Macondo Well Research Articles

BIOTIC AND ABIOTIC OIL DEGRADATION AFTER THE DEEPWATER HORIZON DISASTER LEADS TO FORMATION OF RECALCITRANT OXYGENATED HYDROCARBONS: NEW INSIGHTS USING GC×GC

ABSTRACT We found that biodegradation, as well as photooxidation, of Macondo well (MW) oil led to rapid formation of recalcitrant oxygenated hydrocarbons (OxHC) after the Deepwater Horizon disaster. These compounds, which appear to be an abundant product of natural oil degradation, are poorly characterized in terms of molecular composition. We used various bulk and molecular techniques to characterize the OxHC fraction of weathered MW oil. Furthermore, we compared the characteristic disappearance of various petroleum hydrocarbons to gain insights into on-going biotic, as well as abiotic, oil oxygenation processes, that ultimately determine the fate of petroleum hydrocarbons in the environment. We found that biodegradation as well as photooxidation was responsible for the observed degradation of alkanes and PAHs in MW oil. Furthermore, we identified labile as well as recalcitrant biomarker compounds; these labile biomarker compounds should be used with caution for oil fingerprinting.

High Resolution Forensic Analysis Of Surface Sheens Helps Pinpoint Source Of Oil Leakage From The Deepwater Horizon

Alkenes commonly found in synthetic drilling-fluids were used to identify sources of oil sheens that were first observed in September 2012 close to the Deepwater Horizon (DWH) disaster site more than two years after the Macondo MC-252 well was sealed. Exploration of the sea floor by BP confirmed that the well was capped and sound. BP scientists and engineers identified the likely source as leakage from an 80-ton cofferdam abandoned during a failed attempt to control the Macondo well in May 2010. We acquired and analyzed sheen samples at the sea-surface above the Deepwater Horizon wreckage as well as oil collected directly from the cofferdam using comprehensive two-dimensional gas chromatography (GC×GC). This allowed the identification of drilling-fluid C16- to C18-alkenes in sheen samples that were absent in cofferdam oil. Furthermore, the spatial pattern of evaporative losses of sheen oil alkanes indicated that oil surfaced closer to the Deepwater Horizon wreckage than the abandoned cofferdam site. Lastly, ratios of alkenes and petroleum hydrocarbons pointed to a common source of oil found in both sheen samples and recovered from oil-coated Deepwater Horizon riser pipe buoyancy compensator module debris collected shortly after the explosion. These lines of evidence suggest that the observed sheens do not originate from the Macondo well, cofferdam, or from natural seeps. Rather, the likely source is oil trapped in tanks and pits on the Deepwater Horizon wreckage, representing a finite oil leakage volume.

Characterization of the BP petroleum residuals in the sediment of the Salt Marshes in the Northern Gulf of Mexico by Fourier Transform Ion Cyclotron Resonance mass spectrometry

Of the estimated 5 million barrels of crude oil released into the Gulf of Mexico from the BP Deepwater Horizon event, a fraction heavily oiled Louisiana's coastal salt marshes. Oil inputs may significantly alter the abundance, structure and diversity of the microbial communities inhabited in the sediments, and subsequently affect essential microbial services. In this study, detailed analysis was conducted to investigate the possible impact of petroleum residuals on soil microbial communities of salt marsh in northern Barataria Bay of the Gulf of Mexico after the oil spill. Sediment samples from heavily, moderately, non-oiled sites were collected after 7 months, 16 months and 29 months of the spill and Total Petroleum Hydrocarbons (TPH) were measured. Since traditional gas chromatography (GC) analysis cannot identify heavy fractions of the oil containments, we incorporated ultrahigh resolving power Fourier Transform Ion Cyclotron Resonance mass spectrometry (FT-ICR-MS) to address the compositional complexity of high molecular weight, nonvolatile petroleum fractions of the oil containments that are not readily degraded by the indigenous microbial community. The petrogentic material was extracted with methylene chloride followed by positive and negative electrospray (ESI) FT-ICR-MS characterization. These data can be correlated with the analysis of the diversity and structure of the microbial community to elucidate how the oil contamination perturbed the microbial community and how the microbes responded to the perturbation. Mass spectrometry analysis of these samples display a 1.5 to 2.5 fold increase in the molecular complexity, particularly oxygen compounds relative to the original Macondo well oil and ketone species were abundantly present in the oiled sediment extracts. The comprehensive analysis on the petroleum residues will help us better understand the fate of oil released into the environment and the long-term impact of BP oil spill.

