Successful Installation of a Completion System for Gas Migration Prevention

Abstract

Completion systems will be presented for prevention of gas migration composed of an annular casing packer with remote-set technology activated by either an acoustic wave generator or casing wiper plug (CWP) with a magnetic array. Proven and reliable zero-extrusion gap element technology provides a gas-tight annular seal while reliability is enhanced by eliminating all communication ports and potential leak paths between the packer's ID and casing annulus. Design and qualification of these systems will be discussed along with the recent successful field installation of a shallow depth 18 5/8" × 24" system in a Sakhalin Island offshore well. There are three main benefits of these systems. They provide a reliable mechanical barrier to flow after cementing which can result in a significant financial impact to the operators and their service providers. They eliminate issues with annular casing pressure (ACP) and sustained casing pressure (SCP). They also provide a permanent seal between casing strings that reduces risks of costly plug and abandonment (P&A) operations. One system for shallow depth applications employs an acoustic wave generator at the rig floor to initiate the setting sequence upon completion of cementing operations. Another system activates the packer setting sequence with the CWP during cementing operations. An optional contingency setting sequence can be programmed prior to deployment and later deactivated if not required. Industry standards are focused on reducing annular flow prior to, during, and after completion of primary cement jobs. While these changes will improve annular isolation, conventional cementing contains fundamental limitations that complicate control of shallow gas hazards and water flows. The above completion systems will help alleviate these concerns.