A tubing string for detecting annulus sand surface according to electromagnetic induction and its detection method

Abstract

The present invention discloses a pipe string for detecting annular sand surface based on electromagnetic induction and a detection method thereof, belonging to the field of oil well logging technology. According to the principle of electromagnetic induction, a test curve of the annular sand surface position is changed by lowering a magnetic ball, thereby obtaining the annular sand surface position. The annular sand surface position detection can be realized quickly and simply, solving the problem of high requirements for traditional testing process and inconvenient actual operation, and providing a basis for the next step of oil pipe cutting.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum well logging, and particularly relates to a pipe string for detecting annular sand surfaces based on electromagnetic induction and a detection method thereof. Background Art

[0002] During oil well operations, it is often necessary to detect the sand surface at the bottom of the well. Currently, a combined logging instrument is used to detect the sand surface, replacing the work team's sand surface detection. This not only saves time, reduces the workload of workers, and reduces wear on pipes and rods. Existing storage-type combined logging instruments consist of downhole instruments and surface instruments. The downhole instrument is lowered into the well to collect, process, and store downhole logging information. The surface instrument replays and prints the stored logging information, comparing the printed curve with the casing or perforation records to calculate the depth of the sand surface. However, the equipment used in this method—the downhole combined logging instrument, cable winch, and CNC logging instrument—is expensive and requires a large number of operators. Some wells are too small for the CNC logging vehicle to enter, and lowering the cable is difficult in high-pressure wells. Therefore, this method of detecting the sand surface requires high technical requirements and is not easy to operate. At present, most of the underground annular sand surface detection methods are in the exploration and theoretical research stage, and few of them are truly put into practice. There is currently no effective method to quickly and easily realize the detection of the annular sand surface position. Summary of the Invention

[0003] In order to overcome the defects of the existing annular sand surface position detection method, such as high process requirements and inconvenient operation, the present invention provides a pipe string and a detection method for detecting the annular sand surface based on electromagnetic induction. According to the principle of electromagnetic induction, a magnetic ball is lowered to change the test curve of the annular sand surface position, thereby obtaining the annular sand surface position.

[0004] The technical solution adopted by the present invention to solve its technical problems is: a pipe string for detecting annular sand surfaces based on electromagnetic induction, including casing and an oil pipe inserted into the casing, an oil-casing annulus is formed between the casing and the oil pipe, an electromagnetic testing instrument is inserted into the oil pipe, and the electromagnetic testing instrument can move vertically in the oil pipe; a sand surface detection device is inserted into the oil-casing annulus, and the sand surface detection device contains magnetic balls and can release the magnetic balls.

[0005] As a further embodiment of the present invention, an electromagnetic testing instrument is lowered into the oil pipe from an eccentric wellhead via a steel wire a.

[0006] As a further embodiment of the present invention, the electromagnetic testing instrument is an electromagnetic flaw detector.

[0007] As a further embodiment of the present invention, the sand surface detection device is lowered into the oil casing annulus from the eccentric wellhead through the steel wire b.

[0008] As a further embodiment of the present invention, the sand surface detection device includes a ball barrel, a battery pack, a motor, and a baffle.

[0009] The ball cylinder is hollow inside, with a ball placement port at the bottom and a baffle at the ball placement port. The magnetic ball is located inside the ball cylinder.

[0010] The battery pack and the motor are located inside the ball cylinder. The battery pack is connected to the motor to provide power to the motor. The motor output shaft is connected to the baffle to drive the baffle to open or close.

[0011] As a further embodiment of the present invention, the sand surface detection device further includes a centralizer connected to the ball barrel.

[0012] As a further embodiment of the present invention, the battery pack and the motor are respectively mounted on the inner wall of the ball cylinder by screws.

[0013] A detection method for annular sand surface based on electromagnetic induction, using the above-mentioned pipe string, an electromagnetic testing instrument is lowered into the oil pipe, and before the sand surface detection device is lowered, the electromagnetic testing instrument performs a first test to obtain a first test curve; after the first test is completed, a sand surface detection device containing magnetic balls is lowered into the oil casing annulus, and after the sand surface detection device releases the magnetic balls, the electromagnetic testing instrument performs a second test to obtain a second test curve, and the two measured test curves are compared, and the abnormal part of the curve is determined to be the location of the annular sand surface.