Resolving Biodegradation Patterns of Persistent Saturated Hydrocarbons in Weathered Oil Samples from the Deepwater Horizon Disaster

Biodegradation plays a major role in the natural attenuation of oil spills. However, limited information is available about biodegradation of different saturated hydrocarbon classes in surface environments, despite that oils are composed mostly of saturates, due to the limited ability of conventional gas chromatography (GC) to resolve this compound group. We studied eight weathered oil samples collected from four Gulf of Mexico beaches 12-19 months after the Deepwater Horizon disaster. Using comprehensive two-dimensional gas chromatography (GC × GC), we successfully separated, identified, and quantified several distinct saturates classes in these samples. We find that saturated hydrocarbons eluting after n-C22 dominate the GC-amenable fraction of these weathered samples. This compound group represented 8-10%, or 38-68 thousand metric tons, of the oil originally released from Macondo well. Saturates in the n-C22 to n-C29 elution range were found to be partly biodegraded, but to different relative extents, with ease of biodegradation decreasing in the following order: n-alkanes > methylalkanes and alkylcyclopentanes+alkylcyclohexanes > cyclic and acyclic isoprenoids. We developed a new quantitative index designed to characterize biodegradation of >n-C22 saturates. These results shed new light onto the environmental fate of these persistent, hydrophobic, and mostly overlooked compounds in the unresolved complex mixtures (UCM) of weathered oils.

The effects of oil exposure on peripheral blood leukocytes and splenic melano-macrophage centers of Gulf of Mexico fishes

In August and November 2010 we collected and examined peripheral blood and tissues from three species of Gulf of Mexico fish. Findings were compared to non-exposed control fish. The leukocyte counts of exposed alligator gar were not significantly different from controls, while exposed Gulf killifish and sea trout had significantly decreased lymphocyte counts. Liver ethoxyresorufin-O-deethylase (EROD) values from sea trout were significantly greater than control sea trout EROD values, suggesting poly aromatic hydrocarbon exposure. Splenic melano-macrophage centers (MMCs) from exposed sea trout and Gulf killifish showed a significant increase in number compared to non-exposed fish. Sea trout splenic MMCs were also significantly greater in size. These findings suggest that Gulf fish sampled were exposed to crude oil from the Macondo well and were in a lymphopenic or immuno-compromised state.

Evaluation of Pulmonary and Systemic Toxicity of Oil Dispersant (COREXIT EC9500A(®)) Following Acute Repeated Inhalation Exposure.

INTRODUCTIONOil spill cleanup workers come into contact with numerous potentially hazardous chemicals derived from the oil spills, as well as chemicals applied for mitigation of the spill, including oil dispersants. In response to the Deepwater Horizon Macondo well oil spill in the Gulf of Mexico in 2010, a record volume of the oil dispersant, COREXIT EC9500A, was delivered via aerial applications, raising concern regarding potential health effects that may result from pulmonary exposure to the dispersant.METHODSThe current study examined the effects on pulmonary functions, cardiovascular functions, and systemic immune responses in rats to acute repeated inhalation exposure of COREXIT EC9500A at 25 mg/m3, five hours per day, over nine work days, or filtered air (control). At one and seven days following the last exposure, a battery of parameters was measured to evaluate lung function, injury, and inflammation; cardiovascular function; peripheral vascular responses; and systemic immune responses.RESULTSNo significant alterations in airway reactivity were observed at one or seven days after exposure either in baseline values or following methacholine (MCh) inhalation challenge. Although there was a trend for an increase in lung neutrophils and phagocyte oxidant production at one-day post exposure, there were no significant differences in parameters of lung inflammation. In addition, increased blood monocytes and neutrophils, and decreased lymphocyte numbers at one-day post exposure also did not differ significantly from air controls, and no alterations in splenocyte populations, or serum or spleen immunoglobulin M (IgM) to antigen were observed. There were no significant differences in peripheral vascular responsiveness to vasoconstrictor and vasodilator agonists or in blood pressure (BP) responses to these agents; however, the baseline heart rate (HR) and HR responses to isoproterenol (ISO) were significantly elevated at one-day post exposure, with resolution by day 7.CONCLUSIONSIn summary, acute repeated exposure to COREXIT EC9500A did not alter pulmonary function, lung injury/inflammation, systemic immune responses, or vascular tone, but did cause transient chronotropic effects on cardiac function.

