A deep well drilled at the Colombian foothills, with a combined casing and liner string, finished with a 4 ½” liner set at approx. 19,800ft.
The task was to effectively clean out the 4 ½” X 7” X 9 5/8” liner, ensuring proper flow rates in the adjacent liner and casing sections for efficient hole cleaning.
The operator required the ability to pump at different flow rates, in different sections of the well, so that optimal annulus flow rates could be achieved for effective hole cleaning.
The flow rates required were between 60gpm and 460gpm. Currently, there are no standalone tools that could effectively deliver flow rates in that range.
Ecopetrol and DSI-BITO engineering teams designed a solution based on a combined BHA, including 1 x 2 7/8” OD and 1 x 4 ¾” OD PBL® Bypass Tools set at the appropriate positions.
Considering the well profile, which consisted of 11¾” OD and 4 ½” OD liners, set apart by 9,842ft, DSI designed a solution that would deliver effective flow rates at the required depths. We placed a 4 ¾” PBL® tool at the transition point and a 2 7/8” PBL® tool at the lower section of the hole. The plan was to activate and pump through the 2 7/8” PBL® first to ensure hole cleaning inside the 4 ½” liner, considering the tool OD and max flow rates allowed in that well section. While pulling out of hole and reaching 9,842ft we then activated the 4 ¾” PBL to pump at significantly higher flow rates enhancing the hole cleaning process at optimal annular velocity and ensuring a complete debris cleanout.
This was a very successful well bore clean out operation which optimized and reduced the circulating time and excellent hole cleaning was observed in the subsequent BHAs Run in Hole. No restrictions or string plugging were experienced and clear access to work with wireline/braided line down to 19,500 ft was achieved without any issues.
