Cleaning sand fill out of large diameter, deviated wellbores with low-bottom-hole pressure has proven to be a major challenge. During a conventional coiled tubing cleanout on these lower reservoir wells, either a low density fluid, such as diesel, or a nitrified system, is utilized to maintain an underbalanced condition during the cleanout process. It is common that many of these cleanout operations are conducted with limited annular fluid velocities. Sand vacuuming technology addresses these challenges by utilizing a jet pump powered by single phase liquid which carries all of the returns up the concentric coiled tubing (CCT) annulus. Previous field practices indicate that most of the sand/well vacuuming jobs were applied in low-pressure reservoirs, unconsolidated sands with relatively small size solids (less than 20/40 mesh) in horizontal slotted liner completions.

There are still some challenging issues for sand vacuuming operations. These include the use of heavy coil in coil strings, limited jet pump capacity for deep, extended reach wells, vacuuming large particulates through the narrow flow intake to the concentric coiled tubing annulus, and breaking consolidated sand bridges with limited forward flow jetting. This paper discusses the modification of a previous jet pump with a three-way switch tool (sand vacuum, well vacuum and jetting mode) to clean large size proppant (8/14 mesh). The modified bottom hole assemblies were tested in a full scale flow loop. The flow loop setup and test results will be discussed. The distance of the rear facing jets to the intake of the jet pump and the pull-out-of-hole speed of BHA are crucial to insure the sand can be completely removed. A few field cases are also discussed in this paper. Both flow loop tests and field operations indicate that a proper designed jet pump with a jetting switch tool could effectively vacuum the larger proppant in low pressure extended reach wellbores.

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