GEOPHYSICAL CABLE FOR SURVEYING HORIZONTAL AND RISING WELL SECTIONS

Abstract

This invention relates to cable equipment, specifically, to geophysical cables, and is intended for lowering and lifting of geophysical instruments and devices, for supplying them with electric power, and for providing communication between surface equipment and instruments used during geophysical studies of horizontal and uphill portions of oil and gas wells. The geophysical cable for study of horizontal and uphill portions of wells contains at least one current-conducting core and an outside coating; at least one current-conducting core is located in a mass of polymer composite material armoured with glass or carbon fibers. The technical result of the proposed invention is to increase the longitudinal elasticity of a geophysical cable for study of horizontal and uphill portions of wells, which would ensure its self-rectification during operation, while preserving its strength and stiffness for pushing geophysical devices in horizontal portions of wells.

Claims

1. A geophysical cable for study of horizontal and uphill portions of wells, comprising at least one current-conducting core and an outside coating, wherein at least one current-conducting core is located in the mass of polymer composite material armoured with glass or carbon fibers.

2. A geophysical cable as per claim 1, wherein, in parallel to at least one current-conducting core, a steel wire is located in the mass of polymer composite material.

3. A geophysical cable as per claim 1, wherein, in parallel to at least one current-conducting core, optic fiber is located in the mass of polymer composite material.

4. A geophysical cable as per claim 1, wherein the outside coating is made of polymer material.

5. A geophysical cable as per claim 4,wherein the outside coating is made of gelcoat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The invention is explained by the following illustrations.

[0018] FIG. 1 shows the design of a geophysical cable for study of horizontal and uphill portions of wells, where:

[0019] 1current-conducting cores;

[0020] 2polymer composite material;

[0021] 3steel wire;

[0022] 4outside coating;

[0023] 5optical fiber.

[0024] FIG. 2 shows a process diagram of study of a well using the proposed geophysical cable, where:

[0025] 6proposed geophysical cable for study of horizontal and uphill portions of wells;

[0026] 7drum with stiff geophysical cable of KGJ type;

[0027] 8stiff metal geophysical cable of KGJ type;

[0028] 9cable end of stiff geophysical cable;

[0029] 10geophysical lift;

[0030] 11roller assembly;

[0031] 12cable end of the proposed geophysical cable;

[0032] 13cable head of the proposed geophysical cable;

[0033] 14geophysical device;

[0034] 15wellhead equipment;

[0035] 16stop;

[0036] 17shutter.

DETAILED DESCRIPTION OF THE INVENTION

[0037] The geophysical cable for study of horizontal and uphill portions of wells includes one or multiple current-conducting cores 1, located in a mass of polymer composite material 2, armoured with glass or carbon fibers. Parallel to at least one current-conducting core 1, a steel wire 3 for emergency retrieval of a geophysical device from the well and an optical fiber 5 for data transfer are located in the mass of polymer composite material 2. Over the polymer composite material 2, an outside coating 4 is applied for protection against premature wear; it is made of gelcoat or other polymer material. The nominal diameter of the cable can be from 8 to 30 mm, depending on the well's curvature radius and on the length of the well's horizontal portion.

[0038] The use of the proposed cable for study of horizontal and uphill portions of wells simplifies the study process and consists in the following.

[0039] 25 to 30 metres away from the wellhead, a geophysical lift 10 is installed, with a stiff metal geophysical cable 8 of GKJ type wound onto a drum 7. The cable has a cable end 9 on the outside end of the cable 8.

[0040] 25 to 30 metres away from the well, a drum is installed with the proposed geophysical cable 6 for study of horizontal portions of wells wound on it. The cable 6 has a cable end 12 on the outside (in relation to the drum) end, while on the inside end, it has a cable head 13, attached to the drum. A geophysical device 14 is fastened to the cable end 12. The cable 6 is passed through the roller assembly 11; then, the roller assembly 11 is suspended on the lift.

[0041] The device 14 on the cable 6 is lowered into the well, being passed into the wellhead equipment 15 through the stop 16 and shutter 17 installed on the wellhead equipment 15. The device 14 is lowered into the well to the whole length of the cable 6, and the cable 6 is fixed using the stop 16.

[0042] The cable head 13 of the proposed cable 6 is disconnected from the drum and connected to the cable end 9 of the geophysical cable 8. The cable 8 is slightly tensioned.

[0043] The stop 16 on the wellhead equipment 15 is released, and the cable 6 begins to be lowered using the geophysical lift 10.

[0044] Once the device 14 is lowered to the beginning of the horizontal portion of the well bore (the heel), the cable 6 continues to be lowered to the end of the horizontal portion of the well (the toe); in this case, the mass of the geophysical cable 8 located in the vertical portion of the well serves as the driver for pushing the proposed cable 6 to the toe of the well. The geophysical parameters of the well are recorded in various modes of the well's operation, moving the device 14 from the toe to the heel and back. The device 14 is lifted by winding the geophysical cable 8 on the drum 7.

[0045] Once the connected cable end 9 and the cable head 13 of the proposed cable 6 exit the well, the connection is pulled up to the drum of the geophysical lift 10, and the stop 16 is fixed on the well head. The cable end 9 and the cable head 13 of the proposed self-rectifying cable 6 are unbolted. The cable head 13 is fastened on the drum. The stop 16 on the well head is released, and the shutter 17 is closed in order to clean well fluid off the cable 6. Using an injector, the proposed cable 6 is pulled to the drum and simultaneously wound on the drum.

[0046] Once the geophysical device 14 exits the well, it is unbolted from the cable end 12 of the proposed self-rectifying cable 6, and the rest of the cable 6 is wound on the drum.

[0047] The design of the proposed geophysical cable allows to push geophysical devices into elongated horizontal portions of wells without using special downhole mechanisms.

[0048] Therefore, the proposed invention design will find a widespread application in geophysical studies of horizontal and uphill portions of wells.