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CN-121578392-B - Density logging instrument structure and assembling method

CN121578392BCN 121578392 BCN121578392 BCN 121578392BCN-121578392-B

Abstract

The application relates to the technical field of logging equipment, in particular to a density logging instrument structure and an assembling method, the density logging instrument structure comprises a logging instrument shell, a cylinder and a gravity center deflection part, wherein the gravity center deflection part deflects the gravity center of the shell to one side of a well wall and is internally provided with a containing cavity, a shielding body is arranged in the cavity, the shielding body is provided with a first mounting hole and a radiation hole for mounting a radiation source, a radiation source protection piece is arranged in the radiation hole, the gravity center deflection part is provided with a protection cover plate, and the radiation window cover plate is opposite to the radiation hole; the method for assembling the structure is also included, such as the steps of fixing the shielding body, plugging the protecting piece, installing the radioactive source, installing the protecting cover plate and the like. The application achieves the technical effects that the gravity center of the logging instrument structure is deviated to the side of the well wall, the contact measurement with the well wall surface is convenient, the assembly method is safe and convenient, and the radioactive source can be effectively protected.

Inventors

  • LU HONGYANG
  • CHEN SHUBO
  • GONG LIXIAO

Assignees

  • 依拿威特科技开发(北京)有限公司

Dates

Publication Date
20260505
Application Date
20260127

Claims (8)

  1. 1. A structure of a density logging instrument, characterized by comprising the following steps: The well logging instrument shell (1) comprises a column body (11) and a gravity center deflection part (12), wherein the gravity center deflection part (12) is arranged on one side of the column body (11), the gravity center deflection part (12) is used for deflecting the gravity center of the well logging instrument shell (1) to one side of a well wall, a containing cavity (121) is formed in the gravity center deflection part (12), a shielding body (2) is arranged in the containing cavity (121), a first mounting hole (21) for mounting a radioactive source (4) and a radiation hole (22) are formed in the side wall of the shielding body (2), the radiation hole (22) is communicated with the first mounting hole (21), a radiation source protection piece (23) is arranged in the radiation hole (22), a protection cover plate (3) is arranged on one side, far away from the column body (11), of the protection cover plate (3) is provided with a ray window cover plate (31), the ray window cover plate (31) is arranged opposite to the radiation hole (22), and the deflection part (12) is far away from the side of the column body (11), and the protection cover plate (122) can be attached to the surface of the well wall (122), and the same arc surface (122) can be attached to the arc surface; The cylinder (11) is a semi-cylinder (111), one side of the semi-cylinder (111) far away from the gravity center deflection part (12) is provided with a semi-arc surface (1111), the gravity center deflection part (12) comprises a plane (123), the plane (123) is connected between the semi-arc surface (1111) and the arc fitting surface (122), and an orifice of the first mounting hole (21) is positioned on one side of the plane (123); The utility model discloses a radiation source, including shield body (2), shield body (2) are close to plane (123), mounting groove (24) with first mounting hole (21) intercommunication, radiation source (4) include fixed part (41), fixed part (41) are arranged in mounting groove (24) and pass through mounting groove (24) with shield body (2) can dismantle and be connected, one side that fixed part (41) deviate from first mounting hole (21) is located within mounting groove (24) notch.
  2. 2. The density logging tool structure according to claim 1, wherein a second mounting hole (25) is formed in one side of the mounting groove (24) away from the fixing portion (41), a connecting hole (26) is formed in the bottom of the mounting groove (24), and a fastener can be inserted into the second mounting hole (25) and the connecting hole (26), wherein the orifice of the second mounting hole (25) is exposed outside the shielding body (2).
  3. 3. A density logging tool arrangement according to claim 1, wherein the first mounting hole (21) extends in a direction perpendicular to the axis of the column (11).
  4. 4. A density tool structure according to claim 1, wherein the radiation holes (22) are arranged obliquely so that the radiation holes (22) are arranged obliquely downwards when the tool structure is placed in a well for measurement.
  5. 5. A density logging tool arrangement according to claim 1, wherein the first mounting hole (21) and the radiation hole (22) are circular holes, the radiation source protector (23) is a sealing plug, one end of the sealing plug close to the first mounting hole (21) is in an arc structure, and the arc structure can be in contact with the radiation source (4).
  6. 6. The density logging tool structure according to claim 1, wherein a horizontal mounting plane (1211) and an inclined mounting plane (1212) are provided on a side of the receiving cavity (121) close to the cavity wall, respectively, the horizontal mounting plane (1211) is horizontally arranged, the inclined mounting plane (1212) is inclined downward, the side wall of the shielding body (2) is attached to the horizontal mounting plane (1211) and the inclined mounting plane (1212), and the shielding body (2) is detachably connected to the gravity center deflection part (12) at the positions of the horizontal mounting plane (1211) and the inclined mounting plane (1212).
  7. 7. A method for assembling a density logging tool structure according to any one of claims 1-6, characterized in that the method comprises the steps of S1, fixing the shielding body (2) on the logging tool shell (1), S2, plugging the radioactive source protector (23) into the radioactive hole (22), S3, placing the radioactive source (4) into the first mounting hole (21) from the side surface of the shielding body (2) and fastening the radioactive source (4) and the shielding body (2), and S4, mounting the protective cover plate (3) on the side, far away from the cylinder (11), of the gravity center deflection portion (12), and completely pressing the radioactive source protector (23) into the radioactive hole (22) through the protective cover plate (3).
  8. 8. The method of assembling a density tool configuration of claim 7 wherein step S3 includes clamping the radiation source (4) with a remote operation tool and placing it into the first mounting hole (21) S31 and tightening the radiation source (4) with the shield (2) with a remote operation tool S32.

