RU2488147C2 - Method to exhaust vapours of cryogenic liquids from cryogenic system of submersible logging equipment - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: method is proposed to exhaust to surface vapours of cryogenic liquids from a cooling system of a submersible logging instrument, using cryogenic liquids for maintenance of low temperatures in some devices of the logging instrument (superconducting magnets, transceiving antennas, cryogenic sensors of various purpose). The output of the cryostat of the logging instrument is connected to atmosphere or an accumulating tank on the earth surface by means of one or several capillaries, which are simultaneously strands of a power cable included into a rope, on which the submersible logging instrument is suspended. To calculate the necessary radius of the capillary, the formula $$r_0=\sqrt[4]{\frac{8\eta LQ}{\pi \Delta P}}$$

and $$r_0=\sqrt[4]{\frac{8\eta LQ}{\pi \Delta Pn}}$$

is used depending on the number of strands-capillaries in the power cable.

EFFECT: higher intensity of logging instrument cooling.

1 dwg

Description

The invention relates to the field of manufacture, calibration and maintenance of instruments and devices for geophysical measurements. It can be used in logging equipment containing a cooling system using cryogenic fluids.

Known submersible logging devices incorporating a cryogenic system for cooling superconducting magnets and sensors for various purposes. The closest to the essence of the claimed invention is the known method [1] according to the patent US 6,411,087 B1. - January 25, 2002. "NMR Logging Tool with HI-TC Trap Field Magnet." In the known invention according to the patent US 6,411,087 B1, a superconducting magnet is used to create a strong constant magnetic field around the borehole zone of the well around the NMR logging tool. To achieve cryogenic temperatures, a superconducting magnet is placed in a cryostat with liquid helium or nitrogen, or a cryocooler is used for cooling. The disadvantage of the identified prototype [1] is the lack of reliable information on how to remove vapors of cryogenic fluid from the cryostat of the logging tool. In industrial and scientific equipment with cooling systems, which are a cryostat with a cryogenic liquid, during operation, the cryogenic liquid gradually turns into a vaporous state, which leads to the need to remove the generated vapors outside the cryostat. The generally accepted solution to this problem is the release of the generated vapors into the atmosphere, or their accumulation in special containers. However, under the conditions of using cryostats in submersible downhole tools with a diameter of about 150 mm, there is no possibility of releasing vapors beyond the cryostat, in principle, due to the presence of both high pressure values in the wellbore (typical values of ~ 50-100 atm) and high temperatures reached 150 ° C. Thus, the practical use of storage tanks is difficult for the above reasons and their excessive dimensions (sizes).

There is another possibility of achieving cryogenic temperatures in downhole tools - the use of cryocooler based cooling systems. However, cryocoolers, which, as is well known, do not require the removal of gaseous substances during their operation, currently do not find application in cooling systems for logging submersible devices due to their excessive overall dimensions (from 500 mm in diameter).

Thus, it is possible to state the following unresolved problems at the filing date of application materials, which do not allow in practice to realize the problem of well research using cryogenic cooling systems:

- the impossibility in a logging submersible device to remove vapors of cryogenic liquids outside the cryostat of the cooling system directly to the wellbore, which can lead to the destruction of wellhead equipment due to the fact that when 1 l of liquid helium is vaporized, up to 800 l of gas is formed under normal conditions;

- excessive required sizes of storage tanks for vapors of evaporating cryogenic fluids, which does not allow them to be placed in the wellbore;

- excessive dimensions of cryocoolers.

The aim of the invention is to remedy these disadvantages of the prototype, namely:

- providing the ability to divert the vapors of cryogenic liquids beyond the cryostat of the cooling system in a downhole tool at the wellhead,

- the exception of storage tanks for vapors of evaporating cryogenic fluids, which makes it possible to place equipment in the wellbore,

- a significant reduction in the size of the cooling system due to the design features of the claimed technical solution,

- improving the operational characteristics of logging equipment containing a cryogenic cooling system by solving the problem of removing vapor of evaporating cryogenic liquids through capillaries, which are also conductors of power supply, effective vapor removal allows, for example, to use superconducting magnets in immersion devices, characterized by several times stronger magnetic fields, which allows to increase the depth of measurements by NMR,

- providing the possibility of more efficient use of other equipment and sensors, whose operational characteristics improve when operating in the low temperature region, for example, it is well known that in radio frequency transmitting and receiving antennas thermal noise decreases as they cool,

In addition, the purpose of the alleged invention is:

- expanding the scope of logging equipment, as efficient removal of cryogenic liquid vapors allows the use of cryostat-based cooling systems with high cooling capacity in logging tools, which allows the use of new sensors and devices that work efficiently at low temperatures, but require intensive cooling.

- the alleged invention allows to increase the reliability of the measurement results by some methods, for example, by increasing the signal-to-noise ratio in RF systems at low temperatures, increasing the resonant frequency of NMR analyzers incorporating superconducting magnets, etc.

The goals are achieved by the fact that the removal of cryogenic fluid vapors to the surface from the cooling system of the logging tool operating in the wellbore is proposed to be carried out using a long metal capillary or a system of capillaries woven into a cable on which the logging tool is suspended in the well. At the same time, the capillaries are the veins of a power electric cable, through which electrical energy is supplied to devices operating as part of a logging tool.

The claimed technical solution is illustrated by the following materials:

The drawing schematically shows a well with cooled logging equipment, which, according to the applicant, is the most effective embodiment of the claimed technical solution.

