CN203559897U - Underground hanging-piece corrosion test unit - Google Patents

Abstract

The utility model relates to the on-site corrosion monitoring technology of wellheads in oil and gas fields, in particular to a downhole corrosion hanger test device, which includes a salvage head, a downhole choke, and a corrosion hanger seat. The sheet seat is fixedly arranged at the bottom of the downhole choke; the side wall of the downhole choke is provided with slips; the utility model can go deep into the downhole for downhole corrosion testing, and is easily fixed on the tubing wall through the slips, so that the hanging The plate device can be suspended without touching the wall and falling into the bottom of the well, so that the downhole corrosion of the gas well can be effectively and truly detected; moreover, the test piece and the corrosion hanging piece seat are isolated by plastic screws, which can effectively prevent the phenomenon of electrical corrosion; through the hemispherical baffle It prevents downhole dirt from adhering to the test piece, improves the accuracy of the test data, makes the air flow purer through the diversion groove and acts on the test piece, and obtains accurate test data.

Description

Downhole corrosion coupon test device

technical field

The utility model relates to the on-site corrosion monitoring technology of wellheads in oil and gas fields, in particular to a downhole corrosion coupon test device.

Background technique

At present, on-site corrosion monitoring techniques in oil fields generally include the following types: on-site coupon test, electrochemical rapid corrosion monitoring technology, residual concentration analysis of corrosion inhibitors, and colorimetric analysis of metal ions.

Among them, the on-site hanging piece test adopts the weight loss method, hangs the test piece on the corrosion hanging piece hanger, puts the hanger into the wellhead, and monitors the test piece through the weight loss method, so as to achieve the purpose of grasping the corrosion degree of the fluid in the well to the pipe .

The test of weight loss corrosion coupon is to put the test piece with known weight and the same material as the monitored object into the corrosive environment under the two conditions of no filling and adding corrosion inhibitor. After a period of time, it will be analyzed and calculated The corrosion rate of the two test pieces is used to calculate the corrosion inhibition rate of the corrosion inhibitor. The emergence of the coupon weight loss method marks the beginning of the standardization of corrosion monitoring. As one of the most primitive methods, its principle is simple and it is widely used in oil and gas fields at home and abroad. It is suitable for various media, namely electrolyte and non-electrolyte, and the monitoring period is more than 1 month.

The traditional wellhead corrosion coupon device developed according to the wellhead corrosion coupon: first select different materials, prepare the test piece into specifications, hang it on the hanger shown in Figure 1 after weighing, place the hanger on the wellhead, and When hanging the test piece, there is insulation between the test piece and the test piece, between the test piece and the hanger, and the plane of the test piece is parallel to the airflow direction. Take a part of each material in each cycle for on-site observation and record the surface corrosion and corrosion adhesion, and then process the test piece in the laboratory to calculate the corrosion rate and conduct corrosion evaluation.

However, due to the large difference between the wellhead pressure, temperature, gas-liquid ratio, flow rate and the bottom of the gas well, the corrosion law research shows that the pipe string basically does not corrode at the wellhead; therefore, it is difficult for the wellhead corrosion coupon to truly reflect the downhole corrosion of the gas well. It is necessary to carry out downhole corrosion coupon experiments to evaluate the downhole corrosion status of gas wells.

In order not to affect the normal production of the gas well, the medium pressure in the tubing is very high. In the case of more complicated flow conditions, it is required that the corrosion test piece cannot touch the pipe wall on the one hand; on the other hand, it cannot fall into the bottom of the well. At the same time, it also requires the harsh conditions of high temperature and high pressure. This puts forward certain difficulty and requirements for the design of the hanging device.

Utility model content

In order to solve the above-mentioned technical problems, the utility model provides a downhole corrosion hanger test device, which can effectively and truly detect the downhole corrosion status of gas wells, and the suspension does not touch the wall or fall into the bottom of the well.

The technical scheme of the utility model is as follows:

The downhole corrosion coupon test device is characterized in that it includes a fishing head, a downhole choke, and a corrosion coupon seat, the fishing head is arranged on the top of the downhole choke, and the corrosion coupon seat is fixedly arranged on the bottom of the downhole choke; The side wall of the downhole choke is provided with slips. When fishing, the tool string and the special fishing head are lowered, and the slips are lifted by shaking downwards. At the same time, the fishing head squeezes the center rod of the tool, and the slips return to the natural contraction state. Down, lift up and salvage to complete the construction work.

When the utility model is put into the oil pipe, the delivery head and the utility model are connected by pins, and the slips are loose during the downward process. After the utility model is put into the design depth, the slips are lifted up, and the slips are supported on the wall of the oil pipe to shock upwards. Cut the pin to achieve setting.

The corrosion coupon seat is provided with a test piece fixing hole for installing the test piece, and the test piece is fixed on the corrosion coupon seat through a screw rod and a nut.

Further, the test piece is provided with a mounting hole, and a plastic screw is used to pass through the mounting hole of the test piece and the test piece fixing hole of the corroded hanging piece seat, and is fixed by the plastic locking nuts and plastic nuts at both ends of the test piece. The use of plastic screws can isolate the test piece from the hanging piece holder to prevent the influence of electric corrosion on the test piece data.

