A.A.P.G.-S.E.P.M.

F I E L D T R I P G U I D E T O

S A N T A R O S A I S L A N D

Saturday, October 19, 1968

COMMITTEE: John A. Forman Mobil Oil Corporation K. B. Hall Consultant, Ojai Donald W. Weaver....University of California, Santa Barbara W. E . Kennett ". Phillips Petroleum Company Tom W. Redin Union Oil Company of California Lowell E. Redwine Union Oil Company of California

ACKNOWLEDGMENTS: Al Vail has most generously granted permission to land for our lunch stop on the south side of Santa Rosa Island. Particular thanks are due the Western Offshore Drilling Company, Tidewater Marine, and General Marine Transport Company for donating the services of the crew boats used on this field trip.

© AAPG Pacific Section, 2009 ‐ Santa Rosa Island (1968)

I T I N E R A R Y

START

7:00 A.M. Leave Navy dock at Santa Barbara.

7:20 A.M. + 6% statute miles to: "STOP" 1. Site of the Union Oil platform being installed on Block 402. In March, Block 402 was the location of the first oil discovery on these Channel leases. Union is the operator for itself, Gulf Oil Corporation, Mobil Oil Corporation and Texaco, Inc. The platform, capable of holding 56 wells, will be positioned in about 190 feet of water five and a half miles off the coast. A second, 59-well platform is scheduled to arrive in October and a 56-well platform in December. It will take approximately six weeks to complete the initial platform a.nd to install drilling equipment. Actual drilling operations are scheduled to begin in November with the first production from the platform being shipped during December.

7:35 A.M. 4 miles to: "STOP" 2. Circle Platform Hogan having passed the George F. Ferris jack-up drilling barge drilling the seventh test on Block 401 for Sunray, et. al. Platform Hogan is operated by Phillips Petroleum on the 298 Federal Drainage Tract. It is currently producing over 7000 B/D carried by pipeline to an onshore site near Rincon. To the east along the plunge of the anticline are two Standard Oil Platforms (Hope and Heidi). Fifty-nine wells on these platforms are producing approximately 11,000 B/D which is carried by pipeline to a Standard Oil onshore facility at Carpinteria.

8:10 A.M. 11 miles to: "STOP" 3. We are in the middle of the Santa Barbara Channel over "Middle Ground" topographic high. This is a westerly continuation of the onshore Oak Ridge Anticline. Gulf Oil recently abandoned a 12,125 foot wildcat test of this structure. Six miles due west Humble drilled a 9630 foot wildcat in 994 feet of water! The barge WODECO IV was used to drill this test using special risers and anchoring equipment. Eight additional wildcats have been abandoned on the inshore extensions of this structure with no reported discoveries.

9:00 A.M. 14 miles to: "STOP" 4. "Painted Cave" on the north shore of Santa Cruz Island. The cave is developed in faulted, Middle Miocene volcanic rocks which dip north and constitute most of the northern half of Santa Cruz Island. The cave has several chambers and is more than 600 feet in length with an entrance over 150 feet high.

9:45 A.M. 4% miles to: "STOP" 5. West Point of Santa Cruz Island. Elevated wave-cut terrace cut in volcanic rocks.

10:10 A.M. 6k miles to: "STOP" 6. Skunk Point at the eastern end of Santa Rosa Island. The Santa Rosa Island fault extends from this point westerly through the Island. Outcropping in Beecher's Bay in a southeasterly plunging syncline are the white, tuffaceous sediments of Middle and possibly Upper Miocene "Santa Margarita" formation.

10:20 A.M. 3h miles to: "STOP" 7. East Point of Santa Rosa Island. From this point to "STOP" 8 (Ford Point) we will travel as close to the shoreline as possible to view the geologic sections exposed in the sea cliffs. It dips uniformly to the northeast and is illustrated in the Stratigraphic Column and Geologic Map of this guidebook.

West of the sand spit at East Point the massive cliffy exposures are "Santa Margarita" volcanic conglomerates. They are separated by a fault from the weaker Monterey section. At the base of the cliffs is a "blow hole" where the surge from breaking waves causes a spray of water to blow up into the air. This Monterey section contains numerous volcanic sandstone and tuffaceous beds. Extensive minor, faulting in this section has been unraveled by the UCSB geologists to measure a stratigraphic section.

The Rincon shale section is a weaker zone below the Monterey. Hard resistant ledges of fossil "reefs" (pectens, oysters and turritellas ) strike across the sandy beach. The small bight ahead is formed by a resistant sill of Middle Miocene volcanic rock. Three outlying rocks mark the seaward extensions of the sill. Below the volcanic outcrops is the remainder of the Rincon shale section.

