JOINT ASSEMBLY, PRODUCTION WELL MANUFACTURING METHOD, AND GAS PRODUCTION METHOD

Abstract

The present disclosure provides a joint assembly for selectively isolating an isolation target layer in an open hole drilled into a stratum comprising a hydrocarbon-impregnated layer and the isolation target layer, and a production well manufacturing method and a gas production method that use said joint assembly. A joint assembly 110 comprises a tubular body section 111 inserted into an open hole 210 and installed in a position of passing through an isolation target layer ITL, and a light-emitting device 112 that is provided over the entire circumference of the outer peripheral portion of the body section 111 and that emits light for curing an uncured photocurable resin LCR introduced between the body section 111 and a hole wall 211 of the open hole 210.

Description

[Technical field]

[0001] The present disclosure relates to a joint assembly, a production well preparation method, and a gas production method. [Background technology]

[0002] Conventionally, measures against sand and water outflow have been known as issues that arise when producing methane hydrate, as described in the following Non-Patent Document 1. In the methane hydrate production method described in the following Patent Document 1, as a measure against formation compaction and underground sand outflow, which are problems in the production of sand layer-type methane hydrate, an improver capable of sufficiently fixing sand particles is injected into the gaps (pores) between unconsolidated or weakly consolidated sand particles that constitute the stratum to be developed.

[0003] The hydrocarbon recovery method described in the following Patent Document 2 is characterized by a composition used to prevent sediment contained in the seabed from flowing into a production well. Specifically, this hydrocarbon recovery method uses, as the composition, a composition used by microorganisms that generate carbon dioxide or sulfate ions to promote the precipitation of calcium carbonate to generate carbon dioxide or sulfate ions.

[0004] The following Patent Document 3 discloses a process for lining an open hole and a tool for producing a coating for an open hole. This tool is attached to a drilling bit at the tip of a drill string, has multiple injectors and multiple emitters on a part of the outer circumferential surface in the circumferential direction, and produces a coating for an open hole by curing a fluid composition supplied from the injectors to the outer periphery of the tool by light irradiated from the emitters.

[0005] The following Patent Document 4 discloses a method and system for sealing a casing in an open hole by light activation. This method is used for cementing to fix a casing in an open hole, and an optical fiber cable is attached to the outside of the casing and inserted into the open hole, and a sealant is activated in the open hole by the optical fiber cable, and the sealant is hardened by the reaction.

[0006] The following Patent Document 5 discloses a method for sealing a circulation loss zone, such as a cavity that becomes an obstacle when drilling an underground well. In this method, a drill string has an ultraviolet system, an actuator, and a fluid flow path, and when drilling an underground well, an ultraviolet-curable material is supplied to the fluid flow path of the drill string, and ultraviolet light is irradiated to the fluid flow path of the drill string by the ultraviolet system. As a result, the activated ultraviolet-curable material is sent from the fluid flow path of the drill string to the circulation loss zone and hardens to fill the cavity or the like. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. WO2020 / 003551 [Patent Document 2] JP 2019-11612 A [Patent Document 3] U.S. Patent No. 7,931,091 [Patent Document 4] US Patent Application Publication No. 2021 / 0238953 [Patent Document 5] U.S. Pat. No. 1,086,5620 [Non-patent literature]

[0008] [Non-Patent Document 1] Koji Yamamoto, "About the Second Offshore Production Test", [online], November 29, 2017, Methane Hydrate Forum 2017, [Retrieved February 2, 2022], Internet,<URL:https: / / www.mh21japan.gr.jp / mh21wp / wp-content / uploads / mh21form2017_doc02_1.pdf> Summary of the Invention [Problem to be solved by the invention]

[0009] In the methane hydrate production method of Patent Document 1, a casing is installed in the excavated well, and cementing is applied to the gap between the well wall and the casing. Furthermore, by forming a through hole in the casing and the cementing by gun perforation, material exchange between the target stratum and the well is possible. However, while this production method has excellent mechanical stability of the production well, it not only increases the construction cost of the production well, but also reduces the gas production efficiency compared to an open well without a casing. The same is true for the methods of Patent Documents 2 and 4, which use a casing.

[0010] In addition, the tool for producing the coating for an open hole of Patent Document 3 requires the tool having an emitter on a part of the circumferential direction of the outer peripheral surface to rotate in a circumferential direction in order to harden the fluid composition over the entire circumference of the open hole wall. However, the rotation of the tool may be hindered by the partially hardened fluid composition. In addition, it is not realistic to harden the fluid composition supplied from the injector to the outer periphery of the tool from the hole wall side by light irradiated from the emitter without allowing it to settle in the open hole. In addition, the method of Patent Document 5 activates the ultraviolet-curable material by irradiating it with ultraviolet light in the fluid flow path of the drill string, and sends it to a cavity in the stratum to harden it, but the feasibility of this method is questionable.

[0011] The present disclosure provides a joint assembly for selectively isolating a layer to be isolated in an open borehole drilled into a stratum including a hydrocarbon-bearing layer and a layer to be isolated, and a production well production method and a gas production method using the joint assembly. [Means for solving the problem]

[0012] One aspect of the present disclosure is a joint assembly for selectively isolating a hydrocarbon-bearing layer and a layer to be isolated in an open shaft drilled into a stratum containing the layer, the joint assembly comprising: a tubular main body that is inserted into the open shaft and installed at a position penetrating the layer to be isolated; and a light-emitting device that is provided around the entire outer periphery of the main body and irradiates light to harden uncured photocurable resin introduced between the main body and the hole wall of the open shaft.

[0013] The joint assembly according to the above aspect of the present disclosure is used in a state where the tubular main body is inserted into an open hole and installed at a position penetrating the isolation target layer of the stratum, and uncured photocurable resin is introduced between the main body and the hole wall of the open hole. In this state, the joint assembly irradiates light for curing the photocurable resin from a light emitting device provided around the entire outer periphery of the main body. This allows the annular or cylindrical photocurable resin cured between the main body and the hole wall of the open hole to cover the hole wall at the portion penetrating the isolation target layer, and allows the isolation target layer to be selectively isolated from the open hole.

[0014] The joint assembly according to the above aspect of the present disclosure may include a contraction mechanism that contracts the outer circumferential portion from an expanded position on the radially outer side of the main body portion to a contracted position on the radially inner side.

