JP2020100676A - Filler and use thereof - Google Patents

Abstract

To provide a filler or the like that can temporarily fill pores even under a high temperature environment.SOLUTION: A filler is for filling a pit wall. The filler contains first powder and second powder with different compositions. The first powder is powder formed from a resin composition containing an aromatic isocyanate polyurethane resin, and the second powder is powder formed from a resin composition containing an aliphatic isocyanate polyurethane resin.SELECTED DRAWING: None

Description

The present invention relates to a sealing agent for temporarily sealing a pit wall and its use.

Oil and gas produced from conventional oil wells and hydrocarbon resources such as shale gas and shale oil, which have been attracting attention in recent years, are generally drilled in rock formations rich in oil and gas. Produced through wells.

For drilling and finishing work of wells, excavation generated from around the drill during well drilling is transported to the ground surface, underground pressure is adjusted to maintain stability inside the well, suppress geological collapse, and A circulating fluid (muddy water or finishing fluid) is used to cool the.

Here, if the reservoir, which is the production layer, is a highly permeable stratum, or if there is a natural fracture (crack) in the shale layer, the fluid will be washed away through the highly permeable strata and the cracks in the well wall, and the circulating mud The volume may decrease and the muddy column pressure may decrease.

As a result, not only is there a risk of destabilizing the inside of the well, reducing the efficiency of drilling and processing work, and causing production failure of the reservoir due to the fluid remaining in the reservoir, as well as highly functional and expensive fluid. There is a possibility that the excavation cost will increase due to the outflow of water. Therefore, in order to suppress the outflow of fluid as much as possible, a method of temporarily sealing the pit wall using a degradable sealing agent is used.

Calcium carbonate or the like is generally used as the eye-blocking agent, but when shifting to production, it is necessary to decompose calcium carbonate, which is the eye-blocking agent, by acid treatment. In addition to the work time required for carrying out this acid treatment, insufficient acid treatment may reduce the amount of resource recovery due to insoluble residues such as residual calcium carbonate, which is a sealing agent.

Therefore, in order to reduce the acid treatment cost while shortening the work time required for the acid treatment and prevent the reduction of the amount of resource recovery due to the remaining of the sealing agent, it is disassembled after a predetermined period and the sealing function is Eye-catching agents using degradable materials that disappear are attracting attention.

Patent Document 1 describes a synthetic resin-containing sealing agent having a sealing function for a period of 40 days or less at a temperature of 93°C (200°F) to 204°C (400°F).

Patent Documents 2 and 3 describe a sealing agent using a decomposable material containing an aliphatic polyester resin such as polylactic acid and polyglycolic acid.

International publication WO2015/072317 U.S. Patent Application Publication No. 2008/0139417 US Patent Application Publication No. 2008/0070805

With the decrease in the amount of oil and gas recoverable in individual wells and the increase in energy consumption that increases year by year as production progresses, oil development moves from easy locations to more severe locations, and polar areas with severe weather conditions. There is a demand for deep well drilling in the deep water well development area of the ocean. In particular, as the depth of the well increases, the conditions for laying the well become severer. For example, at a high depth of more than about 3000 m in the ground, a high temperature environment of about 110° C. or higher is obtained depending on the location. Therefore, there is a demand for a sealing agent that can be temporarily sealed even in such a high temperature environment.

Further, the fracture has various widths, among them, the width of the crack in the opening or inside of the fracture is several mm or less, or several hundred μm to several μm in the highly permeable stratum, especially around 50 μm. There is a need for a sealing agent that can temporarily seal the narrow pores.

However, Patent Documents 1 to 3 do not describe any sealing agent capable of temporarily sealing the pores in an appropriate time even in a high temperature environment.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a sealing agent or the like capable of suitably temporarily sealing pores even in a high temperature environment.

In order to solve the above-mentioned problems, the present inventors have made earnest studies, and as a result, have reached the following present invention.

A sealing agent (embodiment 1) according to the present invention is a sealing agent for sealing a pit wall, wherein the sealing agent includes a first powder and a second powder having different compositions from each other. One powder is a powder formed from a resin composition containing an aromatic isocyanate polyurethane resin, and the second powder is a powder formed from a resin composition containing an aliphatic isocyanate polyurethane resin. It is characterized by

Further, a sealing agent (Aspect 2) according to the present invention is a sealing agent for sealing a pit wall, wherein the sealing agent is a powder of a resin composition containing a thermoplastic polyurethane resin, and The thermoplastic polyurethane resin is characterized by being an aliphatic isocyanate-based polyurethane resin and an aromatic isocyanate-based polyurethane resin.

Further, in the sealing agent (Aspect 1) according to the present invention, the weight ratio of the first powder to the second powder is preferably in the range of 40:60 to 99:1.

In the sealing agent (Aspect 2) according to the present invention, the weight ratio of the aliphatic isocyanate polyurethane resin to the aromatic isocyanate polyurethane resin is in the range of 80:20 to 0:100. preferable.

Further, in the sealing agent (Aspect 1 and Aspect 2) according to the present invention, the aromatic isocyanate constituting the aromatic isocyanate polyurethane resin is selected from diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and naphthalene diisocyanate. The aliphatic isocyanate that is at least one aromatic isocyanate selected from the group consisting of the aliphatic isocyanate-based polyurethane resin is hexamethylene diisocyanate, isophorone diisocyanate, norbornane diisocyanate, hydrogenated xylylene diisocyanate, and dicyclohexyl. It is preferably at least one aliphatic isocyanate selected from the group consisting of methane diisocyanate.

Moreover, in the sealing agent (Aspect 1 and Aspect 2) according to the present invention, at least one of the aromatic isocyanate polyurethane resin and the aliphatic isocyanate polyurethane resin contains at least a polyester skeleton. preferable.

In addition, in the sealing agent (Aspect 1 and Aspect 2) according to the present invention, a sheet-shaped molded product formed from a resin composition for forming a powder containing the aromatic isocyanate polyurethane resin at 23° C. The durometer type D hardness is preferably 29 or more.

The well fluid according to the present invention is characterized by containing the above-mentioned plugging agent (Aspect 1 and Aspect 2).

Further, the well drilling method according to the present invention is characterized in that the above-mentioned filling agent (Aspect 1 and Aspect 2) is used to perform temporary filling.

INDUSTRIAL APPLICABILITY The present invention has an effect of being able to provide a sealing agent or the like capable of temporarily sealing pores even in a high temperature environment.

It is a figure which shows schematically the plug testing machine used for the sealing test by the sealing agent which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described in detail.

<Sealing agent (first embodiment)>
In the present embodiment, the time-degradable-lost circulation materials generally means a fluid into a well wall having a highly permeable strata or a crack layer in various steps of well drilling. A material mixed with circulating fluid such as drilling mud or finishing fluid for the purpose of temporarily stopping runoff.

The sealing agent according to the present invention is a powder blend containing a first powder and a second powder, and the first powder and the second powder have different resin compositions from each other.

