摘要 |
A hydraulic underreamer for enlarging a wellbore includes improved packer, cutting, jet pump, and mill sections. Each of the sections and their associated advantages are described herein in detail. The packer section is designed to minimize wear on its sealing elements, the cutting and jet pump sections are designed to minimize pressure requirements and optimize hydraulic efficiency, and the mill section has a removable center assembly which allows effective well control when pulling the underreamer out of a "live" well filled with a gas, such as methane.
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