SU859619A1 - Apparatus for locating leakage in operational strings of the borehole - Google Patents

Description

(54) DEVICE FOR DETERMINING LEAKAGE PLACE IN OPERATING WELLS

The invention relates to oil and gas production and is intended to determine the location of a leak in the production casing. A device is known for determining the location of a fluid leak in a pipe string, including a landing cone installed in the internal cavity of the pipe, and a valve ClJ. The drawback of the device lies in the fact that it does not provide sufficient accuracy in determining the location of the leak and when it is used it is necessary to carry out additional descent and lifting operations. The closest to the present invention is a device for detecting leakage in production columns, including a housing with cuffs located on its outer surface, a valve with a stem installed in the axial channel of the housing, a suspension assembly and pressure sensors G23. The disadvantage of the design lies in its complexity, and also the need to perform several tripping operations to determine a single leak. The purpose of the invention is to simplify the design and operation of the device. The goal is achieved by the fact that the valve is spring-loaded relative to the body, and the valve stem is tin with a suspension assembly. Moreover, to facilitate lifting, the cuffs are mounted on the body with the possibility of axial movement. The drawing shows a device for determining the location of a leak in production columns. The device contains a detachable housing 1, consisting of two parts of a mating with each other threaded connection. Valve seat 2 is made in the lower part of the body and is overlapped by valve 3 that is spring-loaded relative to the body. External grooves 4 are designed to accommodate rubber cuffs 5. The lower part of the body of the device ends with a spherical guide surface b. The valve 3 is made of one blank together with the stem 7. The ends of the stem are threaded 8 and 9. On the upper part of the stem 7 is screwed on the weel of the suspension, including the detachment of the coupling Yu and the associated cable 11. On the lower part of the stem to fix the flared 3 in series a fluoroplastic gasket 12, a metal washer 13, a nut 14 and a lock nut 15 are mounted. An aperture 16 in the upper part of the body serves for the flow of fluid as well as for equalizing the fluid pressure between the rubber cuffs 5,

A spring 17 fixes the valve in an assembly condition. When removing the device from the well in order to reduce the effect of the liquid column on the cable, the rubber cuffs 5 are moved to the grooves 18. The cuffs are installed with the possibility of axial movement relative to the housing and, when being lifted, the devices are moved downward into the grooves 18.

The operation of the device is as follows. A field lubricator and a KPKT-6 cable are used to locate the defect in the production cords of the skzazhin. The cable is fastened to the detachable coupling 10 of the device, which is screwed onto the rod 7, the cable is passed through the lubricator, attached to the device, then the device is directed to. well and fasten the lubricator.

The filtering part of the well is compacted with sand or clay, and the entire barrel of the production string is filled with liquid. The device is pushed by the cementing unit to the bottom of the well along the production string. Under the action of the spring 17 and the hydraulic pressure developed by the unit, the valve 3 closes the opening in the device. The rubber cuffs 5 seal the device in the production string, preventing leakage of fluid between the device and the production string. Thus, the production string is divided into two parts. As the unit operates, the device moves to the bottom, as long as the fluid from the device below in the wellbore is able to pass beyond the column at the site of its defect. When the proposed device closes the defect in the production string of a well, pressure rises on the gauge of the cementing unit and it is easy to determine by the cable that the device has stopped moving. The meter at the winch determines how deep the fluid is leaking.

The lift of the device is carried out in the following order.

Relieve pressure at the wellhead and begin to slowly lift the device. When the device is raised, the valve 3 opens, creating a flow of fluid that allows the device and wells to freely lift.

Due to friction against the walls, the columns of the cuff 5 are displaced from their seats, 5 which contributes to a more rapid lifting of the device, and the cuffs themselves are raised on the grooves 18.

Technical and economic efficiency is to reduce the material costs associated with the repair of production wells.

Claims (2)

1. A device for determining the location of a leak in the production casing of wells, including a housing with cuffs located on its outer surface, a valve with a stem installed in the axial channel of the housing, and a suspension assembly, so that in order to simplify the design and operation of the device, the valve is spring-loaded relative to the housing, and the valve stem is rigidly connected to the suspension assembly. 2. The device according to claim 1, characterized in that the cuffs are mounted with the possibility of axial movement relative to the body. Sources of information taken into account in the examination 1. USSR author's certificate j 130224, cl. E 21 B 17/00, 1959. 2. Authors certificate of the USSR 589380, cl. E 21 B 47/10, 1972 (prototype).