[0014] As a further implementation scheme of the present invention, the electromagnetic testing instrument performs a first test, specifically: using an eccentric wellhead to lower the electromagnetic testing instrument into the oil pipe in the well through the steel wire a, after encountering resistance, the electromagnetic testing instrument is powered on and starts working, the electromagnetic testing instrument is lifted and tested to a position 200 meters away from the resistance position, and after the test is completed, the electromagnetic testing instrument is lowered again to the resistance position.

[0015] As a further implementation scheme of the present invention, an eccentric wellhead is used to lower the sand surface detection device into the annulus of the oil casing through the steel wire b. Then the centralizer of the sand surface detection device is opened, and the upper and lower support arms of the centralizer are extended to center the sand surface detection device. The battery pack drives the motor to open the baffle of the sand surface detection device, and the magnetic balls are released from the ball release port. The magnetic balls accumulate on the sand surface of the annulus, and the sand surface detection device is lifted out.

[0016] As a further implementation scheme of the present invention, the electromagnetic testing instrument is tested for the second time, specifically: the electromagnetic testing instrument is powered on again, the electromagnetic testing instrument is lifted up for testing to a position 200 meters away from the obstruction location, and the electromagnetic testing instrument is removed after the test is completed.

[0017] The beneficial effects of the present invention include: according to the principle of electromagnetic induction, the test curve of the annular sand surface position is changed by lowering a magnetic ball, thereby obtaining the annular sand surface position, which can quickly and easily realize the annular sand surface position detection, solves the problem of high requirements for traditional testing technology and inconvenient actual operation, and provides a basis for the next step of oil pipe cutting. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the tubular structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the bottom structure of the sand surface detection device according to embodiment 1 of the present invention;

[0020] Figure 3 It is a comparison diagram of the test curves of the present invention.

[0021] Explanation of the reference numerals in the figure: 1-eccentric wellhead, 2-casing, 3-oil tubing, 4-steel wire a, 5-steel wire b, 6-sand surface detection device, 6.1-centralizer, 6.2-battery pack, 6.3-motor, 6.4-ball cylinder, 6.5-ball release port, 6.6-magnetic ball, 6.7-baffle, 7-annulus sand surface, 8-electromagnetic testing instrument. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that the terms "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used solely to distinguish components and should not be construed as indicating or implying relative importance.

[0024] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Example 1

[0026] A pipe string for detecting annular sand surface based on electromagnetic induction comprises a casing 2 and an oil pipe 3 lowered into one side of the casing 2. An oil-casing annulus is formed between the casing 2 and the oil pipe 3. The wellhead adopts an eccentric wellhead 1.

[0027] The electromagnetic testing instrument 8 is lowered into the oil pipe 3 from the eccentric wellhead 1 through the steel wire a4. The electromagnetic testing instrument 8 can move vertically in the oil pipe 3.

[0028] Preferably, the electromagnetic testing instrument 8 is an electromagnetic flaw detector.

[0029] The sand surface detection device 6 is lowered from the eccentric wellhead 1 into the casing annulus through the steel wire b5. The sand surface detection device 6 contains a magnetic ball 6.6 and can release the magnetic ball 6.6.

[0030] Based on the above embodiment, the sand surface detection device 6 includes:

[0031] Ball barrel 6.4, battery pack 6.2, motor 6.3, baffle 6.7, centralizer 6.1;

[0032] The centralizer 6.1 is connected to the ball cylinder 6.4 to stabilize the sand surface detection device 6 and prevent it from tilting.

[0033] The ball cylinder 6.4 is hollow inside, with a ball outlet 6.5 at the bottom, a baffle 6.7 at the ball outlet 6.5, and a magnetic ball 6.6 located inside the ball cylinder 6.4.

