Abstract
In the 1980s, economic conditions in the oilfield were demanding improvements in economic and completion efficiency, and all phases of the industry were requiring that strategies to improve cost be revisited. Sand-control completion methodologies were no exception; they were no longer capable of meeting the economic and completion-efficiency required to complete the long stacked intervals being attempted. To address this problem, a single-trip multiple-zone gravel-pack system was developed. The concept was successful for the targeted formations, but as with all new technologies, certain shortcomings concerning rathole intervals, complexity of the systems, and longer, more deviated wellbores prevented its use in all types of reservoir scenarios.
An improved version that was introduced in the early 1990's attempted to address these shortcomings. This system was successfully deployed and is still being run in the Far East today. However, limitations that were still experienced with the single-trip multiple-zone systems have prevented their wide spread adoption, causing them to remain a niche completion technique predominately used in the Far East and Italy.
Industrial drivers for deepwater development have again caused operating companies to revisit the viability of multiple-zone systems. Once considered too complex and risky for offshore operations; the development of the ultra deepwater lower-tertiary play in the Gulf-of-Mexico has provided the impetus for renewed interest in multi-zone concepts. This interest has been driving the development of the latest generation of the cased-hole multiple-zone system as well as an openhole multiple-zone frac-pack-compatible completion system.
The intent of this paper is to chronicle the development of cased-hole single-trip multiple-zone completion systems with a focus on the latest generation of these systems — the systems developed for deepwater applications. The paper will also discuss why previous systems have not proliferated globally to become an accepted mainstream sand-face completion technique.
The improved functionality of the newest system will be described and compared to the previous generation of systems. The integration testing to qualify the new multiple zone system is included in the discussions. Several installations have been planned, and the case histories will be included if available by paper time.
