Nuclear magnetic logging instrument centralizing device with rotational degree of freedom

Abstract

A nuclear magnetic logging instrument centralizing device with rotational degree of freedom belongs to the field of logging instrument centralizing devices and comprises a centralizing body, centralizing prisms, a split limiting sleeve and a split threaded sleeve, the centralizing body is provided with connecting internal threads, the centralizing prisms are arranged on the outer circumferential surface of the centralizing body, and the split limiting sleeve is sleeved with the split threaded sleeve. The split limiting sleeve and the split threaded sleeve are circular sleeve bodies formed by combining split tile sleeves, an inlay flange is arranged on the inner side arc surface of the split limiting sleeve, a hanging convex ring is arranged on the outer side arc surface of the split limiting sleeve, a connecting ring groove is formed in the inner side arc surface of the split threaded sleeve, and a connecting external thread is arranged on the outer side arc surface of the split threaded sleeve; the centralizing body can be hung on the nuclear magnetic logging instrument through the structural cooperation of the split limiting sleeve and the nuclear magnetic logging instrument, and the rotational degree of freedom of the centralizing body relative to the nuclear magnetic logging instrument can be established through the structural cooperation of the split threaded sleeve and the split limiting sleeve. The centralizing body keeps a dynamic centering centralizing state during self-adaptive rotation, meanwhile, the space posture and the motion state of the nuclear magnetic logging instrument cannot be disturbed and influenced, and the logging precision is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of logging instrument straightening devices, specifically to a nuclear magnetic resonance logging instrument straightening device with rotational degrees of freedom. Background Technology

[0002] Nuclear magnetic resonance (NMR) logging is a technique that utilizes the magnetic resonance phenomenon of hydrogen nuclei in a magnetic field. By analyzing the signals generated during proton relaxation, it obtains parameters such as porosity, permeability, and fluid saturation of rock samples or formations. Based on the different target objects and application environments, specialized testing equipment can be mainly divided into three categories: portable NMR logging tools, field-mobile full-diameter NMR equipment, and NMR logging-while-drilling (LWD) tools. LWD tools are installed in the drill string assembly and run downhole to measure NMR parameters in the formation in real time during drilling. To ensure the accuracy of the obtained NMR data, in addition to regularly calibrating and maintaining the equipment according to testing standards to maintain its functional accuracy, the testing process must also strictly adhere to technical specifications to ensure operational accuracy. Maintaining the NWD tool centered and preventing axial rotation during NMR testing is fundamental to ensuring data accuracy. Therefore, in actual production, dedicated centering devices are usually required when using NWD tools to enhance stability. While the reliability of the centralizing device is important, current technologies utilize radially horizontally bolted centralizing devices that are securely connected to the antenna collar of the NMR logging-while-drilling (LMD) instrument. During logging, if the centralizing device is subjected to protruding structures on the wellbore or unbalanced forces in non-vertical sections, it is highly likely to exhibit adaptive deflection. Since the centralizing device and the LMD instrument are integrally fixed and have no relative degrees of freedom, this deflection will inevitably cause the LMD instrument to rotate axially, negatively impacting the accuracy of NMR detection. Therefore, it is necessary to research and improve the centralizing devices currently used in production to further enhance the accuracy of NMR detection in oilfields. Utility Model Content

[0003] The purpose of this invention is to provide a centralizing device for nuclear magnetic resonance (NMR) logging instruments with rotational degrees of freedom, so that the centralizing device has axial rotational freedom relative to the NMR logging instrument, thereby avoiding the NMR logging instrument from adaptively rotating with the centralizing device, improving the accuracy of NMR detection, and ensuring efficient oilfield production.

[0004] A centralizing device for a nuclear magnetic resonance (NMR) logging instrument with rotational degrees of freedom includes: a centralizing body, a centralizing prism, a split limiting sleeve, and a split threaded sleeve. The centralizing body is a cylindrical sleeve with an inner hole corresponding to the outer diameter of the NMR logging instrument antenna drill collar, and has an internal thread at its upper end. The centralizing prism is provided on the outer circumferential surface of the centralizing body, and the centralizing prism is evenly distributed along the outer circumferential surface of the centralizing body. The split limiting sleeve and the split threaded sleeve are both circular sleeves composed of split semi-circular arc-shaped sleeves. An inwardly protruding inlay flange is provided on the inner arc surface of the split limiting sleeve. The inlay flange corresponds to and can be fitted into the chuck groove structure on the NMR logging instrument antenna drill collar. An outwardly protruding annular hooking ring is provided on the outer arc surface of the split limiting sleeve. A concave connecting annular groove is formed on the inner arc surface of the split threaded sleeve. The connecting annular groove corresponds to the hooking convex ring structure. Through the annular groove insert fit between the two, the split threaded sleeve fitted on the outer circumferential surface of the split limiting sleeve can be hooked onto the split limiting sleeve, and the split threaded sleeve maintains a rotational degree of freedom relative to the split limiting sleeve. A connecting external thread is provided on the outer arc surface of the split threaded sleeve. The connecting external thread corresponds to the connecting internal thread structure at the upper end of the centering body. The centering body is fixedly connected to the nuclear magnetic logging instrument through the thread fit between them.

