Logical Approach Yields Correct Injection Water Quality

Abstract

Logical Approach Yields Correct Injection Water Quality

Experience shows that North Sea oilfields need water injection from the first day of production to maintain reservoir pressure and ensure maximum ultimate production. Because of the importance of water injection to a successful production operation, a logical approach should be used in the treatment system’s design, maintenance, and operation.

By failing to plan carefully, several things can happen:

• The injection well is damaged by plugging at the wellbore face, reducing injectivity.
• The reservoir is damaged by the introduction of sulfate-reducing bacteria.
• The entire project becomes uneconomic because of overdesign.
• The system design is unacceptable because of platform weight restrictions.

Design of a successful water injection plant depends on detailed knowledge of:

• Chemical and biological makeup of the source water.
• Suspended solids in the course water.
• Changes in the source water with time (seasonal).
• Reservoir characteristics.