Downhole perforating gun tube and components
A gun tube for a downhole perforating gun assembly includes a body having a cavity and one or more weights in the cavity. Gravity acts on the weights, which causes the tube body to rotate around its longitudinal axis so the weights are adjacent the lower part of the wellbore in which the gun assembly is positioned when oriented horizontally. This position shape charges in the gun tube in a desired position prior to the shape charges being fired. The gun tube may also include one or more end connectors with electrical contacts having a first, extended position, and a second, contracted position, and/or end connectors that can be assembled by hand without the use of tools.
1 . A downhole perforating gun system, comprising:
an outer body configured to connect to the downhole perforating gun system;
an inner body disposed inside the outer body and having at least one explosive charge receptacle, the inner body having a longitudinal axis and having a center of gravity offset from the longitudinal axis of the inner body;
a first rotational assembly comprising a first structure and a second structure, the first and second structures being rotatable relative to one another, the first structure engaged with at least a portion the inner body, the second structure engaged with at least a portion of the outer body, the first rotational assembly rotatably supporting the inner body relative to the outer body and being configured to permit radial orientation of the inner body about the longitudinal axis relative to the outer body based on the center of gravity of the inner body; and
an electrical connection having a first portion and a second portion, the first portion being configured to conduct electrical communication of the downhole perforating gun system through the first rotational assembly, the second portion being configured to conduct the electrical communication at least partially through the inner body.
2 . The downhole perforating gun system of claim 1 , wherein the first structure of the first rotational assembly comprises a first housing member of a bearing housing; wherein the second structure of the first rotational assembly comprises a second housing member of the bearing housing; and wherein the first rotational assembly comprises one or more bearings disposed between the first and second housing members of the bearing housing.
3 . The downhole perforating gun system of claim 1 , wherein the first portion of the electrical connection comprises a first electrical contact being associated with the inner body and being biased between an extended position and a contracted position.
4 . The downhole perforating gun system of claim 3 , wherein the second portion of the electrical connection comprises one or more wires in electrical communication with the first electrical contact and being configured to conduct the electrical communication at least partially through the inner body.
5 . The downhole perforating gun system of claim 1 , wherein the outer body comprises:
an outer casing having first and second ends and defining an interior therein, the inner body disposed inside the interior of the outer casing; and
a first sub-assembly configured to connect to the first end of the outer casing,
wherein the second structure of the first rotational assembly is engaged with at least a portion of the first sub-assembly.
6 . The downhole perforating gun system of claim 1 , wherein the outer body comprises:
an outer casing having first and second ends and defining an interior therein, the inner body disposed inside the interior of the outer casing; and
a first sub-assembly configured to connect to the first end of the outer casing,
wherein the second structure of the first rotational assembly is engaged with at least a portion of the outer casing.
7 . The downhole perforating gun system of claim 6 , wherein the second structure of the first rotational assembly is further engaged with at least a portion of the first sub-assembly.
8 . The downhole perforating gun system of claim 1 , wherein the first portion of the electrical connection comprises a first electrical contact associated with the inner body; and wherein the outer body comprises:
an outer casing having first and second ends and defining an interior therein, the inner body disposed inside the interior of the outer casing; and
a first sub-assembly configured to connect to the first end of the outer casing, the first sub-assembly having a second electrical contact of the electrical connection, the second electrical contact being configured to electrically contact the first electrical contact.
9 . The downhole perforating gun system of claim 8 , wherein at least one of:
at least a portion of the first electrical contact is biased relative to the second electrical contact; and
at least a portion of the second electrical contact is biased relative to the first electrical contact.
10 . The downhole perforating gun system of claim 8 , wherein:
the first electrical contact is associated with the inner body toward the first end of the outer casing;
the electrical connection comprises a third electrical contact associated with the inner body toward the second end of the outer casing; and
the outer body further comprises a second sub-assembly configured to connect to the second end of the outer casing, the second sub-assembly having a fourth electrical contact of the electrical connection, the fourth electrical contact being configured to electrically contact the third electrical contact.
