JPH09178573A - Method and apparatus for detecting temperature of geothermal well - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide method and apparatus for measuring the temperature in mine shaft being used for detecting the temperature of geothermal well having high stratum temperature accurately. SOLUTION: A temperature measuring probe containing a plurality of kinds of temperature indicating agent 2 having different melting temperature performance is lowered down into a geothermal well by means of a wire rope and held at an inspecting position of required depth. It is then recovered onto the ground and the stratum temperature is measured by checking the fusion of each temperature indicating agent 2. A plurality of containing carriers 3, each provided with a temperature indicating agent containing space, are encapsulated in a tubular temperature measuring probe body 1 while being coupled in the axial direction. A plurality of kinds of temperature indicating agent 2 having different melting temperature performance is contained, individually, in the containing space of carrier 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used to measure the temperature inside a well of a geothermal well for geothermal power generation, and particularly, among geothermal production wells, observation wells, reduction wells and the like used for geothermal power generation. This is a proposal for a method of logging the well temperature with a particularly high formation temperature (≧ 400 ℃) by using a temperature indicator, and a logging device for measuring the well temperature used during this well logging.

[0002]

2. Description of the Related Art Geothermal wells that are excavated to collect geothermal steam for geothermal power generation, and reduction wells that reduce the hot water separated from the geothermal steam into the stratum, are for research and analysis. Various loggings such as temperature, pressure and flow velocity are performed. One of these well loggings is temperature logging.

The above-mentioned temperature logging means, for example, when it is desired to know the range of high temperature regions that can be developed by grasping the temperature distribution of the whole area by investigating the temperature inside the well of each heat producing well, or , When distinguishing whether each well is located in the rising area, falling area of natural convection, or in the heat conduction area where natural convection does not occur, the flow of low-temperature water such as reduced hot water and surface water is also clear. It is something you do when you want to.

For this purpose, it is necessary to accurately measure the temperature inside the well of the geothermal well, that is, the temperature of the geothermal fluid.
Then, for the measurement, a dedicated thermometer for high temperature, which is used by descending into the well, is required. In general, there are various thermometers such as thermocouple thermometers, resistance thermometers, fiber optic thermometers, and infrared thermometers, in addition to those that utilize the thermal expansion of gas, liquid, and solid. Each has different characteristics, and we select and use the appropriate one according to the characteristics. However, if the object to be measured is special, for example, in the case of the geothermal well described above, the measurement position is 2000
Since it is underground to a depth of more than m and is intended for geothermal fluids in wells, special temperature measuring methods and measuring devices must be used.

Conventionally, as a method and apparatus for performing such wellbore temperature logging, for example, for wellbore temperature measurement at 315 ° C. or lower, a platinum thermometer is used using a cable called an armored cable with an electric wire inserted therein. ing. Also,
Regarding the temperature in the well with hot parts exceeding 315 ℃,
It was measured with a mechanical thermometer (bimetal thermometer) with an upper limit of 418 ° C.

[0006]

However, with these known temperature measuring methods, it is not possible to perform wellbore temperature logging having a formation temperature exceeding 418 ° C. This is because recent geothermal wells (especially production wells) for geothermal power generation are located in geothermal areas that have high-temperature reservoirs that eject high-temperature fluids above 418 ℃ and sometimes above 500 ℃ in order to improve power generation efficiency. Since it is often drilled and the excavation depth is large, it is the actual situation that the above-mentioned conventional temperature measuring method and apparatus cannot sufficiently cope with the situation.

Therefore, the main object of the present invention is to develop a new temperature logging technique for measuring the temperature inside a well such as a geothermal well. Another object of the present invention is to propose a well bore temperature measuring method and measuring apparatus for accurately performing temperature logging of a geothermal well having a high formation temperature.