[0034] The battery pack 6.2 and the motor 6.3 are located inside the ball tube 6.4 and are respectively mounted on the inner wall of the ball tube 6.4 by screws. The battery pack 6.2 is connected to the motor 6.3 to provide power to the motor 6.3. The output shaft of the motor 6.3 is connected to the baffle 6.7 to drive the baffle 6.7 to open or close.

[0035] Preferably, the baffle 6.7 has two plates, which are driven by the motor 6.3 to slide to both sides and separate or to slide to the middle and close.

[0036] Example 2

[0037] The ball cylinder 6.4 is hollow inside, with a ball outlet 6.5 at the bottom, a baffle 6.7 at the ball outlet 6.5, and a magnetic ball 6.6 located inside the ball cylinder 6.4.

[0038] The baffle 6.7 is a circular plate structure, which moves up and down under the drive of the motor 6.3 to open or close the ball release port 6.5.

[0039] Except for the structure of the baffle 6.7, the rest of the configuration is the same as that of Example 1.

[0040] Example 3

[0041] The ball cylinder 6.4 is hollow inside, with a ball outlet 6.5 at the bottom, a baffle 6.7 at the ball outlet 6.5, and a magnetic ball 6.6 located inside the ball cylinder 6.4.

[0042] The baffle 6.7 is a circular plate structure, and a horizontal axis is provided at the ball release port 6.5. The baffle 6.7 is driven by the motor 6.3 to turn up and down around the horizontal axis to open or close the ball release port 6.5.

[0043] Except for the structure of the baffle 6.7, the rest of the configuration is the same as that of Example 1.

[0044] It should be noted that the structure of the baffle 6.7 is not limited to the above embodiments. In order to open or close the ball release port 6.5, other structures that can be opened and closed under external force can be used as an option.

[0045] Example 4

[0046] A method for detecting annular sand surfaces using electromagnetic induction, using the tubing string described in Examples 1-3, comprises the following steps:

[0047] First, the electromagnetic test instrument 8 is lowered into the oil pipe 3 in the well through the steel wire a4 through the eccentric wellhead 1. When it encounters resistance, the electromagnetic test instrument 8 is powered on and starts working. The first test is performed. The electromagnetic test instrument 8 is lifted and tested to a position 200 meters away from the resistance position. After the test is completed, the electromagnetic test instrument 8 is lowered again to the resistance position to obtain the first test curve.

[0048] After the first test of the electromagnetic testing instrument 8 is completed, the sand surface detection device 6 is lowered into the casing annulus through the eccentric wellhead 1 via the steel wire b5. Then, the centralizer 6.1 of the sand surface detection device 6 is opened, and the upper and lower support arms of the centralizer 6.1 are extended to center the sand surface detection device 6. The battery pack 6.2 drives the motor 6.3 to open the baffle 6.7 of the sand surface detection device 6, and the magnetic balls 6.6 are released from the ball release port 6.5. The magnetic balls 6.6 accumulate on the sand surface 7 of the annulus, and the sand surface detection device 6 is pulled out.

[0049] After the sand surface detection device 6 releases the magnetic ball 6.6, the electromagnetic testing instrument 8 performs a second test. The electromagnetic testing instrument 8 is powered on again and is lifted up to a position 200 meters away from the obstruction. After the test is completed, the electromagnetic testing instrument 8 is removed to obtain a second test curve.

[0050] According to the electromagnetic principle, the metal outside the oil pipe increases, and the curve will be abnormal at the position of the annular sand surface. Comparing the two test curves, the abnormal curve is judged to be the position of the annular sand surface 7. Figure 3 shown.

