RU2574657C1 - Device for control of behind-casing flows between two formations - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device for control of behind-the-casing flows between two formations comprises a container for tracer fluid run in at the logging cable with delivery unit and depressurization unit as well with measurement sensor. Ferrofluid is used as tracer fluid and devices for magnetic field measurement are used as measurement sensors. The container is placed to the pipe string equipped from outside with a packer set between the upper and lower formations. The delivery unit is installed in the pipe string above the packer opposite the upper formation and made as a filter blinded from the bottom and perforated plug rigidly fixed in the pipe string above the filter. At that the depressurization unit is made as a stepped rod with larger D diameter at the top and less d diameter at the bottom. In transportation position the stepped rod with larger D diameters is installed hermetically to the central opening made at the container bottom, and in working position at interaction of the stepped rod with perforated plug in the delivery unit the stepped rod can be moved axially upwards in regard to the container placing the stepped rod with less d diameter opposite the central opening in the container. The measurement sensor is placed at the lower end of the pipe string opposite the lower formation.

EFFECT: improved operational reliability of the device, improved efficiency of the device operation, improved accuracy for determination of behind-the-casing flow between the two formations, excluding encapsulation of the logging cable at the wellhead.

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Description

The invention relates to the oil and gas industry, in particular to means for monitoring annular fluid flows in the well.

It is known "Device for monitoring annular flows" (patent RU No. 2057926, E21B 47/10, 33/14, publ. BI No. 10, dated 10.04.96) liquid and gas containing a column, a hollow container with a solution of "labeled" liquid and a depressurization unit of the container, the device is equipped with a sleeve with through radial holes placed outside the columns and rigidly connected with the latter, and the container is formed by the outer surface of the column and the sleeve and is made with upper and lower pistons fixed with shear elements on the column and separating cavity to an overshift chamber on the over-piston, inter-piston, and sub-piston chambers, wherein the over-piston chamber is filled with air, the solution of the “labeled” fluid is placed in the inter-piston chamber, and the depressurization unit is placed in the under-piston chamber and is made in the form of a powder charge with electric ignition elements.

The disadvantages of the proposed device are:

- firstly, stationarity and disposability, that is, the impossibility of examining several intervals with one device and several times during the period of well operation;

- secondly, the use of a powder charge to eject a "labeled" fluid in the annulus can lead to violations of the lining and, as a result, provoke overflows.

Also known is a "Device for measuring the radioactivity of an isotope of an atom introduced into a well support" (US Patent No. 4771635, E21B 47/10 of January 29, 1987) containing a container for a liquid "marked" with a radioactive isotope of a liquid atom with depressurization nodes and feed, a sensor for measuring radioactivity.

The disadvantages of this device are:

- firstly, the use of radioactive substances, which requires the use of expensive materials for the container, attracting workers with permission to carry out such work and applying increased safety measures and, as a result, the inability to perform work by the service crews, which together require large material costs;

- secondly, to measure the parameters, the device needs to be moved up and down relative to the studied interval, which excludes the possibility of studying the process in time in a stationary position, based on which it is impossible to draw a conclusion about the speed of annular flows.

The closest in technical essence and the achieved result is a "Device for monitoring annular flows" (patent RU No. 2252500, E21B 47/10, publ. BI No. 18, dated June 27, 2005), containing a container for a "labeled" run-off on a geophysical cable "liquids with depressurization and supply nodes, a measuring sensor, characterized in that the device is equipped with measuring sensors of more than one, while the measuring sensors are located above and below the studied interval of the reservoir at least one on each side, and as a" labeled "liquid ferromagnetic fluid is used in the bone, and devices for measuring the magnetic field are used as measuring sensors.

The disadvantages of the proposed device are:

- firstly, the low reliability of the operation of the device (emptying the container from ferromagnetic fluid), which occurs according to the electric signal supplied to the geophysical cable, while the signal may not reach the container due to cable damage during descent or failure of the feed and / or depressurization units devices in operation;

- secondly, the low efficiency of the device, due to the fact that with a high degree of probability the “labeled” fluid (ferromagnetic fluid) will not be pushed through the perforation holes of the well into the formation with technical fluid, but will settle on the bottom of the well, especially if the formation has low injectivity ;

- thirdly, the low accuracy of determining the presence of a casing flow between two layers, since the ferromagnetic fluid enters the empty "pocket" formed in the casing space of the well, for example, when attaching (cementing) the casing of the well, to which the measuring sensor of the magnetic field responds, but this does not mean at all that there is an annular flow between two layers;

- fourthly, it is necessary to seal the geophysical cable at the wellhead when pushing ferromagnetic fluid into the formation with possible fluid leaks.

