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protective casing, when the well hit a high-pressure zone in the field, it blew out, spewing enormous quantities of oil and gas into the water from the sea floor. While crews were able to cap the wellhead and relieve the pressure there, the adjacent geologic formations were not strong enough to contain the pressure, and lacking a steel protective casing, the reservoir fluid and gas ripped through the sedimentary sand layers directly on the ocean floor; the result was the
333:(CEQA). Opposition to oil drilling was nothing new in Santa Barbara – local residents, led by a newspaper publisher, objected enough to the expansion of the Summerland field in the 1890s to organize a late-night derrick-destroying party near the present-day Miramar Hotel – but the spill intensified the local hostility to oil drilling to the point that few new platforms were installed, and none at all within the 3-mile limit.
36:
123:
314:
Unocal succeeded in installing the first four wells from its
Platform A by January 1969, but their attempt to install the fifth well was catastrophic, and resulted in one of the most notorious environmental disasters in United States history. Because the drillers were using an insufficient length of
67:
limit, it is a federally leased field, regulated by the U.S. Department of the
Interior rather than the California Department of Conservation. It is entirely produced from four drilling and production platforms in the channel, which as of 2009 were operated by Dos Cuadras Offshore Resources (DCOR),
216:
While the existence of the field was suspected in the 1950s, the field was not discovered until 1968. Unocal and several other oil companies took out leases on the field in
February 1968, and put in the first well, and the first platform, that same year. Data regarding the four platforms are as
336:
After the disaster and cleanup, Unocal continued drilling wells from the two platforms that were already in place ("A" and "B", began producing from them in March 1969, and installed two more platforms ("C" and "Hillhouse"). Production from the field peaked quickly, reaching a maximum in 1971,
207:
Oil has been known in the Santa
Barbara Channel since prehistoric times; the native Chumash people used tar from the numerous natural seeps as a sealant, and tar regularly washes up on the beaches from the offshore seeps. The world's first offshore oil drilling took place at the
345:
Unocal continued to produce from the field until they sold all of their
California production assets in 1996 to Nuevo Energy, as operated by Torch Energy Advisors. In 1997 Nuevo took over the operations of the four platforms directly, and in 2004 passed them on to
100:, making it subject to U.S. government rather than California regulation. The four platforms are arranged in a line running from east to west, spaced one-half mile apart, with Platform Hillhouse on the east, and Platforms "A", "B", and "C" in order to the west.
341:
technologies (such as water or gas injection). In 1985, Unocal tried waterflooding, and then polymer flooding, to improve production rates, and then in 1990 they began a horizontal drilling program to reach reservoirs impractical to exploit any other way.
354:
According to the
Minerals Management Service (MMS), the field retains about 11.4 million barrels of oil in reserves recoverable with current technology. At the beginning of 2008, there were 145 producing oil wells distributed between the four platforms.
337:
during which year almost 28 million barrels of oil were extracted. The field experienced a gradual decline in production afterwards, approximately 8 percent per year, as is typical of fields when the reservoir pressure declines, and in the absence of
111:, about a mile southeast of La Conchita. From there oil travels down to Ventura along the M-143 pipeline to the Ventura pump station, and then to Los Angeles area refineries by way of a TOSCO pipeline in the Santa Clara River Valley.
187:
fields, where it is also folded into anticlinal traps. In the Dos
Cuadras field, the oil-bearing strata are at depths ranging from 500 to 4,200 feet below the sea floor, and individual strata are separated by impermeable layers of
324:
Following the spill, the
Secretary of the Interior ended all offshore oil drilling in the Outer Continental Shelf (OCS) until measures for better oversight were put in place, which happened in 1970 with the passage of the federal
212:
in 1896, only five miles north of the Dos
Cuadras field. Those wells were put in from piers in shallow water. Technology for drilling in deeper water from platforms did not come about until the middle of the 20th century.