Oceanographic conditions in the Gulf of Mexico in July 2010, during the Deepwater Horizon oil spill

Circulation in the Gulf of Mexico (GOM) is dominated by mesoscale features that include the Loop Current (LC), Loop Current Rings (LCRs), and smaller frontal eddies. During May–June 2010, while oil was still flowing from the Macondo well following the Deepwater Horizon (DWH) platform explosion on April 20, 2010, drifter trajectories, satellite observations, and numerical simulations indicated a potential for direct connectivity between the northern Gulf and the Florida Straits via the LC system. This pathway could have potentially entrained particles, including northern GOM contaminants related to the oil spill, carrying them directly towards the coastal ecosystems of south Florida and northern Cuba. To assess this connectivity, and to evaluate the potential oil impacts on economically important GOM fisheries, an interdisciplinary shipboard survey was conducted in the eastern Gulf during July 2010. Analysis of the resulting hydrographic data confirmed that: (1) by July 2010 a large LCR had become separated from the main LC by a cyclonic eddy resulting in the loss of a direct transport mechanism from the northern GOM to the Florida Straits, leaving only indirect pathways available to potential contaminants; and (2) with the exception of four hydrographic stations occupied within 84km of the wellhead, no evidence of oil was found during the survey on the surface or within the water column. These results corroborated analysis of satellite altimetry observations of the GOM surface circulation and verified official surface oil coverage forecasts where they intersected with the survey track. This cruise sampled the LC, LCR, and frontal eddies to a depth of 2000m, with the results suggesting that any oil entrained by circulation features in prior months had either been weathered, consumed by bacteria, dispersed to undetectable levels, or was only present in unsurveyed areas. The assembled subsurface measurements represent one of only a few data sets collected across the dominant GOM mesoscale circulation features at a time when there was great concern about the potential long-range spreading of DWH related contaminants. Direct observations such as these are critical for the assessment of particle trajectory and circulation models utilized during the spill, and for the improvement of future numerical forecast products.

Assessment of photochemical processes in marine oil spill fingerprinting

Understanding weathering processes plays a critical role in oil spill forensics, which is based on the comparison of the distributions of selected compounds assumed to be recalcitrant and/or have consistent weathering transformations. Yet, these assumptions are based on limited laboratory and oil-spill studies. With access to additional sites that have been oiled by different types of oils and exposures, there is a great opportunity to expand on our knowledge about these transformations. Here, we demonstrate the effects of photooxidation on the overall composition of spilled oils caused by natural and simulated sunlight, and particularly on the often used polycyclic aromatic hydrocarbons (PAHs) and the biomarker triaromatic steranes (TAS). Both laboratory and field data from oil released from the Macondo well oil following the Deepwater Horizon disaster (2010), and heavy fuel-oil from the Prestige tanker spill (2002) have been obtained to improve the data interpretation of the typical fingerprinting methodology.