In the present embodiment, the first powder contained in the sealing agent is a powder formed from a resin composition containing an aromatic isocyanate polyurethane resin, and the second powder is an aliphatic isocyanate polyurethane resin. It is a powder formed from the resin composition containing. Here, the resin composition containing the aromatic isocyanate-based polyurethane resin generally has a slow decomposition rate. Further, the aliphatic isocyanate-based polyurethane resin has a higher decomposition rate than the aromatic isocyanate-based polyurethane resin.

When a powder formed from a mixture of two different powders having different decomposition rates is used as a sealing agent, the mechanical strength is lowered or the particle size is reduced due to the decomposition of the powder. The powder with a high rate passes through the gap between the powders with a slow decomposition rate to recover the voids, and eventually the sealing is released. As a result, it is possible to preferably control the stoppage maintenance time. Further, for example, even in a high temperature environment of 110° C. or higher and 200° C. or lower, pores having a width of 1 μm or more and 800 μm or less, more preferably pores having a width of 10 μm or more and 500 μm or less can be temporarily stopped.

The sealing agent according to the present embodiment has a strength reduction due to the decomposition of the sealing agent and the elution of the generated decomposition product, so that the sealing portion that seals the pores with the sealing agent has a pressure applied to the sealing. The time until it is unbearable, deformed or disintegrated, and the sealing is released (stopping maintenance time) is 110° C. or more and 200° C. or less, for example, 1 hour or more and 960 hours (40 days) or less. be able to. As a result, it is possible to release the plugging by the end of the various works while securing various working times inside and outside the well during the plugging.

The weight ratio of the first powder to the second powder is preferably in the range of 40:60 to 99:1. As a result, it is possible to obtain a sealing agent that can be suitably stopped temporarily until various operations are completed under a high temperature environment.

The median diameter (50% D) of each of the first powder and the second powder is preferably 50 μm or more and 800 μm or less, more preferably 100 μm or more and 750 μm or less, and 300 μm or more and 700 μm or less. Is more preferable. This makes it more difficult for the resin composition or the like having reduced strength to leak from the sealing portion, and it is possible to more suitably temporarily seal the pores at high temperatures. It is more preferable that the difference in median diameter between the first powder and the second powder is small.

The first powder is formed into a powder form by melt-kneading an aromatic isocyanate-based polyurethane resin or the like and pulverizing the obtained resin composition (first resin composition). Similarly, the second powder is formed into a powder form by melt-kneading an aliphatic isocyanate-based polyurethane resin or the like and pulverizing the obtained resin composition (second resin composition).

The heating temperature and time during melt kneading may be appropriately adjusted in consideration of the melting point of the aromatic isocyanate-based polyurethane resin or the aliphatic isocyanate-based polyurethane resin. The first powder and the second powder can be obtained by appropriately pulverizing each resin composition obtained by melt-kneading by a known method.

The resin composition containing the aromatic isocyanate polyurethane resin or the resin composition containing the aliphatic isocyanate polyurethane resin may be pulverized into powder by freeze pulverization, for example. This makes it possible to obtain a sealing agent in which the median diameter of particles formed from these resin compositions is small.

The shape of the particles of the first powder and the second powder is not limited, but may be spherical, scale-like, plate-like, ellipsoidal, prismatic, rod-like, star-like, polygonal-like, and so on. It may be fibrous (short fibers) or the like, or may be porous with small holes. Further, of these, a combination of those having different shapes and a combination of those having different particle sizes may be used.

[Resin composition]
The first resin composition is a resin composition for forming the first powder, and contains an aromatic isocyanate polyurethane resin. The second resin composition is a resin composition for forming the second powder, and contains an aliphatic isocyanate polyurethane resin.

By including the aromatic isocyanate-based polyurethane resin in the first resin composition, the durometer type D hardness at 23° C. of the sheet-shaped molded product formed from the resin composition can be suitably adjusted to 29 or more. The first resin composition may have a hardness (durometer type D hardness at 23° C.) of 29 or more. The durometer type D hardness at 23° C. is preferably 29 or more and 80 or less, and more preferably 29 or more and 75 or less. This makes it possible to suitably obtain the first powder having a relatively slow decomposition rate.

The first resin composition preferably comprises an aromatic isocyanate-based polyurethane resin, but when the aliphatic isocyanate-based polyurethane resin is included, the weight ratio of the aliphatic isocyanate-based polyurethane resin and the aromatic isocyanate-based polyurethane resin is It is preferably in the range of 80:20 to 0:100, and the weight ratio of the aliphatic isocyanate polyurethane resin is smaller than the weight ratio of the aliphatic isocyanate polyurethane resin contained in the second resin composition. Thereby, the first resin composition having a durometer type D hardness at 23° C. of 29 or more and 80 or less can be obtained, and the first powder having a relatively slower decomposition rate than the second powder can be suitably obtained. You can

Since the second resin composition contains the aliphatic isocyanate polyurethane resin, the durometer type D hardness at 23° C. of the sheet-shaped molded article formed from the resin composition is the same as the durometer D hardness of the first resin composition. Is different. Therefore, it is possible to form the second powder having a different decomposition rate from the first powder having a relatively low decomposition rate.

The durometer type D hardness at 23° C. of the sheet-shaped molded article formed from the second resin composition may be smaller than 29, and the durometer type D hardness at 23° C. may be 29 or more, but 23° C. The durometer type D hardness in is more preferably 20 or more and 65 or less.

The second resin composition preferably comprises an aliphatic isocyanate-based polyurethane resin, or, when containing an aromatic isocyanate-based polyurethane resin, the weight ratio of the aliphatic isocyanate-based polyurethane resin and the aromatic isocyanate-based polyurethane resin. Is preferably in the range of 20:80 to 100:0, and the weight ratio of the aliphatic isocyanate polyurethane resin is larger than the weight ratio of the aliphatic isocyanate polyurethane resin contained in the first resin composition. Thereby, the second resin composition having a durometer type D hardness at 23° C. of 20 or more and 65 or less can be obtained, and the second powder having a relatively faster decomposition rate than the first powder can be suitably obtained. You can

The durometer type D hardness of the first resin composition and the second resin composition may be measured using a molded body formed using these resin compositions. The durometer type D hardness can be measured according to ISO7619/JIS K6253. The measurement position of the hardness measuring test piece is 12 mm or more inside from the end of the test piece. When measuring hardness at a plurality of locations, the distance between the measurement points is 6 mm or more. The thickness of the test piece is usually 6 mm or more. As the molded body (test piece) of the resin composition for measuring the durometer type D hardness, two sheets obtained by melt-extruding the resin composition in a sheet form are laminated in accordance with ISO7619/JIS K 6253. The one with 6 mm is used. When the resin composition is a thermoplastic polyurethane resin, the molded body is a part of the resin composition obtained by melt-kneading the polyurethane resin when producing the sealing agent with a known kneading extruder or the like. Can be sampled and, if necessary, formed into a sheet by using a processing method such as hot pressing. When the resin composition is a thermosetting polyurethane resin, for example, the thermosetting polyurethane resin raw material before curing is poured into a mold for manufacturing a test piece for hardness measurement, and after defoaming, it is heated to a predetermined temperature for a predetermined time. Hold. Thereby, the resin raw material can be cured to obtain a test piece. In addition, before the test, the test piece may be heat-treated at a predetermined temperature for a predetermined time in order to remove mechanical strain during molding and stabilize the hardness, if necessary.

