Abstract: A downhole tool includes a mandrel configured to be coupled to a liner, the mandrel defining a first port and a second port, the first and second ports being axially offset from one another and extending radially through a wall of the mandrel, a slips assembly coupled to the mandrel, an outer cylinder received around the mandrel and configured to transmit an axially-directed force onto the slips assembly, and a retaining assembly positioned radially between the mandrel and the outer cylinder. The retaining assembly has a first configuration that prevents the outer cylinder from moving relative to the mandrel, and a second configuration that permits the outer cylinder to move axially along the mandrel and set the slips assembly. The retaining assembly is configured to actuate from the first configuration to the second configuration in response to a pressure in the first port exceeding a pressure in the second port.

Abstract: A downhole tool includes a mandrel configured to be coupled to a liner, the mandrel defining a first port and a second port, the first and second ports being axially offset from one another and extending radially through a wall of the mandrel, a slips assembly coupled to the mandrel, an outer cylinder received around the mandrel and configured to transmit an axially-directed force onto the slips assembly, and a retaining assembly positioned radially between the mandrel and the outer cylinder. The retaining assembly has a first configuration that prevents the outer cylinder from moving relative to the mandrel, and a second configuration that permits the outer cylinder to move axially along the mandrel and set the slips assembly. The retaining assembly is configured to actuate from the first configuration to the second configuration in response to a pressure in the first port exceeding a pressure in the second port.

Abstract: Methods for forming a portion of a wellbore are provided. The well is drilled from a first selected depth to a second selected depth to form a bore through a surrounding earth formation. A fluid heating apparatus is disposed within the bore on a working string. Fluid is then heated by moving the fluid through the fluid heating apparatus in the wellbore. The process of circulating fluid adjacent the earth formation serves to also heat the surrounding formation so as to increase the fracture gradient. The fluid heating process may be conducted during a drilling procedure. Alternatively, the fluid heating process may be conducted in connection with a liner hanging and cementing process. A fluid flow restrictor is provided along a run-in assembly that serves to warm the fluids as they are circulated. The warm fluids provide convective heat to the surrounding earth formation, thereby reducing the formation's fracture gradient.

Abstract: Methods for forming a portion of a wellbore are provided. The well is drilled from a first selected depth to a second selected depth to form a bore through a surrounding earth formation. A fluid heating apparatus is disposed within the bore on a working string. Fluid is then heated by moving the fluid through the fluid heating apparatus in the wellbore. The process of circulating fluid adjacent the earth formation serves to also heat the surrounding formation so as to increase the fracture gradient. The fluid heating process may be conducted during a drilling procedure. Alternatively, the fluid heating process may be conducted in connection with a liner hanging and cementing process. A fluid flow restrictor is provided along a run-in assembly that serves to warm the fluids as they are circulated. The warm fluids provide convective heat to the surrounding earth formation, thereby reducing the formation's fracture gradient.