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Selective Seep Truth

There's an organization in Santa Barbara, California called SOS California, which stands for Stop Oil Seeps. This group, which has received oil industry funding, started out years ago as Bring Oil Back, in response to Get Oil Out.

SOS's main arguments are that:

  • Offshore Oil Drilling is now very safe.
  • More drilling will be an economic boon to Santa Barbara County and the state.
  • More drilling will reduce the natural oil seeps that occur near Coal Oil Point and elsewhere in the Santa Barbara area, thereby reducing both marine and air pollution.

To back up this last point, they reference a study published in 1999 that was co-authored by UCSB professor Bruce Luyendyk. Luyendyk's study was for a small area (1 square kilometer) around Platform Holly. It did show a decrease in oil seeps in this area over a 22-year period. Only one problem - Dr. Luyendyk is more than a little upset with SOS's liberal interpretation of his work and has now gone on record twice at hearings conducted by the Santa Barbara County Board of Supervisors (8/26/08) (about 5:19 into the hearing) and the Santa Barbara City Council (9/9/08) (starting about 5:24) to state that his findings are being too broadly interpreted by SOS and that the geologic conditions at Coal Oil Point are not necessarily representative of other areas in the Santa Barbara Channel. Here's his written statement to the County Board of Supervisors:

August 18, 2008

TO: Board of Supervisors, Santa Barbara County
RE: Statement on oil seeps and drilling for August 26 meeting, “State and National Energy Crisis – Discussion”

The local group Stop Oil Seeps (SOS) has gained a lot of traction lately as alarmed southern Californians react to sharply increasing gasoline prices. Part of the SOS agenda is to promote offshore drilling and oil production as a means of reducing natural oil and gas seepage and their effects in the Santa Barbara Channel. Their premise is based on interpretation of two 1999 UCSB studies[1],[2] on oil seeps offshore Coal Oil Point in Goleta, the location of Venoco’s platform Holly. As a member of that UCSB research team I want to point to several qualifications in this SOS argument.

The relationship between ongoing production and decreasing seepage remains a hypothesis that is not fully tested. The relationship is well established for the Coal Oil Point field under current production methods but not tested by scientific studies elsewhere in the Channel. Many oil reservoirs offshore in fact are not seeping so drilling them would have no effect. Those reservoirs that are seeping, to my knowledge, are discharging far less that the Coal Oil Point field, minimizing any effect of drilling on seepage. Even if drilling were to go forward as a means of decreasing seepage, some seeps are located where oil drilling would not occur either because of non-economic deposits or legal restrictions. Further, any relationship between ongoing production and decreasing seepage could only apply in the early history of an oil field during a phase known as primary production where natural subsurface conditions allow easy extraction of hydrocarbons. As oil fields age more elaborate Enhanced Oil Recovery measures are required, and these could have the opposite result of increasing seepage.

The argument is also made by SOS that most of the oil floating on the surface of the ocean today is of natural origin, not industrial, and that therefore our enemy is really natural seepage. It is true that natural oil seepage may be the major source of oil in the ocean: to what degree is uncertain. However, labeling this natural floating oil to be pollution is not so simple. Ecosystems have adapted to ongoing hydrocarbon seepage as they have done at Coal Oil Point. On the other hand, a sudden accidental spill of even a small magnitude is something that natural systems experience as acute stress and could have far greater impact than continual natural sources.

The Coal Oil Point field emits gases that are classified as noxious air pollutants and precursors to ozone. These are likely of large magnitude offshore but are highly dispersed once they blow onshore to Goleta. That area is rarely beyond state or federal air quality (ozone) standards according to our county monitoring records.

Our 1999 UCSB studies were made on a special case of marine seeps; one of the worlds’ most active. However, these seeps occur over a limited area. To extrapolate the findings of our studies beyond the Coal Oil Point area can not yet be substantiated, and there are many reasons to caution against generalizing our study results to the greater Santa Barbara Channel, much less to the California continental shelf.

