The Snapper field, which is located in Bass Strait, offshore south-eastern Australia, contains a large gas reservoir, the "N-1", with an 8 metre "pancake" oil leg. While Snapper was developed primarily as a gas field, initial work has concentrated on maximizing oil recovery prior to eventual large scale gas production. Phase I development was undertaken during 1981-1983 with fourteen N-1 oil completions coming on-stream. Encouraged by the successful performance of these wells, a second drilling phase was undertaken during 1986-87, resulting in nine new oil completions.

Some gas production has been required to meet gas market demand. This production, from gas completions and-gas coning in oil wells, has caused the oil zone to steadily rise. Over the next few years, workovers in many of the wells will extend production as the column continues to rise.

This paper examines the highly variable performance of the mature Phase I wells and the early performance of the Phase II wells. This will assist other operators in planning similar, thin oil developments.

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