SU1247517A1 - Cable head - Google Patents

Description

The invention relates to a well logging technique and can be used to electrically connect downhole instruments with a cable.

The purpose of the invention is to increase reliability in operation and simplify the design.

The drawing shows a cable head, option.

The cable head comprises a housing 1 rigidly connected to the geophysical cabins of a part of the cavity (3-5 cm). From the Mendeleev-Klaiperon equation, the volume of air filling the cable head body at the wellhead {at atmospheric pressure) is determined.

With a maximum hydrostatic pressure in the well of 250–350 atm and a temperature of 160–180 ° C, the free volume of the body cavity will be 600-UOOcm. For cable head with outer diameter

Lem 2, and adapter 3, connected with a well-10 70-80 mm cavity length will be 12-20cm,

with a gummy device 4 by means of a sealed connector (not shown in the drawing). A thrust bearing 5, installed between the housing 1 and the adapter 3, ensures their independent coaxial rotation

which is quite acceptable for well-known cable heads.

The device works as follows.

During the descent of the geophysical instrument into the well borehole fluid 6 through the windows

relative to each other. In the upper part in the case 1 it fills the cavity b, the helix cavities of the case 1 are made of a narrow channel with the air in it

a, and in its lower part b there are through-12. As the depth increases, the drain holes in the free communicative device into the well and the pressure of the liquid in the lower part of the device housing increases. The bone level in the cavity in the cavity of the well filled with the mud 20 of the housing 1 rises. If there is a vrab. In the upper part of the cavity, i.e. In an effort on the cable, it can, together with the body 1 of the cable head, rotate freely with respect to the adapter 3, and hence the device 4 pressed against the borehole wall. Reliability

A geophysical instrument 4. Contact 9 makes electrical contact at the same time is provided in insulating sleeve 10 and is spring-loaded with the collector in a spring 11 with the possibility of an air-filled medium. Since the ratio of free spaces along adapter 3. Before the discharge volumes of parts a and b of the housing cavity of the instrument into the well, the cavity of the housing is determined based on the Mende 1 equation of the head filled with air 12. Free-Clayperon, then under action the maximum volume cavities of the head housing, i.e. thirty

com channel a, there is a collector 7, made in the form of a system of contacts 8, electrically connected to the conductors of cable 2, and contacts 9, electrically connected to

the difference between the full volume of the cavity and the volume of structural elements in it is determined from the Mendeleev-Klaiperon control, so that under the action of maximum hydrostatic pressure in the well, the upper part and the cavity of the cable head body, where the collector is located, would be guaranteed to be in the air environment.

35

The maximum pressure in the well is in the air.

The technical advantage of the proposed device in comparison with the known is the high reliability of the electrical contact of the collector, due to its protection from the effects of the well fluid with air, which is one of the best insulators, and the exclusion of the use of special means of sealing, Based on design considerations, 40 False cable head design.

take the value of the free volume of the upper part of the cavity of 3-5 cm. Taking into account that when the maximum hydrostatic pressure is applied, the collector should be in the air, the volume of compressed air should be equal to the free volume of the top. The absence of sealing elements for parts of the cable head rotating in aggressive liquid increases its reliability operation, which guarantees the reliability of the free relative rotation of the housing and the adapter.

it part of the cavity (3-5 cm). From the Mendeleev-Klaiperon equation, the volume of air filling the cable head body at the wellhead {at atmospheric pressure) is determined.

With a maximum hydrostatic pressure in the well of 250–350 atm and a temperature of 160–180 ° C, the free volume of the body cavity will be 600-UOOcm. For cable head with outer diameter

 70-80 mm cavity length will be 12-20cm,

which is quite acceptable for well-known cable heads.

The device works as follows.

During the descent of the geophysical instrument into the well borehole fluid 6 through the windows

c in casing 1 fills cavity b; in this case, the air in it

electrical contact is provided by the location of the collector in the air environment. Since the ratio of the free volumes of the parts a and b of the body cavity is determined on the basis of the Mendeleev-Clayperon equation, under the action of maximal

The maximum pressure in the well is in the air.

The technical advantage of the proposed device in comparison with the known is the high reliability of the electrical contact of the collector, due to its protection from the effects of the well fluid with air, which is one of the best insulators, and the exclusion of the use of special means of sealing, which complicates the design of the cable head.

The absence of sealing elements for parts of the cable head rotating in aggressive liquid dramatically increases the reliability of its operation, which guarantees the reliability of free relative rotation of the housing and adapter.

Claims (1)

CABLE HEAD, comprising a housing connected to a cable, an adapter connected to the downhole tool and mounted coaxially inside the housing with axial rotation, and a collector for electrical communication of the downhole tool with a cable, characterized in that, in order to increase operational reliability and simplify the design , in the upper part of the housing there is an air channel in which the collector is located, and in the lower part of the housing there are holes for connecting the cavity of the housing with the environment. SU,. „1247517