dispersant was added to lower the interfacial tension between oil and water and thereby

reduce the size of oil droplets formed by wave action (surface) or by ejection of oil and gas out

of the wellhead (deepwater)6. Prior to this incident, no deepwater applications of dispersant had

been conducted, thus no data was available on the environmental fate of dispersants in

deepwater.

Dispersants change the distribution, not the amount, of oil within a marine environment.

Non-mechanical methods such as in-situ burning and chemical dispersants can contribute to the

elimination or breakdown of the oil. In response to the Deepwater Horizon oil spill, BP used

large amounts of the dispersant Corexit 9500 and some Corexit 95277.

Dispersants have two main components: a surfactant and a solvent. Molecules of

surfactants are made up of two parts: an oleophilic part (with an attraction to oil) and a

3 Ibíd. p, 147 4 See Figure 2. Oil budget. Taken from ubchenco, Jane. BP Deepwater Horizon Oil Budget: what happened to the

oil? Silver Spring, Md: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, 2010. 5 Figures on the volume of dispersant are taken from, the Operations and Ongoing Response daily reports for the

Deepwater Horizon Response, available at http://www.restorethegulf.gov. 6 Kujawinski, E, M Kiso Soule, D Valentine, A Boysen, K Longnecker, and M. Redmond. "Fate Dispersants

Associated with the Deepwater Horizon Oil Spill." Environmental Science and Technology, no. 45 (January 2011).

p, 1298. 7 National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. "The use of surface and

subsea dispersants during the BP Deepwater Horizon oil spill [electronic resource] / National Commission on the BP

Deepwater Horizon Oil Spill and Offshore Drilling." Staff Working paper; no. 4, Washington D.C, 2011.

hydrophilic part (with an attraction to water). When dispersants are sprayed onto an oil slick, the

solvent will transport and distribute the surfactants through the oil slick to the oil/water interface

where they arrange themselves so that the oleophilic part of the molecule is in the oil and the

hydrophilic part is in the water. This creates a reduction in the surface tension at the oil/water

interface and small oil droplets will break away from the oil slick with the help of wave energy.

These droplets will be of varying sizes and although the larger ones may rise back to the surface

some will remain in suspension and will drift apart and become degraded by naturally occurring

bacteria. If dispersion is successful, a characteristic brown plume will spread slowly down from

the water surface a few minutes after treatment.8

Even though dispersants have been usually applied for combating oil spills, their effects

in marine life and environment are broadly discussed. There is uncertainty on whether or not the

use of dispersant is more toxic than the oil itself. The fact that due to patent issues, the

composition of Corexit 9500 is not fully understood, it made it difficult for the EPA to make a

well based decision into defining the outlines for the use of dispersants in the Deepwater Horizon

oil spill9.

During the spill response operations, the use of dispersants grew abruptly throughout the

days (Figure 1 shows a projection of this fact). The application on the subsea was handled

carefully due to the unknown effects on marine life of dispersants (particularly for the effect of

the surfactant used in the dispersant Corexit 950010

). However as shown in the graphic (figure 1)

8 See International Tanker Owners Pollution Federation Ltd, Dispersants, http://www.itopf.com/spill-

response/clean-up-and-response/dispersants/. 9 National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. "The use of surface and

subsea dispersants during the BP Deepwater Horizon oil spill [electronic resource] / National Commission on the BP

Deepwater Horizon Oil Spill and Offshore Drilling." Staff Working paper; no. 4, Washington D.C, 2011. 10

Ibid. p 12

the dispersant used in deep sea increased exponentially. The deep-water dispersed oil droplets

(that had a concentration of less than 10 ppm total petroleum hydrocarbons) have been likened to

a “cloud”. This “cloud” of dispersed oil could be detected by fluorescence moving away from the

wellhead, generally in a southwesterly direction. O2 concentration drops that did not result in

anoxic conditions were also often detected in association with the “cloud” of dispersed oil in the

deep-sea11

. The deep-sea “cloud” of dispersed oil was found to have lower PO43- and dissolved

O2 concentrations, slightly higher NH4+ concentrations and significantly lower NO3

concentrations suggesting bacterial activity in the “cloud” of dispersed oil. The total bacterial

density was significantly higher in the “cloud” (up to 105 cells/mL) versus outside the “cloud”

(approximately 103 cells/mL)12

. However as of today it is too early to know how the column

water environment has been affected by the use of these changes of chemical conditions. There is

little or no information regarding to the environmental fate of Corexit 9500.