350:
on that firm's acquisition of Nuevo. Plains only ran the platforms for a little more than four months, selling the operation to DCOR in March 2005. As of 2009, DCOR retains operational control of the Dos
Cuadras field.
63:. Discovered in 1968, and with a cumulative production of over 260 million barrels of oil, it is the 24th-largest oil field within California and the adjacent waters. As it is in the Pacific Ocean outside of the 3-mile
319:
of 80,000 to 100,000 barrels, which eventually coated over 40 miles of southern California coastline with oil, an ecological disaster which killed upward of 10,000 birds and numerous sea mammals and other creatures.
638:
96:
The Dos Cuadras field is one of many underneath the ocean bottom offshore of Southern California, most of which were discovered in the 1960s and 1970s. All of the field is outside of the
783:
199:
of 25, with a range from 18 to 34, which classifies as medium-grade crude. Reservoir pressure began at 750 psi, sufficient for easy pumping in the early years of field development.
172:. By far the most productive unit is the Repetto Sands portion of the Pico Formation. Only one well has produced from the Santa Margarita; all the others are in the Repetto Sands.
793:
744:
697:
645:
803:
683:
107:. Oil and gas produced on the Dos Cuadras field are pumped about 12 miles east to the Rincon Oil & Gas Processing Plant on a hilltop adjacent to the
594:
420:
798:
713:
409:
175:
The Repetto Sands unit consists of layers of mudstone, siltstone, and shale, and due to its depositional environment the general grain size and
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517:
330:
621:
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increase towards the east. It is the same formation which is richly productive in the oil fields of the Los Angeles Basin, such as the
788:
347:
326:
114:
The ocean bottom is relatively flat in the vicinity of the field, and all platforms are in a water depth of approximately 190 feet.
85:
694:
482:
142:
446:
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169:
60:
31:
Platform A, Dos Cuadras Oilfield, 2006 photo. The 1969 Santa Barbara Oil Spill originated from this platform.
184:
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73:
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40:
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A pair of undersea pipelines, one for oil and one for gas, connect the four platforms to the shore near
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720:
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714:"Minerals Management Service, Pacific OCS Region: Field Reserve Estimate Summary, December 2008"
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306:
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27:
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that was formative for the modern environmental movement, and spurred the passage of the
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131:
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17:
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accumulation. It is part of the larger Rincon Anticlinal Trend, which includes the
43:. They are, in order from left to right: Platforms Hillhouse, "A", "B", and "C".
684:
New York Times: Unocal to sell oil and gas fields in California, February 21, 1996
122:
370:. Sacramento: California Department of Conservation (DOGGR). 1998. Archived from
457:
196:
138:
519:
Evaluation of horizontal wells in an offshore reservoir in Southern California
456:. Minerals Management Service, U.S. Department of the Interior. Archived from
299:
759:
746:
386:
California Department of Conservation, Oil and Gas Statistics, Annual Report,
126:
Map showing relation of the Dos Cuadras Field to the Rincon anticlinal trend.
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97:
64:
35:
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158:
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structure which plunges at both ends, thereby forming an ideal trap for
166:
39:
The four platforms producing from the Dos Cuadras Field, as seen from
595:"Minerals Management Service: Dos Cuadras Field platform information"
77:
305:
293:
189:
121:
34:
26:
719:. U.S. Minerals Management Service. December 2008. Archived from
673:. Santa Barbara, California: Tecolote Books. p. 80.
447:"California Offshore Oil and Gas Energy Resources Study"
695:
Minerals Management Service: Lease operatorship book
157:
fields onshore. Oil is found in two formations, the
639:"69 Oil Spill Leaves Mark on SB Environmentalism"
619:Brief oil and gas history of Santa Barbara County
298:"Hillhouse" platform, Dos Cuadras. 2006 photo by
525:(MS thesis). Stanford University. Archived from
784:Oil fields in Santa Barbara County, California
794:Geography of Santa Barbara County, California
410:"Oil and Gas Statistics: 2007 Annual Report"
80:'s Platform A – was responsible for the 1969
8:
404:
402:
55:is a large oil and gas field underneath the
483:"APCD Permit to Operate No. 9110-R3, p. 8"
562:
560:
550:
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511:
509:
219:
398:
454:California Department of Conservation
417:California Department of Conservation
7:
331:California Environmental Quality Act
329:(NEPA), and in California, with the
804:1969 disasters in the United States
644:. Daily Nexus, UCSB. Archived from
419:. December 31, 2007. Archived from
348:Plains Exploration & Production
637:Haier, Daniel Haier (2005-01-28).