[0005] The aforementioned nuclear magnetic resonance logging instrument centering device with rotational freedom preferably has a sliding bearing plate installed between the axial bearing surfaces of the annular groove insert fitting structure between the split limiting sleeve and the split threaded sleeve, so that the split threaded sleeve is hooked onto the split limiting sleeve through the sliding bearing plate, thereby reducing the motion friction resistance between the split limiting sleeve and the split threaded sleeve, and improving the flexibility and reliability of the centering body's adaptive rotation relative to the nuclear magnetic resonance logging instrument.

[0006] The aforementioned nuclear magnetic resonance logging instrument centering device with rotational degrees of freedom preferably has a through-hole on the centering body that penetrates the sidewall. This improves the flow of well fluid in the gap space between the inner circumferential surface of the centering body and the outer circumferential surface of the nuclear magnetic resonance logging instrument antenna collar, eliminates the pressure difference between the inner and outer circumferential surfaces of the centering body caused by mud and well fluid, and also helps to flush away impurities and debris deposited in the gap space, further reducing the frictional resistance of the centering body relative to the nuclear magnetic resonance logging instrument during rotation.

[0007] The aforementioned nuclear magnetic resonance (NMR) logging instrument centering device, which has rotational degrees of freedom, requires the use of a chuck slot on the antenna drill collar during the connection and installation of the NMR logging instrument and its auxiliary systems. Since the chuck slot cannot be continuously occupied before the NMR logging instrument is deployed into the well, it is preferable to have a through-wall process screw hole on the circumferential surface of the centering body, with a matching fastening screw installed. Before assembling the NMR logging instrument and its auxiliary systems, the centering body can be temporarily fixed to the NMR logging instrument by tightening the fastening screw. After the connection and installation of the NMR logging instrument and its auxiliary systems are completed, the split limiting sleeve and the split threaded sleeve can be sequentially assembled and installed on the chuck slot at the wellhead. Then, the fastening screw is loosened from the NMR logging instrument, and the centering body is axially moved to connect to the split threaded sleeve. After connection, the NMR logging instrument can be deployed into the well for logging operations.

[0008] The aforementioned nuclear magnetic resonance logging instrument centering device with rotational degrees of freedom preferably has an inlay groove on the outer circumferential surface of the centering body. The inlay groove corresponds to the structure and position of the centering prism, so that the centering prism can be fitted into the inlay groove and detachably fixed to the centering body. This facilitates timely and repeated replacement of the worn and damaged centering prism, ensuring continuous use of the centering body, reducing production costs, and improving economic efficiency.

[0009] The beneficial effect of this utility model is that it provides a centralizing device for nuclear magnetic resonance (NMR) logging instruments with rotational degrees of freedom. Taking advantage of the structural feature of the antenna drill collar of the NMR logging instrument having a chuck groove on its outer circumference, it employs a combination of a split limiting sleeve and a split threaded sleeve. On one hand, the structural fit between the split limiting sleeve and the antenna drill collar allows the centralizing body to be attached to the NMR logging instrument. On the other hand, the structural fit between the split threaded sleeve and the split limiting sleeve establishes a rotational degree of freedom for the split threaded sleeve relative to the split limiting sleeve, giving the centralizing body, fixedly connected to the split threaded sleeve, a rotational degree of freedom relative to the NMR logging instrument. During NMR logging operations, the NMR logging instrument... When the centering device on the instrument is obstructed by the well wall, the centering body can adaptively adjust itself by self-rotation. By adjusting the arrangement of the centering prisms on the circumference of the cross section, the arrangement orientation of the centering prisms is adapted to the well wall structure. Since the centering body has the degree of freedom of axial rotation relative to the NMR logging instrument, the adaptive rotation of the centering body can maintain its own dynamic centering and centering state, but will not interfere with the downhole spatial attitude and motion state of the NMR logging instrument. That is, it will not affect the centering effect of the NMR logging instrument, nor will it cause the NMR logging instrument to rotate axially, effectively ensuring the detection accuracy of NMR logging. Attached Figure Description

[0010] Figure 1 This is a front view of the centralizer structure of a nuclear magnetic resonance logging device with rotational degrees of freedom.