[0051] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

[0052] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the appended claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein from the foregoing claims is not intended to be a disclaimer of such subject matter, nor should it be assumed that the inventors did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A method for detecting annular sand surface based on electromagnetic induction, characterized in that: The following structure is used for the pipe string: comprising a casing (2) and an oil pipe (3) lowered into the casing (2), an oil-casing annulus is formed between the casing (2) and the oil pipe (3), an electromagnetic testing instrument (8) is lowered into the oil pipe (3), and the electromagnetic testing instrument (8) can move vertically in the oil pipe (3); a sand surface detection device (6) is lowered into the oil-casing annulus, and a magnetic ball (6.6) is contained in the sand surface detection device (6) and can release the magnetic ball (6.6); The method for detecting the annular sand surface using the tubing string is as follows: the electromagnetic testing instrument (8) is lowered into the oil pipe (3), and before the sand surface detection device (6) is lowered, the electromagnetic testing instrument (8) performs a first test to obtain a first test curve; after the first test is completed, the sand surface detection device (6) containing the magnetic ball (6.6) is lowered into the oil casing annulus, and after the sand surface detection device (6) releases the magnetic ball (6.6), the electromagnetic testing instrument (8) performs a second test to obtain a second test curve, and the two measured test curves are compared, and the abnormal part of the curve is determined to be the location of the annular sand surface.

2. The method for detecting annular sand surface by electromagnetic induction according to claim 1, characterized in that: The electromagnetic testing instrument (8) is lowered into the oil pipe (3) from the eccentric wellhead (1) through the steel wire a (4).

3. The method for detecting annular sand surface by electromagnetic induction according to claim 2, characterized in that: The electromagnetic testing instrument (8) is an electromagnetic flaw detector.

4. The method for detecting annular sand surface by electromagnetic induction according to claim 2, characterized in that: The sand surface detection device (6) is lowered into the casing annulus from the eccentric wellhead (1) via the steel wire b (5).

5. The method for detecting annular sand surface by electromagnetic induction according to claim 4, characterized in that: The sand surface detection device (6) includes a ball barrel (6.4), a battery pack (6.2), a motor (6.3), and a baffle (6.7). The ball cylinder (6.4) is hollow inside, and a ball outlet (6.5) is provided at the bottom. A baffle (6.7) is provided at the ball outlet (6.5). The magnetic ball (6.6) is located inside the ball cylinder (6.4). The battery pack (6.2) and the motor (6.3) are located inside the ball cylinder (6.4). The battery pack (6.2) and the motor (6.3) are connected to provide power to the motor (6.3). The output shaft of the motor (6.3) is connected to the baffle (6.7) to drive the baffle (6.7) to open or close.

6. The method for detecting annular sand surface by electromagnetic induction according to claim 5, characterized in that: The sand surface detection device (6) further comprises a centralizer (6.1) connected to the ball barrel (6.4).

7. The method for detecting annular sand surface by electromagnetic induction according to claim 5, characterized in that: The battery pack (6.2) and the motor (6.3) are respectively mounted on the inner wall of the ball cylinder (6.4) by screws.

8. The method for detecting annular sand surface by electromagnetic induction according to claim 1, characterized in that: The electromagnetic testing instrument (8) is tested for the first time, specifically: the electromagnetic testing instrument (8) is lowered into the oil pipe (3) in the well through the steel wire a (4) using the eccentric wellhead (1). When resistance is encountered, the electromagnetic testing instrument (8) is powered on and starts working. The electromagnetic testing instrument (8) is lifted up for testing to a position 200 meters away from the resistance position. After the test is completed, the electromagnetic testing instrument (8) is lowered again to the resistance position.

9. The method for detecting annular sand surface by electromagnetic induction according to claim 8, characterized in that: The sand surface detection device (6) is lowered into the casing annulus through the steel wire b (5) using an eccentric wellhead (1). Subsequently, the centralizer (6.1) of the sand surface detection device (6) is opened, and the upper and lower support arms of the centralizer (6.1) are extended to center the sand surface detection device (6). The battery pack (6.2) drives the motor (6.3) to open the baffle (6.7) of the sand surface detection device (6), and the magnetic balls (6.6) are released from the ball release port (6.5). The magnetic balls (6.6) are accumulated at the sand surface (7) of the annulus, and the sand surface detection device (6) is pulled out.

10. The method for detecting annular sand surface by electromagnetic induction according to claim 9, characterized in that: The electromagnetic test instrument (8) is tested for the second time, specifically: the electromagnetic test instrument (8) is powered on again, the electromagnetic test instrument (8) is lifted up for testing to a position 200 meters away from the obstruction position, and the electromagnetic test instrument (8) is removed after the test is completed.

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