Persistence of Gulf of Mexico Surface Oil from the 2010 Deepwater Horizon Spill

Persistence of Gulf of Mexico Surface Oil from the 2010 Deepwater Horizon Spill Rick C. Crowsey (bio) British Petroleum (BP) began drilling the Macondo well in the Gulf of Mexico (approximately 50 m (80 km) East-Southeast of South Pass, Louisiana) using the Marianas rig in October 2009. Drilling had reached more than 9,000 feet (2,743 m) below sea level (approximately 4,000 feet (1,219 m) below the sea floor) when Hurricane Ida damaged the rig, requiring it be towed in for repairs. The Deepwater Horizon rig arrived at the Macondo site on January 31, 2010 to complete the planned additional 9,000 feet (2,743 m) of drilling (Graham et al. 2011). After several months of drilling, a negative pressure test was begun on the morning of April 20th as one of the final steps planned for the semisubmersible Deepwater Horizon. An unexpected loss of power, followed by an explosion occurred at approximately 9:49 p.m. that evening. The fire started by the explosion raged aboard the Deepwater Horizon oil rig on the Macondo Prospect for approximately 36 hours before the rig sank (Bly 2010). Hydrocarbons flowed from the reservoir through the well bore until it was finally capped on July 15, 2010 (Graham et al. 2011). When the fire began on the Deepwater Horizon, no one expected it would trigger one of the largest oil spills in the Gulf of Mexico or that it would negatively impact the U.S. Gulf Coast from Texas to Florida. It was only after the rig sank that NOAA ordered acquisition of any and all imagery of the Gulf of Mexico surrounding the Macondo well. Estimates of the flow rate varied widely. Early reports by Unified Command and SkyTruth estimated only a few thousand barrels per day through the end of April 2010 (Ramseur 2011). By the end of May, estimates ranged between a few thousand barrels per day (again reported by Unified Command) to as much as 100,000 barrels per day (by Chiang as a range of 10,000 to 100,000 barrels per day). While the circumstances limit the ability to accurately determine the amount of hydrocarbons expelled from the well prior to the July 15th capping, the On Scene Coordinator Report estimates the total discharge to be approximately 5 million barrels (210 million gallons; Ramseur 2011). Regardless of the accuracy of this value, the magnitude and length of time over which this occurred is chilling. My work as a forensic geographer began when I left NASA in 1996 and has included analysis for one side or the other on lawsuits spawned by similar disasters, including Hurricane Katrina, railroad accidents, oil spills, marine collisions and [End Page 359] spills, light pollution, refinery fires and explosions. Based on this experience I followed the progress of this event with some interest, expecting a call to address what would become a surprisingly difficult question to answer: "Where did the oil go?" As hydrocarbons continued to escape from the well bore at an alarming rate, the question of where the oil was and where it went became more important each day. Surprisingly, the data needed to answer this question quickly became increasingly difficult to find or to access. While NOAA had begun collecting satellite imagery from a variety of sources, including RADARSAT, ENVISAT, and MODIS, the archive of these data along with in situ data was turned over to BP within weeks of the creation of a comprehensive GIS. BP housed it behind a secure firewall. Repeated requests by others and me outside BP for access to the data were met with what appeared to be delay, misdirection, and obfuscation. While access to the source data was denied or limited, most requests were pointed to the ERMA Deepwater Gulf Response website (http://gomex.erma.noaa.gov/erma.html). This site was developed and is maintained jointly by NOAA, EPA, and the University of New Hampshire's Coastal Response Research Center. While this site provides access to visualizations of much of the data needed to figure out where the oil went, it doesn't provide access to the daily imagery or shapefiles of oil extent created by NOAA...

Characterization of epibenthic and demersal megafauna at Mississippi Canyon 252 shortly after the Deepwater Horizon Oil Spill

The Deepwater Horizon Oil Spill resulted in the release of a large quantity of oil and gas into the northern Gulf of Mexico from a bathypelagic source. Due to a lack of pre-spill quantitative data the baseline condition of the communities near the spill site is unknown. This makes it difficult to determine the impact of the spill on deepwater megafauna. Remotely operated vehicles were used to quantify megafauna at five study sites during August and September 2010:2000m north, west, south, and east, and 500m north of the Macondo well. Comparisons of animal abundances indicated that 2000m-N and 2000m-W had the greatest taxonomic richness and highest abundances while 2000m-E had slightly lower values. In contrast 500m-N and 2000m-S had the lowest taxonomic richness and abundances. Our study also suggests that certain taxa were potentially more resistant or sensitive to the spill.