[0008]

As a geothermal well temperature logging method suitable for the above purpose, the present invention is characterized by utilizing a temperature indicator instead of using a conventional platinum thermometer or bimetal thermometer. We propose a well logging method and its equipment. That is, the present invention, in the well of the geothermal well, after lowering the temperature measuring probe that stores a plurality of types of temperature indicating agents having different melting performance with respect to temperature with a wire and holding it at the logging position of the required depth. Collect the temperature probe on the ground,
A temperature logging method for geothermal wells, characterized in that the geological temperature is measured depending on whether or not each of the temperature indicators melts. Further, the present invention, in the above-mentioned temperature logging, a tubular temperature measuring probe main body having a cap at the tip and anchoring a suspending wire via a wire socket at the rear end,
A plurality of storage carriers enclosed in this main body can be stacked and connected in the axial direction with a packing interposed, and each storage carrier is provided with a temperature indicating agent storage space.
A temperature logging device is used in which a plurality of types of temperature indicating agents having different melting performances with respect to temperature are individually stored in the accommodation space of each storage carrier.
It should be noted that packing is not necessarily required to connect the storage carriers.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a technique developed for temperature logging of geothermal wells for geothermal power generation, and particularly for geothermal production having a geological formation with a high temperature such that the measurement position in the well exceeds 418 ° C. The method is particularly advantageously applied to well logging, but of course, it can also be applied to observation wells, reducing wells, and hot spring wells.

As described above, the characteristic feature of the temperature logging according to the present invention lies in the use of a thermochromic agent so that it can withstand the measurement of geothermal fluids exceeding 500 ° C. Here, the thermochromic agent, especially the irreversible thermochromic agent which is advantageously applicable to the present invention, includes those based on a thermal decomposition method, a sublimation phenomenon method, a chemical reaction method, a melting phenomenon method, an electron transfer method, a PH change, etc. However, in the temperature logging method of the present invention, a melting phenomenon method having a characteristic that it melts clearly when a specific temperature is reached, and does not return to its original shape even when the temperature is lowered, is particularly advantageously suited. This method will be described in detail.

The above-mentioned melting type temperature indicator utilizes the phenomenon that a crystalline solid substance becomes a liquid when the temperature rises. Once liquefied, it solidifies by cooling but does not return to its original form. . In contrast to the thermal decomposition method that utilizes the discoloration due to the chemical change of the solid,
Since it simply utilizes the physical change from solid to liquid, it is constant with almost no effect of other conditions on its transition temperature, which has the advantage of enabling accurate temperature measurement during temperature measurement. is there.

The product form of this melting type temperature indicator is as follows:
There are rod-shaped, granular, liquid (paint-shaped) or label-shaped (seal-shaped), but the rod-shaped,
It is granular. For example, pressure molding a molten material,
It is solidified into a rod shape or a granular shape, and the usage method is that the probe body is heated by the temperature measurement target, for example, the geothermal fluid in the well, and the storage carrier in the probe body is heated, so that the surface of the temperature indicator melts. Whether or not the temperature of the geothermal fluid is measured. The indicated temperature is the temperature of the highest melting temperature indicator among the enclosed temperature indicators.

Next, a specific method of temperature logging of the geothermal well according to the present invention will be described. For logging, the temperature probe is dropped into the well of a geothermal well where an attempt is made for temperature logging. At this time, in the temperature measuring probe, there are 5 to 10 temperature indicating agents that melt at different temperatures in the cylinder axis direction.
Use the one enclosed with the type and storage carrier. This temperature probe is used to lower the inside of the well using a wire and guide it into the geothermal fluid at the bottom of the well (2000 to 4000 m) at a predetermined depth, hold it there for about 30 minutes to 1 hour, and then wind the wire. And collect it on the ground. Then, the storage carrier in which the temperature indicator is enclosed is taken out from the temperature measuring probe, and the temperature of the enclosed temperature indicator up to which the surface has melted can be confirmed by observing the shape deformation, if necessary.
Specify the indicated temperature and use it as the measured value.

As the temperature indicator to be used, compounds having various melting temperatures, for example, inorganic compounds such as potassium compounds, sodium compounds, barium compounds, tungsten compounds, chromium compounds or molybdenum compounds are used, and these are rod-shaped. Encapsulate (crayon) or granular (tablet or pellet) into the temperature probe.

Next, as an apparatus used for the above-mentioned temperature logging, in the present invention, an apparatus having a structure as shown in FIG. 1 is used. Reference numeral 1 shown in the figure is a metal-made tubular temperature measuring probe main body having a cap 1a at its tip (falling end) which is fixed by welding or detachably fitted, and its rear end.
At the (rear end) portion, the suspension wire 4 is anchored via the wire socket 1b.