(Aromatic isocyanate-based polyurethane resin)
The aromatic isocyanate-based polyurethane resin is a polyurethane resin having a structure derived from an isocyanate having an aromatic ring. That is, in the present specification, the “aromatic isocyanate-based polyurethane resin” is defined by the fact that the isocyanate for producing the polyurethane resin is the “aromatic isocyanate”. That is, the “aromatic isocyanate-based polyurethane resin” is not defined by whether or not the skeleton such as the polyester skeleton constituting the main chain of the polyurethane resin has the “aromatic” hydrocarbon skeleton.

The aromatic isocyanate-based polyurethane resin is a polyurethane resin produced using an aromatic isocyanate, and the aromatic isocyanate typically includes an aromatic diisocyanate. Here, examples of the aromatic diisocyanate include diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), and naphthalene diisocyanate (NDI). The aromatic isocyanate-based polyurethane resin may contain an aromatic diisocyanate and an isocyanurate compound (trimer) of these aromatic diisocyanates in combination. Among them, the aromatic isocyanate is more preferably diphenylmethane diisocyanate (MDI). In this specification, an aromatic isocyanate-based polyurethane resin produced by using diphenylmethane diisocyanate (MDI) may be referred to as a diphenylmethane diisocyanate-based polyurethane resin (MDI-based polyurethane resin).

The skeleton constituting the main chain of the aromatic isocyanate-based polyurethane resin includes, for example, a polyether skeleton, a polyester skeleton, a polyether ester skeleton, and a poly(meth)acrylate skeleton, and these skeletons are aromatic isocyanate-based polyurethanes. It may coexist as the main chain of the resin. Among them, the skeleton constituting the main chain of the aromatic isocyanate-based polyurethane resin is either or both of a polyester skeleton and a polyetherester skeleton, from the viewpoint that desired hardness and hydrolyzability can be obtained. Is preferred. In particular, a polyol containing a polyester skeleton or a polyether ester skeleton is called a polyester polyol, and contains at least a polyester skeleton. For example, by reacting a polyester polyol with an aromatic isocyanate, an aromatic isocyanate system suitable as a sealing agent is used. A polyurethane resin is obtained.

Here, the polyester skeleton is not limited, but is formed by ring-opening polymerization of glycolide, α-acetolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone and the like. Skeletons, dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid, and phthalic acid, and ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,6- It may be a skeleton formed by condensation with a diol such as hexanediol, or a skeleton formed by combining these.

Further, the polyether ester skeleton may be a copolymer of a polyether constituent unit having 1 to 6 carbon atoms in the repeating unit and a polyester constituent unit having 2 to 20 carbon atoms in the repeating unit. Here, examples of the polyether constitutional unit include polyacetal, polyethylene glycol and polytetramethylene glycol, and examples of the polyester constitutional unit include the above polyester skeleton.

The weight average molecular weight of the aromatic isocyanate-based polyurethane resin is preferably 5,000 or more and 100,000 or less, more preferably 10,000 or more and 70,000 or less, and 15,000 or more, Most preferably, it is 50,000 or less. When the weight average molecular weight of the aromatic isocyanate-based polyurethane resin is 5,000 or more and 100,000 or less, a sealing agent having appropriate hydrolyzability can be obtained.

As the aromatic isocyanate-based polyurethane resin, those represented by the following chemical formula (I) are typically preferable.

Here, in the chemical formula (I), m ¹ is an integer of 1 or more and 10 or less, and n ¹ is an integer of 5 or more and 40 or less.

Examples of the MDI-based polyurethane resin product represented by the chemical formula (I) include Pandex (registered trademark) T-5070 manufactured by DIC Covestropolymer Co., Ltd., and the like.

(Aliphatic isocyanate-based polyurethane resin)
The aliphatic isocyanate-based polyurethane resin is a polyurethane resin having a structure derived from an acyclic or cyclic aliphatic isocyanate. That is, in the present specification, the “aliphatic isocyanate-based polyurethane resin” is defined by the fact that the isocyanate for producing the polyurethane resin is the “aliphatic isocyanate”. That is, the “aliphatic isocyanate-based polyurethane resin” is not defined depending on whether or not the skeleton such as the polyester skeleton constituting the main chain of the polyurethane resin has the “aliphatic” hydrocarbon skeleton.

The aliphatic isocyanate-based polyurethane resin is a polyurethane resin produced by using an aliphatic isocyanate, and the aliphatic isocyanate typically includes an aliphatic diisocyanate. Here, examples of the aliphatic diisocyanate include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), norbornane diisocyanate (NBDI), hydrogenated xylylene diisocyanate (H6XDI), and dicyclohexylmethane diisocyanate. The aliphatic isocyanate-based polyurethane resin may contain an aliphatic diisocyanate and an isocyanurate compound (trimer) of these aliphatic diisocyanates in combination. Among them, the aliphatic isocyanate is more preferably hexamethylene diisocyanate (HDI). In addition, in this specification, the aliphatic isocyanate type polyurethane resin produced using hexamethylene diisocyanate (HDI) may be called a hexamethylene diisocyanate type polyurethane resin (HDI type polyurethane resin).

The skeleton that constitutes the main chain of the aliphatic isocyanate-based polyurethane resin is the same as the skeleton that constitutes the main chain of the aromatic isocyanate-based polyurethane resin, such as a polyether skeleton, a polyester skeleton, a polyether ester skeleton, and a poly(meth)acrylate skeleton. Etc., but detailed description is omitted.

The weight average molecular weight of the aliphatic isocyanate-based polyurethane resin is preferably 10,000 or more and 250,000 or less, more preferably 50,000 or more and 200,000 or less, and 100,000 or more, Most preferably, it is 150,000 or less. When the weight average molecular weight of the aliphatic isocyanate-based polyurethane resin is 10,000 or more and 250,000 or less, a sealing agent having appropriate hydrolyzability can be obtained.

As the aliphatic isocyanate-based polyurethane resin, those represented by the following chemical formula (II) are typically preferable.

Here, in the chemical formula (II), m ² is an integer of 1 or more and 10 or less, and n ² is an integer of 20 or more and 130 or less.

Examples of the aliphatic isocyanate-based polyurethane resin products include Pandex (registered trademark) T-R3080 manufactured by DIC Covestropolymer Co., Ltd., and the like.

[Other compounding agents in resin composition]
The eye-sealing agent according to one embodiment may further contain various compounding agents which are usually added to the eye-sealing agent within a range that does not impair the purpose of the above-described embodiment. Examples thereof include various additives such as a crosslinking agent, a decomposition accelerator, a filler, an antioxidant, and a decomposition inhibitor. These various additives can be used alone or in combination of two or more. That is, in the sealing agent according to one embodiment, not only the thermoplastic polyurethane resin such as the aliphatic isocyanate-based polyurethane resin and the aromatic isocyanate-based polyurethane resin contained in the resin composition, but also these thermoplastic polyurethane resins are cross-linked. The thermosetting polyurethane resin described above can also be used.

