Increasing Production with an Innovative Through Flow Line (TFL) Multi-Zone Completion Design for a Major Norwegian Operator

Abstract

Abstract Norsk Hydro operates the Snorre Field in the Norwegian sector of the North Sea with a tension leg platform (TLP) and a sub-sea production system. The initial sub-sea wells were designed with completions that would allow through-flow-line servicing, and while the wells were functioning as designed, production had been declining. Therefore, Norsk Hydro felt that the completion concepts should be evaluated for new field developments. The ensuing investigation and development project led to a novel well completion concept, which is the first "intelligent well" subsea completion installation offshore Norway. This innovative design changes retain the original through-flow-line (TFL) service technique system and subsea infrastructure without any modifications, maximize production by introducing 7-in. tubing, and include hydraulically operated inflow control devices. The supplier and operator developed the concept during the winter 1998/1999 and designed the resulting system during spring 1999. License approval for prototype development and qualification was given in the summer of 1999, and the system components were in-house tested at the supplier base in Dallas during the fall of 1999. A thorough system qualification was performed at an independent Norwegian drilling and well test center during spring/summer of 2000. The qualification included a full test-well installation and necessary intervention activities to prove the functionality of the concept. The system was qualified during the summer of 2000. The first subsea well installation was done at Snorre and put on production in December 2000. The well completion consisted of a 4-zone/interval design for improved reservoir management. The concept principles also have application for other type wells on platforms where modifications to the wellhead and tree are not feasible. The development process and qualification of the system has been conducted in a very short time period from idea to offshore implementation. This is mainly the result of a very focused personnel team with competent and dedicated personnel between supplier, operator, and 3rd party testing contractor. This paper will discuss the improved system and testing that resulted from this project. The first new production system was installed in a side-tracked well, and the results of the completion will also be discussed.