[0015] In this manner, the joint assembly can contract the outer periphery of the main body from an expanded position radially outward of the main body to a contracted position radially inward of the main body by operating the contraction mechanism, thereby separating the outer periphery of the outer periphery of the main body from the inner periphery of the cured photocurable resin covering the hole wall of the portion of the open hole that penetrates the layer to be isolated, and allowing the main body to be extracted from the open hole in which the layer to be isolated is isolated by the cured photocurable resin.

[0016] The joint assembly according to each of the above aspects of the present disclosure may include an anti-adhesion layer provided on an outer surface of the main body portion to prevent adhesion between the photocurable resin and the main body portion after hardening.

[0017] In this manner, the joint assembly is configured such that the light-emitting device irradiates the uncured photocurable resin through the light-transmitting anti-adhesion layer provided on the outer surface of the main body with light, causing the photocurable resin to harden in contact with the anti-adhesion layer. Therefore, the anti-adhesion layer prevents the cured photocurable resin from adhering to the outer surface of the main body, and when the contraction mechanism is operated to contract the outer periphery of the main body inward in the radial direction, the outer periphery of the outer periphery can be easily separated from the inner periphery of the cured photocurable resin.

[0018] Another aspect of the present disclosure is a production well manufacturing method using the joint assembly according to each of the above aspects, the production well manufacturing method including the steps of: drilling the open hole in the stratum; identifying the positions of the hydrocarbon-bearing layer and the layer to be isolated in the stratum; inserting the main body into the open hole and installing it at a position penetrating the layer to be isolated; introducing the uncured photocurable resin between the main body and the hole wall of the open hole; irradiating the light from the light-emitting device to cure the uncured photocurable resin between the main body and the hole wall of the open hole over the entire circumference of the main body, thereby forming a production well in which the layer to be isolated in the open hole is selectively isolated by the cured photocurable resin; and recovering the uncured photocurable resin remaining in the portion of the open hole where the hydrocarbon-bearing layer is exposed.

[0019] According to the production well manufacturing method according to the above-mentioned aspect of the present disclosure, an open well is drilled in a stratum including a hydrocarbon-bearing layer and a layer to be isolated, and the positions of the hydrocarbon-bearing layer and the layer to be isolated in the stratum can be identified. Then, the main body of the joint assembly according to each of the above-mentioned aspects can be inserted into the open well and installed at a position penetrating the layer to be isolated in the stratum, and light can be irradiated from the light-emitting device provided around the entire periphery of the main body in a state where uncured photocurable resin is introduced between the main body and the wall of the open well. This allows the uncured photocurable resin in contact with the layer to be isolated exposed on the wall of the open well to be selectively cured around the entire wall, and a production well in which the layer to be isolated is selectively isolated from the open well by the cured photocurable resin can be formed. Then, by recovering the uncured photocurable resin remaining in the part of the open well where the hydrocarbon-bearing layer is exposed, a production well capable of producing hydrocarbons from the hydrocarbon-bearing layer selectively exposed on the wall of the open well can be manufactured.

[0020] In the production well manufacturing method of the above aspect, in the step of forming the production well, uncured photocurable resin may be left above the cured photocurable resin.

[0021] In this manner, when the cured photocurable resin shrinks and a gap forms between the wall of the open hole and the cured photocurable resin, the uncured photocurable resin remaining above the cured photocurable resin flows into the gap and hardens to fill the gap. This prevents a gap from being formed between the cured photocurable resin and the layer to be isolated that is exposed to the wall of the open hole, and makes it possible to more reliably isolate the layer to be isolated from the open hole.

[0022] In the production well manufacturing method of the above aspect, the hydrocarbon-bearing layer may be a gas hydrate-bearing layer, and the layer to be isolated may be an aquifer.

[0023] According to this embodiment, a production well can be formed by drilling an open well into a stratum including a gas hydrate-bearing layer that holds hydrocarbons such as methane hydrate and an aquifer, and selectively isolating the aquifer from the open well. Therefore, a production well can be manufactured that can efficiently produce hydrocarbon gases such as methane gas from the gas hydrate-bearing layer selectively exposed on the wall of the open well.

[0024] Another aspect of the present disclosure is a gas production method including the production well manufacturing method of the above aspect, which includes, after a step of recovering the uncured photocurable resin, a step of depressurizing the production well and recovering gas released from the gas hydrate-bearing layer to the production well.

[0025] According to the gas production method according to the above-described aspect of the present disclosure, the aquifer exposed to the wall of the open well is selectively isolated, and gas can be efficiently produced by a depressurization method using a production well that can efficiently produce hydrocarbon gases such as methane gas from the gas hydrate-bearing layer selectively exposed to the wall of the open well. Effect of the Invention

[0026] According to the above-described aspects of the present disclosure, it is possible to provide a joint assembly for selectively isolating a layer to be isolated in an open borehole drilled into a stratum including a hydrocarbon-bearing layer and a layer to be isolated, and a production well manufacturing method and a gas production method using the joint assembly. [Brief description of the drawings]

[0027] [Figure 1] 1 is a schematic cross-sectional view showing a first embodiment of a joint assembly according to the present disclosure. [Diagram 2] FIG. 2 is a schematic enlarged cross-sectional view of a production well into which the joint assembly shown in FIG. 1 will be inserted. [Diagram 3] FIG. 1 is a flow diagram showing a first embodiment of a gas production method according to the present disclosure. [Figure 4] FIG. 1 is a flow diagram showing a first embodiment of a production well manufacturing method according to the present disclosure. [Diagram 5]FIG. 5 is a schematic enlarged cross-sectional view illustrating the open-hole drilling and logging process of FIG. 4. [Figure 6] 5 is a schematic enlarged cross-sectional view showing the state after the step of installing the SCA in FIG. 4 is completed. [Figure 7] FIG. 7 is a perspective view showing an example of a joint assembly constituting the SCA of FIG. 6. [Figure 8] 5 is a schematic enlarged cross-sectional view illustrating a step of introducing the photocurable resin shown in FIG. 4. [Figure 9] 5 is a schematic enlarged cross-sectional view illustrating a resin curing process by light irradiation in FIG. 4. [Figure 10] FIG. 4 is a schematic enlarged cross-sectional view illustrating the gas producing process of FIG. 3. [Figure 11] FIG. 11 is a horizontal cross-sectional view illustrating a second embodiment of a joint assembly according to the present disclosure. [Figure 12] FIG. 11 is a horizontal cross-sectional view illustrating a second embodiment of a joint assembly according to the present disclosure. [Figure 13] FIG. 13 is a horizontal cross-sectional view showing a modification of the joint assembly of FIGS. 11 and 12 . [Figure 14] FIG. 13 is a horizontal cross-sectional view showing a modification of the joint assembly of FIGS. 11 and 12 . [Figure 15] 14 is a cross-sectional view showing the outer periphery of the main body portion of FIG. 11 and FIG. 13 in an expanded position. [Figure 16] 15 is a cross-sectional view showing the outer periphery of the main body of FIG. 12 and FIG. 14 in a retracted position; [Figure 17] Schematic cross-sectional view of the apparatus used in Experiment 1. [Figure 18] Schematic cross-sectional view of the apparatus used in Experiment 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] [Embodiment 1] Hereinafter, a first embodiment of a joint assembly, a production well manufacturing method, and a gas production method according to the present disclosure will be described with reference to FIGS. 1 to 10.