Oxygenated weathering products of Deepwater Horizon oil come from surprising precursors

Following the release of crude oil from the Macondo well in 2010, a wide range of weathering processes acted on the spilled oil. A recent study revealed that samples from this spill were oxidized into oxygenated hydrocarbons (OxHC) comprising more than 50% of the extracted hydrocarbons. The precursors of these compounds were not identified despite using a wide range of analytical tools, including gas chromatography (GC). To search for these precursors, over 40 samples were analyzed by comprehensive two-dimensional gas chromatography (GC×GC), one of the largest studies of its kind to date. Partial least squares regression was employed to elucidate the GC×GC peaks that could be the precursors of OxHC in our samples. We found that the formation of OxHC correlated with the disappearance of saturated hydrocarbons, including alkylcyclopentanes, alkyl cyclohexanes, alkylated bicyclic saturated compounds, tricyclic terpanpoids, and alkylbenzenes. These results indicate a previously under-reported chemodynamic process in oil spill weathering.

Toxicity and Mutagenicity of Gulf of Mexico Waters During and After the Deepwater Horizon Oil Spill

The Deepwater Horizon oil spill is unparalleled among environmental hydrocarbon releases, because of the tremendous volume of oil, the additional contamination by dispersant, and the oceanic depth at which this release occurred. Here, we present data on general toxicity and mutagenicity of upper water column waters and, to a lesser degree, sediment porewater of the Northeastern Gulf of Mexico (NEGOM) and west Florida shelf (WFS) at the time of the Deepwater Horizon oil spill in 2010 and thereafter. During a research cruise in August 2010, analysis of water collected in the NEGOM indicated that samples of 3 of 14 (21%) stations were toxic to bacteria based on the Microtox assay, 4 of 13 (34%) were toxic to phytoplankton via the QwikLite assay, and 6 of 14 (43%) showed DNA damaging activity using the λ-Microscreen Prophage induction assay. The Microtox and Microscreen assays indicated that the degree of toxicity was correlated to total petroleum hydrocarbon concentration. Long-term monitoring of stations on the NEGOM and the WFS was undertaken by 8 and 6 cruises to these areas, respectively. Microtox toxicity was nearly totally absent by December 2010 in the Northeastern Gulf of Mexico (3 of 8 cruises with one positive station). In contrast, QwikLite toxicity assay yielded positives at each cruise, often at multiple stations or depths, indicating the greater sensitivity of the QwikLite assay to environmental factors. The Microscreen mutagenicity assays indicated that certain water column samples overlying the WFS were mutagenic at least 1.5 years after capping the Macondo well. Similarly, sediment porewater samples taken from 1000, 1200, and 1400 m from the slope off the WFS in June 2011 were also highly genotoxic. Our observations are consistent with a portion of the dispersed oil from the Macondo well area advecting to the southeast and upwelling onto the WFS, although other explanations exist. Organisms in contact with these waters might experience DNA damage that could lead to mutation and heritable alterations to the community pangenome. Such mutagenic interactions might not become apparent in higher organisms for years.

Recurrent Oil Sheens at the Deepwater Horizon Disaster Site Fingerprinted with Synthetic Hydrocarbon Drilling Fluids

We used alkenes commonly found in synthetic drilling-fluids to identify sources of oil sheens that were first observed in September 2012 close to the Deepwater Horizon (DWH) disaster site, more than two years after the Macondo well (MW) was sealed. While explorations of the sea floor by BP confirmed that the well was sound, they identified the likely source as leakage from an 80-ton cofferdam, abandoned during the operation to control the MW in May 2010. We acquired sheen samples and cofferdam oil and analyzed them using comprehensive two-dimensional gas chromatography. This allowed for the identification of drilling-fluid C16- to C18-alkenes in sheen samples that were absent in cofferdam oil. Furthermore, the spatial pattern of evaporative losses of sheen oil alkanes indicated that oil surfaced closer to the DWH wreckage than the cofferdam site. Last, ratios of alkenes and oil hydrocarbons pointed to a common source of oil found in sheen samples and recovered from oil-covered DWH debris collected shortly after the explosion. These lines of evidence suggest that the observed sheens do not originate from the MW, cofferdam, or from natural seeps. Rather, the likely source is oil in tanks and pits on the DWH wreckage, representing a finite oil volume for leakage.

