Schlumberger

Performance Report: Peru: Mechanical Casing Cleaning Clears Way for Completion and Production

Challenge: Wellbore cleanup following operations such as cementing a liner should be considered as critical and not routine, since minimizing formation damage and, hence, maximizing well productivity depend on a successful cleanup operation. A client, however, was spending excessive rig time in coiled tubing intervention runs after the clean up and displacement while conducting an inflow test to confirm liner integrity prior to perforating. The operator requested a solution for reducing rig time, while at the same time minimizing the cross contamination of fluids to reduce surface volumes during the displacement to optimize pit space and improve waste disposal.

Solution: An M‐I SWACO Specialized Tools group recommended a cleanup string, including a WELL COMMISSIONER tool, for inflow testing the liner top. The client accepted the recommendation to conduct an inflow test and casing/liners cleanup operation using the following wellbore cleanup tools: 13⅜-in., 9⅝-in. and 7-in. MAGNOSTAR; 13⅜8-in. WELL PATROLLER; 13⅜-in., 7-in. RAZOR BACK Heavy Duty; 9⅝-in. WELL COMMISSIONER

Result: A successful 1½ hour- inflow test of the 7-in. liner lap was conducted after scraping production packers setting depths. The displacement and cleanup operation was deemed a success with the following debris volumes recovered from the well: 12 kg with 13 ⅜-in. WELL PATROLLER; 30 kg with MAGNOSTAR; 20 kg with 9 ⅝-in. MAGNOSTAR; 5 kg with 7-in. MAGNOSTAR. The operator saved a total of 24 hours rig time by eliminating a planned coil tubing run that would have been required previously to remove seawater from the well.

Two cleaning runs were made:

Run #1: 8 ½ in. bit, 9 ⅝ in. RAZOR BACK HEAVY DUTY, 9 ⅝ in. BRISTLE BACK HEAVY DUTY 9 ⅝ in. and 7 in. MAGNOSTAR. The string was run in the hole to the top of 7 in. liner where it cleaned the 9 ⅝ in. casing. The last stands were run by rotating, circulating and reciprocating for better cleaning and going through cement shoulders without problems. A viscous pill was circulated and the string pulled to surface. The MAGNOSTAR tool recovered 8 lb (3.6 kg) of magnetic debris.

Run #2: 6 ⅛ in. bit, bit sub, 7 in. RAZOR BACK HEAVY DUTY, 7 in. BRISTLE BACK HEAVY DUTY, 7 in. MAGNOSTAR, 9 ⅝ in. RAZOR BACK HEAVY DUTY, 9 ⅝ in. Bristle Back Heavy Duty, 9 ⅝ in. MAGNOSTAR. The string was run in the hole to the top of 7 in. liner before the top drive was connected and then run in the hole while rotating, circulating, and reciprocating to enhance wellbore cleaning. A viscous pill was pumped and circulated until clean returns appeared at surface, and then pulled the string to surface. The 9 ⅝ in. MAGNOSTAR tool recovered 18 lb (8.2 kg) and 7 in. MAGNOSTAR tool recovered 15 lb (6.8 kg) of metallic debris.


Download: Peru: Mechanical Casing Cleaning Clears Way for Completion and Production (0.26 MB PDF)

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