[0029] Fig. 1 is a schematic cross-sectional view of a first embodiment of a joint assembly according to the present disclosure. Fig. 2 is a schematic enlarged cross-sectional view of a production well 200 into which a sand control assembly 100 including the joint assembly 110 shown in Fig. 1 is inserted.

[0030] The joint assembly 110 of this embodiment is inserted into an open hole 210 drilled into the stratum GS including the hydrocarbon-bearing layer HCL and the isolation target layer ITL, and selectively isolates the isolation target layer ITL exposed at the hole wall 211 of the open hole 210 by the hardened photocurable resin CR. Here, the open hole 210 is a portion of a production well 200 drilled into the stratum GS into which a casing 201 is not inserted.

[0031] The stratum GS in which the production well 200 is excavated is, for example, a seabed stratum with a water depth of 500 m or more, and includes an upper ground UG including the seabed surface, and a hydrocarbon-bearing layer HCL and a sequestration target layer ITL alternately deposited below the upper ground UG. A casing 201 is inserted in the part of the production well 200 penetrating the upper ground UG, and below the upper ground UG of the production well 200 is an open well 210 in which the casing 201 is not inserted. In other words, the stratum GS in which the open well 210 is excavated includes the hydrocarbon-bearing layer HCL and the sequestration target layer ITL.

[0032] The hydrocarbon-bearing layer HCL is, for example, a gas hydrate-bearing layer GHL that bears hydrocarbon gas. The gas hydrate-bearing layer GHL is, for example, a methane hydrate-bearing layer MHL or a natural gas hydrate-bearing layer NGL. The isolation target layer ITL is, for example, an aquifer SWL. The stratum GS into which the open well 210 is excavated is not limited to a seabed stratum, and may be, for example, a stratum in a land area including permafrost. In this embodiment, the hydrocarbon-bearing layer HCL is a methane hydrate-bearing layer MHL, and the isolation target layer ITL is an aquifer SWL.

[0033] The tubular joint assemblies 110 are, for example, alternately connected with tubular sand filters 120 to form a tubular sand control assembly (SCA) 100 extending from the top end to the bottom of the open well 210. That is, the sand control assembly 100 includes a plurality of joint assemblies 110 and a plurality of sand filters 120 connected in a straight line in the depth direction of the open well 210, and is inserted into the open well 210 for installation.

[0034] The sand control assembly 100 has a configuration in which one or more joint assemblies 110 installed at positions corresponding to each isolation target layer ITL and one or more sand filters 120 installed at positions corresponding to each hydrocarbon-bearing layer HCL are alternately connected in the depth direction of the open borehole 210.

[0035] In other words, the sand control assembly 100 has one or more joint assemblies 110 at positions overlapping with each of the isolation target layers ITL and has one or more sand filters 120 at positions overlapping with each of the hydrocarbon-bearing layers HCL when inserted and installed in the open well 210. Note that the joint assemblies 110 and the sand filters 120 may each be prepared in several different lengths according to the thickness of the isolation target layer ITL and the thickness of the hydrocarbon-bearing layer HCL.

[0036] The upper end of the sand control assembly 100 is supported via a packer 203 inside a casing 201 fixed with cement 202 to a portion of the production well 200 penetrating the upper ground UG, as shown in, for example, Fig. 1 and Fig. 2. An inner tubing 204 is inserted inside the tubular sand control assembly 100, as shown in, for example, Fig. 2. The inner tubing 204 extends, for example, from below the liquid level LL inside the casing 201 to the inside of the tip of the sand control assembly 100 located at the bottom of the open well 210, and has a perforation 204p that opens into the inside of the tip of the sand control assembly 100.

[0037] A pump 205 is installed below the liquid level LL inside the casing 201. The pump 205 is connected to a water production tube 301 that extends to above the sea surface OS. When the pump 205 pumps the water inside the casing 201 to the floating production facility 300 above the sea surface OS, the pressure in the open well 210 is reduced, and the decomposition of methane hydrate is promoted in the methane hydrate-bearing layer MHL, which is the hydrocarbon-bearing layer HCL near the open well 210, and methane gas flows into the sand control assembly 100 through the sand filter 120 together with water.

[0038] The water and methane gas that flow into the sand control assembly 100 inserted into the open well 210 flow into the perforation 204p at the tip of the inner tubing 204 inserted inside the sand control assembly 100, rise inside the inner tubing 204, and flow out into the casing 201 fixed to the upper end of the production well 200. The water and methane gas that flow into the casing 201 are separated into gas and liquid within the casing 201.

[0039] An explosion-proof system (BOP) 206 installed on the seabed at the upper end of the casing 201 has a water production tube 301 passing through it, which extends to a floating production facility 300 on the sea surface OS, and a gas production tube 302 is attached to it, which communicates with the space above the liquid level LL in the casing 201 and extends to the floating production facility 300. The floating production facility 300 has, for example, a platform 303 floating on the sea surface OS, and a produced water tank 304, a switching device 305, and a photocurable resin tank 306 provided on the platform 303.

[0040] Fig. 3 is a flow diagram showing a first embodiment of a gas production method according to the present disclosure. Fig. 4 is a flow diagram showing a first embodiment of a production well manufacturing method according to the present disclosure.

[0041] The gas production method GPM of this embodiment shown in Fig. 3 includes a step S1 of producing a production well, and a step S2 of producing gas from the production well produced in the step S1. In the step S1 of producing a production well, a production well 200 is produced by the production well production method WPM of this embodiment shown in Fig. 4 using the joint assembly 110 shown in Figs. 1 and 2.