[0011] Figure 2 This is a top view of the centralizer structure of a nuclear magnetic resonance logging device with rotational degrees of freedom.

[0012] Figure 3 This is a side cross-sectional view of the centralizer of a nuclear magnetic resonance logging device with rotational degrees of freedom.

[0013] Figure 4 for Figure 3 Enlarged view of section I in the middle.

[0014] Among them: 1 is the straightening body, 2 is the straightening prism, 3 is the split limiting sleeve, 4 is the split threaded sleeve, 5 is the sliding bearing plate, 6 is the fastening screw, 7 is the inlaid flange, 8 is the hanging protrusion ring, 9 is the connecting hole, 10 is the nuclear magnetic logging instrument, 11 is the connecting hole, 12 is the first bolt, and 13 is the second bolt. Detailed Implementation

[0015] Furthermore, the technical solution for which protection is sought in this utility model will be described in detail with reference to specific embodiments and accompanying drawings.

[0016] A centralizing device for nuclear magnetic resonance logging instruments with rotational degrees of freedom, such as... Figures 1 to 4As shown, the device comprises a straightening body 1, straightening prisms 2, split limiting sleeves 3, split threaded sleeves 4, and sliding bearing plates 5. The upper end of the straightening body 1 has an internal thread, and six axially arranged strip-shaped inlay grooves are formed on its outer circumferential surface. These grooves are evenly distributed across the circumferential cross-section. The straightening prisms 2 are respectively fitted into the grooves and detachably fixed to the straightening body 1 using bolts. Simultaneously, 18 through-holes 11, which are axially arranged strip-shaped holes, are evenly arranged on the circumferential cross-section of the straightening body 1, alternating with the inlay grooves. The opening of 11 also helps to reduce the weight of the straightening body 1. Four process screw holes are also provided on the lower part of the outer circumferential surface of the straightening body 1, and fastening screws 6 are installed accordingly. The process screw holes are evenly distributed on the circumferential cross-section of the straightening body 1 to temporarily fix the straightening body 1. The split limiting sleeve 3 and the split threaded sleeve 4 are both circular sleeves composed of split semi-circular arc-shaped sleeves. The combination structure of the split limiting sleeve 3 and the split threaded sleeve 4 is locked and fixed using the first bolt 12 and the second bolt 13 respectively. Two symmetrical inwardly protruding inlaid flanges 7 are provided at the upper end of the inner arc surface of the split limiting sleeve 3, and an outwardly protruding annular hanging ring 8 is provided on the outer arc surface. A concave connecting ring groove, corresponding to the structure of the hooking protrusion 8, is formed on the inner arc surface of the split threaded sleeve 4. The sliding bearing plate 5 is fastened to the lower annular surface of the connecting ring groove with screws. The connecting ring groove can be fitted onto the hooking protrusion 8 to hook the split threaded sleeve 4 onto the opening limiting sleeve 3, so that the split threaded sleeve 4 has circumferential rotational freedom relative to the split limiting sleeve 3 and maintains a small rotational frictional resistance. At the same time, an external connecting thread is provided on the outer arc surface of the split threaded sleeve 4, so that the split threaded sleeve 4 can be threadedly connected to the centering body 1, thereby suspending the centering body 1 on the nuclear magnetic logging instrument 10.

