RU60984U1 - BOTTOM TELEMETRIC SYSTEM FOR DEPRESSION DRILLING - Google Patents

Abstract

The utility model relates to equipment for monitoring well drilling for oil and gas.

The task of creating a utility model is to increase the reliability of the device when working on depression.

The solution to this problem was achieved due to the fact that in a downhole telemetry system operating on a depression, containing an antenna connected to ground receiving and processing equipment, a downhole tool with measuring primary transducers, a transmitter, a power source, and an electric splitter acting as a dipole formed in the result of electric separation of the drill string, characterized in that at least one spring centralizer is installed below the electric separator. At least one spring centralizer may also be installed above the electrical isolator. Metal spring centralizers are installed on special sub, screwed with a downhole telemetry system.

1 sec p-ct f-ly, 4 head. pp., ill. - 2

Description

The utility model relates to field geophysics and is designed to measure downhole parameters during the drilling of directional and horizontal wells in the depression.

Depression drilling is a method of opening a reservoir in which the hydrostatic pressure of the drilling fluid on the formation is less than the reservoir pressure. In this way, mud filtrate is prevented from entering the formation. (penetration of the mud filtrate into the formation significantly affects the reservoir properties of the formation). And so that the well does not start gushing out the mouth is sealed with special equipment (as one of the options). In general, this is an advanced drilling method, more complex than traditional.

During the opening of the formation in depression, the hydrostatic pressure in the bottomhole zone is maintained lower than the reservoir pressure of the object being opened. Depending on the geological and geological characteristics of the reservoir being discovered, this condition can be fulfilled by using different densities as flushing fluids (in the case of high reservoir pressures). For opening oil reservoirs with a pressure below hydrostatic, the depression between the bottomhole and reservoir pressure is achieved through the use of oil-based solutions of various densities or by aeration of oil with gas or air. The most common gas agent is nitrogen, which does not form explosive compounds with the components of the reservoir.

The benefits of drilling on depression and balance.

Depression drilling allows you to:

- increase the productivity of formations by 4-6, and in individual wells by 8-10 or more times;

- save reservoir properties of the reservoir;

- reduce costs and time for well development;

- start production while drilling;

- improve the quality of the hydrodynamic assessment of reservoirs

- increase the recovery rate of formation products;

- evaluate the properties of reservoirs during the drilling process;

- increase the mechanical speed of penetration and the use of the resource of rock cutting tools;

- to prevent the absorption of drilling fluid and reduce the likelihood of sticking of a drilling tool during the opening of reservoirs with zones of absorption;

- reduce the negative impact on the environment, as there is no need to dispose of the used drilling fluid;

- involve in the active development of low-profitable oil deposits and fields with hard to extract oil reserves.

Drilling on depression is associated with certain technical and technological difficulties. Successful drilling with depression on the formation depends on the availability of reliable information about the properties of the formation and its geological characteristics, as well as the correct selection of the drilling mode when opening the formation. The success of using this technology depends on maintaining a negative pressure drop across the drilled formation throughout the entire drilling and completion process.

Known downhole telemetry system according to the patent of the Russian Federation No. 2161701, 7 E 21 V 47/022. This system contains an electric separator, a non-magnetic insert, a deep block with zenith angle and azimuth sensors and a power source, as well as a ground-based receiving complex. The system uses an electromagnetic (electrical) communication channel to transmit information from the bottom to the surface.

The disadvantage is a decrease in the power of the emitted signal when it is transmitted through an aerated drilling fluid or oil-based mud due to the reduced electrical conductivity between the borehole wall and the elements of the bottom of the drill string assembly (BHA), which is the elements of the radiating antenna of the television system.

The tasks of creating a utility model are to increase the reliability of signal transmission during drilling on a depression.

The solution to this problem was achieved due to the fact that in a downhole telemetry system operating without depression, containing an antenna connected to ground receiving and processing equipment, a downhole tool with measuring primary transducers, a transmitter, a power source, and an electric splitter acting as a dipole formed in as a result of electrical separation of the drill string, characterized in that at least one spring metal central R. At least one spring metal centralizer may also be installed above the electrical isolator. Metal spring centralizers can be installed on special sub, screwed downhole telemetry system.

Centralizers made of metal with high electrical conductivity provide power transfer from the separator through the walls of the borehole to the rock. To reduce the influence of the magnetic mass of centralizers on the accuracy of azimuth measurements, they can be made of non-magnetic steel.

