Oil and Natural Gas Supply
The Arctic Energy Office
Alaska’s Potential from unconventional sources:
- The Alaska heavy oil resource is large, on the order of 45 billion barrels of original oil in place.
- The West Sak PA is believed to contain between 15 and 20 billion barrels of oil (BBO) with variable oil gravity from 10 to 22°API.
- West Sak development is restricted to a core area of about 2 BBO of which only 1.2 BBO is considered to be economical to develop.
- The Schrader Bluff PA is believed to contain between 15 and 20 BBO of 17°API oil.
- Schrader Bluff development is restricted to a core area of about 2 BBO of which only 1.3 BBO is considered to be economical to develop.
- Other heavy oil producing formations are Ugnu, Tabasco, Orion, and Polaris.
Development of advanced enhanced oil recovery technologies,
especially for “heavy oil,” to increase the recovery from known fields is critical for maintaining TAPS trough-put. Heavy oil is a
dense, viscous type of crude oil with an API gravity between
10° and 20°. Generally, this oil has a viscosity between 100 and
10,000 centipoise, and does not flow readily in the reservoir
without dilution and/or the introduction of heat. Particular
emphasis needs to be placed on evaluating technologies that could help recover more of this underdeveloped heavy oil
resource in Alaska. Advanced oil recovery technologies, such as miscibility enhanced CO2-EOR will be essential for recovering
more from the largely undeveloped heavy oil resource.
Initial steps are being taken to produce a portion of
the in-place oil resource from two large heavy oil reservoirs
on the Alaska North Slope. The Schrader Bluff Formation in the Milne Point Unit has experienced a steady growth
in heavy oil production, reaching 19,000 barrels per day in 2003, from a few thousand barrels per day in the 1990s. It
is now producing about 12,000 barrels per day. The West
Sak Formation in the Kuparuk River Unit, after years of
experimentation and delay, produced 18,100 barrels of heavy
oil per day in 2007. The Unit operator has submitted plans
to the Department of Natural Resources, Alaska to conduct
an aggressive program of horizontal well drilling and water
injection to increase West Sak heavy oil production to a
peak 26,000 barrels per day in 2015.
Further advances in heavy oil recovery technology,
adapted particularly to the special geological, reservoir, environmental, and operational situations in Alaska, will
be essential for increasing oil recovery from Alaska’s large
heavy oil endowment. Current research supported by the NETL’s Arctic Energy Office includes:
Use of Polymers to Recover Viscous Oil
API 10° crude
Alaska’s North Slope contains a very large unconventional
oil resource—over 45 billion barrels of heavy/viscous oil.
Production has been limited to pools in the core area that flow with thermal or miscible gas injection/water-
alternating-gas, but the majority of the oil is stranded.
The project will be valuable in establishing the most
cost-effective path forward to develop Alaska heavy oil resources, studying both existing and new viscoelastic
polymers to change the viscosity, new methods for
improved injectivity during polymer injection, sweep
efficiency enhancements, and effects of induced fracturing
and formation parting.
Fluid and Rock Property Controls on Production and Seismic Monitoring Alaska Heavy Oils
A prime factor limiting the efficiency of heavy oil recovery
is the heterogeneity of the system. Variability includes the
heavy oil with varying resin and asphaltene contents and
the rock matrices’ with different porosities, permeability,
connectivity, and mineral content. Using seismic data, this
study is attempting to characterize the reservoir fluid and
rock properties such that a geophysical monitoring program
can potentially be used to enhance heavy oil recovery.
Phase 2–Drilling and Production Testing the Methane Hydrate Resource Potential Associated with the Barrow Gas Fields
Previous research efforts funded by the DOE, supported
the hypothesis that methane hydrates exist within the Barrow gas fields. Based on detailed reservoir modeling and
other favorable conditions (i.e., formation gas composition,
formation water chemistry, and reservoir pressure), it is
believed that these accumulations may be interacting
with the free gas reservoirs, providing pressure support
through dissociation of the hydrates. During Phase 2 of the
project, a production test well will be designed, drilled, logged, and cored, and a continuous reservoir surveillance
and monitoring program will be implemented to prove
the commercial potential of producing methane hydrate
through depressurization dissociation from the gas zone
underlying the hydrates.
Producing Light Oil from a Frozen Reservoir: Reservoir and Fluid Characterization of Umiat Field, National Petroleum Reserve, Alaska
The Umiat oil field contains light oil in a shallow, frozen
reservoir and may be typical of an abundant supply across
the Arctic permafrost. Most prior efforts researching how
to produce in these strata of rock/ice/light oil system at low pressures has been focused upon techniques for heavy oil in
unconsolidated but unfrozen sands or on gas hydrates. This research project is developing a robust reservoir model to
test possible production methods for Umiat and similar frozen reservoirs that do not use steam or a liquid that will freeze.