[Polyurethane resin]
Polyurethane resin generally refers to a polymer compound derived from an isocyanate compound with or without a urethane bond. Specifically, it is a polymer compound composed of a urethane bond, and in some cases, a chemical bond such as a urea bond or an amide bond. Examples of the polyurethane resin include thermoplastic polyurethane resin and thermosetting polyurethane resin.

The thermoplastic polyurethane resin and the thermosetting polyurethane resin can be formed from an aliphatic isocyanate-based polyurethane resin and an aromatic isocyanate-based polyurethane resin. Therefore, in the present specification, when simply described as “polyurethane resin”, the “polyurethane resin” includes “thermoplastic polyurethane resin” and “thermosetting polyurethane resin”, and “aliphatic isocyanate-based polyurethane resin”. , And “aromatic isocyanate-based polyurethane resin”.

The thermoplastic polyurethane resin is a polyurethane resin that can be repeatedly brought into a molten state by heating, and is a polyurethane resin having a branched structure among aliphatic isocyanate-based polyurethane resin and aromatic isocyanate-based polyurethane resin. Although it may exist, a polyurethane resin having a linear structure is more preferable.

Further, the thermosetting polyurethane resin is a polyurethane resin obtained by curing a prepolymer in a molten state by heating. More specifically, it is a polyurethane resin that can be obtained by crosslinking a thermoplastic polyurethane resin or a prepolymer of a polyurethane resin with a crosslinking agent. Examples of the thermosetting polyurethane resin include those obtained by a molding processing method such as (i) to (iii) below.
(I) Millable gum molding method For example, a hydroxyl group-terminated prepolymer having a structure derived from an aliphatic isocyanate or an aromatic isocyanate having at least an ester skeleton as a main chain is produced, and a cross-linking agent is kneaded by roll kneading. It can be obtained by putting it in a mold, heating it, and promoting crosslinking.
(Ii) Cast molding method For example, after producing an isocyanate group-terminated prepolymer having at least an ester skeleton as a main chain and having a structure derived from an aliphatic isocyanate or an aromatic isocyanate, and adding a crosslinking agent thereto It is obtained by pouring the liquid mixture of the above into a mold and connecting the ends by chain extension or crosslinking.
(Iii) Thermoplastic molding method For example, it is obtained by melting pellets of a thermoplastic polyurethane resin by heating and performing extrusion molding or injection molding. Further, a partially cross-linked polyurethane resin can be obtained by adding a cross-linking agent as needed during melting. Further, if necessary, the thermoplastic polyurethane resin to which a crosslinking agent is added is heat-treated at a predetermined temperature for a predetermined time, whereby crosslinking can be promoted and hardness can be adjusted.

The prepolymer used in the millable gum molding method and the cast molding method is, needless to say, a prepolymer of the above-mentioned aliphatic isocyanate polyurethane resin or a prepolymer of the above-mentioned aromatic isocyanate polyurethane resin. Yes.

(Crosslinking agent)
In the above embodiment, the durometer type D hardness at 23° C. of each resin composition may be individually adjusted by blending a crosslinking agent in the first resin composition and the second resin composition.

The cross-linking agent is preferably at least one cross-linking agent selected from the group consisting of polyfunctional isocyanate compounds, monomers having an ethylenically unsaturated group, polyvalent amines, polyhydric alcohols, and polyfunctional epoxy compounds. Further, a network-like crosslinked structure can be formed in the polyurethane resin by a combination of a plurality of these. Therefore, the hardness of the resin composition can be adjusted appropriately.

The crosslinking agent may be added to the aliphatic isocyanate-based polyurethane resin or the aromatic isocyanate-based polyurethane resin as described above (thermoplastic molding method), and in addition to the prepolymer for forming these polyurethane resins. Good (Millable gum molding method and cast molding method). The heating temperature and time during melt kneading may be appropriately adjusted in consideration of the reaction temperature of the crosslinking agent. Further, by performing heat treatment at a predetermined temperature for a predetermined time after melt-kneading, crosslinking can be further advanced and hardness can be adjusted. The heat treatment may be performed in air, in an inert gas such as nitrogen, or under reduced pressure, if necessary.

(1) Polyfunctional isocyanate compound The resin composition may contain a polyfunctional isocyanate compound as a crosslinking agent. The polyfunctional isocyanate compound is a functional compound having an active hydrogen present at the terminal or main chain of these polyurethane resins when melt kneading either or both of the aliphatic isocyanate-based polyurethane resin and the aromatic isocyanate-based polyurethane resin. Crosslink to the base.

Examples of the polyfunctional isocyanate compound include the above-mentioned aliphatic diisocyanates and aromatic diisocyanates, and isocyanurates formed from these aliphatic diisocyanates or aromatic diisocyanates.

As an example of the polyfunctional isocyanate compound, as shown in the following general formula (III), the isocyanate group has an allophanate bond with a urethane bond existing in the main chain of the polyurethane resin. In addition, R shown in (III) below represents an aliphatic residue or an aromatic residue of the polyfunctional isocyanate compound. R'represents the end of the skeleton that constitutes the main chain of the polyurethane resin.

Thereby, the main chain of one polyurethane resin and the main chain of another polyurethane resin are crosslinked via the polyfunctional isocyanate compound. When the polyurethane resin has a urea bond, the polyfunctional isocyanate can form a burette bond with the urea bond. Even by such a buret bond, the polyfunctional isocyanate compound crosslinks the main chain of one polyurethane resin and the main chain of another polyurethane resin through the polyfunctional isocyanate compound.

Moreover, when adding a crosslinking agent to a 1st resin composition, it crosslinks so that the weight ratio of the aromatic isocyanate type polyurethane resin before addition and a crosslinking agent may be in the range of 100:0 to 50:50. It is preferable to add an agent. It is preferable that the aromatic isocyanate polyurethane resin and the cross-linking agent are added in a weight ratio of 99.7:0.3 to 60:40, preferably 99.6:0.4 to 70:30. It is more preferable to add it so as to be within the range. By adding the crosslinking agent in the above range, the hardness of the crosslinked aromatic isocyanate-based polyurethane resin becomes higher, and the pores can be more preferably temporarily stopped at high temperature. When a cross-linking agent is added to the prepolymer of the aromatic isocyanate-based polyurethane resin, the cross-linking agent is added so that the weight ratio of the prepolymer and the cross-linking agent is in the range of 100:0 to 50:50. It is preferable to add (millable gum mold processing method). That is, the preferable range of the weight ratio of the prepolymer and the crosslinking agent is in accordance with the preferable range of the weight ratio of the aromatic isocyanate polyurethane resin and the crosslinking agent.

