Work under the contract includes detailed engineering design for the topsides facilities of a wellhead platform and a production utilities and quarters platform.
The company has recently completed a front-end engineering design for the project.
The contract is expected to be complete by the end of 2012.
CB&I President and CEO Philip Asherman said this contract builds on their decades of experience in the offshore industry.
"Following our successful completion of two projects in the Buzzard field, we are pleased to extend our relationship with Nexen for additional work in the North Sea," Asherman added.