[0017] In oilfield nuclear magnetic resonance logging operations, the centralizing device for a nuclear magnetic resonance logging instrument with rotational freedom described in this embodiment is used as follows: First, the centralizing prisms 2 are sequentially inserted into the corresponding slots on the centralizing body 1, and the centralizing prisms 2 are fastened to the centralizing body 1 using mounting bolts. After confirming that the centralizing prisms 2 are securely connected, the centralizing body 1 is fitted onto the lower part of the chuck slot on the 10-antenna drill collar of the nuclear magnetic resonance logging instrument. Four fastening screws 6 are respectively installed in the process screw holes on the centralizing body 1 and tightened sequentially. The centralizing body 1 is then secured using the fastening screws 6. Body 1 is temporarily pre-secured to the antenna drill collar to ensure that the alignment of body 1 will not affect the hoisting operation of the nuclear magnetic resonance logging instrument and its auxiliary systems. Then, the nuclear magnetic resonance logging instrument and its auxiliary systems are connected and installed according to standard operating procedures. After the connection and installation are completed, the nuclear magnetic resonance logging instrument is first lowered to the wellhead, so that the chuck groove on the antenna drill collar is in the wellhead working area. The combination structure of the split limiting sleeve 3 and the split threaded sleeve 4 is then locked and fixed in sequence using the first bolt 12 and the second bolt 13. Through the interlocking engagement between the inlaid flange 7 on the split limiting sleeve 3 and the chuck groove, the split... The limiting sleeve 3 is fixedly mounted on the antenna drill collar. Through the fitting between the hooking protrusion 8 on the split limiting sleeve 3 and the connecting annular groove on the split threaded sleeve 4, the split threaded sleeve 4 is mounted on the split limiting sleeve 3 and maintains a degree of rotational freedom relative to the split limiting sleeve 3. Then, the fastening screws 6 mounted on the straightening body 1 are loosened, detaching the fastening connection between the straightening body 1 and the antenna drill collar. The straightening body 1 is then raised to mate with the lower end of the split threaded sleeve 4. A hook wrench is used to rotate the split threaded sleeve 4 to mate with the straightening body. The body 1 is fixedly connected by a threaded fit. After the connection is secure, the nuclear magnetic resonance logging instrument can continue to be sent down for logging operations. During the logging operation, the nuclear magnetic resonance logging instrument straightening device with rotational degree of freedom can straighten the nuclear magnetic resonance logging instrument. Before starting the logging operation, it is necessary to remove all four fastening screws 6 from the straightening body 1 to avoid the fastening screws 6 accidentally locking the straightening body 1 and restricting the rotational degree of freedom of the straightening body 1 relative to the nuclear magnetic resonance logging instrument 10, thereby limiting the full function of the nuclear magnetic resonance logging instrument straightening device with rotational degree of freedom.

Claims

1. A centralizing device for a nuclear magnetic resonance logging instrument with rotational degrees of freedom, characterized in that, include: The system comprises a centering body (1), a centering prism (2), a split limiting sleeve (3), and a split threaded sleeve (4). The centering body (1) is a cylindrical sleeve with an inner hole that corresponds to the outer diameter of the drill collar of the nuclear magnetic logging instrument (10). An internal thread is provided at the upper end. The centering prism (2) is provided on the outer circumference of the centering body (1). The centering prism (2) is evenly distributed along the outer circumference of the centering body (1). The split limiting sleeve (3)... Both the split sleeve (3) and the split threaded sleeve (4) are circular sleeves composed of split semi-circular arc-shaped sleeves. An inwardly protruding inlay flange (7) is provided on the inner arc surface of the split limiting sleeve (3). The inlay flange (7) corresponds to the chuck groove structure opened on the antenna drill collar of the nuclear magnetic logging instrument (10) and can be fitted into the chuck groove. An outwardly protruding annular hooking ring (8) is provided on the outer arc surface of the split limiting sleeve (3). A concave connecting ring groove is provided on the inner arc surface of the split threaded sleeve (4). The connecting ring groove corresponds to the structure of the hooking convex ring (8). Through the ring groove insert between the two, the split threaded sleeve (4) fitted on the outer circumferential surface of the split limiting sleeve (3) can be hooked onto the split limiting sleeve (3) and the split threaded sleeve (4) can maintain a rotational degree of freedom relative to the split limiting sleeve (3). A connecting external thread is provided on the outer arc surface of the split threaded sleeve (4). The connecting external thread corresponds to the connecting internal thread structure at the upper end of the centering body (1) and is fixedly connected through the threaded engagement between them. The centering body (1) is suspended and connected to the nuclear magnetic logging instrument (10).

2. The nuclear magnetic resonance logging instrument straightening device with rotational degree of freedom as described in claim 1, characterized in that: A sliding bearing plate (5) is installed between the axial bearing surfaces of the annular groove sleeve fit structure between the split limiting sleeve (3) and the split threaded sleeve (4), so that the split threaded sleeve (4) is hooked onto the split limiting sleeve (3) through the sliding bearing plate (5).

3. A nuclear magnetic resonance logging instrument straightening device with rotational degree of freedom as described in claim 1 or 2, characterized in that: A through hole is provided on the straightening body (1) to penetrate the side wall.

4. The nuclear magnetic resonance logging instrument straightening device with rotational degree of freedom as described in claim 3, characterized in that: Process screw holes that penetrate the sidewalls are provided on the circumferential surface of the straightening body (1), and fastening screws (6) are installed accordingly.

5. The nuclear magnetic resonance logging instrument centering device with rotational degree of freedom as described in claim 4, characterized in that: An inlay groove is provided on the outer circumferential surface of the straightening body (1). The inlay groove corresponds to the structure and setting position of the straightening prism (2), so that the straightening prism (2) can be inlaid in the inlay groove and fixedly connected to the straightening body (1) in a detachable manner.

Images