25:
445:Hargis, Dean (January 26, 2000).
327:National Environmental Policy Act
86:National Environmental Policy Act
799:Oil spills in the United States
671:Santa Barbara, Past and Present
59:about eight miles southeast of
143:Carpinteria Offshore Oil Field
76:near one of these platforms –
53:Dos Cuadras Offshore Oil Field
1:
516:Vassilieva, Svetlana (1999).
367:California Oil and Gas Fields
310:Platform C, Dos Cuadras, 2006
68:LLC, a private firm based in
669:Tompkins, Walker A. (1975).
317:1969 Santa Barbara oil spill
195:Oil from the field averages
145:to the east, as well as the
130:The Dos Cuadras field is a
820:
789:Santa Barbara, California
170:Santa Margarita Formation
61:Santa Barbara, California
98:3-mile geographic limit
82:Santa Barbara oil spill
311:
303:
203:History and production
127:
48:
41:Summerland, California
32:
309:
297:
125:
57:Santa Barbara Channel
38:
30:
18:Dos Cuadras Oil Field
760:34.3466°N 119.6184°W
210:Summerland Oil Field
756: /
265:Platform Hillhouse
240:September 14, 1968
165:and the underlying
765:34.3466; -119.6184
700:2010-05-28 at the
624:2011-05-27 at the
532:on 30 January 2016
388:December 31, 2007.
339:secondary recovery
312:
304:
282:February 28, 1977
268:November 26, 1969
128:
49:
33:
584:Vassilieva, p. 14
575:DOGGR, p. 614-615
566:Vassilieva, p. 15
554:Vassilieva, p. 17
292:
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254:November 8, 1968
229:First production
45:Santa Cruz Island
16:(Redirected from
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109:Rincon Oil Field
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285:August 1, 1977
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243:March 3, 1969
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163:Pico Formation
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47:in background.
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730:December 30,
728:. Retrieved
721:the original
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653:. Retrieved
646:the original
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603:. Retrieved
599:the original
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527:the original
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497:. Retrieved
490:the original
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467:December 30,
465:. Retrieved
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421:the original
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232:Water depth
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52:
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763: /
751:119°37′06″W
536:31 December
279:Platform C
251:Platform B
237:Platform A
197:API gravity
139:hydrocarbon
105:La Conchita
778:Categories
748:34°20′48″N
655:2010-01-02
605:2009-12-31
499:2009-12-31
430:August 25,
378:2009-12-31
359:References
300:Doc Searls
226:Installed
192:material.
135:anticlinal
288:192 feet
274:190 feet
260:190 feet
246:188 feet
217:follows:
181:Salt Lake
65:tidelands
698:Archived
622:Archived
177:porosity
159:Pliocene
167:Miocene
155:Ventura
132:faulted
118:Geology
92:Setting
74:blowout
70:Ventura
153:, and
147:Rincon
78:Unocal
724:(PDF)
717:(PDF)
649:(PDF)
642:(PDF)
542:p. 16
530:(PDF)
523:(PDF)
493:(PDF)
486:(PDF)
461:(PDF)
450:(PDF)
424:(PDF)
413:(PDF)
393:Notes
223:Name
190:shaly
161:-age
72:. A
732:2009
538:2009
469:2009
432:2009
183:and
51:The
780::
559:^
547:^
508:^
452:.
415:.
401:^
149:,
88:.
734:.
658:.
608:.
540:.
502:.
471:.
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381:.
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20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