When the cross-linking agent is added to the second resin composition, the weight ratio of the aliphatic isocyanate-based polyurethane resin before the addition and the cross-linking agent is in the range of 99.8:0.2 to 50:50. It is preferable to add a crosslinking agent to the. The weight ratio of the aliphatic isocyanate-based polyurethane resin to the cross-linking agent is more preferably added so as to be in the range of 99.7:0.3 to 60:40, and 99.6:0.4 to 70: It is more preferable to add it in the range of 30. By adding the crosslinking agent within the above range, the hardness of the crosslinked aliphatic isocyanate polyurethane resin can be further increased. Therefore, in a high temperature environment, it is possible to obtain a sealing agent that can more preferably temporarily seal the pores. When a cross-linking agent is added to the prepolymer of the aliphatic isocyanate polyurethane resin, the weight ratio of the pre-polymer and the cross-linking agent should be in the range of 99.8:0.2 to 50:50. It is preferable to add a cross-linking agent to (millable gum mold processing method). That is, the preferable range of the weight ratio of the prepolymer and the crosslinking agent is in accordance with the preferable range of the weight ratio of the aliphatic isocyanate polyurethane resin and the crosslinking agent.

Note that some of these polyfunctional isocyanate compounds may exist in the first powder and the second powder in an unreacted state.

(2) Monomer Having Ethylenically Unsaturated Group For the crosslinking agent, for example, a monomer having an ethylenically unsaturated group can be used.

Examples of the monomer having an ethylenically unsaturated group include triallyl isocyanurate (TAIC), ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol trichloride. Examples include (meth)acrylate and dipentaerythritol hexa(meth)acrylate. Such a cross-linking agent having an ethylenically unsaturated group can be cross-linked by using together with a radical polymerization initiator such as an organic peroxide, or by irradiating with an electron beam. For example, a polyurethane resin is blended with a cross-linking agent having an ethylenically unsaturated group and melt-kneaded to obtain a resin composition, which is then crushed and irradiated with an electron beam to obtain the resin composition. Adjust the hardness of the object. At this time, the cross-linking agent having an ethylenically unsaturated group contained in the resin composition can also cross-link with the main chain of the polyurethane resin while polymerizing with each other.

The irradiation dose of the electron beam is, for example, preferably 5 kGy or more and 150 kGy or less, more preferably 10 kGy or more and 120 kGy or less, and further preferably 20 kGy or more and 100 kGy or less.

(3) Polyvalent amine and polyhydric alcohol For the cross-linking agent, for example, polyvalent amine or polyhydric alcohol can be used. The polyvalent amine or polyhydric alcohol crosslinks by reacting with the isocyanate group remaining at the polyurethane terminal during melt-kneading with the polyurethane resin. Further, in a polyurethane resin having a polyester skeleton or a polyether ester skeleton, a transesterification reaction is caused with an ester group existing in the main chain to form a crosslinked structure via a newly generated amide bond or ester bond. can do. In particular, in a polyurethane resin having no terminal isocyanate group or only a very small amount, a polyvalent amine or a polyhydric alcohol is used in combination with the above-mentioned polyfunctional isocyanate compound to obtain a polyurethane resin composition having a favorable hardness. Can be prepared. The polyvalent amine and the polyhydric alcohol are also a cross-linking agent that cross-links the prepolymer having an isocyanate group terminal (cast molding process).

Examples of polyvalent amines include 3,3'-dichlorobenzidine, 4,4'-methylenebis-2-chloroaniline, and trimethylenebis(4-aminobenzoate).

Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, and 2, Alkylene glycol such as 2,4-trimethyl-1,3-pentanediol, diethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polyoxyalkylene glycol such as polytetramethylene glycol, and bisphenols such as bisphenol A Etc. can be used. As the trihydric or higher alcohols, trimethylolethane, trimethylolpropane, glycerin, pentaerythritol and the like can be used in combination.

(4) Polyfunctional epoxy compound As the cross-linking agent, for example, a polyfunctional epoxy compound can be used. The polyfunctional epoxy compound crosslinks by reacting with the hydroxyl group remaining at the terminal of the polyurethane during melt kneading with the polyurethane resin. Further, in a polyurethane resin having a polyester skeleton or a polyether ester skeleton, a crosslinked structure can be formed by reacting with a carboxyl group existing at the terminal. In particular, in a polyurethane resin having no terminal hydroxyl group or carboxyl group, or a polyurethane resin having only a small amount, a polyurethane resin composition is obtained by using a polyfunctional epoxy compound in combination with the above-mentioned polyvalent amine or polyhydric alcohol. The hardness of the product can be adjusted appropriately.

Examples of polyfunctional epoxy compounds include tris(2,3-epoxypropyl)isocyanurate and poly(glycidyl methacrylate).

(Decomposition accelerator)
The resin composition may contain a decomposition accelerator. The decomposition accelerator accelerates decomposition of the resin composition contained in the sealing agent, and examples thereof include an acid and an acid precursor, and an acid precursor is more preferable.

More specifically, examples of the decomposition accelerator include lactones such as glycolide and lactide, acid anhydrides such as 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), diethyl oxalate and the like. And sulfonic acid esters such as ethyl p-toluenesulfonate, and phosphoric acid esters.

The content of the decomposition accelerator in the resin composition is, for example, preferably 0.1 wt% or more and 20 wt% or less, more preferably 0.3 wt% or more and 15 wt% or less, and 0.5 wt% or more 10 wt%. % Or less is more preferable. According to the above-mentioned preferable range, the content of the decomposition accelerator is not too small, so that the decomposition promotion effect is sufficient. Moreover, since the content is not too large, the initial hardness does not decrease, and a sufficient sealing retention time can be obtained.

(filler)
The resin composition may contain a filler in a blending amount that does not depart from the scope of the present invention. Examples of the filler include organic or inorganic fibrous reinforcing materials, granular or powdery reinforcing materials, and the like, and these can be used alone or in combination of two or more kinds.

Examples of the fibrous reinforcing material include inorganic fibers such as glass fiber, carbon fiber, asbestos fiber, silica fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber and potassium titanate fiber, stainless steel. Examples thereof include metal fibrous substances such as aluminum, titanium, copper and brass, and high melting point organic fibrous substances such as aramid fiber, kenaf fiber, polyamide, fluororesin, polyester resin and acrylic resin.

As the granular or powdery reinforcing material, mica, silica, talc, alumina, kaolin, calcium sulfate, calcium carbonate, titanium oxide, ferrite, clay, glass powder, zinc oxide, nickel carbonate, iron oxide, quartz powder, magnesium carbonate Examples thereof include barium sulfate and the like, but a decomposable reinforcing material that does not affect production defects is more preferable. The filler may be treated with a sizing material or a surface treatment agent, if necessary.

When the filler is added to the resin composition, the content of the filler in the resin composition is preferably 2% by weight or more and 30% by weight or less, preferably 3% by weight or more and 25% by weight or less. Is more preferable, and it is more preferable that the amount is 4 wt% or more and 20 wt% or less. In the above-mentioned preferable range, the content of the filler is not too small, so that the hardness of the polyurethane resin composition becomes sufficiently high. Further, since the content of the filler is not too large, even if the filler remains after the decomposition of the polyurethane resin, the filling can be sufficiently canceled.