The technical task of the invention is the creation of a reliable device that ensures the guaranteed response of the supply and / or depressurization units, as well as an effective device that allows guaranteed to push the ferromagnetic fluid from the well, increasing the accuracy of the annular flow between two layers by installing a measuring sensor opposite the lower layer , from which, in the presence of a casing flow, a ferromagnetic fluid will come out, and the exclusion of sealing official cable at the wellhead.

The problem is solved by a device for monitoring annular flows between two formations, containing a container for a “labeled” fluid with depressurization and supply units launched on a geophysical cable, as well as a measuring sensor, ferromagnetic fluid is used as a “labeled” fluid, and as measuring sensors devices for measuring the magnetic field.

What is new is that the container is placed in a pipe string, provided externally with a packer installed between the upper and lower layers, while the feed unit is installed in the pipe string above the packer opposite the upper layer and is made in the form of a filter blanked from the bottom and a perforated plug rigidly installed in the column pipes above the filter, and the depressurization unit is made in the form of a stepped rod with a large diameter D on top and a smaller diameter d from the bottom, while in the transport position the stepped rod with a large diameter D is hermetically sealed is mounted in the central hole made in the bottom of the container, and in the working position, when the step rod interacts with the perforated plug of the feed unit, the step rod is able to axially move upward relative to the container with the step rod being placed with a smaller diameter d opposite the container’s central hole, and the measuring sensor is mounted on the bottom the end of the pipe string opposite the lower layer.

In figures 1 and 2 schematically shows the proposed device.

The figure 3 shows a diagram of a device in the presence of an annular fluid flow between two layers.

A device for monitoring behind-the-casing flows between two layers (upper 1 and lower 2) (see Fig. 1 and 2) contains a container 4 for a "labeled" liquid 5 with depressurization and supply units, as well as a measuring sensor 6, which is lowered on a geophysical cable 3. As a "labeled" fluid, a ferromagnetic fluid 5 is used, polarized in the presence of a magnetic field. Ferromagnetic fluid 5 consists of particles of nanometer size (10 nm or less) of magnetite, hematite or other material containing iron suspended in a carrier fluid (water), and as a measuring sensor 6, a device for measuring the magnetic field. The container 4 is placed in a pipe string 7 provided externally with a packer 8 mounted between the upper 1 and lower 2 layers. For example, a tubing string with a diameter of 89 mm is used as a pipe string 7, and several interconnected pipes with a diameter of 48 mm are used as a container, for example, four tubes depending on the volume of ferromagnetic fluid 5, which must be pumped into the upper formation 1. The volume of ferromagnetic fluid to be injected into the upper layer is determined by the geological service of the repair enterprise, depending on the injectivity of the upper layer 1. As a packer 8, a packer of any known design is used, n Example checkpoint anchor packer with a mechanical rotary setting-PRO-YAM2 YAG1 (F) or PRO-YAM3 YAG2 (F) (100 MPa) manufactured by Scientific-Production Company "packer" (of October, Bashkortostan, Russia). The feed unit is installed in the pipe string 7 above the packer 8 opposite the upper layer 1 and is made in the form of a filter 10 plugged with a plug 9 from the bottom and a perforated plug 11 rigidly installed in the pipe string 7 above the filter 9. The depressurization unit is made in the form of a stepped rod 12 with a large diameter D on top and a smaller diameter d on the bottom.

In the transport position, the step rod 12 with a large diameter D is hermetically installed in the central hole 13 made in the bottom of the container 4. In the working position, when the step rod 12 interacts with the perforated plug 11, the step rod 12 is able to axially move upward relative to the container 4 with the placement of the step rod 12 smaller diameter -d opposite the central hole 13 of the container 4. The measuring sensor 6 is installed on the lower end of the pipe string 7 opposite the lower layer 2.

The device operates as follows.

Mount the device in the well, as shown in figure 1, while the packer 8 is planted in the well below the sole of the upper formation 1, for example, 1-3 meters, while the borehole fluid (shown in Figs. 1, 2, 3 conditionally) through the holes of the filter 6 fills the pipe string 7. At the wellhead, the container 4 is filled with ferromagnetic fluid 5, while the container 4 is in the transport position, and the stepped rod 12 with a large diameter D is sealed in the central hole 13 made in the bottom of the container 4.

