RU2196216C1 - Device for connection of flexible metal pipe with downhole tool - Google Patents

Abstract

FIELD: drilling equipment, particularly, devices for operation with flexible metal pipes in drilling of horizontal part of oil and gas wells. SUBSTANCE: device end has rigid metal branch pipe inside flexible metal pipe and is provided with sub in the form of body whose lower inner part has thread for connection with downhole tool. Middle part internal surface has circular bore for packing ring. Upper part is made with internal conical surface whose cone is directed upward, and external surface is connected with internal cylindrical surface of pressure nut and locking device preventing unscrewing in the course of drilling. Upper part of pressure nut is in the form of truncated cone with radial bores forming ribs having transverse holes receiving handle for screwing-unscrewing of threaded joint. Radial bores have circular grooves under which dismantling holes of power slips are located. Power slips are located in gap between conical surface of body upper part and external wall of flexible metal pipe. EFFECT: reliable connection of flexible metal pipe with downhole tool in the course of drilling. 2 dwg

Description

 The invention relates to the field of drilling equipment, in particular to devices for working with flexible metal pipes (HMT) when drilling a horizontal section of the wellbore of oil and gas wells.

 Analysis of the current level of technology showed the following.

 A well-known welded joint of gas-turbine and downhole tools is available (see Aminov S.M. Use of continuous-pipe installations for well repair in SPSNP and KRS of Surgutneftegas OJSC and assessment of work efficiency in comparison with traditionally used technology. Collection of scientific papers. Drilling and repair of wells small diameter using flexible pipes (based on the materials of the intersectoral scientific and practical conference in Anapa on September 27–30, 1999), issue 3, Krasnodar, Ministry of Fuel and Energy of the Russian Federation, OAO NPO Burenie, 1999, p. 20). The welding unit makes the docking of the pipe, soldering of the holes in the argon medium. To connect the pipe to the tool, rolling tools and mechanical cutters are used.

 The disadvantages of the known connection of the HMT with the downhole tool is the possibility of an emergency during the drilling of a horizontal section of the wellbore due to the fact that the weld weakens the pipe body to 30%, which can lead to tool breakage during drilling. In addition, welding is a laborious and expensive process. When dismantling, it becomes necessary to cut the downhole tool.

 As a prototype, a device was used to connect the hydraulic plug with a downhole tool, containing a sub (literally: a docking device, the lower part of which has a thread for connection with a downhole tool), a sealing ring (support ring), a pressure nut (outer sleeve), a wedge grip (split clamping sleeve) with elements on the inner surface: sharp ridges that increase friction (see RF patent 2153058 from 09.14.95, class E 21 B 19/22, publ. in OB 20, 2000).

A disadvantage of the known device is the possibility of an emergency during the drilling of a horizontal section of the wellbore, due to a number of reasons:
- unreliable connection of the hydraulic cylinder with the downhole tool and the possibility of deformation at the connection; when a flexible thin-walled metal pipe is pressed by a wedge grip with sharp ridges, the latter will inevitably deform at the junction with a possible subsequent break of the tool;
- instability of the connection to vibration during drilling due to the absence of a locking device.

 The absence of a dismantling device does not ensure the complete release of the GMT from the wedge grip. In addition, deformation at the junction of the HMT with the downhole tool leads to a decrease in the diameter of the HMT, which causes an increase in hydraulic losses and, as a result, the absolute pressure at the mud pumps increases.

The technical result that can be obtained by carrying out the invention,
- failure-free drilling process of the horizontal section of the wellbore due to the improved design of the device, which ensures the reliability of the connection of the hydraulic tool with the downhole tool without deformation at the connection, maintaining the reliability of the connection from vibration of the downhole tool during drilling;
- elimination of additional hydraulic losses.

 The technical result is achieved using a known device for connecting a hydraulic cylinder with a downhole tool, including a sub, a sealing ring, a pressure nut, a wedge grip with elements on the inner surface that increase friction, in which it is additionally provided at the end inside the hydraulic cylinder with a rigid metal pipe, and as the sub contains a housing, the inner surface of the lower part of which has a thread for connection with the downhole tool, the middle part on the inner surface has an annular a groove under the o-ring, the upper part is made upward with the conical surface facing upward, and the outer surface is connected to the inner cylindrical surface of the compression nut and a locking device that prevents unscrewing during drilling, the upper part of the compression nut being truncated-conical with radial grooves forming ribs having transverse openings under the handle for screwing - unscrewing the threaded connection, and radial grooves have annular grooves, under which are the dismantling holes of the wedge grip, made in the form of wedge dies located in the gap between the inner conical surface of the upper part of the housing and the outer wall of the flexible metal pipe.