A diversion groove with a hemispherical baffle at the bottom is provided at the lower end of the corrosion hanger seat. The hemispherical baffle can effectively prevent the dirt in the well from directly adhering to the test piece, which will affect the accuracy of the test piece monitoring data, and then the air flow can smoothly pass through the diversion groove to act on the test piece.

The lower part of the downhole choke is connected with the corrosion coupon seat through threads. When in use, no throttling element (oil nozzle) is installed in the downhole choke. After the downhole choke is connected with the corrosion hanger seat, it is lowered to the designated position through steel wire operation, and the slips are lifted up to fix the whole device. on the inner wall of the tubing.

The beneficial effects of the utility model are as follows:

The utility model can go deep into the well for downhole corrosion testing, and is easily fixed on the tubing wall through the slips, so that the hanging piece device can be suspended without touching the wall and falling into the bottom of the well, so that the downhole corrosion condition of the gas well can be effectively and truly detected; and, The plastic screw is used to isolate the test piece and the corrosion hanging piece seat, which can effectively prevent the phenomenon of electric corrosion; the hemispherical baffle prevents the downhole dirt from adhering to the test piece, which improves the accuracy of the detection data and makes the air flow through the diversion groove more purely Act on the test piece to obtain accurate detection data.

Description of drawings

Figure 1 is a schematic structural diagram of a conventional corrosion coupon device installed at the wellhead

Fig. 2 is the structural representation of the utility model

Fig. 3 is the schematic diagram of the front view structure of the corrosion coupon of the utility model

Fig. 4 is the schematic diagram of the side structure of the corrosion coupon of the utility model

Among them, the reference signs are: 1 fishing head, 2 downhole choke, 3 slips, 4 test piece fixing hole, 5 corrosion hanging piece seat, 6 diversion groove, 7 test piece, 8 plastic screw, 9 plastic nut , 10 plastic lock nuts.

Detailed ways

Example

As shown in Figure 2-4, the downhole corrosion coupon test device includes a fishing head 1, a downhole choke 2, and a corrosion coupon seat 5. The fishing head 1 is set on the top of the downhole choke 2, and the corrosion coupon seat 5 It is fixedly installed at the bottom of the downhole choke 2; the side wall of the downhole choke 2 is provided with slips 3. When fishing, the tool string and the special fishing head 1 are lowered down, and the slips 3 are lifted by shaking downwards, and at the same time The salvage head 1 squeezes the center rod of the tool, the slips 3 return to the state of natural contraction, and the construction work is completed by lifting and salvage.

When the utility model is put into the oil pipe, the delivery head and the utility model are connected by pins, and the slips 3 are loose during the downward process. After being put into the design depth, the slips 3 are lifted up, and the slips 3 are supported on the wall of the oil pipe. Shock the shear pin upwards to set.

The corrosion coupon seat 5 is provided with a test piece fixing hole 4 for installing the test piece 7, and the test piece 7 is fixed on the corrosion coupon seat 5 by a screw rod and a nut.

Further, the test piece 7 is provided with a mounting hole, and a plastic screw rod is used to pass through the mounting hole of the test piece 7 and the test piece fixing hole 4 of the corrosion hanging piece seat 5, and pass through the plastic locking nuts and Plastic screw caps secure. By adopting plastic screws, the test piece 7 can be isolated from the hanging piece holder, so as to prevent electric corrosion phenomenon from affecting the data of the test piece 7 .

The lower end of the corrosion hanger seat 5 is provided with a diversion groove 6 with a hemispherical baffle at the bottom. The hemispherical baffle can effectively prevent the dirt in the well from directly adhering to the test piece 7, affecting the accuracy of the monitoring data of the test piece 7, and then the air flow can pass through the diversion groove 6 to act on the test piece 7 smoothly.

The lower part of the downhole restrictor 2 is connected with the corrosion coupon seat 5 through threads. When in use, no throttling element (oil nozzle) is installed in the downhole throttle 2. After the downhole throttle 2 is connected with the corrosion hanger seat 5, it is lowered to the designated position through steel wire operation, and the slip 3 is lifted up. , the whole device is fixed on the inner wall of the tubing.

Claims (5)

1. Downhole corrosion coupon test device, characterized in that it includes a fishing head (1), a downhole choke (2), a corrosion coupon seat (5), and the fishing head (1) is set on the downhole choke (2) The corrosion coupon seat (5) is fixedly arranged on the bottom of the downhole choke (2); the side wall of the downhole choke (2) is provided with slips (3). 2. The downhole corrosion coupon test device according to claim 1, characterized in that: the corrosion coupon seat (5) is provided with a coupon fixing hole for installing the test piece (7), and the The test piece (7) is fixed on the corrosion coupon seat (5). 3. The downhole corrosion coupon test device according to claim 2, characterized in that: the test piece (7) is provided with a mounting hole, and a plastic screw is used to pass through the mounting hole of the test piece (7) and the corrosion coupon The test piece fixing hole (4) of the seat (5) is fixed by the plastic locking nut and the plastic nut at both ends of the test piece (7). 4. The downhole corrosion coupon test device according to claim 1, characterized in that: the lower end of the corrosion coupon seat (5) is provided with a diversion groove (6) with a hemispherical baffle at the bottom. 5 . The downhole corrosion coupon test device according to claim 1 , characterized in that: the lower part of the downhole restrictor ( 2 ) is connected to the corrosion coupon seat ( 5 ) through threads.

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