Finally it is clear that the government was not adequately prepared for the use of

dispersants to address such a large oil spill. As a result, the National Incident Commander, the

EPA Administrator, and the NOAA Administrator were seriously handicapped when the

Macondo well explosion occurred and decisions had to be made immediately in the absence of

adequate contingency planning13

. The incomplete toxicity data they possessed was questionable

and limited to acute lethal effects on two estuarine species. It did not consider potential

environmental persistence resulting from repeated or continuous sublethal effects, such as

11Atlas, R, and T Hazen. "Oil Biodegradation and Bioremediation: A Tale of the Two Worst Spills." Environmental

Science and Technology, no. 45 (June 2011). 12 Ibid. p, 6713 13 National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. Deep Water: The Gulf Oil

Disaster and the Future of Offshore Drilling. Report to the President, Washington, DC: U.S. Government Printing

Office, 2011.

endocrine disruption14

. The absence of adequate contingency planning had a further negative

impact on the effectiveness of the government’s response. It made unclear the lines of authority

between various federal agencies in determining whether dispersants should be used. Because

federal agencies had failed to plan adequately, they did not possess the scientific information that

officials most certainly would have wanted to guide their choices. They had to make choices

nevertheless: Millions of gallons of oil were flowing from the Macondo well into the Gulf of

Mexico every day, imperiling the responders who worked in the immediate vicinity of the spill,

residents living along the Gulf Coast, the Gulf marine ecosystem, and the fishing and tourism

industries.

Response Actions Evaluation

On a final review to the facts, the National Commision on the BP Deepwater Horizon oil

spill and Offshore Drilling sated: “Over the time, you realize that this is the kind of accident that

people said could not happen. It could be said that maybe for the first six weeks the government

was trying to play a lot of catch up. They were dependent on information they got from BP that

was not always reliable. The government did take charge quiet effectively… What we discovered

is that the technologies that were available to clean the oil spill after the Exxon Valdez 20 years

ago, were exactly the same that were available today. And not only the technology is virtually

the same but its efficiency is very, very low…”15

The urge to new technologies to respond at oil spills.

14 National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. "The use of surface and

subsea dispersants during the BP Deepwater Horizon oil spill [electronic resource] / National Commission on the BP

Deepwater Horizon Oil Spill and Offshore Drilling." Staff Working paper; no. 4, Washington D.C, 2011. 15 National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. Deep Water: The Gulf Oil

Disaster and the Future of Offshore Drilling. Report to the President, Washington, DC: U.S. Government Printing

Office, 2011.

Currently used methods are decades old, low technology, and manpower intensive, some

with unknown environmental consequences. On the basis of these current methods, most spilled

oil is wasted and becomes pollutants in our air and water. A novel proposal16

for combating oil

spills has been published in ACS’s journal Energy and Fuels. It has been well accepted by the

scientific community17,18,19

.

The design of the research approach has been focused around the design of a new oil

super absorbent polymer (oil-SAP) than can offer comprehensive solution for combating future

oil spills. The new oil-SAP should simultaneously exhibit a combination of several essential

properties, including:

a) high oil absorption capacity,

b) fast kinetics,

c) no water absorption,

d) buoyancy and good mechanical strength for easy recovery from the water

surface,

e) recovered oil/oil-SAP mixture suitable in a regular oil-refining process, and

f) cost effectiveness

A series of amorphous 1-Octane/ Styrene / Divinilbenzene (OS-DVB) terpolymers were

systematically synthesized using heterogeneous Ziegler-Natta catalyst that shows suitability for

preparing high-molecular weight OS-DVB terpolymers with good control of composition and

16 Yuan, X, and T.C. Chung. "Novel Solution to Oil Spill Recovery: Using Thermmodegradable Polyolefin Oil

Superabsorbent Polymer (Oil-SAP)." Energy and Fuels 26 (July 2012) Available online in

http://pubs.acs.org/doi/abs/10.1021/ef300388h 17 http://www.sciencedaily.com/releases/2012/10/121003150906.htm 18 http://www.chemistryviews.org/details/news/2709651/Superabsorbent_Polymer_For_Oil_Spill_Treatment.html 19

http://phys.org/news/2012-10-solution-oil-spill-cleanup.html

random structure and only engaging mono-enchainment for DVB20

. Polyolefins made of olefins

such as 1-Octane, Styrene, and Divinilbenzene are fully saturated hydrocarbon molecules (much

less than one double bond per molecule), which is the basis of their properties. The weak van der

Waals forces between polyolefin molecules result in lower melting and crystallization

temperatures than for polymers with stronger interaction. This means that they are easier to

process because of the lower melting point21

.

The Zieggle-Natta catalyst [ ] used for the

polymerization is a heterogeneous solid. The (transition metal component) is the catalyst

and the is the organometallic part. Because Ziegler-Natta catalyst may be rendered

inactive (“poisoned”) even by traces of oxygen and water, it must be handled under and inert

atmosphere (nitrogen gas in this case). Despite passage of more than 57 years since the basic

discoveries, the mechanism of Ziegler-Natta polymerization is still not fully understood22

.

