Sand fill cleanout on wireline enables access to additional perforation zones in gas well producer

Abstract

An Australian operator wanted to explore options for wireline conveyed sand bailing in one of their offshore deviated ‘S’ shape gas producing wells. The objective was to remove approximately 24 m of sand fill inside 9.625″ production casing, with an internal diameter (ID) of 8.681″. To limit the number of cleanout runs, the latest technology in wireline deployed suction tools with a 4.25″ overall diameter (OD) was chosen, which provided increased recovery volume, plus real-time surface control and monitoring. Because of the tool’s overall diameter, the landing nipple also required milling to allow access. Therefore, a specially designed 4.412″ mill bit was manufactured and run on a milling tool. The electric line deployed milling technology successfully milled through the landing nipple and a ball catcher in four runs, thus increasing the ID sufficiently to allow access for the cleanout tool string. A well fluid column of about seven bars is required to enable operation of the suction tool. The cleanout tool was configured with three bailer sections (seven max) for the first run, to determine sand recovery optimisation. Three different sizes of bailer filters are provided; prior knowledge of debris particle size is therefore advantageous. In this case, a slickline bailing sand sample had been recovered, which immediately aided filter choice. Seventeen bailing runs were conducted over 5 days, successfully recovering a total of 918 L of sand, equating to about 2.4 tons. Ultimately, the process enabled perforation of two additional gas zones to increase production.