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The cliff-forming exposures below the Rincon are Vaqueros sandstone. Because the Rincon becomes sandier towards its base, the location of the contact is somewhat arbitrarily placed at a Turritella inezana horizon. Sespe sandstones outcrop below the Vaqueros.. These sands weather reddish-brown and contain some interbeds of variegated shale. The uppermost Eocene section is Cozy Dell shale. It is underlain by sandstones of the Matilija formation from here to Ford Point.

10:40 A.M. 5 miles to: "STOP" 8. FORD POINT. From this point to the anchorage at Johnsons Lee and as far as South Point we will view outcrops of Eocene Matilija sandstone. A faulted syncline at the Camp exposes Sespe.

11:00 A.M. 3% miles to: STOP 9. Pier in Johnsons Lee. This was the site of an Air Force "Early Warning" scanning station. It was built in the early 1950's at considerable expense and abandoned in 1962. We will disembark to eat lunch here and examine some of the Matilija sandstone and Sespe sections along the beach.

11 :00 A.M. t o 12 NOON L U N C H & B E E R

12:00 to 2:00 P.M. Examine Beach Section.

2:00 P.M. Board boats for return trip to Santa Barbara. Forty miles to Navy Dock.

*4:00 P.M. Arrive Santa Barbara

*These times assume boat speed of 20 mph and may be a trifle optimistic,

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tt - it PLATFORM A

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Union's core hole drilling on Block 402 has delineated a major oil field which will re­quire 3 rather unique platforms in its develo: ment. As outlined on the map, the field is narrow and elongate. Additionally, the top of the producing measures occur as shallow as 500 feet and extending downward to 3600 feet. 1500 feet of net Repetto pay sand has been encountered in this interval. To reach such shallow pay sands from fixed platforms, Union has designed a "tilted-rig" which, through inclined conductor pipes and

a tilted rotary table, will be' able to spud a hole with an initial deviation of 30°. Platform "A" will have 20 shallow-zone wells drilled with this inclined rig. An additional 36 holes will be drilled with a conventional platform rig. The latter will produce the lower part of the Repetto oil sands in the interval from 1200 to 3600 feet. A deep zone at 10,000 feet was discovered in the 1+02 #1 core hole but testing of the well was inconclusive. It is hoped that the zone will prove productive. Platform "A" is in 190 feet of water and is 5-1/2 miles off the coast. A 12 mile pipeline will connect it with Mobil's onshore facility at Rincon. Two further platforms ("B" & "C") will be installed on Block 1+02 capable of drilling and producing 59 & 56 wells respectively.

The discovery well of Block 402, 0CS P-02"+l #2 vas drilled from a floating barge (W0DEC0 i) in the north central part of the lease. (See map near "B" platform). It encountered in excess of 1000 feet of net oil sand and was bottomed at 3775 feet. On test, the well flowed at an 1800 B/D rate of 27.8° gravity oil through a l/2 inch bean from sands in the interval from 2000 to 2700 feet. The confirmation test k02 #1 (0CS P-021+1 #l) was a deep test drilled from the jack-up barge George Ferris near the east line of the ^02 lease. This well passed through 1500 feet of oil sand and discovered the deep oil zone at 10,000 feet.

Sunray DX has drilled several wells on Tract U01 to the east of Union's U02 Block. The 1+01 #1 well was drilled in the eastern part of the Block and was abandoned as non commercial.

The "+01 #2 well was drilled closer to the Union confirmation test and found over 700 feet of oil sand before bottoming at 1+312 feet. The well flowed at the rate of 1*190 B/D of 3I4.20 gravity oil from the interval from 3U37 to 3535 feet.

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TRATIG^APHIC COLUMN SOUTHEAST COAST OF SANTA ROSA ISLAND

After:

"SANTA MARGARITA"

FAULT

S c a l e : 1" - 500'

RINCON

1120'

VAQUEROS

435'

SESPE

5001

COZY DELL

4101

Avila, D. Doerner, D. Weaver (U.C.S.B.) L. Redwine

Oct. 1968 - J. A. Forman VOLCANIC CONGLOMERATE: Light colored, massive, resistant. Interbeds of vol. ss. & siliceous shale. Andesite, basalt, rhyolite & schist clasts.

WEAVER SAMPLES SR 67-20 , SR 67-21 (Luisian)

SHALE: Brown, siliceous, platy, with many interbeds of vol. sandstone and ash. Zones of convolute sedimentary structures.

