Petroleum Technology Overview
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North Slope Drilling Rig

Photo: appliedmechanics.com

Introduction

Petroleum technology has continually advanced as the industry remains an important part of our economy. Since the oil boom in the 1970's, the petroleum industry's strong presence in Alaska has enabled it to join with industry leaders in finding newer and more efficient ways of drilling for oil.


Exploration

Advances in seismic imaging have allowed organizations and companies the ability to determine more accurate estimates of oil reserves. Seismic imaging uses sound waves that bounce off of underground rock structures, revealing formations that possibly contain oil and gas reservoirs. 3-D seismic imaging creates high-definition images of the geology beneath the earth's surface. 3-D seismic images can be taken at different times to produce 4-D information, showing a reservoir at various stages of depletion.1 A solid understanding of a site's subsurface structure can help engineers determine whether a site is a good location for drilling and helps in building safer, more efficient rigs.


Drilling

Drilling technology has steadily improved in Alaska, with less surface space required than in the past. Different techniques have emerged that allow for more productive wells and less damage to the surrounding environment. Besides drilling straight into the ground, advances in drilling technology allow wells to utilize directional or horizontal drilling.

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Directional Drilling

Image: theinfomine.com

Onshore Petroleum Production

Offshore Petroleum Production


Extraction and Recovery

Primary Recovery

During primary recovery, oil is extracted from a well due to natural pressure from water displacing the oil, expansion of natural gas in the reservoir, gravity drainage, and/or the use of artificial lift techniques, such as pumps, are used to bring oil to the surface. Only about 10% of the reservoir's oil contents are extracted from primary recovery.2

Secondary Recovery

Over time, the natural pressure in an oil reservoir decreases due to drilling and external energy must be used to continue to extract oil. There are several methods used for this, including pumps, water injection, natural gas injection, or gas lift. These methods increase the pressure in the reservoir, driving up 20%-40% of the original oil.3

Tertiary Recovery

Tertiary recovery, or enhanced recovery, methods manipulate the oil in ways that make it easier to extract. There are various methods, including heating the oil through thermally enhanced recovery methods, using surfactants to change the surface tension between the oil and the water in the reservoir, carbon dioxide flooding, or using microbial treatments. Tertiary recovery methods can result in the extraction of 30%-60%, or more, or the original oil.4 Tertiary recovery methods are expensive, so there needs to be a significant economic incentive before they are used to extract oil from a reservoir. Of these methods CO2 injection has been gaining increasing attention as a viable way of extracting the remaining oil from a reservoir that might have ordinarily been abandoned.


Transportation

Oil is generally transported through pipelines to refineries or distribution facilities. The Trans-Alaska Pipeline System (TAPS) ends in Valdez, where crude oil is loaded onto tankers for transportation to refineries.


Refining

Alaska has 6 operable oil refineries in Kenai, Valdez, North Pole, Kaparuk, and Prudhoe Bay, for a total operating capacity of 295,034 barrels per calendar day in 2011.5


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