Bruce P. Luyendyk
Professor of Marine Geophysics
UC Santa Barbara

[1] Quigley, D. C., J. S. Hornafius, B. P. Luyendyk, R. D. Francis, J. F. Clark, and L. Washburn (1999), Decrease in Natural Marine Hydrocarbon Seepage near Coal Oil Point, California Associated with Offshore Oil Production, Geology, 27 (11), 1047-1050.

[2] Hornafius, J. S., D. C. Quigley, and B. P. Luyendyk (1999), The world’s most spectacular marine hydrocarbons seeps (Coal Oil Point, Santa Barbara Channel, California): quantification of emissions, Journal Geophysical Research - Oceans, 104 (C9), 20703-20711.

To further clarify this issue and point out some of the mis-representations by SOS, Get Oil Out has published a fact sheet which states:

Myth 1: Seeps are the largest source of air pollution in SB County.
The Truth: While seeps are a natural source of air pollution, they make up a relatively small portion of the pollution in SB County. SB Air Pollution Control District 2002 estimates indicate that seeps contribute only 11% of the total ozone precursor pollutant emissions while anthropogenic sources contribute about 59% and vegetation contributes 29%. Similarly, while seeps do emit methane gas into the water column, research suggests that only 1% actually enters the atmosphere (Mau et al. 2007). The rest is transported below the surface and degraded by bacteria.

Myth 2: Seeps negatively affect water quality and marine organisms.
The Truth: Most of the hydrocarbons released by seeps dissolve, disperse or biodegrade without a detectable impact on water quality and marine ecosystems (Mau et al. 2007). In fact, marine life in seep communities is adapted to elevated hydrocarbon levels and seep oil that reaches the surface forms slicks so thin it is harmless to marine animals (Science Daily 2000). The California State Lands Commission states that artificial oil spills are much “more acutely toxic than the slow discharge of hydrocarbons from naturalseafloor seeps” (CSLC 2008).

Myth 3: All the tar on SB beaches comes from natural seeps.
The Truth: While a portion of the tar on SB beaches comes from seeps, it is impossible to conclude that all beach tar is attributable to natural seepage because samples collected from natural seepage can’t be differentiated from Platform Holly oils (Lorenson et al. 2004, as cited in CSLC 2008). This implies that artificial sources of oil, such as leakage from platforms and ships, also contribute to tar.

Myth 4: Increased offshore oil production will reduce natural seepage.
The Truth: Increased offshore drilling has not been proven to decrease seepage and could actually increase seepage. (See Below) The suggestion that increased oil production will reduce natural seepage is based on the misinterpretation of a single study that reported a 50% reduction in seepage between 1973 and 1995 in a 1 km2 area immediately around Platform Holly (Quigley et al. 1999). The study’s authors propose that this decrease is a result of oil production at Platform Holly but caution that their evaluation is limited by a small study area and thus that a “change in seep distribution farther from Holly is unknown.” There is no evidence of an overall decline in seepage in the greater Coal Oil Point seep field. The decline attributed to drilling is too limited relative to the entire seep field to conclude that increased drilling will result in decreased seepage (Ger 2003). Furthermore, no significant changes in seepage between 1996 and 1999 have been found (Luyendyk and Egland 2001, as cited in Del Sontro 2006) even though oil production continued. In fact, drilling practices may increase seepage. A common practice in oil production is the injection of fluids or gas created during production back intoreservoirs in order to maintain pressure to force more oil and gas out. This practice can contribute to natural seepage. For example, one of the stated impacts of the recently proposed Venoco Ellwood Full Field Development Project is increased natural oil and gas seepage as a result of waste water reinjection into formations that contribute to natural seepage (DEIR p. 4.1-27). Accidents due to oil production can also increase seepage. For instance, seepage in the vicinity of Platform A is attributed to a blowout caused by well drilling which resulted in fissures forming on the sea floor and expelling oil (Wilkinson 1973).

• Offshore seeps are natural and are not a significant source of air or water pollution.
• Increased oil drilling has not been shown to reduce seepage and could, in fact, increase seepage.