In the temperature measuring probe body 1, a storage carrier 3 for accommodating the above-mentioned various temperature indicating agents 2 ...
However, a plurality of them are sealed in a stacked state in the cylinder axis direction. That is, the storage carrier 3 has a cup-like shape having a storage space 5 for storing the temperature indicator 2, and can be stacked in the cylinder axis direction (vertical direction) and connected to each other. By inserting a metal packing 6 such as a seal ring, the storage carriers 3, that is, the storage spaces 5 can be isolated from each other. The metal packing 6 used for separating each storage carrier 3 welds or O-rings the cap 1a, the wire socket 1b and the temperature measuring probe main body,
It is not always necessary to use it when sealing with metal packing or the like.

The size of the temperature-measuring probe main body 1 depends on the number of storage carriers 3 to be enclosed, that is, the number of temperature-indicating agents 2 to be enclosed. Be long enough for Regarding the number of the thermoindicators enclosed,
Select appropriately according to the purpose and measurement range.

[0018]

EXAMPLE This example is an example in which temperature logging was performed in a survey well for geothermal power generation having a high-temperature geothermal layer that cannot be measured by a conventional apparatus. The measurement environment is summarized in Table 1. Regarding the used temperature indicator, seven types of pellets (P), six types of crayons (M) and nine types of pellets were stored in the storage carrier in the temperature probe body shown in Fig. 1. And provided for measurement. Table 2 shows the measurement results. The main component of the used sample (indicator) is (The crayon-shaped temperature indicator M is a crayon-shaped product obtained by adding a small amount of a binder and a dye to a hot-melt compound and pressurizing it, and the heat-meltable compound varies depending on the indicated temperature .... .)

[0019]

[Table 1]

[0020]

[Table 2]

As shown in Table 2, according to the temperature evaluation with a thermochromic agent, the first: pellets (P-399, 427, 482, 500, 510,
538, 550) ・ Pellets (P-399, 427, 482, 500) are surface-melted. -Pellets (P-510, 538, 550) are not surface-melted. 2nd: Crayons (M-395, 430, 460, 490, 520,
545) and pellets (P-343, 371, 399, 427, 482, 500,
510, 538, 550) ・ Crayons (M-395, 430, 460, 490) are surface-melted.・ Crayon (M-520, 545) does not melt on the surface. -Pellets (P-343, 371, 399, 427, 482, 500) are surface-melted. -Pellets (P-510, 538, 550) are not surface-melted. Therefore, the temperature of the well (bottom) formation in this example is 5
It is estimated to be 00 to 510 ℃. In this way, the accurate temperature of the hot geothermal layer could be measured.

[0022]

As described above, according to the present invention, 41
It is possible to accurately measure the temperature inside a well of a geothermal well having a high-temperature geothermal layer exceeding 8 ℃.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a main part of a temperature logging device.

[Explanation of symbols]

 1 Temperature probe main body 2 Temperature indicator 3 Storage carrier 4 Suspending wire 5 Storage space 6 Packing

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[Procedure amendment]

[Submission date] February 1, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

[0018]

EXAMPLE This example is an example in which temperature logging was performed in a survey well for geothermal power generation having a high-temperature geothermal layer that cannot be measured by a conventional apparatus. The measurement environment is summarized in Table 1. Regarding the used temperature indicator, seven types of pellets (P), six types of crayons (M) and nine types of pellets were stored in the storage carrier in the temperature probe body shown in Fig. 1. And provided for measurement. Table 2 shows the measurement results. Incidentally, the samples used (temperature indicating agents), bets below
It is a cage. (The crayon-shaped temperature indicator M is a crayon-shaped product obtained by adding a small amount of a binder and a dye to a hot-melt compound and pressurizing it, and the heat-meltable compound varies depending on the indicated temperature .... The numerical value in parentheses is the indicated temperature. .) 【

Claims (2)

[Claims] 1. A thermometer probe containing a plurality of types of temperature indicating agents having different melting performances with respect to temperature is lowered by a wire into a well of a geothermal well, and the temperature measuring probe is held at a logging position of a required depth. A temperature logging method for a geothermal well, characterized in that the temperature measuring probe is collected on the ground, and the formation temperature is measured by the presence or absence of melting of each of the temperature indicating agents. 2. A tubular temperature measuring probe main body having a cap at the front end and a suspension wire being anchored at the rear end via a wire socket, and a temperature indicator enclosed in the main body. A plurality of cup-shaped storage carriers that have an agent storage space and can be stacked and connected in the axial direction by interposing packings therebetween, and the storage space of each storage carrier has a plurality of melting performances that differ depending on the temperature. A logging device for measuring the temperature inside a well, characterized in that each type of thermometer is stored separately.