[Electron beam irradiation]
In addition, the first resin composition and the second resin composition may be subjected to electron beam irradiation to both or at least one of these resin compositions. Thereby, the hardness of these resin compositions can be adjusted by cutting or cross-linking the main chains of the first resin composition and/or the second resin composition and the polyurethane resin. In this case, these resin compositions may or may not include a crosslinking agent.

The irradiation dose of the electron beam is, for example, preferably 5 kGy or more and 150 kGy or less, more preferably 10 kGy or more and 120 kGy or less, and further preferably 20 kGy or more and 100 kGy or less.

<Sealing agent (second embodiment)>
The sealing agent according to the present invention is not limited to the above embodiment (first embodiment). For example, the sealing agent according to one embodiment (second embodiment) is a powder formed from a resin composition containing an aliphatic isocyanate-based polyurethane resin and an aromatic isocyanate-based polyurethane resin as the thermoplastic polyurethane resin. That is, in the present embodiment, rather than controlling the blinding retention time by using a plurality of different powders in combination, the decomposition rate of the resin composition is controlled by using a plurality of thermoplastic polyurethane resins in combination. By doing so, the sealing retention time of the sealing agent obtained from the resin composition is controlled. As a result, the time until the filling is released (stopping maintenance time) can be in the range of 1 hour or more and 960 hours (40 days) or less at 110° C. or more and 200° C. or less.

[Resin composition]
The resin composition for forming the powder contains an aliphatic isocyanate-based polyurethane resin and an aromatic isocyanate-based polyurethane resin, so that a sheet-like molded product formed from the resin composition has a durometer type D hardness at 23°C. Can be suitably adjusted to 29 or more. The resin composition may have a hardness (durometer type D hardness at 23° C.) of 29 or more. The durometer type D hardness at 23° C. is preferably 29 or more and 80 or less, and more preferably 29 or more and 75 or less.

In this embodiment, the resin composition preferably has a weight ratio of the aliphatic isocyanate-based polyurethane resin and the aromatic isocyanate-based polyurethane resin in the range of 80:20 to 0:100. This makes it possible to suitably obtain a powder having a relatively slow decomposition rate.

The weight ratio of the aliphatic isocyanate-based polyurethane resin and the aromatic isocyanate-based polyurethane resin is preferably in the range of 80:20 to 0:100, more preferably in the range of 75:25 to 40:60. , 70:30 to 55:45 is more preferable. Thereby, the durometer type D hardness of the resin composition can be suitably adjusted so as to be within a predetermined range. Therefore, in a high temperature environment of 110° C. to 200° C., it is possible to preferably manufacture a sealing agent capable of temporarily sealing the pit wall.

The method for producing the powder from the resin composition and the median diameter of the powder in the sealing agent according to the present embodiment are the same as those in the first embodiment, and thus the description thereof will be omitted.

<Well fluid>
The well fluid according to the present embodiment includes the above-mentioned plugging agent (first embodiment and second embodiment).

Well fluid is also commonly referred to as a finish fluid. The sealing agent according to the present embodiment has higher dispersibility in water and higher wettability than a starch derivative which is one of the dehydration reducing agents contained in the well fluid. The high dispersibility of the filling agent in the well fluid is effective for effectively filling the pores, and a tool for injecting the well fluid into the well (for example, a drill and its peripheral members, etc.) ) Also contributes to prevent clogging by the sealing agent. Therefore, the plugging agent according to the present embodiment can be preferably used as a plugging agent to be mixed with an aqueous well fluid.

Well fluid according to the present embodiment, the environment in the well hole using the well fluid, particularly, depending on the temperature or pressure of the high temperature environment, the type of resin composition contained in the filler, the physical properties , Composition (including additives, etc.), shape, size and the like can be appropriately selected and combined. Therefore, the sealing material according to the present embodiment may use different materials or a combination of materials.

The content of the above-mentioned sealing agent in the well fluid according to the present embodiment is not particularly limited and is usually 1% by weight or more and 15% by weight or less, and preferably 3% by weight or more and 10% by weight or less.

In addition to the above-mentioned filler, the well fluid according to the present embodiment may contain various compounding agents that are usually added to the well fluid, as long as the purpose of the present embodiment is not impaired. For example, an inorganic weighting agent such as barite (BaSO ₄ ) and calcium carbonate, a clay swelling inhibitor of an alkali metal halide or an alkaline earth metal halogen compound (salt) such as NaCl, KCl and CaCl ₂ , or a solid-free specific gravity Regulators, organic colloid agents such as guar gum and carboxymethyl cellulose (CMC), inorganic colloid agents (clays, etc.), dispersant demulcent agents, surfactants, pH adjusters, other mud-preventing agents, converters, defoamers. Agents, lubricants, preservatives, bactericides, anticorrosion agents and the like, and they can be contained at a concentration according to the environment in the wellbore where the well fluid is used.

<How to drill wells>
In the well drilling method according to the present embodiment, the above-mentioned filling agent (first embodiment and second embodiment) is used to perform temporary filling.

For example, in the well drilling method according to the present embodiment, the above-mentioned filling agent is used, for example, for drilling a well hole in a reservoir section using a drill, or for drilling a shale layer that produces shale gas or oil. It can be used in well drilling. Further, in the well drilling method according to the present embodiment, the fluid for a sealing agent containing the sealing agent according to the present embodiment, prior to inflowing a well fluid of another type into the well hole, You may let it flow into Inai.

Further, the environment in which the sealing agent according to the present embodiment is used, in particular, depending on the temperature or pressure of a high-temperature environment, the type, physical properties, composition, shape, and size of the resin composition contained in the sealing agent are determined. It can be appropriately selected and combined.

Examples will be shown below to describe the embodiments of the present invention in more detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various aspects are possible in details. Further, the present invention is not limited to the above-described embodiments, various modifications can be made within the scope of the claims, and the present invention is also applicable to embodiments obtained by appropriately combining the disclosed technical means. It is included in the technical scope of the invention. Moreover, all the documents described in this specification are incorporated by reference.

With respect to Examples 1 and 2 and Comparative Example, a sealing agent was produced under the following conditions.

<Example 1>
[Production of evaluation sample]
[Production of hardness evaluation sample]
(Melting and kneading of polyurethane resin)
As the MDI polyurethane resin, Pandex (registered trademark) T-5070 manufactured by DICCO BESTRO POLYMER CORPORATION was used.

2,000 g of MDI polyurethane resin was weighed, charged into the following kneading extruder, held at a temperature of 230° C. for 5 minutes, and melt-extruded from a die. As a result, a 3 mm-thick sheet-like sample for evaluating hardness of the MDI-based polyurethane resin (polyurethane resin molded body) was obtained.
・Kneading extruder: 2D30W2 (manufactured by Toyo Seiki Seisakusho Co., Ltd.)
・Screw size: Diameter 30mmφ, L/D=30
・Screw rotation speed: 50 rpm
As the HDI-based polyurethane resin, Pandex (registered trademark) T-R3080 manufactured by DIC Cobestropolymer Co., Ltd. was used. 2,000 g of HDI-based polyurethane resin was weighed, and a 3 mm-thick sheet-like sample for hardness evaluation of HDI-based polyurethane resin was obtained in the same manner as in the case of MDI-based polyurethane resin.

