American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.


Atlantic Richfield has completed eight sea-floor wells in the Eugene Island Block 175 Field, offshore Louisiana. Initial installation was in 1966. These wells are remotely operated and serviced from a central platform through flowlines of lengths up to 6,175 feet. Operation of the wellheads and a variety of through-flowline (TFL) procedures have been performed repeatedly since installation. performed repeatedly since installation. Although equipment failures have occurred, control of the wells has always been maintained.

This paper describes the surface, seafloor and downhole equipment installed, TFL operations and significant problems encountered.


The Eugene Island Block 175 Field is 70 miles southwest of Morgan City, Louisiana. Water depth is 85 feet. It is a piercement salt dome, multi-reservoir field, with productive intervals between 7,000 and 12,000 feet. Original oil production was established in 1957 with wells drilled from a platform ("A") located on the southern portion of the block. Another platform ("B") was set in the center of the block in 1958. Platform "A" was destroyed during Hurricane "Hilda" in October, 1964. Consequently all wells from that platform were reentered and plugged. This loss platform were reentered and plugged. This loss resulted in the decision to utilize seafloor completions to minimize the chance of losing wells to hurricanes and to expedite reestablishment of oil production.

Two wells were initially drilled and made seafloor completions to exploit the reserves from the Platform "A" area. The wells were connected by flowlines to the "B" platform. Production from these wells was initiated in Production from these wells was initiated in September, 1966. Exploratory drilling in the northeast quarter of the block resulted in discovery of a major field extension. Again, early exploitation was afforded by drilling and completion with a mobile rig and flowline tie-ins to "B" platform. Five seafloor wells were completed on the east flank under that program. The final seafloor well was program. The final seafloor well was completed in the "A" platform area in August, 1969.

Subsequent to the completion of the eight seafloor wells, an 18-slot platform was installed and field development was completed by drilling directional wells. Economic comparison of seafloor wells to platform wells is not attempted in this appraisal.

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