A downhole tool for use within a wellbore extending into an underground formation includes a wellbore wall disengaging assembly having a tubular string defining a longitudinal axis, and a plurality of longitudinal blades forming a retractable sleeve around the tubular string, the retractable sleeve having a substantially contiguous inner profile in a closed position, and wherein the retractable sleeve is actuated based on an internal pressure in the tubular string proximate to the downhole tool. A method of disengaging a downhole tool from a wall of a wellbore extending into an underground formation includes lowering a wellbore wall disengaging assembly, the assembly comprising a tubular string defining a longitudinal axis, and a plurality of longitudinal blades forming a retractable sleeve around the tubular string, the retractable sleeve having a substantially contiguous inner profile in a closed position, and actuating the retractable sleeve.

A system (100) for positioning a working tool (21) in a wellbore (1). The positioning system (100) comprises a casing element (110) with a marker (111, 112, 113) provided on an inner surface, the marker (111, 112, 113) having a distinct diameter different from the inner diameter of the casing element (110). The system further comprises a positioning tool (120) with a latching element (121, 122) adapted to form a latch (115) with the marker (111, 112, 113), and a force detector (130) adapted to detect an axial latching force (F.sub.L) applied to a tubing string (20) from the latch (115) when the casing element (110) is located within the wellbore (1) and the force detector (130) is located at a surface (2) outside the wellbore (1).

A centralizer includes a centralizer body to be situated at the outer surface of a pipe string in the form of casing, liner, or the like used while drilling, the centralizer body being formed with a plurality of outer centralizer blades arranged in an inclined manner to the longitudinal axis thereof, wherein the centralizer body has an separate split inner tube secured to the pipe string by means of a press fit, and low friction inner surface of the centralizer body and separate center tube facing each other are made from low friction material.

Adjustment of the angle of a bent sub or other steering feature in a drill string relative to a reference angle of a downhole sensor is facilitated by a rotatable coupling between the bent sub and the sensor. The rotatable coupling may be rotated to align the high side with a reference indicium and locked at the set angle. Rows of ceramic balls retained in circumferential channels may be provided to permit rotation while carrying tensile and compressional forces. Calibration of the sensor is facilitated and opportunities for certain measurement errors are eliminated. An embodiment provides a mechanism for locking the rotatable coupling at a desired angle. The embodiment comprises a ring with teeth that engage a downhole portion of the coupling and depressions that engage an uphole portion of the coupling.

A junction box for connecting at least two downhole tools to a section of tubing is disclosed. The junction box is made of a body member defining a first port and a second port, the first port adapted to receive a first portion of a first downhole tool, and the second port adapted to receive a second portion of a second downhole tool, the body member having one or more external surfaces, the first port and the second port having a first end intersecting the one or more external surfaces, a second end positioned within the body member, and first and second lengths extending between the first end and the second end, the first and second lengths being less than lengths of the first downhole tool and the second downhole tool, the body member defining an electric chamber intersecting the first port and the second port within the body member; a first mechanical connection on the first port for securing the first downhole tool; a second mechanical connection on the second port for securing the second downhole tool; a first electric connector installed on the second end of the first port; a second electric connector installed on the second end of the second port; and electric wiring positioned within the electric chamber and connected to the first electric connector and the second electric connector to couple the first electric connector and the second electric connector.

There is provided an underground water pumping pipe assembly, comprising: a first pipe coupled to an underground water motor pump; second to n-th pipes wherein the second pipe is coupled to the first pipe; a packing configured to wrap the first pipe; clamping bands, each band coupled to each first securing portion to fix the packing to the first pipe; and first coupling members to receive therein the first pipe and be coupled to the top and bottom of the packing respectively, wherein each first coupling member has a first member body and first and second guides formed on the body to be vertically arranged to be alternated with each other to define spaces therebetween, wherein an electrical wire and a wire rope for the motor pump extend through the spaces respectively.

A centralizer includes one or more centralizer fins radially extending from a body of the centralizer. The centralizer fins may include one or more chambers extending through the outer surfaces of the centralizer fins. The one or more chambers may change shape in response to a compression force being applied to the centralizer fins to cause the centralizer fins to deform. The centralizer fins may be deformed for installation of the centralizer in a drill collar. The centralizer may also include a split-ring clamp for coupling the centralizer to a drilling tool positioned in a through-bore of the centralizer body. The split-ring clamp may apply a load on the drilling tool in response to an end cap being torqued to an end portion of the centralizer body.

A junction box is disclosed. The junction box is made of a body member defining a first port and a second port, the first port adapted to receive a first portion of a first downhole tool, and the second port adapted to receive a second portion of a second downhole tool, the body member defining an electric chamber intersecting the first port and the second port within the body member; a first mechanical connection on the first port for securing the first downhole tool; a second mechanical connection on the second port for securing the second downhole tool; a first electric connector installed on the first port; a second electric connector installed on the second port; and electric wiring positioned within the electric chamber and connected to the first electric connector and the second electric connector to couple the first electric connector and the second electric connector.

A centralizer includes a centralizer body to be situated at the outer surface of a pipe string in the form of casing, liner, or the like used while drilling, the centralizer body being formed with a plurality of outer centralizer blades arranged in an inclined manner to the longitudinal axis thereof, wherein the centralizer body has an separate split inner tube secured to the pipe string by means of a press fit, and low friction inner surface of the centralizer body and separate center tube facing each other are made from low friction material.

A centralizer includes a centralizer body to be situated at the outer surface of a pipe string in the form of casing, liner, or the like used while drilling, the centralizer body being formed with a plurality of outer centralizer blades arranged in an inclined manner to the longitudinal axis thereof, wherein the centralizer body has an separate split inner tube secured to the pipe string by means of a press fit, and low friction inner surface of the centralizer body and separate center tube facing each other are made from low friction material.