A
s oil production during primary and secondary recovery
declines over time, the oil and gas industry has looked
toward other, more aggressive methods to meet global
energy demands. Recovering additional oil through enhanced oil
recovery (EOR) techniques provides new opportunities, but also
results in unique challenges during implementation. As low oil prices
make new developments and capital expenditures difficult, it has
never been more imperative to recover the most oil with minimal
changes to existing infrastructure. This is especially true for low
permeability carbonate reservoirs, which account for more than 60%
of global oil reserves.
1
Most of these reservoir rocks have a tendency
to trap substantial amounts of oil in small capillaries, making it
challenging to recover more oil through conventional methods.
Thus, the development of advanced technologies is necessary to
capture valuable hydrocarbons at the lowest possible cost.
Decliningoil andrisingwater
A typical oil recovery factor during the primary recovery process
(i.e. the depletion of hydrocarbon reserves under natural drive)
in carbonate reservoirs is approximately 10 ‑ 20% of the original
reserves. During secondary recovery, operators are able to extract
additional hydrocarbons, generally through the process of water
injection into the reservoir, using the pressure drive to induce the
production of more fluids. This industrial practice effectively results
in incremental oil recovery of approximately 20 ‑ 30% of the original
reserves; however, not without challenges. Many mature water
P. ROZOWSKI, C. ACEVEDO-VÉLEZ, J. MUKHERJEE AND W. YU,
THE DOW CHEMICAL COMPANY,
EXAMINE ENHANCED WATER
FLOODING METHODS DESIGNED TO IMPROVE OIL RECOVERY IN
TIGHT CARBONATE OIL RESERVOIRS.
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