Page 97 - Principles of Applied Reservoir Simulation 2E

82 Principles of Applied Reservoir Simulation

9.4 Environmental Impact

Environmental issues must always be considered when developing a
reservoir management strategy. For example, the Louisiana Offshore Oil
Production (LOOP) facility is designed to keep hydrocarbon transfer operations
from pipelines to tankers away from sensitive coastal areas. Periodic water
sampling of surface and produced waters can assure the fresh water sources are
not contaminated. In addition, periodic testing for the excavation or production
of naturally occurring radioactive materials helps assure environmental
compliance,
A well-managed field should be compatible with both the surface and
subsurface environment. The advantages of operating a field with prudent
consideration of environmental issues can pay economic dividends. In addition
to improved public relations, a sensitivity to environmental issues can minimize
adverse environmental effects that may require costly remediation and financial
penalties. Remediation is often in the form of clean-up, such as the clean-up
required after the oil spill from the Exxon-Valdez oil tanker in Alaska. New
technologies are being developed to improve our ability to clean-up environmen-
tal pollutants. For example, bioremediation uses living microorganisms or their
enzymes to accelerate the rate of degradation of environmental pollutants
[Westlake, 1999].

Subsidence
An issue of special importance to reservoir characterization is subsidence.
Subsidence is a compressibility effect that depends on the geomechanics of the
produced interval and its overburden. Subsidence, or the change in thickness
A& of the reservoir, can be estimated from the compressibility and pressure
depletion of the system using the equation
A/z = c BhAP = <kc fhAP

where
1
bulk compressibility [psia" ]
C B
1
formation compressibility [psia" ]
c f