Expansion of the Analytical Window for Oil Spill Characterization by Ultrahigh Resolution Mass Spectrometry: Beyond Gas Chromatography

Traditional tools for routine environmental analysis and forensic chemistry of petroleum have relied almost exclusively on gas chromatography-mass spectrometry (GC-MS), although many compounds in crude oil (and its transformation products) are not chromatographically separated or amenable to GC-MS due to volatility. To enhance current and future studies on the fate, transport, and fingerprinting of the Macondo well oil released from the 2010 Deepwater Horizon disaster, we created an extensive molecular library of the unadulterated petroleum to compare to a tar ball collected on the beach of Louisiana. We apply ultrahigh resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry to identify compositional changes at the molecular level between native and weathered crude oil samples and reveal enrichment in polar compounds inaccessible by GC-based characterization. The outlined approach provides unprecedented detail with the potential to enhance insight into the environmental fate of spilled oil, improved toxicology, molecular modeling of biotic/abiotic weathering, and comprehensive molecular characterization for petroleum-derived releases. Here, we characterize more than 30,000 acidic, basic, and nonpolar unique neutral elemental compositions for the Macondo well crude oil, to provide an archive for future chemical analyses of the environmental consequences of the oil spill.

Nitrate Addition Has Minimal Effect on Anaerobic Biodegradation of Benzene in Coastal Saline (salt), Brackish and Freshwater Marsh Sediments

In response to the 2010 British Petroleum (BP) Deepwater Horizon Macondo well oil spill, saline (salt), brackish and freshwater marsh sediments were used to study whether nitrate addition could stimulate petroleum biodegradation. Benzene was selected as a model petroleum hydrocarbon, and its biodegradation was assumed to follow first-order kinetics. The results show that the intrinsic benzene degradation activities in the marsh sediments were inversely correlated (R 2 = 0.83, n = 9) with the sediment salinity, with following order of benzene degradation rate regardless of nitrate treatments, freshwater > brackish > salt (P < 0.05). Addition of nitrate shows a minimal potential to stimulate the benzene degradation. Increase of redox potentials by addition of nitrate even shows a slight inhibition effect on benzene degradation in these coastal marsh sediments without a clear mechanism. Excessive loading of nitrate has been causing frequent occurrence of coastal eutrophication and hypoxia in the Gulf of Mexico. Therefore, application of additional nitrate to the coastal marsh sediments for the remediation of the 2010 BP oil spill is not recommended.

Human error analysis of the Macondo well blowout

The Macondo well blowout resulted in 11 fatalities and caused the largest nonintentional oil spill in history. The situation stemmed from a series of human errors through all stages of the project leading up to the blowout and subsequent explosion. These errors include faulty interpretation of signals indicating problems with well and safety system integrity, inappropriate modifications to safety systems, inadequate design of critical systems, failure to provide redundancy in the design stage, failure to adhere to administrative controls for the safe operation, failure to follow the American Petroleum Institute Recommended Practices 75 on drilling mud circulation, and others. Twenty five specific errors have been identified and classified into eight categories. The results show that the majority of the errors are latent errors and caused by poor leadership in the organization or management. In order to resolve these issues it is necessary to create a safety culture in which safety is paramount in operations and facilities. There are many lessons learned from this incident, but the most important lesson is that safety must be a way of life, beginning in the design stage and carrying through the project life cycle. © 2013 American Institute of Chemical Engineers Process Saf Prog 32: –, 2013

Biodegradability of Corexit 9500 and Dispersed South Louisiana Crude Oil at 5 and 25 °C

The reported persistence of the dioctyl sodium sulfosuccinate (DOSS) surfactant in Corexit 9500 in the oil plumes formed during the Deepwater Horizon oil spill has contributed to concerns regarding the biodegradability and bioavailability of dispersed oil and dispersants used as an oil spill countermeasure in the Gulf of Mexico. We studied the biodegradation of DOSS and dispersed South Louisiana crude oil (SLC) in laboratory microcosms. Two oil-degrading cultures from the Gulf of Mexico were isolated, one from the surface (meso) and one from close to the area of the Macondo well (cryo). Each was enriched on SLC, the former at 25 °C, the latter at 5 °C. Results indicated that the meso culture rapidly and completely degraded DOSS, alkanes, and aromatics. The cryo culture metabolized the same compounds but with a lag of 28 d and a remaining residual of iso-alkanes, n-C(30-35), and the 4-ring PAHs.

