Abstract: 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.

Abstract: 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.

Abstract: An apparatus for use down a bore hole to reduce the viscosity of a hydrocarbon-containing fluid in the bore hole. The apparatus includes a housing having a size for disposition in the bore hole. At least one ultrasonic transducer is carried by the housing. The ultrasonic transducer preferably has an active element changeable from a first shape to a second shape in the presence of an electromagnetic field. An electromagnetic field is provided through at least a portion of the active element to change the shape of the active element. An acoustic element is coupled to the active element for providing ultrasonic energy to the hydrocarbon-containing fluid in the bore hole. A method for reducing the viscosity of a hydrocarbon-containing fluid in a bore hole is additionally provided.

Abstract: 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.

Abstract: 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.