Since no local crude oil sources exist, every drop of petroleum consumed in Oregon originates from outside sources and is distributed multi-modally to consumers. As population continues to increase and oil sources dwindle, this reliance may add financial and environmental risks to Oregonian' s quality of life. This paper examines Oregon's oil distribution system, and analyzes the risks oil movements pose in the state. A comprehensive understanding of oil distribution in Oregon can best be gained geographically. Pipelines, ships, barges, railroads and trucks play different roles in this system, yet data for these transport modes are maintained by different groups and unstandardized. Therefore, the data must be normalized to present a map of how oil is being moved around the state. This study sets all levels to a barrels (42 U.S. gallons) per month (assumed 30 days) standard. Oil's role in the economy of our state, most noticeably in the sale of motor gasoline, creates different types of risk. The most obvious risk results from transportation, and Oregon is plagued daily by unintended releases. A second type of risk, supply risk, exists because of our reliance on the petroleum networks of Alaska, Washington and California, and was evident during the 1974 oil embargo. Lastly, economic risk should theoretically be present since Oregon is a downstream consumer from adjacent states. During times of shortages, Oregon should be at the mercy of those who provide its supply. The data do not support this, but suggest that oil is purely a global commodity, and price and supply are determined worldwide in response to typical marketing forces. The distribution systems detailed herein are dynamic, and outside forces such as the proposed export of Alaskan crude oil, the increased exploration of offshore oil fields, and the development of a cross-Cascades pipeline may alter this scheme. Oregonians can ensure the most effective petroleum distribution systems only by understanding them and their associated risks.

Sequence stratigraphic analysis of the southern Tyee basin, Oregon Coast Range, reveals that the lower to middle Eocene forearc and subduction zone strata comprise four depositional sequences. Sequence I (lower Umpqua Group) represents a partially subducted accretionary wedge. Sequence II (upper Umpqua Group) is a deltaic sequence that filled irregular lows and thinned over submarine highs created by intrabasin, imbricate thrust faulting. Farther north, Sequences I and II rapidly thin and distally onlap oceanic basalt islands and searnounts of the Siletz River Volcanics to form a condensed section and then thicken again northward. These sequences are overlain by a tectonism-forced transgressive systems tract deposited during an onlap caused by tectonic subsidence and dockwise basin rotation approximately 50 Ma. By middle Eocene, sandy submarine fans and wave-dominated deltas of Sequences III and IV (Tyee, Elkton, Bateman, and Spencer formations) prograded northward down the axis of the Tyee forearc basin and across the structural trend of the Umpqua Group. Organic geochemistry indicates that most units are thermally immature and contain lean, gas-prone Type III kerogen. However, some beds (coals) are sufficiently organic-rich to be sources of biogenic and thermogenic methane discovered in numerous seeps. Reservoir-quality porosities and permeabilities are identified in a few delta front and turbidite sandstones of Sequences II and III, although zeolite, clay, and quartz diagenesis has destroyed most potential sandstone reservoirs. The overall hydrocarbon potential of the basin is moderately low. Several requirements f or commercial accumulations of hydrocarbons, however, probably exist locally within and adjacent to the basin. Three speculative petroleum systems are identified. The first includes the southern part of the basin near the border with the Mesozoic Klamath Mountains and is related to a proposed subduction zone maturation mechanism along thrust faults. The second is centered in the northern part of the study area and may be associated with basin-center gas in an overpressured zone. The third occurs near the eastern border of the basin where maturation is related to local heating by sills and migration of hydrothermal fluids associated with mid- Tertiary volcanism in the Western Cascade arc. / Graduation date: 1995

This study examined source rock geochemistry of the southern Tyee Basin. Total organic carbon, rock-eval pyrolysis, vitrinite reflectance, thermal alteration index and visual assessments were performed on splits from cutting samples from five wells and on outcrop samples from four measured sections. Organic matter was found to be dispersed, averaging about 0.5 weight percent. The organic matter is primarily terrestrial in origin, or type I l l , with low potential for gas production and no oil potential. Three coal samples are clearly the richest sources of organic matter examined in this study.