CN-121994127-A - Device and method for measuring thread parameters of petroleum drilling tool

CN121994127ACN 121994127 ACN121994127 ACN 121994127ACN-121994127-A

Abstract

The invention discloses a device for measuring screw thread parameters of a petroleum drilling tool, which comprises a hardware part and a software part, wherein the hardware part comprises a light source and a camera, the light source and the camera are positioned on the same axis, and are called as a double telecentric structure, the camera is connected with a CCD camera, and the CCD camera is connected with a processor. The invention also discloses a method for measuring the thread parameters of the petroleum drilling tool, which comprises the steps of 1, collecting the thread profile images of three sections of the petroleum drilling tool, 2, determining the accurate position in the L ft section and measuring the length. The invention belongs to the technical field of thread detection of petroleum drilling tools, and solves the problems that in the prior art, L ft is low in measurement efficiency due to the fact that a plurality of measuring devices are used, and measurement accuracy is affected due to the fact that magnitude transmission errors exist, and measurement results are subjective.

Inventors

BAI XIAOLIANG
YU ZHI
FU ZHENGUO
SHEN QI
AI YUFENG
WEI ZUNYI
FENG NA

Assignees

中国石油天然气集团有限公司
中国石油集团工程材料研究院有限公司

Dates

Publication Date: 20260508
Application Date: 20241108

Claims (8)

1. The device for measuring the screw thread parameters of the petroleum drilling tool is characterized by comprising a hardware part and a software part, wherein the hardware part comprises a light source (1) and a camera (3), the light source (1) and the camera (3) are positioned on the same axis, and are of a double telecentric structure, the camera (3) is connected with a CCD type camera, and the CCD type camera is connected with a processor.
2. The device for measuring thread parameters of petroleum drilling tools according to claim 1, wherein the light source (1) is capable of emitting parallel light beams to irradiate the detected part.
3. The device for measuring thread parameters of petroleum drilling tool according to claim 1, wherein the software part is preset in the processor, can complete the data operation processing of the collected thread profile, and compares the calculation result of the thread profile with the drawing size of the detected part to determine whether the use state of the detected part is qualified.
4. The method for measuring the screw thread parameters of the petroleum drilling tool is characterized by comprising the following steps of: step 1, acquiring thread profile images of three sections of a petroleum drilling tool; Step 2, determining the accurate position in the L ft interval and measuring the length to obtain the accurate length of L ft , L ft is the distance from the shoulder to the first complete external thread, and L ft is measured in two steps, the interval in which L ft is located is determined first, then the exact position in the interval of L ft is determined and the length is measured.
5. The method for measuring thread parameters of a petroleum drilling tool according to claim 4, wherein in step 1, the specific process is as follows: The petroleum drilling tool (2) is placed at the center line of the light source (1) and the camera (3), after the thread profile is irradiated by the light source, CCD imaging is completed by the camera (3), and a complete thread profile diagram is formed; During acquisition, firstly acquiring a thread profile image of a section A of the petroleum drilling tool (2), then rotating the petroleum drilling tool (2) by 60 degrees, acquiring a thread profile image of a section B, and then rotating the petroleum drilling tool (2) by 60 degrees again, and acquiring a thread profile image of a section C.
6. The method for measuring thread parameters of a petroleum drilling tool according to claim 4, wherein in step 2, the interval in which L ft is located is determined, and the specific process is as follows: establishing a pixel coordinate system for the thread profile image acquired in the step 1, selecting the root of the complete thread of the petroleum drilling tool as a data point, and fitting a straight line by adopting a least square method; Defining a group of virtual spheres with radius r, which are closely attached to tooth sides of two sides of a thread, and calculating the fitting linear distance from the circle center of the sphere to a complete thread section, wherein the distance from the circle center of the sphere to the fitting linear is r in the complete thread section, and the distance from the circle center of the sphere to the fitting linear is larger than r at the beginning of tool withdrawal and gradually increases along with tool withdrawal; And comparing the sizes of X 1 、X 2 、X 3 、X 4 、X 5 、X 6 according to the representations of the six partitions to obtain the section where L ft is located.
7. The method for measuring thread parameters of a petroleum drilling tool according to claim 6, wherein the three conditions of the variation of X are as follows: First, the thread is complete before reaching the L ft position, the variation of the section is ; Second, after reaching the L ft position, the variation of this segment interval is the ratio of 60 ° interval in one turn, namely: ; thirdly, since L ft is included, the amount of change in the interval of this segment is: 。
8. the method for measuring thread parameters of a petroleum drilling tool according to claim 4, wherein in the step 2, the precise length of L ft is obtained by the following steps: Assuming that L ft is in the intervals of A 1 and B 1 , the angle of L ft to B 1 is theta, the distance from the first virtual sphere to the fitting straight line is not 0, the adjacent thread crest in the small end direction is the position of the complete thread of the first tooth, the thread profile of the section at the position L ft comprises the virtual sphere and the fitting straight line, the distance from the thread end face to the middle diameter of the thread is L, the thread cone angle is beta, the difference between the distance from the section of B 1 to the L 2 ,L ft position L and the distance from the section of B 1 to the L 2 position L is shown as the formula (4): ,(4) Since the thread has a taper angle T and the distance between adjacent thread crests is a pitch P, the variation Δh of adjacent thread heights is shown in formula (5): ,(5) Assuming that the taper angle of the complete thread segment is T 1 and the taper angle of the incomplete thread segment is T 2 due to the tool withdrawal, the height change of the adjacent tooth from the complete thread segment to L ft in the interval (A 1 ,B 1 ) is as shown in the following formula (6): ,(6) The height change of adjacent teeth after the L ft position is: ,(7) Since in the complete thread segment the taper angle T 1 = β, substituting T 1 with β, combining equation (4), equation (6), equation (7), the exact length of L ft is obtained as shown in the following equation: 。