The proposed technical solution has novelty and industrial applicability, i.e. all the criteria of a utility model. The novelty of the utility model is confirmed by patent research.

The essence of the utility model is illustrated in figures 1 and 2, where:

Figure 1 shows the drilling scheme for depression,

Figure 2 shows the design of a special sub 23.

The composition (Fig. 1) includes: a drill pipe string 1 to which a pump 2 is connected for supplying drilling fluid through the drilling fluid supply line 3 and a gas supply pipe 4 for aerating the drilling fluid. The ground equipment includes an antenna 5, a cable 6 connecting the antenna 5 to the receiving device 7, a computer 8, a monitor 9, a printer 10. The second input of the receiving device 7 is connected to the drill pipe string 1.

Usually use a personal computer. Operating systems: Windows-95, -98, -XP, signal transmission via RS-232 or USB.

The downhole part of the telemetry system includes a downhole tool 11, which in turn contains measuring primary transducers 12 and a transmitter 13 installed in a non-magnetic casing 14, a power source 15, for example, an electric generator connected to the downhole tool 11, an electrical splitter 16 separating the drill pipe string 1 into two parts: upper 17 and lower 18, downhole motor 19 and rock cutting tool 20.

In the arrangement below, at least one spring centralizer 21 is installed below the electrical separator 16. It is possible (but not necessary) to install at least one upper spring centralizer 22 above the electric separator 16. Installing more spring centralizers increases the level of transmitted power from the separator to the rock.

Special sub 23 (figure 2) is designed to install on it a metal spring centralizer 21 or 22, or both at the same time. Special Sub 23 contains:

Sub housing 24 and metal spring centralizer 21 or 22

During operation, the downhole telemetry system is assembled in the arrangement according to FIG. 1. If necessary, transfer downhole parameters include a downhole tool

11 and the signal from the primary sensors of the transducers 12 is transmitted to the transmitter 13 and then to the upper and lower parts of the drill pipe string 17 and 18, respectively. Next, the signal through an electromagnetic (electric) communication channel is transmitted to the antenna 5 and via cable 6 to the receiving device 7, where it is amplified and converted, then the signal is transmitted to computer 8, and, if necessary, to monitor 9 and printer 10.

The use of spring centralizers 21 and 22 allowed, despite the low electrical conductivity of the aerated or oil drilling mud, to transmit the signal from the upper and lower parts of the drill pipe string 17 and 18 to the borehole walls and into the rock, through which the signal is then fed to the receiving antenna.

Application of the utility model allowed:

1. To ensure uninterrupted transmission of downhole information when drilling in a depression through a drilling fluid having low conductivity, for example, aerated with gas, air or oil-based.

2. To increase the accuracy of measuring navigation parameters due to the centering of the television system along the axis of the well and reducing the level of vibration of the television system.

3. To increase the resource and improve the performance of the telemetry system.

4. Use telesystems with an electromagnetic (electric) communication channel with the rotary and turborotor methods of drilling wells with rotation of the drill string.

Claims (5)

1. Downhole telemetry system for drilling on a depression, containing an antenna connected to ground receiving and processing equipment, a downhole tool with measuring primary transducers, a transmitter, a power source and an electric splitter that acts as a dipole formed as a result of electrical separation of the drill string elements, characterized in that at least one metal spring centralizer is installed below the electrical divider, providing reliable electrical to bottom contact of the electrical separator with the rock for transmitting the emitted signal. 2. The downhole telemetry system according to claim 1, characterized in that at least one metal spring centralizer is installed above the electric separator, which ensures reliable contact of the upper part of the electric separator with the rock to transmit the emitted signal. 3. Downhole telemetry system according to claim 1 or 2, characterized in that the metal spring centralizers are mounted on special sub, screwed with the downhole telemetry system. 4. The downhole telemetry system according to claim 1, or 2, or 3, characterized in that the spring centralizers providing reliable contact of the electric separator with the rock are made of non-magnetic metal to reduce the influence of magnetic masses on azimuth measurements. 5. The downhole telemetry system according to claim 1, or 2, or 3, characterized in that the metal spring centralizers are made freely rotating on the elements of the separator and the drill string for using the telesystem for rotary and turbo-rotor drilling with rotation of the drill string.