HPHT 101-What Petroleum Engineers and Geoscientists Should Know About High Pressure High Temperature Wells Environment

On April 20, 2010, BP’s Deepwater Horizon oil rig exploded in the Gulf of Mexico. This turned out to be one of the worst environmental disasters in recent history. This high-profile blowout at the Macondo well in the Gulf of Mexico, brought the challenges and the risks of drilling into high-pressure, high-temperature (HPHT) fields increasingly into focus. New Technology, HSE regulations, new standards, such as newly recommended procedures by the American Petroleum Institute (API), and extensive training programs for the drilling crew seem to be vital in developing HPHT resources. High-pressure high-temperature fields exist in Gulf of Mexico, North Sea, Southeast Asia, Africa and the Middle East. Almost a quarter of HPHT operations worldwide are expected to happen in the American continent particularly in North America. Major oil companies have tried to identify key challenges in HPHT development and production, and several service companies have offered many insights regarding current or planned technologies to meet these challenges. However, there are so many factors that need to be addressed and learned in order to safely overcome the challenges of drilling into and producing from HPHT oil and gas wells.Drilling into HPHT wells is a new frontier for the oil and gas industry. The growing demand for oil and gas throughout the world is driving the exploration and production industry to look for new resources. Some of these resources are located in deeper formations. According to US Minerals Management Service (MMS), over 50% of proven oil and gas reserves in the US lie below 14,000 ft. subsea. As we drill into deeper formations we will experience higher pressures and temperatures.Drilling operations in such high pressure and high temperature environments can be very challenging. Therefore, companies are compelled to meet or exceed a vast array of technical limitations as well as environmental, health and safety standards. This paper explains the technological challenges in developing HPHT fields, deepwater drilling, completions and production considering the reports from the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE), formerly known as the Minerals Management Service (MMS). It reviews the HPHT related priorities of National Energy Technology Laboratory (NETL), operated by the US Department of Energy (DOE), and DeepStar Committees for Technology Development for Deepwater Research.

Characterization of oil components from the Deepwater Horizon oil spill in the Gulf of Mexico using fluorescence EEM and PARAFAC techniques

Three-dimensional (3D) fluorescence spectroscopy and parallel factor analysis (PARAFAC) were used to characterize oil components and to examine their fate and transformation processes during the unprecedented Deepwater Horizon oil spill in the Gulf of Mexico. Water samples were collected during two cruises in May and June 2010 soon after the spill began. Fluorescence excitation-emission matrix (EEM) spectra of seawater samples strongly resemble those of crude oil from the Macondo well and weathered oil collected from Gulf surface waters. This indicates the influence of oil on marine dissolved organic matter (DOM) which yielded elevated dissolved organic carbon (DOC) concentrations, higher UV–vis absorbance, and higher optically inferred molecular weight DOM in the water column. Two major types of DOM were found in the water column: one with low abundance but high optical activity and the other with high mass concentration yet low optical activity. Higher specific UV absorbance but lower spectral slope values observed for deep-water samples indicates the presence of less degraded or fresher crude oil in deep waters. Results of PARAFAC modeling revealed three oil-related components corresponding to crude and weathered oil in the water column: the most prominent one (namely C1) centered on Ex/Em 226/340nm and the other two components (C2 and C6) centered on 236/360 and 252/311nm, respectively. In addition, there is another DOM component (C3), partially representing chemically dispersed oil. Interestingly, the oil component ratios, an intensive property, varied with time and the degradation status of oil. We hypothesize that C2 (236/360nm) is mostly a degraded product while C6 (252/311nm) is a crude oil component with lower molecular weight, but at the same time, could be derived from oil degradation. Changes in fluorescence component ratios can thus be used as a compelling index to track the fate and transport of oil in marine environments.

Gulf spill two years out

Summary Two years on, the national spotlight seems to have turned away from the Gulf oil spill, but a massive assessment of the environmental impacts is quietly under way. As Cyrus Martin reports, several recent observations, and a study of deepwater coral communities, suggest we may not be out of the woods yet.