ConocoPhillips is developing the Magnolia field with a Tension Leg Platform (TLP) in 4,674 ft of water at Garden Banks blocks 783-784 in the Gulf of Mexico. The field consists of an extended tension leg platform containing full processing capability with oil and gas export pipelines. To date the field has produced 35 million barrels of oil equivalent. The base development plan includes both rig and thru-tubing operations. Since first oil in December 2004 eight thru-tubing operations with coil tubing have been conducted on the platform. Included in this work were two thru-tubing fracpack recompletions.
This paper will review the objectives, design considerations, execution results and lessons learned from the two thru-tubing recompletion projects using coil tubing. Some of the major challenges that had to be addressed for the operation involved coiled tubing and wire line operations in the deep, high angle wellbores, gravel pack screen selection and qualification testing, thru-tubing perforating and coiled tubing screen deployment challenges.
The results from both wells will be discussed. The first thru-tubing recompletion had to be abandoned due to inability to washout sand fill and gravel pack screen movement. The lessons learned from the operations on this well were applied to the second recompletion with very successful results. A special gun loading scheme was used for thru-tubing perforating to maximize entry hole for gravel pack completion and minimize near wellbore issues during the frac-pack operation. The methods, procedures, equipment and fluids used to improve wash out operations in high deviation and wide range of IDs will be shared. A down hole video camera was used to inspect a locked out safety valve and perform casing and packer inspection for integrity. Changes have been made to the gravel pack release tool based on results from the first well. The need for proper centralization and use of an indexing tool to improve reliability of thru-tubing retainers in deviated wellbores has been identified. A total of 19 key learning have been identified that will be provided. These lessons learned and best practices developed for thru-tubing recompletions will be shared. These will be invaluable to all future Magnolia and other deep water well work over operations.