Container 4 is lowered into the pipe string 7 on the geophysical cable 3 of the geophysical elevator (not shown in FIGS. 1, 2, 3). The descent of the container 4 (see FIGS. 1 and 2) on the geophysical cable 3 is continued until the container 4 is completely unloaded onto the perforated a plug 11 of the supply unit, while the stepped rod 12 moves upward relative to the container 4 with the placement of the stepped rod 12 (see Fig. 2) with a smaller diameter d opposite the central hole 13 of the container 4 and the container 4 occupies an operating position. Thus, the depressurization unit of the container 4 is triggered.

The ferromagnetic fluid is emptied from the container 4 and through the supply unit: a perforated plug 11 and the holes of the filter 10, plugged from below by a plug 9, fill the borehole above the packer 8. The emptying of the ferromagnetic fluid from the container 4 is controlled by the weight indicator on the geophysical elevator, for example, the weight of the container with a ferromagnetic the liquid was 9 kN, and after emptying the container 4 and lifting it 1-2 m upwards using a geophysical cable 3, the weight of the container 4 is 5 kN. This means that container 4 has been emptied. The actuation of the feed and depressurization units is carried out mechanically (by unloading the container to the perforated plug 11 in the pipe string) and by monitoring the weight indicator, which increases the reliability of the device. The container 4 with the geophysical cable 3 is removed from the well. Removing the container 4 with the geophysical cable 3 before pushing the ferromagnetic fluid into the formation eliminates the need to seal the geophysical cable at the wellhead and possible leaks when pumping the fluid into the well.

Then, squeezing fluid is pumped into the pipe string 7 and it is pushed through the ferromagnetic fluid from the borehole through the perforated holes 14 into the upper formation 1. The presence of a packer 8 in the device structure allows to increase work efficiency and guarantee to push the ferromagnetic fluid from the well, i.e. excludes subsidence of ferromagnetic fluid at the bottom of the well.

In the presence of a casing flow, the ferromagnetic fluid 5 passes through the channel 15 (see Fig. 3) of the casing flow into the lower layer 2, from where it passes through the perforations 16 into the borehole below the packer 8, to which the measuring sensor 6 reacts (the signal changes over time) conducting magnetic field measurements in time.

Based on the data obtained from the measuring sensor 6, conclusions are drawn about the presence of behind-the-casing flows and the magnitude, for example:

- the absence of a change in signal indicates the absence of behind-the-casing flows (the entire volume of ferromagnetic fluid 5 is pumped into the upper reservoir 1);

- a change in the signal opposite the perforation holes 16 of the lower layer 2 is insignificant in time - insignificant casing flows;

- changes in the signal opposite the perforation holes 16 of the lower layer 2, growing rapidly in time, - annular flows are significant.

The accuracy of the presence (absence) of the annular flow and its intensity between the two layers increases due to the installation of the measuring sensor opposite the lower layer.

The proposed device allows you to:

- increase the reliability of the device;

- increase the efficiency of the device;

- increase the accuracy of the presence of annular flow between the two layers;

- eliminate the sealing of the geophysical cable at the wellhead.

Claims (1)

A device for monitoring annular flows between two layers, containing a container for a “labeled” liquid with supply and depressurization units, as well as a measuring sensor, launched on a geophysical cable, a ferromagnetic liquid is used as a “labeled” liquid, and devices for measuring are used as measuring sensors magnetic field, characterized in that the container is placed in a pipe string provided externally with a packer installed between the upper and lower layers, while the feed unit is installed in the pipe string e of the packer opposite the upper layer and is made in the form of a filter plugged from below and a perforated plug rigidly mounted in the pipe string above the filter, wherein the depressurization unit is made in the form of a stepped rod with a larger diameter D on top and a smaller diameter d on the bottom, while in the transport position the stepped rod large diameter D is hermetically installed in the central hole made in the bottom of the container, and in the working position, when the step rod interacts with the perforated plug of the feed unit, the step piece ok has the possibility of axial movement upward relative to the container with the placement of a stepped rod with a smaller diameter d opposite the central opening of the container, and the measuring sensor is mounted on the lower end of the pipe string opposite the lower layer.

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