[0042] 4, when the production well production method WPM of the present embodiment is started, first, a bare hole drilling and well logging step S11 is performed. In this step S11, for example, a step of drilling a bare hole 210 in the stratum GS and a step of identifying the positions, i.e., depths, of the hydrocarbon-bearing layer HCL and the isolation target layer ITL in the stratum GS are simultaneously performed.

[0043] Fig. 5 is a schematic enlarged cross-sectional view for explaining the bare hole drilling and logging step S11 of Fig. 4. In the bare hole drilling and logging step S11, for example, a bare hole 210 is drilled in the stratum GS using a bottom hole assembly 400. The bottom hole assembly 400 includes, for example, a plurality of tubular drill pipes 401 that can be connected in a straight line, and a drill bit 402 that is attached to the tip of the drill pipe 401 and drills the stratum GS.

[0044] In the bare hole drilling and logging step S11, the bottom hole assembly 400 is rotated, and seawater or mud water is supplied to the tip of the drill bit 402 through the drill pipe 401 and circulated to drill the bare hole 210 in the stratum GS. The drill pipe 401 is extended as the drilling of the bare hole 210 progresses. The bare hole drilling and logging step S11 may include, for example, a step of installing a casing 201 at the upper end of the bare hole 210.

[0045] Furthermore, in the barehole drilling and logging step S11, logging is performed simultaneously with drilling of the stratum GS by physical logging methods such as LWD (Logging While Drilling) and MWD (Measurement While Drilling). When barehole drilling and logging are performed sequentially, wireline logging may be performed after barehole drilling. By using these logging methods, the positions, i.e., depths, of the hydrocarbon-bearing layer HCL and the isolation target layer ITL can be accurately identified in the depth direction of the barehole 210.

[0046] After the barehole drilling and logging step S11 is completed, the bottom hole assembly 400 is extracted from the barehole 210. Then, step S12 is performed to determine whether the stratum GS into which the barehole 210 has been drilled includes an isolation target layer ITL, such as an aquifer SWL. If it is determined in step S12 that the stratum GS includes an isolation target layer ITL (YES), step S13 is performed to attach the joint assembly 110 to the sand control assembly 100, and step S14 is performed to attach the sand filter 120. Then, step S15 is performed to install the sand control assembly (SCA) 100 in the barehole 210.

[0047] 6 is a schematic enlarged cross-sectional view showing a state after completion of step S15 of installing a sand control assembly (SCA) 100 in an open borehole 210. As shown in FIG. 6, the sand control assembly 100 is, for example, a combination of one or more joint assemblies 110 and one or more sand filters 120, and has a check valve 130 attached to its tip. The check valve 130 allows fluid to flow from a flow path in the sand control assembly 100 to the open borehole 210, and blocks fluid from flowing from the open borehole 210 to a flow path in the sand control assembly 100.

[0048] Each tubular joint assembly 110 is inserted into the open well 210 and installed at a position where it penetrates the isolation target layer ITL. That is, each joint assembly 110 is installed at a position, i.e., a depth, corresponding to the isolation target layer ITL in the depth direction of the open well 210. On the other hand, each tubular sand filter 120 is installed at a position, i.e., a depth, corresponding to the hydrocarbon-bearing layer HCL in the depth direction of the open well 210.

[0049] Each joint assembly 110 includes a tubular main body 111 that is inserted into the open hole 210 and installed at a position penetrating the isolation target layer ITL, and a light emitting device 112 that is provided around the entire outer periphery of the main body 111. Each sand filter 120 includes a tubular main body 121 similar to the main body 111 of the joint assembly 110, and a filter 122 that is provided on the outer periphery of the main body 121.

[0050] Sand filter 120 has a plurality of through holes 123 penetrating the pipe wall of main body 121. The flow path inside sand filter 120 communicates with open hole 210 on the outer periphery of sand filter 120 via the plurality of through holes 123 and filter 122. Note that as sand filter 120, a commercially available sand filter such as EXCLUDER2000 or GeoFORM manufactured by Baker Hughes, Inc. can be used.

[0051] Fig. 7 is a perspective view showing an example of a joint assembly 110 constituting the sand control assembly (SCA) 100 of Fig. 6. As described above, the joint assembly 110 includes a tubular main body 111 and a light emitting device 112 provided around the entire outer periphery 111o of the main body 111. The main body 111 is, for example, a tubular member having a cylindrical flow path therein, and has openings at one end and the other end in the longitudinal direction.

[0052] The main body 111 has, for example, a male thread portion on the outer peripheral surface at one end in the longitudinal direction, and a female thread portion on the inner peripheral surface at the other end in the longitudinal direction. This allows a plurality of joint assemblies 110 to be connected in a straight line in the axial direction. The main body 111 is, for example, a double tube having an outer tube and an inner tube, and the outer tube is made of a material such as acrylic having translucency that transmits light irradiated from the light emitting device 112. The light emitting device 112 is provided between the outer tube and the inner tube of the outer peripheral portion 111o of the main body 111, over the entire circumference of the outer peripheral portion 111o.

[0053] The light emitting device 112 has, for example, a strip-shaped light emitting section 112s having a plurality of LEDs 112l. The strip-shaped light emitting section 112s is, for example, spirally wound around the outer circumferential surface of the inner tube of the main body section 111. The light emitting device 112 is also, for example, built into one end of the outer circumferential section 111o of the main body section 111, and has a battery and a switch for emitting light from the LEDs 112l of the light emitting section 112s.

[0054] The light emitting device 112 irradiates light to cure the uncured photocurable resin LCR (see FIG. 8) introduced between the main body 111 and the wall 211 of the open shaft 210. More specifically, when the photocurable resin LCR is an ultraviolet curable resin, the light emitting device 112 irradiates ultraviolet light from a plurality of LEDs 112l of a light emitting unit 112s provided around the entire circumference of the outer circumferential portion 111o of the main body 111.

[0055] As shown in FIGS. 4 and 6, after step S15 of installing a sand control assembly (SCA) 100 in an open borehole 210, step S16 of introducing a light curable resin LCR into the open borehole 210 is performed.

[0056] Fig. 8 is a schematic enlarged cross-sectional view for explaining step S16 of introducing the photocurable resin LCR in Fig. 4. In this step S16, uncured photocurable resin LCR is introduced between the main body 111 of the joint assembly 110 and the hole wall 211 of the open hole 210. More specifically, for example, the switching device 305 of the floating production facility 300 shown in Fig. 1 is switched to supply the photocurable resin LCR from the photocurable resin tank 306 to the flow path inside the sand control assembly 100 via the water production tube 301.