 The present invention has an inventive step, because the set of essential features of the distinguishing part of the claims used to obtain the claimed result is not revealed by us on the available sources of fame (patent documentation and scientific and technical literature).

The design of the claimed device is illustrated by the following drawings:
- figure 1 is a longitudinal section of a device;
- figure 2 is a top view of the device.

 The end of the gas cylinder 1 inside is equipped with a rigid metal pipe 2, which prevents its deformation. The device comprises a housing 3, the inner surface of the lower part of which has a thread 4 for connection with a downhole tool. The middle part on the inner surface has an annular groove 5 under the o-ring 6 of oil-resistant rubber. The upper part of the body is made with the conical surface facing upward, and the outer surface of the upper part is connected to the inner cylindrical surface of the pressure nut 7 and a locking device that prevents unscrewing during drilling.

 The locking device consists of a bolt 8, which enters the transverse hole of the housing 3, connected to the stopper 9, which is included in the longitudinal groove of the pressure nut 7. The upper part of the pressure nut 7 is truncated-conical with three radial grooves 10 forming three ribs 11 having transverse holes 12 under the handle for screwing - unscrewing the threaded connection. Radial grooves 10 have annular grooves 13, under which are located the dismantling holes 14 of the wedge grip. The wedge grip is made in the form of three wedge dies 15 with a finned hardened inner surface located in the gap between the inner conical surface of the upper part of the housing 3 and the outer wall of ГМТ1.

The device has the following dimensions:
Outer diameter of the case, mm - 90
Length, mm - 200
For drilling a horizontal section of the borehole of the Novo-Urengoyskoye gas field, equal to 600 m, a gas turbine is used.

 A coil with wound ГМТ1 (Chance Collar Co.) with a diameter of 60.3 mm, a length of 3500 m, and a wall thickness of 4.0 mm is installed on the transport device. A downhole tool is located on the bridges of the drilling rig, consisting of a turbodrill designed by the Kungursky Machine-Building Plant and a rolling-cutter bit model III 120.6 TZTSA, manufactured by Uralburmash, pos. Top Earrings. A rigid metal pipe 2 is mounted at the end inside the ГМТ1. The ГМТ1 end is inserted into the device with a pre-screwed nut 7 on the casing 3. The unscrewed nut 7 is unscrewed by means of a handle inserted into the transverse hole 12 and it is lifted to a distance enabling three wedge dies 15 to enter The wedge dies 15 are located under the radial grooves 10. After inserting the wedge dies 15, the pressure nut 7 is screwed and the wedge dies moving down the conical surface firmly grasp the ГМТ1.

 To prevent unscrewing during drilling of the pressure nut 7, a locking device is installed. The stop 9 enters the longitudinal groove of the pressure nut 7 and is bolted to the housing 3. The downhole tool is connected to the device by means of a thread 4 located on the inner surface of the lower part of the housing 3. The tool connected to GMT1 is lowered to a depth of 1800 m through the injector of the drilling rig , after which they begin drilling a horizontal section of the wellbore.

 After the completion of drilling, unroll the ГМТ1 onto a coil, raise the downhole tool to the bridges of the well. Carry out the dismantling of the device. To do this, unscrew the nut 7 by 1-2 turns. A gap is formed between the wedge dies 15 and the pressure nut 7. Insert the bolts into the annular grooves 13, screw them into the dismantling holes 14 of the wedge dies 15 and screw in clockwise to release the wedge dies 15 from their capture of GMT1. Then disconnect the downhole tool.

 The universality of the design of the device allows, after changing the appropriate dimensions, to use it for all standard sizes of gas-turbine engines. The device is manufactured on the basis of the central repair shops of the Stavropol Office of Drilling and Repair and Restoration Work of the Kavkaztransgaz enterprise.

 The design of the device provides the claimed technical result.

Claims (1)

 A device for connecting a flexible metal pipe with a downhole tool, including a sub, a sealing ring, a pressure nut, a wedge grip with elements on the inner surface that increase friction, characterized in that it is additionally provided at the end inside the flexible metal pipe with a rigid metal pipe, and as the sub contains a housing, the inner surface of the lower part of which has a thread for connection with the downhole tool, the middle part on the inner surface has a ring a groove under the o-ring, the upper part is made with the conical surface upward, and the outer surface is connected to the inner cylindrical surface of the pressure nut and a locking device that prevents unscrewing during drilling, and the upper part of the pressure nut is truncated-conical with radial grooves forming ribs having transverse openings under the handle for screwing-unscrewing the threaded connection, and radial grooves have annular grooves, p One of which is the dismantling hole of the wedge grip, made in the form of wedge dies located in the gap between the inner conical surface of the upper part of the housing and the outer wall of the flexible metal pipe.

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