The resulting OS-DVB terpolymer containing some pendent styrene moieties (thermal

crosslinkers), is completely processable (soluble) in forming various sizes and shapes. However

upon thermal heating (>220°C), it becomes a completely insoluble network structure by

engaging in a Diels-Alder [2+4] interchain cycloaddition reaction between styrene units in the

20 Yuan, X, and T.C. Chung. "Novel Solution to Oil Spill Recovery: Using Thermmodegradable Polyolefin Oil

Superabsorbent Polymer (Oil-SAP)." Energy and Fuels 26 (July 2012). Available online at

http://pubs.acs.org/doi/abs/10.1021/ef300388h. p, 4898 21 C. Carraher, "Applied Polymer Science: 21st Century," Elsevier, 2000. 22

Malpass, Dennis B. "Introduction to Industrial Polyethylene: Properties, Catalysts, and Processes." Chap. 3, 133.

John Wiley & Sons, 2010

adjacent polymer chains. In this cycloaddition, two new bonds are formed while two bonds

are broken. It is for this reason than most cycloadditions exhibit a significant driving force23

.

Under an inert atmosphere, the OS-DVB terpolymer starts its thermal decomposition at

300°C and readily decreases its weight around400°C. At 450°C, the OS-DVB terpolymer was

completely decomposed without any residue, indication the formation of volatile small

hydrocarbon molecules. Finally, the lightly cross-linked oil-Sap sample, with amorphous

morphology, gradually absorbs oil in its matrix, increasing its weight by more than 10 times

within 10 min and reaching 40 times its weight after 12 h.

In addition to effective oil recovery, the resulting oil-swelled gel mixture can be treated

as crude oil, suitable for regular refining processes (distillation and cracking). The mixtures

contain no water and have nearly the same composition of the original crude oil. Furthermore,

polyolefin products are the most inexpensive of polymeric materials and are capable of large-

scale production around the globe. With conservative estimates, the production cost of new oil-

SAP material comes below $2/lb.

This new technology needs to be tested in the sea environment in order to confirm its

effectiveness and efficiency. However it seems to be a suitable proposal for the recovery and

reuse of oil after an oil spill. The Deepwater Horizon oil spill was awaken, it made it clear that

new technologies are been created to make oil exploration more easy, however the same kind of

attention is not given to response operations in case of any sort of failures.

23

Bruckner, Reinhard. Advanced Organic Chemistry : Reaction Mechanisms. Academic Press, 2002. p, 505

Figure 2

0,00E+00

2,00E+05

4,00E+05

6,00E+05

8,00E+05

1,00E+06

1,20E+06

23

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20

10

01

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20

10

09

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20

10

17

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10

25

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02

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lon

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Dispersants Distribution

Surface

Subsea

Figure 1 Weekly Use of dispersant from April 23 to August 5, 2010

Figure 3

Ziegler-Natta

Catalyst

Processing

OS-DVB

product

Thermal cross-linking

os

os

x

5

yCH2 CH

CH2

CH3

CH2 CH CH2 CH

HC CH2

z

Bibliography

Alger, Mark S. M. Polymer Science Dictionary. Springer, 1997.

Atlas, R, and T Hazen. "Oil Biodegradation and Bioremediation: A Tale of the Two Worst Spills."

Environmental Science and Technology, no. 45 (June 2011): 6709- 6715.

Author United States. National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling,

creator. The amount and fate of the oil. Washington D.C, Updated, Jan 2011.

Bruckner, Reinhard. Advanced Organic Chemistry : Reaction Mechanisms. Academic Press, 2002.

Carraher, C. Applied Polymer Science: 21st Century. Elsevier, 2000.

Kujawinski, E, M Kiso Soule, D Valentine, A Boysen, K Longnecker, and M. Redmond. "Fate Dispersants

Associated with the Deepwater Horizon Oil Spill." Environmental Science and Technology, no. 45

(January 2011): 1298-1306.

Lubchenco, Jane. BP Deepwater Horizon Oil Budget: what happened to the oil? Silver Spring, Md: U.S.

Dept. of Commerce, National Oceanic and Atmospheric Administration, 2010.

Malpass, Dennis B. "Introduction to Industrial Polyethylene: Properties, Catalysts, and Processes." Chap.

3, 133. John Wiley & Sons, 2010.

National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. Deep Water: The Gulf

Oil Disaster and the Future of Offshore Drilling. Report to the President, Washington, DC: U.S.

Government Printing Office, 2011.

National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. "The use of surface

and subsea dispersants during the BP Deepwater Horizon oil spill [electronic resource] /

National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling." Staff Working

paper; no. 4, Washington D.C, 2011.

Yuan, X, and T.C. Chung. "Novel Solution to Oil Spill Recovery: Using Thermmodegradable Polyolefin Oil

Superabsorbent Polymer (Oil-SAP)." Energy and Fuels 26 (July 2012).