[0057] This causes the photocurable resin LCR to be discharged from the check valve 130 at the tip of the sand control assembly 100 to the bottom of the open hole 210. Photocurable resin LCR, such as ultraviolet curable resin, has a higher specific gravity than fluids, such as seawater, in the open hole 210. Therefore, the uncured photocurable resin LCR discharged from the check valve 130 at the tip of the sand control assembly 100 to the bottom of the open hole 210 gradually accumulates upward from the bottom of the open hole 210, filling the space between the main body 111 of each joint assembly 110 and the hole wall 211 of the open hole 210.

[0058] In step S16 of introducing the photocurable resin LCR, the supply of the photocurable resin LCR continues until the photocurable resin LCR is introduced between the main body 111 of all the joint assemblies 110 constituting the sand control assembly 100 and the hole wall 211 of the open hole 210. Thereafter, the supply of the photocurable resin LCR from the photocurable resin tank 306 to the sand control assembly 100 is stopped, and the resin curing step S17 by light irradiation shown in FIG. 4 is carried out.

[0059] Fig. 9 is a schematic enlarged cross-sectional view illustrating the resin curing step S17 by light irradiation in Fig. 4. In this step S17, light is irradiated from the light emitting device 112 of the joint assembly 110 to cure the uncured photocurable resin LCR between the main body 111 and the well wall 211 of the open well 210 over the entire circumference of the main body 111. This forms a production well 200 in which the isolation target layer ITL of the open well 210 is isolated by the cured photocurable resin CR.

[0060] More specifically, for example, ultraviolet light is emitted from a plurality of LEDs 112l of a light emitting unit 112s of a light emitting device 112 provided around the entire circumference of an outer circumferential portion 111o of a main body 111 of a joint assembly 110. This causes the photocurable resin LCR, which is an uncured ultraviolet curable resin between the main body 111 and the wall 211 of the open shaft 210, to cure, and the isolation target layer ITL exposed to the wall 211 of the open shaft 210 is covered with the cured photocurable resin CR.

[0061] As a result, in this resin curing step S17 by light irradiation, a production well 200 is formed in which the isolation target layer ITL of the open well 210 is selectively isolated by the cured photocurable resin CR. Note that in the production well manufacturing method WPM of this embodiment, in the resin curing step S17 by light irradiation, which is a step of forming the production well 200 in which the isolation target layer ITL is selectively isolated, uncured photocurable resin LCR is left above the cured photocurable resin CR.

[0062] Next, as shown in Fig. 4, step S18 is carried out to discharge the uncured photocurable resin LCR. In this step S18, for example, the pump 205 in the casing 201 of the production well 200 shown in Fig. 2 is operated to pump up the uncured photocurable resin LCR remaining in the flow path of the sand control assembly 100. As a result, the pressure in the flow path inside the sand control assembly 100 becomes lower than the pressure of the open well 210 around it.

[0063] As a result, the uncured photocurable resin LCR remaining in the exposed portion of the open well 210 where the hydrocarbon-bearing layer HCL is exposed flows into the internal flow passage of the sand filter 120 through the filter 122 and the multiple through holes 123 of the sand filter 120. Furthermore, the uncured photocurable resin LCR that has flowed into the internal flow passage of the sand filter 120 is pumped up by the pump 205 in the casing 201, and is collected in the photocurable resin tank 306 of the floating production facility 300, for example, via the inner tubing 204 and the water production tube 301.

[0064] On the other hand, in the step S12 of judging whether or not the isolation target layer ITL shown in Fig. 4 exists, if it is judged that the isolation target layer ITL does not exist (NO), the step S19 is carried out in which the joint assembly 110 is not attached to the sand control assembly 100, and only the sand filter 120 is attached. After that, the step S20 of installing the sand control assembly 100 in the open well 210 is carried out.

[0065] Thus, step S1 for producing the production well 200 shown in Figures 3 and 4 is completed. Thereafter, in the gas production method GPM of this embodiment, step S2 for producing gas is carried out as shown in Figure 3. In this step S2, after step S18 for recovering the uncured photocurable resin LCR in step S1 for producing the production well 200 or step S20 for installing the sand control assembly 100 without the joint assembly 110 in the open well 210, the production well 200 is depressurized to recover the gas released from the gas hydrate-bearing layer GHL to the production well 200.

[0066] Fig. 10 is a schematic cross-sectional view for explaining the step S2 of producing gas in Fig. 3. In this step S2, for example, the pump 205 in the casing 201 of the production well 200 shown in Fig. 2 is operated to pump up liquid such as seawater or groundwater from the flow passage of the sand control assembly 100. As a result, the pressure of the flow passage inside the sand control assembly 100 becomes lower than the pressure of the open well 210 around it, and seawater or groundwater flows from the open well 210 into the flow passage inside the sand control assembly 100 through the filter 122 of the sand filter 120 and the multiple through holes 123.

[0067] This reduces the pressure in the open well 210 around the sand filter 120, accelerating the decomposition of gas hydrates such as methane hydrate in the hydrocarbon-bearing layer HCL around the open well 210. As a result, gas G such as methane gas or natural gas flows into the open well 210 from the hydrocarbon-bearing layer HCL together with seawater and groundwater, and further flows from the open well 210 into the flow passage inside the sand control assembly 100 through the filter 122 and the multiple through holes 123 of the sand filter 120. Furthermore, the gas G such as methane gas or natural gas that flows into the flow passage inside the sand control assembly 100 together with seawater and groundwater is pumped up by the pump 205 in the casing 201, and gas and liquid are separated in the casing 201.

[0068] The gas G separated in the casing 201 is sent through a gas production tube 302 to a floating production facility 300 on the sea surface OS and recovered, as shown in Fig. 1. Liquid such as seawater or groundwater separated in the casing 201 is pumped up by a pump 205 and recovered in a produced water tank 304 of the floating production facility 300 on the sea surface OS through a water production tube 301. This completes the gas production method GPM shown in Fig. 3.

[0069] The operations of the joint assembly 110, the production well preparation method WPM, and the gas production method GPM of this embodiment will be described below.