Description

Device and method for measuring thread parameters of petroleum drilling tool Technical Field The invention belongs to the technical field of petroleum drilling tool thread detection, relates to a petroleum drilling tool thread parameter measuring device and also relates to a petroleum drilling tool thread parameter measuring method. Background In order to explore deep oil and gas resources, a petroleum drilling tool is required to be used for drilling operation, and when the petroleum drilling tool works underground, a thread part connected with a petroleum drilling tool part is extremely easy to crack and break due to long-term stretching and torsion states. In order to ensure the reliability and durability of the threaded connection of the petroleum drilling tool and ensure the safety of drilling operation, the threaded parameter of the petroleum drilling tool needs to be accurately checked, and L ft is one of the important parameters of the threaded connection of the petroleum drilling tool. The standard API SPEC 7-2 specifies that L ft is the distance from the shoulder to the first complete external thread and that L ft is too long, which can affect the overall strength of the connection, causing excessive stress concentration when the joint is subjected to strong external forces, causing the oil drilling tool to fracture. At present, when a detector of a petroleum drilling tool manufacturing factory examines a petroleum drilling tool, a thread sample plate gauge is generally adopted to rotate along a thread line to search an intersection point of complete threads and incomplete threads, and then a depth gauge is used to measure the length from a shoulder to the intersection point, so that L ft is measured. The method needs to detect the approximate position of the thread tooth where the intersection point is located by naked eyes of a detector, then rotates a sample plate gauge to determine the position, and then uses a depth gauge to measure. The measurement error exists in the multiple quantity value transmission, and the accuracy of the measurement result is affected to a certain extent. In addition, the operation steps of measuring L ft are complicated, a plurality of measuring devices are needed, and the measuring efficiency depends on the experience and the manipulation of the detecting personnel more. Therefore, there is a need to develop a new device and method for measuring screw thread parameters of petroleum drilling tools, which effectively solve the problem of insufficient accuracy of the measurement results. Disclosure of Invention The invention aims to provide a device for measuring thread parameters of a petroleum drilling tool, which solves the problems that L ft has low measuring efficiency and magnitude transmission errors, influences measuring accuracy and causes subjective measuring results due to the fact that a plurality of measuring devices are used in the prior art. The invention further aims to provide a method for measuring the screw thread parameters of the petroleum drilling tool, which solves the problems of complicated operation steps and insufficient measurement accuracy caused by the use of a plurality of measuring devices in the prior art. The technical proposal adopted by the invention is that the petroleum drilling tool thread parameter measuring device comprises a hardware part and a software part, The hardware part comprises a light source and a camera, wherein the light source and the camera are positioned on the same axis, and are called a double telecentric structure, the camera is connected with a CCD camera, and the CCD camera is connected with a processor. The invention adopts another technical proposal that the method for measuring the thread parameters of the petroleum drilling tool is implemented according to the following steps: step 1, acquiring thread profile images of three sections of a petroleum drilling tool; Step 2, determining the accurate position in the L ft interval and measuring the length to obtain the accurate length of L ft, L ft is the distance from the shoulder to the first complete external thread, and L ft is measured in two steps, the interval in which L ft is located is determined first, then the exact position in the interval of L ft is determined and the length is measured. The device and the method for measuring the thread parameter L ft of the petroleum drilling tool have the advantages of high measuring efficiency, good measuring accuracy and objective measuring result, and realize one-time efficient measurement of the L ft parameter of the petroleum drilling tool. Drawings FIG. 1 is a schematic diagram of a device for measuring thread parameters of a petroleum drilling tool according to the present invention; FIG. 2 is a schematic image acquisition diagram of the method for measuring thread parameters of a petroleum drilling tool according to the present invention; FIG. 3 is a virtual sphere and a fitted straight line on the thr