RIASSUNTO
Abstract
This paper discusses the development and operational experience of the Snorre Through Flow Line (TFL) system. Included is a review of the TFL system development, installation, qualification and commissioning. Practical experiences, TFL operation and the development of a TFL logging tool are also discussed. Continuity and enthusiasm of personnel have resulted in a high quality, well qualified TFL system, enabling a wide range of operations to be performed.
Introduction
The Saga Petroleum operated Snorre Field is located 150 km west of Floro off the Norwegian coast. The development of the Snorre Field is one of the most challenging projects undertaken in the North Sea area. Several drilling and completion challenges are being met to develop the field in a cost effective manner.
The field is developed with a Tension Leg Platform (TLP) and a subsea production system (SPS) at 350 m water depth (see fig. 1). The subsea wells are all TFL completed with 2 x 3-1/2"" tubing, being tied back to the host platform (TLP) some 6-112 km away through 2 x 3-112"" flexible service lines.
The selection of TFL servicing for Snorre was based on safety, simultaneous drilling and production aspects and the ability to obtain routine bottom hole pressure information for reservoir performance monitoring. Other key operations and options were to change chokes in the subsea tree, install insert safety valves and to have a method to kill the wells in a controlled circulation mode. Batch scale inhibition through the 3-1 /2"" circulation system along with other benefits contributed to the decision of choosing TFL.
The first subsea well was completed in January 1993, and the first downhole TFL operation was conducted in February 1994.
Parallel to the offshore activities, Saga is currently qualifying a TFL operated production logging tool.
System Description
A TFL completion system includes not only the pipe arrangement with all its integrated valves and heads. Important elements are also the pump operation philosophy, as well as the bottom hole completion design and the TFL service tools. The complexity of expected operations to be performed throughout the life of the field forms an important basis for practical and innovative engineering.
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