[0070] The geological layer GS where the production well 200 is drilled includes an isolation target layer ITL such as an aquifer SWL between a hydrocarbon-bearing layer HCL represented by a gas hydrate-bearing layer GHL such as a methane hydrate-bearing layer MHL or a natural gas hydrate-bearing layer NGL. The isolation target layer ITL such as an aquifer SWL causes water inflow that hinders depressurization in the open well 210 during gas production, and is also presumed to be one of the causes of sand outflow.

[0071] A packing device called a packer or a tubing packer is known as a technique for isolating a specific area in the open well 210. However, the hydrocarbon-bearing layer HCL such as the methane hydrate-bearing layer MHL and the isolation target layer ITL such as the aquifer SWL are relatively fragile and easily collapse, and the use of a packer may cause the hole wall 211 of the open well 210 to expand. Therefore, in the open well 210 drilled in such a easily collapsed stratum GS, a packer cannot be used, and the isolation target layer ITL cannot be effectively isolated.

[0072] In contrast, the joint assembly 110 of this embodiment is a device for selectively isolating the isolation target layer ITL in an open hole 210 drilled in a stratum GS including the hydrocarbon-bearing layer HCL and the isolation target layer ITL. The joint assembly 110 includes a tubular main body 111 that is inserted into the open hole 210 and installed at a position penetrating the isolation target layer ITL, and a light emitting device 112 provided around the entire circumference of the outer periphery 111o of the main body 111. The light emitting device 112 is configured to irradiate light that cures uncured photocurable resin LCR introduced between the main body 111 and the hole wall 211 of the open hole 210.

[0073] With this configuration, the joint assembly 110 of this embodiment can be installed at a position penetrating the isolation target layer ITL of the stratum GS by inserting the tubular main body 111 into the open hole 210. Furthermore, the joint assembly 110 of this embodiment can irradiate light for curing the uncured photocurable resin LCR from the light emitting device 112 provided around the entire circumference of the outer periphery 111o of the main body 111 in a state where the uncured photocurable resin LCR is introduced between the main body 111 and the hole wall 211 of the open hole 210.

[0074] 10, the annular or cylindrical photocurable resin CR hardened between the body 111 of the joint assembly 110 and the wall 211 of the open well 210 can cover the wall 211 of the open well 210 at the portion penetrating the isolation target layer ITL, and the isolation target layer ITL can be selectively isolated from the open well 210. This makes it possible to prevent water and sand from the isolation target layer ITL, which would hinder the decompression in the open well 210, and to efficiently produce gas G from the hydrocarbon-bearing layer HCL. Also, even in the open well 210 excavated in the easily collapsing stratum GS, it becomes possible to effectively isolate the isolation target layer ITL without applying a load to the wall 211 of the open well 210.

[0075] The production well manufacturing method WPM of this embodiment is a manufacturing method of a production well 200 using the joint assembly 110 of this embodiment. The production well manufacturing method WPM has a bare hole drilling and logging step S11 including a step of drilling a bare hole 210 in the stratum GS and a step of identifying the positions of the hydrocarbon-bearing layer HCL and the isolation target layer ITL in the stratum GS. The production well manufacturing method WPM also includes a step S15 of inserting the main body 111 of the joint assembly 110 into the bare hole 210 and setting it at a position penetrating the isolation target layer ITL, and a step S16 of introducing uncured photocurable resin LCR between the main body 111 and the well wall 211 of the bare hole 210. The production well manufacturing method WPM also includes a step S17 of irradiating light from the light emitting device 112 to cure the uncured photocurable resin LCR between the main body 111 and the well wall 211 of the open well 210 over the entire circumference of the main body 111, thereby forming a production well 200 in which the isolation target layer ITL of the open well 210 is selectively isolated by the cured photocurable resin CR. Furthermore, the production well manufacturing method WPM includes a step S18 of recovering the uncured photocurable resin LCR remaining in the portion of the open well 210 where the hydrocarbon-bearing layer HCL is exposed.

[0076] With such a configuration, according to the production well production method WPM of this embodiment, the open well 210 can be drilled in the stratum GS including the hydrocarbon-bearing layer HCL and the isolation target layer ITL, and the positions of the hydrocarbon-bearing layer HCL and the isolation target layer ITL in the stratum GS can be specified. Then, the main body 111 of the joint assembly 110 of this embodiment can be inserted into the open well 210 and installed at a position penetrating the isolation target layer ITL of the stratum GS, and light can be irradiated from the light emitting device 112 provided around the entire circumference of the outer periphery 111o of the main body 111 in a state where the uncured photocurable resin LCR is introduced between the main body 111 and the hole wall 211 of the open well 210.

[0077] This allows the uncured photocurable resin LCR in contact with the isolation target layer ITL exposed on the well wall 211 of the open well 210 to be selectively cured around the entire circumference of the well wall 211, and the cured photocurable resin CR to form a production well 200 in which the isolation target layer ITL is selectively isolated from the open well 210. Thereafter, by recovering the uncured photocurable resin LCR remaining in the portion of the open well 210 where the hydrocarbon-bearing layer HCL is exposed, a production well 200 capable of producing hydrocarbons from the hydrocarbon-bearing layer HCL selectively exposed on the well wall 211 of the open well 210 can be manufactured.

[0078] In addition, in the production well manufacturing method WPM of this embodiment, in process S17 in which the uncured photocurable resin LCR is cured to form a production well 200 in which the isolation target layer ITL is isolated, the uncured photocurable resin LCR is left above the cured photocurable resin CR.

[0079] With this configuration, when the cured photocurable resin CR shrinks and a gap is formed between the wall 211 of the open hole 210 and the cured photocurable resin CR, the uncured photocurable resin LCR remaining above the cured photocurable resin CR flows into the gap and cures to fill the gap. This prevents a gap from being formed between the cured photocurable resin CR and the isolation target layer ITL exposed to the wall 211 of the open hole 210, and makes it possible to more reliably isolate the isolation target layer ITL from the open hole 210.

[0080] In addition, in the production well manufacturing method WPM of this embodiment, the hydrocarbon-bearing layer HCL is the gas hydrate-bearing layer GHL, and the isolation target layer ITL is the aquifer SWL.

[0081] With such a configuration, according to the production well production method WPM of this embodiment, it is possible to drill an open well 210 in a stratum GS including a gas hydrate-bearing layer GHL that bears hydrocarbons such as methane hydrate and an aquifer SWL, and form a production well 200 in which the aquifer SWL is selectively isolated from the open well 210. Therefore, it is possible to produce a production well 200 that can efficiently produce hydrocarbon gas such as methane gas from the gas hydrate-bearing layer GHL selectively exposed to the well wall 211 of the open well 210.