The table shows the values of the dynamic viscosity of three gases: helium, nitrogen and carbon dioxide, which can be used to achieve these goals.

The invention is illustrated by the drawing, which schematically shows a well with cooled logging equipment, for example, containing superconducting magnets, measuring instruments, transceivers, antennas. The drawing shows a description of the claimed device:

The claimed device consists of a measuring logging tool 1 with a cryostat 2, inside of which there is a cooled logging equipment filled with liquefied gas, for example, helium; compressor 3; the attachment point of the cable 4 to the logging tool 1; a cable 5 containing tubular electrical cables 6, which are simultaneously capillaries for the removal of vapors of cryogenic liquids, with high tensile strength 7.

Since it is impossible to completely isolate the internal volume of the device from the influx of heat from the external environment (well), the cryogenic components of the cooling system turn into a vapor state throughout the entire time the device is operating in the well. Various substances are used as cryogenic components of the cooling system. Due to its physical and operational properties, helium, nitrogen, and carbon dioxide are the most convenient for use. The cryogenic components evaporating from the cryostat rise to the surface along the capillary (or system of capillaries). For gas to flow through the capillary, a pressure drop must be present at its two ends, due to which the gas moves. The necessary pressure at the inlet to the capillary is created using a compressor (3), connected by the inlet to the output of the cryostat 2.

The removal of vapors of cryogenic liquids when moving along a capillary or a system of capillaries is accompanied by overcoming of viscous friction forces.

The table shows the values of the dynamic viscosity of three gases: helium, nitrogen, and carbon dioxide.

The required internal radius of the capillary is calculated by the experimental formula:

$$r_0=\sqrt[\mathrm{four}]{\frac{8\eta LQ}{\pi \Delta P}}\left(\mathrm{one}\right)$$

where r ₀ is the radius of the capillary, ΔP is the pressure drop at the inlet and outlet of the capillary, L is the length of the capillary, η is the dynamic viscosity of the gas, Q is the gas flow rate at the outlet of the capillary per unit time (m ³ / s).

Table Dynamic viscosity of helium, nitrogen and carbon dioxide. Parameter, designation Value Units Dynamic viscosity 1.89 · 10 ^-5 Pass helium gas at ns, η Dynamic viscosity 1.67 · 10 ^-5 Pass gaseous nitrogen at n.u., η The dynamic viscosity of gaseous carbon dioxide at nu, η 1.4 · 10 ^-5 Pass

The veins of the electric cable are made in the form of capillaries, the inner diameter of which is calculated by the formula (1). The cores of the electric cable are capillaries through which the vapor of cryogenic liquids is removed from the cooling system of the logging tool.

If the electric cable contains more than one core-capillary, then the internal radius of each capillary is calculated by the formula:

$$r_0=\sqrt[\mathrm{four}]{\frac{8\eta LQ}{\pi \Delta Pn}},\left(2\right)$$

where n is the number of core-capillaries in the electric cable.

The example application of the proposed invention shows its usefulness for the removal of gaseous products of evaporation of cryogenic liquids from the cooling system of submersible logging tools. The use of the proposed method improves the performance of logging equipment, expands the scope by increasing the efficiency of the cooling system. In particular, the inventive method allows the use in logging tools of superconducting magnets that generate permanent magnetic fields of high intensity, which contributes to a greater depth of research and greater detail of the information received, that is, it expands the scope of cryogenic logging equipment, increases the reliability of the information received.

The claimed technical solution satisfies the criterion of "novelty" presented to the invention, since when determining the level of technology there is no means that are characterized by identical features (that is, they coincide in the function performed by them, the technical result (s) achieved, the form of execution of these features) all the features listed in the claims, including a description of the purpose.

The claimed technical solution meets the criterion of "inventive step" for inventions, since the applicant has not identified technical solutions from the studied prior art on the filing date of the application materials that have features that match the distinctive features of the claimed technical solution that ensure the achievement of the totality of the stated goals through the used declared signs.

The claimed technical solution meets the criterion of "industrial applicability" to the invention, because it can be implemented in industrial production of logging equipment, while the fundamental possibility of implementing the claimed solution has been tested in the lab. KFU conditions at the pilot plant.

USED SOURCES

1 Nongqiang Fan, Wei-Kan Chu, NMR Logging Tool with HI-TC Trap Field Magnet // PN US 6,411,087 B1. - January 25, 2002.

Claims (1)

A method for removing cryogenic fluids to the surface of a cryogenic logs cooling system using cryogenic fluids to maintain low temperatures in some logging tool devices (such as superconducting magnets, transceiving antennas, cryogenic sensors for various purposes), characterized in that the output of the cryostat of the logging tool is connected with the atmosphere or storage tank on the surface of the earth through one or more capillaries that are simultaneously veins and an electric cable, a component cable, on which is suspended the dip logging tool, wherein for calculating the required capillary radius formula is used $$r_0=\sqrt[\mathrm{four}]{\frac{8\eta LQ}{\pi \Delta P}}$$

or $$r_0=\sqrt[\mathrm{four}]{\frac{8\eta LQ}{\pi \Delta Pn}}$$

depending on the number of core-capillaries in the electric cable,
where r ₀ is the radius of the capillary;
ΔР - pressure drop at the inlet and outlet of the capillary;
L is the length of the capillary;
η is the dynamic viscosity of the gas;
Q is the gas flow rate at the outlet of the capillary per unit time, m ³ / s.