MOBIL SAMPLE 15 (Lower Relizian)

WEAVER SAMPLE SR 67-30 (Basal Relizian)

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MATILUA

710'

FAULT

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MOBIL SAMPLE 13 (Saucesian)

VOLCANIC SILL

MUDSTONE: Grey-brown, massive. Poorly resistant outcrops form rounded soil-covered hills. Thin resistant beds of dolomitic megafossils form "reefs". Unit becomes sandier towards base.

SANDSTONE: Buff, fine-grained, poorly defined bedding,limey concretions. 4' gravel conglomerate near middle. Turritella inezana horizon at top.

SANDSTONE: 'Buff, some surfaces weather reddish or rust colored. Thin-bedded with few thick beds, friable, fine­grained. Rust colored laminae mark cross beds & slump folds. Basal cobble conglomerate. Occ. maroon shales.

SHALE: Bluish-grey, silty towards top. Upper half contains 2' resistant beds of calcereous siltstone.

-MOBIL SAMPLE 8 (Narizian)

MOBIL SAMPLE 10 (Ulatisian)

SANDSTONE: Grey & buff. Thick-bedded medium-grained. "Cannon ball" concret­ions up to l1 and flatened elongate con­cretions as large as 3' X 15*. Shale interbeds often exhibit slump folds.

List of Samples Shown on Stratigraphic Column and Geologic Map

Sample SR67-20: Middle

Bolivina advena striatella CUSHMAN B. cf. B. salinasensis KLEINPELL B. marginata CUSHMAN Bulimina inflata SEGUENZA Eoglobigerina minutissima (BOLLI) Globigerina praebulloides BLOW Globigerinoides triloba (REUSS) Nonion costiferum (CUSHMAN)

Sample SR67-21: Middle

Baggina robusta KLEINPELL Bolivina advena var. striatella

CUSHMAN B. californica CUSHMAN B. imbricata CUSHMAN B. marginata CUSHMAN Globigerina bramlettei LIPPS

Mobil-15: Middle Mio

Baggina robusta KLEINPELL Bolivina spp. B. aff. floridana CUSHMAN Bulimina alligata CUSHMAN & LAIMING Globigerina spp. Nonion costiferum CUSHMAN

Sample SR67-30: Middle Mio

Baggina cancriformis KLEINPELL Cibicides americanus (CUSHMAN) Globigerina praebulloides BLOW Globoquadrina pseudovenezuelana

BANNER & BLOW

Bolivina sp. B. marginata CUSHMAN Bulimina inflata var. alligata

CUSHMAN & LAIMING Dentalina sp. D. pauperata D'ORBIGNY

Miocene - Luisian

Siphogenerina sp. S. collomi CUSHMAN S. kleinpelli CUSHMAN S. nuciformis KLEINPELL S. reedi CUSHMAN Uvigerinella aff. U. obesa CUSHMAN Valvulineria miocenica CUSHMAN V. ornata CUSHMAN

Miocene - Luisian

Globigerina praebulloides BLOW Globigerinoides triloba (REUSS) Nodogenerina advena CUSHMAN & LAIMING Nodosaria longiscata D'ORBIGNY Siphogenerina sp. Uvigerinella aff. U. obesa CUSHMAN Valvulineria ornata CUSHMAN

ene - Relizian

Planulina baggi KLEINPELL Siphogenerina branneri (BAGG) S. kleinpelli CUSHMAN Uvigerinella californica CUSHMAN vars. U. obesa CUSHMAN

ene - Basal Relizian

Siphogenerina branneri (BAGG) S. hughesi CUSHMAN Uvigerinella obesa CUSHMAN

Globigerina sp. Planulina baggi KLEINPELL Robulus mayi ? Siphonodosaria advena CUSHMAN & LAIMING Uvigerina sp.

Mobil-13: Oligocene - Lower Saucesian

Fish remains Sporbo (Discoid) Authigenic quartz Globigerina spp. Ostracoda

Mobil-8: Late Middle Eocene - Lower Narizian

Bulimina corrugata CUSHMAN & SIEGFUS Plectofrondicularia cf. searsi CUSHMAN & STEWART Valvulineria tumeyensis CUSHMAN & SIMONSON Others

Mobil-10: Middle Eocene - Ulatisian

Clavigerinella cf. akersi BOLLI, LOEBLICH, & TAPPAN Globigerina boweri BOLLI (=Glr. frontosa) Globorotalia cf. bullbrooki BOLLI Uvigerina cf. elongata COLE Others

Mobil-6A: Early Middle Eocene - Ulatisian

Bathysiphon spp. Globorotalia spinuloinflata (BANDY) G. aff. spinulosa CUSHMAN Others

Faunal lists on SR samples supplied by Dr. D. W. Weaver; faunal lists on Mobil samples furnished by A. D. Warren.

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