[0082] The gas production method GPM of this embodiment also includes the production well manufacturing method WPM of this embodiment. The gas production method GPM of this embodiment includes a step S2 of depressurizing the production well 200 and recovering the gas G released from the gas hydrate-bearing layer GHL to the production well 200 after the step S18 of recovering the uncured photocurable resin LCR.

[0083] With this configuration, according to the gas production method GPM of this embodiment, the aquifer SWL exposed to the well wall 211 of the open well 210 is selectively isolated, and gas G can be efficiently produced by a depressurization method using a production well 200 that can efficiently produce hydrocarbon gases such as methane gas from the gas hydrate-bearing layer GHL selectively exposed to the well wall 211 of the open well 210.

[0084] As described above, according to this embodiment, it is possible to provide a joint assembly 110 for selectively isolating the isolation target layer ITL in an open hole 210 drilled into a stratum GS containing a hydrocarbon-bearing layer HCL and an isolation target layer ITL, and a production well manufacturing method WPM and a gas production method GPM using the joint assembly 110.

[0085] [Embodiment 2] Hereinafter, a second embodiment of a joint assembly according to the present disclosure will be described with reference to FIGS. 1 to 10 and with reference to FIGS. 11 to 16.

[0086] 11 and 12 are horizontal cross-sectional views illustrating a joint assembly according to a second embodiment of the present disclosure. A joint assembly 110 of this embodiment includes a contraction mechanism 113 that contracts an outer circumferential portion 111o of a main body portion 111 from an expanded position on the outside in the radial direction of the main body portion 111 shown in FIG. 11 to a contracted position on the inside in the radial direction of the main body portion 111 shown in FIG.

[0087] In the joint assembly 110 of this embodiment, with the outer circumferential portion 111o of the main body portion 111 in the expanded position shown in Fig. 11, the light emitting device 112 irradiates light to harden the unhardened photocurable resin LCR between the main body portion 111 and the hole wall 211 of the open hole 210. Thereafter, as shown in Fig. 12, the contraction mechanism 113 is operated to contract the outer circumferential portion 111o of the main body portion 111 to a radially inward contracted position. This allows the outer circumferential surface of the outer circumferential portion 111o of the main body portion 111 to be separated from the inner circumferential surface of the hardened photocurable resin CR covering the hole wall 211 of the open hole 210 at the portion penetrating the isolation target layer ITL.

[0088] The contraction mechanism 113 of the joint assembly 110 is not limited to the configuration shown in FIG. 11 and FIG. 12. FIG. 13 and FIG. 14 are horizontal cross-sectional views showing modified examples of the joint assembly 110 of FIG. 11 and FIG. 12. The joint assembly 110 may include a contraction mechanism 113 having a configuration as shown in FIG. 13 and FIG. 14. According to the joint assembly 110 of this modified example, like the joint assembly 110 of FIG. 11 and FIG. 12, the outer peripheral surface of the outer peripheral part 111o of the main body part 111 can be separated from the inner peripheral surface of the cured photocurable resin CR covering the hole wall 211 of the part penetrating the isolation target layer ITL of the open hole 210. In the example shown in FIG. 11 to FIG. 14, the central shaft supporting the contraction mechanism 113 may be a hollow pipe, and the flow path in the pipe may be a flow path for uncured photocurable resin LCR, water, etc.

[0089] Fig. 15 is a cross-sectional view showing a state in which the outer circumferential portion 111o of the main body portion 111 is in an expanded position in the joint assembly 110 as shown in Fig. 11 and Fig. 13. Fig. 16 is a cross-sectional view showing a state in which the outer circumferential portion 111o of the main body portion 111 is in a contracted position in the joint assembly 110 as shown in Fig. 12 and Fig. 14.

[0090] In the stratum GS, the isolation target layer ITL such as the aquifer SWL is more likely to crumble than the hydrocarbon-bearing layer HCL such as the methane hydrate-bearing layer MHL, and the well wall 211 may be gouged out in a concave shape during excavation of the open well 210. In such a case, as shown in Fig. 15, the hydrocarbon-bearing layer HCL between the well wall 211 and the main body 111 is hardened by irradiating light from the light emitting device 112 with the outer periphery 111o of the main body 111 in the expanded position aligned with the hydrocarbon-bearing layers HCL above and below the isolation target layer ITL.

[0091] 16, the contraction mechanism 113 is operated to contract the outer circumferential portion 111o of the main body 111 to a contracted position on the inside in the radial direction of the main body 111. As a result, the outer circumferential surface of the outer circumferential portion 111o of the main body 111 is separated from the inner circumferential surface of the cured photocurable resin CR, and the joint assembly 110 can be extracted from the open hole 210 in which the isolation target layer ITL is isolated by the cured photocurable resin CR. Then, the sand control assembly 100 equipped with the sand filter 120 is inserted into the open hole 210 in which the isolation target layer ITL is isolated, and the uncured photocurable resin LCR is collected to produce the gas G.

[0092] The joint assembly 110 of this embodiment may include an anti-adhesion layer 114 that is provided on the outer surface of the main body 111 and prevents adhesion between the cured photocurable resin CR and the main body 111. As the anti-adhesion layer 114, for example, grease that transmits the light irradiated from the light emitting device 112, or a polytetrafluoroethylene (PTFE) sheet, etc., may be used.

[0093] With this configuration, in the joint assembly 110 of this embodiment, the light emitting device 112 irradiates the uncured photocurable resin LCR through the light-transmitting anti-adhesion layer 114 provided on the outer surface of the main body 111 with light, so that the cured photocurable resin CR comes into contact with the anti-adhesion layer 114. Therefore, the anti-adhesion layer 114 prevents the cured photocurable resin CR from adhering to the outer surface of the main body 111, and when the contraction mechanism 113 is operated to contract the outer circumferential portion 111o of the main body 111 radially inward, the outer circumferential surface of the outer circumferential portion 111o can be easily separated from the inner circumferential surface of the cured photocurable resin CR.

[0094] As described above, according to this embodiment, it is possible to provide a joint assembly 110 for selectively isolating the isolation target layer ITL in an open hole 210 drilled into a stratum GS containing a hydrocarbon-bearing layer HCL and an isolation target layer ITL, and a production well manufacturing method WPM and a gas production method GPM using the joint assembly 110.