Description

Density logging instrument structure and assembling method Technical Field The application relates to the technical field of logging equipment, in particular to a density logging instrument structure and an assembly method. Background The radioactive density logging instrument is a key device in the petroleum logging field and is mainly used for accurately measuring formation density parameters through interaction of rays emitted by a radioactive source and a formation. As oil and gas exploration and development extends to complex formations and deep reservoirs, the requirements on the accuracy of logging data and instrument safety are increasingly stringent. The traditional density logging instrument adopts a source chamber made of tungsten-nickel-iron alloy to wrap a density source, and obtains data through a direct push type logging method. Tungsten nickel iron materials are widely used for their high density and radiation shielding properties, but their non-magnetic nature has buried significant implications in instrument design. In logging operations, the instrument needs to be in close contact with the borehole wall to ensure directional emission of radiation, which results in a long-term high-intensity friction between the source bin and the borehole wall. It is common practice in the industry to load and secure the radiation source by means of open-close source cartridge structures and mechanical fasteners, but such designs have exposed serious drawbacks in complex downhole environments. The contact mode of the source bin (the part for loading the radioactive source) of the existing logging instrument and the well wall has fundamental defects. It is commonly designed with "line contact", i.e. the instrument is attached to the borehole wall with only a narrow line. This design results in a high concentration of all pressures and a sharp increase in contact stress (up to 8-10 times the surface contact). The method has two serious consequences, namely firstly serious abrasion, rapid abrasion of a high-density W-Ni-Fe alloy source bin under high-pressure friction, pollution of a borehole by generated metal scraps and possibility of serious accidents such as sticking of a drill, and secondly inaccurate measurement, and the unstable contact mode enables an instrument to easily slightly shake when moving in a well, so that the quality of signals received by a gamma ray detector is seriously reduced (the signal to noise ratio is deteriorated by more than 15 percent), and the accuracy and the reliability of stratum density data are directly affected. Disclosure of Invention In order to overcome the defects in the prior art, the application provides a density logging instrument structure and an assembly method, and the gravity center deviation part and the circular arc joint surface are arranged to enable the logging instrument to be stably attached to a well wall, reduce the gap between the instrument and the well wall, improve the stability and the accuracy of signals received by a radioactive source to a stratum and a detector, and ensure the reliability and the measurement accuracy of density logging data. The application is realized by the following technical scheme: a density tool structure comprising: The well logging instrument shell comprises a column body and a gravity center deflection part, wherein the gravity center deflection part is arranged on one side of the column body and is used for deflecting the gravity center of the well logging instrument shell to one side of a well wall, and a containing cavity is formed in the gravity center deflection part; the shielding body is arranged in the accommodating cavity, a first mounting hole for mounting a radioactive source and a radiation hole are formed in the side wall of the shielding body, the radiation hole is communicated with the first mounting hole, and a radioactive source protection piece is mounted in the radiation hole; the protection cover plate is arranged on one side of the gravity center deviation part, which is far away from the column body, and is provided with a ray window cover plate which is arranged opposite to the radiation hole; The center of gravity deviation portion is kept away from one side of cylinder establishes to the circular arc binding face, the circular arc binding face can form the face contact with the wall of a well, the face of protection apron with the circular arc binding face is located same cambered surface. By adopting the technical scheme, the eccentric design and the circular arc joint surface ensure that the instrument can be stably and widely stuck to the well wall, and the gap between the instrument and the stratum for mud (drilling fluid) is reduced to the greatest extent. The mud can seriously influence the measurement result of gamma rays, so the density measurement accuracy can be remarkably improved by closely sticking the well. The surface contact (arc joint surface) is more stable when the instru