11 . The downhole perforating gun system of claim 10 , wherein at least one of:
at least a portion of the third electrical contact is biased relative to the fourth electrical contact; and
at least a portion of the fourth electrical contact is biased relative to the third electrical contact.
12 . The downhole perforating gun system of claim 1 , wherein the inner body comprises one or more weight elements disposed on the inner body and providing the inner body with the center of gravity offset from the longitudinal axis of the inner body.
13 . The downhole perforating gun system of claim 12 , wherein the one or more weight elements are disposed at one or more predefined locations on the inner body and are retained by one or more tabs to the inner body.
14 . The downhole perforating gun system of claim 1 , wherein the first rotational assembly rotatably supports a first end of the inner body; wherein the downhole perforating gun system further comprises a second rotational assembly rotatably supporting a second end of the inner body relative to the outer body; and wherein the first portion of the electrical connection is configured to conduct the electrical communication of the downhole perforating gun system through the first rotational assembly.
15 . The downhole perforating gun system of claim 1 , further comprising an orientation sensor coupled to the downhole perforating gun system and configured to measure one or more positions of the downhole perforating gun system in a wellbore.
16 . The downhole perforating gun system of claim 15 , wherein the orientation sensor comprises a degree of freedom sensor, an accelerometer, a gyroscope, a magnetometer, or a combination thereof.
17 . The downhole perforating gun system of claim 15 , wherein the one or more positions include at least one of rotation, direction, and inclination of one of the outer body and the inner body relative to a vertical axis that is parallel to gravitational force.
18 . A downhole perforating gun system, comprising:
an outer body comprising an outer casing and a first sub-assembly, the outer casing having first and second ends and defining an interior therein, the first sub-assembly being configured to connect the first end of the outer casing to the downhole perforating gun system;
an inner body disposed in the interior of the outer casing and having at least one explosive charge receptacle, the inner body having a longitudinal axis and having a center of gravity offset from the longitudinal axis of the inner body;
a first rotational assembly comprising a first structure and a second structure, the first and second structures being rotatable relative to one another, the first structure engaged with at least a portion of the inner body, the second structure engaged with at least a portion of the first sub-assembly, the first rotational assembly rotatably supporting the inner body relative to the outer body and being configured to permit radial orientation of the inner body about the longitudinal axis relative to the outer body based on the center of gravity of the inner body; and
an electrical connection being configured to conduct electrical communication of the downhole perforating gun system through the first rotational assembly, the electrical connection comprising:
a first electrical conductor associated with the inner body and being configured to conduct the electrical communication at least partially through the inner body, and
a second electrical conductor associated with the first sub-assembly, the second electrical conductor being in electrical contact with the first electrical conductor.
19 . The downhole perforating gun system of claim 18 , wherein the first structure of the first rotational assembly comprises a first housing member of a bearing housing; wherein the second structure of the first rotational assembly comprises a second housing member of the bearing housing; and wherein the first rotational assembly comprises one or more bearings disposed between the first and second housing members of the bearing housing.
20 . A downhole perforating gun system, comprising:
an outer body comprising an outer casing and a first sub-assembly, the outer casing having first and second ends and defining an interior therein, the first sub-assembly being configured to connect the first end of the outer casing to the downhole perforating gun system;
an inner body disposed in the interior of the outer casing, the inner body having a longitudinal axis and having at least one explosive charge receptacle;
one or more weight elements disposed on the inner body and providing the inner body with a center of gravity offset from the longitudinal axis of the inner body;
a first rotational assembly comprising a first structure and a second structure, the first and second structures being rotatable relative to one another, the first structure engaged with at least a portion of the inner body, the second structure engaged with at least a portion of the first sub-assembly, the first rotational assembly rotatably supporting the inner body relative to the outer body and being configured to permit radial orientation of the inner body about the longitudinal axis relative to the outer body based on the center of gravity provided by the one or more weight elements; and
an electrical connection being configured to conduct electrical communication of the downhole perforating gun system through the first rotational assembly, the electrical connection comprising:
a first electrical contact associated with the inner body and being configured to conduct the electrical communication at least partially through the inner body, and
a second electrical contact associated with the first sub-assembly, the second electrical contact being in electrical contact with the first electrical contact.