Case Study: Onshore, Asia
+250 ft of Dual-String Section Milling completed with 2-access cuts and 3-milling runs at +9,700 ft!
The Dynasty Energy Services Team was approached by a company in need of section milling a challenging well in Asia. Given the depth, sustained pressure, fluid type required, and restrictive casing configuration of the well no other company was willing or able to take on the long list of challenges associated with section milling the dual windows required.
The Dynasty Energy Services team analyzed the situation and deployed their Raptor and Predator section mills configured with their proprietary Reaper inserts to take on the challenge.
Working with the rig and operating crew, the Dynasty Team successfully led the crew down their proven optimization path for section milling allowing them to identify and refine best practices for swarf management and achieving optimal milling rates.
The Team completed the dual-window in the 7”_29# x 9-5/8”_47# casing at a depth of ~1.84mi while working through the ID restricted 7”_35# shallower casing in outstanding time, with minimal runs, and no damage to the outer-casing string.
Challenges:
- Optimize swarf management control by addressing clumping and pack-off issues magnified by very tight bottom hole restrictions and sub-optimal oil-based fluid properties.
- Maximize footage per milling run to avoid timely tripping out of the +9,700ft deep hole.
- Maintain well integrity and avoid damaging the outer 13-3/8” casing string.
Results:
- Utilized the Raptor and Predator’s bi-directional milling capabilities to maximize overall milling efficiency and minimize the number of runs required.
- Successfully completed the dual-section windows in the 7” x 9-5/8” casings with a total of +250ft in 9.88 days of milling.
- Zero damage to the outer casing!
Having completed over 114ft of section milling in the 7” casing and milled multiple collars, the swarf build-up downhole was substantial.
Nearing the end of the window, milling progress grinded to a halt with erratic torque and packing-off. Rather than tripping out of the hole for a cleanout run the Dynasty Team demonstrated their versatility by milling the remaining 22ft by milling upward at 1.52 (ft/hr.).