(Durometer type D hardness measurement)
Durometer type D hardness of the hardness evaluation sample was measured by using a hardness meter according to ISO7619/JIS K 6253, by stacking two 3 mm-thick MDI-based polyurethane resin hardness evaluation samples to a thickness of 6 mm. It was measured. A durometer type D GS-720R manufactured by Teclock Co., Ltd. was used as the hardness tester.

As the evaluation sample used for measuring the durometer type D hardness, one having a sufficiently stable durometer type D hardness was used. Specifically, the durometer type D hardness after heat treatment of the evaluation sample in a nitrogen atmosphere at 120° C. for 2 hours does not change by 10% or more as compared with the durometer type D hardness before heat treatment. I was there.

When the durometer type D hardness changes by 10% or more before and after the heat treatment, the heat treatment and the measurement are repeated, and the durometer D hardness when the change in the durometer D hardness before and after the heat treatment is less than 10% is the durometer D of the evaluation sample. Hardness was used.

As shown in Table 2, the durometer type D hardness at 23° C. of the hardness evaluation sample of the MDI polyurethane resin was 60.

Similarly, the durometer type D hardness at 23° C. of the hardness evaluation sample of the HDI polyurethane resin was measured. As shown in Table 2, the durometer type D hardness at 23° C. of the hardness evaluation sample of the HDI polyurethane resin was 28.

[Manufacture of samples for evaluation of sealing]
(Crushing of polyurethane resin)
A strand was obtained by kneading T-5070, which is an MDI-based polyurethane resin, using the above-mentioned kneading extruder at 230° C. for 5 minutes and melt-extruding from a die. The obtained strand was passed through a pelletizer to obtain pellets.
Similarly, after obtaining a strand from T-R3080 which is an HDI-based polyurethane resin, the strand was passed through a pelletizer to obtain pellets.
・Pelletizer: Model SCF-150 (made by Isuzu Kakoki Co., Ltd.)
The obtained pellets of the MDI-based polyurethane resin and the HDI-based polyurethane resin were separately pulverized by the freeze pulverization method by immersion in liquid nitrogen using the pulverizer shown below to obtain powder. Here, the pellet-shaped MDI-based polyurethane resin (or pellet-shaped HDI-based polyurethane resin) immersed in liquid nitrogen for 5 minutes and cooled was charged into the pulverizer at 125 g/min, and at the same time, liquid nitrogen was also pulverized. It was thrown in.
・Grinding machine: Xseed mill EM-1A type (Makino Sangyo Co., Ltd.)
・Turntable:
Pin disk diameter: 160mm
Pin diameter: 3.5 mm
Pin length: 19mm
Body side pin number: 178 body side pin array: 3 rows Body side pin interval: 3.5mm
Door side pin number: 168 Door side pin array: 3 rows Door side pin interval: 2.5 mm
・Crushing speed: Main body side pin disk: 8000 rpm (133 Hz)
・Door side pin disk: 12000 rpm (200 Hz)
(Measurement of median diameter (50%D) of polyurethane resin powder)
The median diameter (50% D) of the obtained powders of MDI-based polyurethane resin and HDI-based polyurethane resin was measured using a laser diffraction particle size distribution measuring device, SALD3000 manufactured by Shimadzu Corporation. As shown in Table 2, the median diameter (50% D) of the MDI polyurethane resin powder was 334 μm. The HDI-based polyurethane resin powder had a median diameter (50% D) of 337 μm.

(Manufacture of sealing agent for evaluation)
100 g of MDI-based polyurethane resin powder was weighed, 100 g of HDI-based polyurethane resin powder was weighed, and put into a polyethylene bag. After charging, a handshake was carried out for 3 minutes, and the MDI polyurethane resin and the HDI polyurethane resin were stirred to obtain a powder mixture (blend). In this way, the MDI-based polyurethane resin and the HDI-based polyurethane resin were mixed at a weight ratio of 50:50 to obtain an evaluation sealing agent as a sealing evaluation sample.

[Production of evaluation fluid (hereinafter also referred to as evaluation muddy water)]
The obtained sealing agent for evaluation and each component of the following Table 1 were mixed in a weight ratio shown in Table 1 to prepare muddy water for evaluation.

The sodium chloride in the 10 wt% sodium chloride aqueous solution in Table 1 is manufactured by Junsei Chemical Co., Ltd. The AMPS polymer is Driscal (registered trademark)-D manufactured by Ternite Co., Ltd. Lignin is available from Halliburton Energy Services, Inc. DURENEX (registered trademark) PLUS manufactured by Mitsubishi. The oxygen scavenger is Ternite (registered trademark) OS-5 manufactured by Ternite Co., Ltd.

[Evaluation of eyesight]
The evaluation of sealing was performed by a sealing test using a plug tester (Fliter Press HPHT 500ML manufactured by Fann Instrument Company) including the filter disk shown in FIG. In the filling test, a Ceramic Filter Disc 50 (Part NO. 210540) manufactured by Fann Instrument Company was used as a ceramic filter having a pore size of 50 μm.

The filling test will be described below with reference to FIG. FIG. 1 is a diagram schematically showing a plug tester used for a filling test with evaluation muddy water.

As shown in FIG. 1, after the evaluation muddy water mixed with the evaluation sealing agent was put into the plug tester, a pressure of 100 psi from above and a pressure of 100 psi from below were applied to the plug tester. As a result, the difference between the pressure from the top and the pressure from the bottom was 0 psi, and the filter disk was kept free from pressure before the temperature was raised.

The upper container containing the muddy water for evaluation was heated to 120° C. and held. After raising the temperature, the plug tester was subjected to a pressure of 600 psi from above. As a result, the difference between the pressure from above and the pressure from below was 500 psi, and the filter disk was subjected to a pressure of 500 psi from above.

Next, the lowering valve of the lower container was opened, and the filling test was started while maintaining the temperature and pressure.

Here, as described above, the filter has pores of 50 μm, and water is allowed to permeate from the upper container to the lower container through the pores. Therefore, the amount of water permeated from the filter was measured every predetermined time. The permeation amount was measured by collecting the water permeated through the lower valve of the lower container in a reserve tank.

The water permeation recovery point (the point where the temporary sealing was canceled) was set when the amount of permeation of water per predetermined time increased, and the sealing test was completed.

The time from the start of the filling test to the point of reaching the water permeation recovery point is defined as the filling maintenance time, and when the filling maintenance time is 1 hour or more and 960 hours (40 days) or less, the filling evaluation is “ "○" was given, and in other cases, the blinding evaluation was given as "x".

As shown in Table 2, the sealing retention time at 120° C. was 402 hours.

<Example 2>
An evaluation sealing agent was obtained in the same manner as in Example 1 except that the MDI polyurethane resin and the HDI polyurethane resin were mixed at a weight ratio of 95:5 instead of being mixed at a weight ratio of 50:50.