[0095] Although the embodiments of the joint assembly, the production well manufacturing method, and the gas production method according to the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and even if there are design changes and the like within the scope of the present disclosure, they are included in the present disclosure. For example, the hydrocarbon-bearing layer is not limited to a gas hydrate-bearing layer such as a methane hydrate-bearing layer as described above, but may be a layer containing petroleum, natural gas, shale gas, oil, etc.

[0096] Below, we will describe experiments that were conducted to verify the effectiveness of the joint assembly according to the present disclosure.

[0097] [Experiment 1] FIG. 17 is a schematic cross-sectional view of the apparatus used in Experiment 1. As shown in FIG. 17, a cylindrical container C2 having a plurality of through holes formed in the side wall was placed inside a cylindrical container C1 larger than the container C2. Furthermore, a hydrocarbon-bearing layer HCL simulating a methane hydrate-bearing layer and an isolation target layer ITL simulating an aquifer were stacked in the inner container C2, and a cylindrical hole simulating an open well 210 was formed in the center. A transparent acrylic pipe P was placed inside the hole, and a light-emitting device 112 was placed around the entire circumference of the pipe P inside the pipe P.

[0098] Furthermore, water W was supplied between the container C1 and the container C2, and the water W was made to permeate from the through-hole in the side wall of the container C2 into the hydrocarbon embryo layer HCL and the isolation target layer ITL by the hydraulic head pressure. Also, uncured photocurable resin LCR was introduced between the hole simulating the open well 210 and the pipe P, and light was irradiated from the light emitting device 112 to cure all of the introduced uncured photocurable resin LCR. As a result, the cured photocurable resin CR contracted, and a gap g was formed between the cured photocurable resin CR and the hole simulating the open well 210.

[0099] Thereafter, the water W that had permeated the hydrocarbon-bearing layer HCL and the isolation target layer ITL and accumulated in the hole simulating the open well 210 was pumped up and the water production amount ΔQ was measured. As a result, the water production amount ΔQ was reduced to about one-third compared to the case where the isolation target layer ITL was not isolated by the cured photocurable resin CR, proving that the isolation of the isolation target layer ITL was being performed effectively.

[0100] [Experiment 2] 18 is a schematic cross-sectional view of the device used in Experiment 2. In Experiment 2, the height of the light-emitting device 112 was made higher than in Experiment 1, and the outer circumferential surface of the upper part of the pipe P was covered with aluminum foil AF. Thereafter, water W was supplied between the container C1 and the container C2 in the same manner as in Experiment 1, and the water W was made to permeate into the hydrocarbon embryo layer HCL and the isolation target layer ITL from the through-hole in the side wall of the container C2 by the hydraulic head pressure. Furthermore, uncured light-curing resin LCR was introduced between the hole simulating the open well 210 and the pipe P, and the light-curing resin LCR was filled up to the middle of the part of the pipe P covered with the aluminum foil AF.

[0101] Thereafter, light was irradiated from the light emitting device 112 to cure the uncured photocurable resin LCR below the portion of the pipe P covered with the aluminum foil AF. As a result, no gap g was formed between the cured photocurable resin CR and the hole simulating the bare hole 210. This is thought to be because the uncured photocurable resin LCR remaining outside the portion of the pipe P covered with the aluminum foil AF was supplied to the gap g formed between the cured photocurable resin CR and the hole simulating the bare hole 210, and cured to fill the gap g.

[0102] After that, the water W that had permeated the hydrocarbon-bearing layer HCL and the isolation target layer ITL and accumulated in the hole simulating the open well 210 was pumped up and the water production amount ΔQ was measured. As a result, the water production amount ΔQ became almost zero, proving that the isolation of the isolation target layer ITL was being performed effectively. In this experiment, resin A (UV resin High transparency manufactured by NOVA3D) and resin B (Alpha Resin LV8-1 manufactured by Alpha Kaken Co., Ltd.) were used as the light-curing resin LCR, and the same results were obtained with both. [Explanation of symbols]

[0103] 110 Joint Assembly 111 Main body 111o outer periphery 112 Light emitting device 113 Contraction Mechanism 114 Anti-adhesion layer 200 producing wells 210 Open pit 211 Pit wall CR Photocurable resin after curing G Gas GHL Gas hydrate host layer GPM Gas Production Method GS Strata HCL Hydrocarbon Embryonic Layer ITL Isolated Layer LCR Uncured light curable resin SWL Aquifer WPM Production Well Manufacturing Method

Claims

1. 1. A joint assembly for selectively isolating a layer to be isolated in an open borehole drilled into a stratum including a hydrocarbon-bearing layer and a layer to be isolated, the joint assembly comprising: A tubular main body that is inserted into the open well and installed at a position that penetrates the isolation target layer; a light emitting device provided around the entire outer periphery of the main body portion and configured to irradiate light for curing uncured photocurable resin introduced between the main body portion and a wall of the open well; A joint assembly comprising:

2. The joint assembly according to claim 1 , further comprising a contraction mechanism for contracting the outer periphery from an expanded position on the radially outer side of the body portion to a contracted position on the radially inner side of the body portion.

3. 3. The joint assembly according to claim 2, further comprising an anti-adhesion layer provided on an outer surface of the body portion to prevent adhesion between the photocurable resin and the body portion after hardening.

4. A production well manufacturing method using the joint assembly according to any one of claims 1 to 3, comprising: drilling the open hole into the formation; identifying the location of the hydrocarbon-bearing layer and the target layer in the formation; Inserting the main body into the open well and placing it at a position where it penetrates the layer to be isolated; introducing the uncured photocurable resin between the body and the well wall of the open well; A step of forming a production well in which the isolation target layer of the open well is selectively isolated by the cured photocurable resin by irradiating the light from the light emitting device to cure the uncured photocurable resin between the main body and the well wall of the open well over the entire circumference of the main body; recovering the uncured photocurable resin remaining in the exposed portion of the open well where the hydrocarbon-bearing layer is exposed; A production well manufacturing method including:

5. The method for manufacturing a production well according to claim 4 , wherein in the step of forming the production well, the uncured photocurable resin is left above the cured photocurable resin.

6. The hydrocarbon-bearing layer is a gas hydrate-bearing layer, The method for producing a production well according to claim 4 , wherein the layer to be isolated is an aquifer.

7. A gas production method including the production well production method of claim 6, A gas production method comprising the step of recovering the uncured photocurable resin, followed by depressurizing the production well and recovering gas released from the gas hydrate-bearing layer to the production well.

Images