Evaluation mud was prepared in the same manner as in Example 1 from the obtained evaluation sealing agent. Further, the filling test was performed in the same manner as in Example 1 except that the filling test was performed at 140° C. instead of 120° C. As shown in Table 2, the sealing time at 140° C. was 60 hours.

<Example 3>
In Example 3, the mixing ratio of the MDI-based polyurethane resin and the HDI-based polyurethane resin was changed to 45:55, and the MDI-based polyurethane resin and the HDI-based polyurethane resin were mixed and then melt-extruded to obtain the hardness and the median diameter. A hardness evaluation sample and an evaluation sealing agent were obtained in the same manner as in Example 1 except that the measurement was performed.

More specifically, 900 g of the above MDI-based polyurethane resin was weighed, 1100 g of the HDI-based polyurethane resin was weighed, and put into a polyethylene bag. After charging, a handshake was carried out in the same manner as in the above-mentioned example, and the MDI-based polyurethane resin and the HDI-based polyurethane resin were stirred to obtain a blend. Thus, the MDI polyurethane resin and the HDI polyurethane resin were mixed at a weight ratio of 45:55.

Then, similarly to the above-mentioned example, the blended product was melt-extruded (melt-kneaded) to manufacture a hardness evaluation sample and an evaluation sealing agent.

As shown in Table 2, the durometer type D hardness at 23° C. of the hardness evaluation sample of the mixture was 34.

The median diameter (50% D) of the evaluation sealing agent obtained by melt-extruding the mixture was 345 μm as shown in Table 2.

Further, an evaluation mud was prepared from the obtained evaluation sealing agent by the same method as in Example 1 and a sealing test was conducted. As shown in Table 2, the sealing time at 120° C. was 62 hours.

The durometer D hardness and median diameter (50% D) shown in Table 2 are the durometer D hardness and median diameter (50% D) of the mixture of the MDI polyurethane resin and the HDI polyurethane resin.

<Example 4>
A hardness evaluation sample and an evaluation sealing agent were produced in the same manner as in Example 3 except that the MDI polyurethane resin and the HDI polyurethane resin were mixed at a weight ratio of 35:65.

As shown in Table 2, the durometer type D hardness at 23° C. of the hardness evaluation sample was 30.

As shown in Table 2, the evaluation sealing agent produced in the same manner as in Example 3 had a median diameter (50% D) of 358 μm.

Next, muddy water for evaluation was prepared from the obtained sealing agent for evaluation in the same manner as in the above-mentioned examples, and a sealing test was performed at 120° C. by the same method as in the above-mentioned examples. As shown in Table 2, the sealing retention time at 120° C. was 1 hour.

<Example 5>
A hardness evaluation sample and an evaluation sealing agent were produced in the same manner as in Example 3 except that the MDI polyurethane resin and the HDI polyurethane resin were mixed at a weight ratio of 30:70.

As shown in Table 2, the durometer type D hardness at 23° C. of the hardness evaluation sample was 30.

As shown in Table 2, the evaluation sealing compound prepared in the same manner as in Example 3 had a median diameter (50% D) of 438 μm.

Next, muddy water for evaluation was prepared from the obtained sealing agent for evaluation in the same manner as in the above-mentioned examples, and a sealing test was performed at 120° C. by the same method as in the above-mentioned examples. As shown in Table 2, the sealing retention time at 120° C. was 2 hours.

<Comparative example>
An evaluation sealing agent was prepared in the same manner as in Example 1 except that the evaluation sealing agent was prepared from only the HDI polyurethane resin instead of mixing the HDI polyurethane resin and the MDI polyurethane resin.

As shown in Table 2, the median diameter (50% D) of the HDI-based polyurethane resin powder used as the sealing agent for evaluation was 337 μm.

Evaluation muddy water was prepared from the obtained sealing agent for evaluation in the same manner as in the above-mentioned Example, and a sealing test was conducted at 120° C. in the same manner as in Example 1. As shown in Table 2, the sealing time at 120° C. was 0 hour.

As is clear from Table 2, as a result of performing the sealing test using the sealing agents of Examples 1 to 5, at 120°C and 140°C, the sealing retention time was 1 hour or more and 960 hours or less. From this, the sealing agent which is a powder of the resin composition containing the MDI-based polyurethane resin and the HDI-based polyurethane resin of Examples 1 to 5 has fine pores at a high temperature of 120°C and 140°C. I found that I could stop it for a while.

On the other hand, the sealing agent which is a powder of the resin composition containing only the HDI-based polyurethane resin of Comparative Example had a sealing time of 0 hours at 120° C. and did not have a sealing function.

From the above, it was found that the sealing agent, which is a powder of the resin composition containing the MDI-based polyurethane resin and the HDI-based polyurethane resin, can suitably temporarily stop the pores at high temperature.

INDUSTRIAL APPLICABILITY The present invention can be used as a filling agent for temporarily filling pores in a high temperature environment such as a well with a deep depth, a well fluid, and the like.

Claims (9)

A filling agent that stops the pit wall,
The eye-blocking agent contains a first powder and a second powder having different compositions,
The first powder is a powder formed from a resin composition containing an aromatic isocyanate polyurethane resin,
The second powder is a powder formed from a resin composition containing an aliphatic isocyanate-based polyurethane resin, which is a sealing agent. A filling agent that stops the pit wall,
The sealing agent is a powder of a resin composition containing a thermoplastic polyurethane resin,
The above-mentioned thermoplastic polyurethane resin is an aliphatic isocyanate-based polyurethane resin and an aromatic isocyanate-based polyurethane resin, and a sealing agent. The weight ratio of said 1st powder and said 2nd powder is the range of 40:60-99:1, The sealing agent of Claim 1 characterized by the above-mentioned. The weight ratio between the aliphatic isocyanate-based polyurethane resin and the aromatic isocyanate-based polyurethane resin is in the range of 80:20 to 0:100, and the sealing agent according to claim 2. The aromatic isocyanate constituting the aromatic isocyanate-based polyurethane resin is at least one aromatic isocyanate selected from the group consisting of diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and naphthalene diisocyanate,
The aliphatic isocyanate constituting the aliphatic isocyanate-based polyurethane resin is at least one aliphatic isocyanate selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate, norbornane diisocyanate, hydrogenated xylylene diisocyanate, and dicyclohexylmethane diisocyanate. The sealant according to any one of claims 1 to 4, wherein At least 1 of the said aromatic isocyanate type polyurethane resin and the said aliphatic isocyanate type polyurethane resin contains the polyester skeleton at least, The sealing of any one of Claims 1-5 characterized by the above-mentioned. Agent. The durometer type D hardness at 23° C. of a sheet-like molded body formed from the resin composition containing the aromatic isocyanate-based polyurethane resin is 29 or more, and any one of claims 1 to 6 is characterized. The described eye-stopper. A well fluid comprising the plugging agent according to any one of claims 1 to 7. A method of excavating a well, comprising performing temporary filling using the filling material according to any one of claims 1 to 7.

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