Patent Application
20240418052
The present disclosure relates to joint assemblies, production well manufacturing methods, and gas production methods.
Conventional techniques to yield methane hydrate have problems including the production of sand and water. Non Patent Literature 1, for example, describes measures for counteracting these problems. To avoid the compaction of the reservoir and the production of sand during the production of methane hydrate, Patent Literature 1 describes a yielding method of methane hydrate from a sand reservoir, and the method includes injecting a grouting agent, which is capable of sufficiently fixing sand particles, into a gap (pore space) of unsolidified or weakly solidified sand reservoir to be developed.
Patent Literature 2 describes a hydrocarbon collection method that is characterized by a composition used to prevent earth and sand contained in the seabed from flowing into a production well. Specifically, this hydrocarbon collection method uses a composition that is used by microorganisms that generate carbon dioxide or sulfate ions to promote deposition of calcium carbonate when they generate carbon dioxide or sulfate ions.
Patent Literature 3 discloses a process for lining an open hole and a tool for producing a coating for open hole. This tool is attached to a drill bit at a tip of a drill string and has multiple injectors and emitters around a portion of a circumferential surface. A fluid composition is supplied from the injectors to an outer periphery of the tool and is cured by light emitted from the emitters to produce an open-hole coating.
Patent Literature 4 discloses a method and system for sealing a casing to an open hole by photoactivation. This method is used for cementing a casing in an open hole, and includes inserting an optical fiber cable attached to the outside of the casing into the open hole, and activating a sealant via the optical fiber within the open hole, thus curing the sealant by the reaction.
Patent Literature 5 discloses a method for sealing a lost circulation zone, such as cavities, which become obstacles when drilling a subterranean well. In this method, a drill string has an ultraviolet (UV) system, an actuator, and a fluid flow path, and the method includes delivering a UV curable material into the fluid flow path of the drill string during drilling of a subterranean well, and applying UV light to the fluid flow path of the drill string from the UV system. This feeds the activated UV curable material through the fluid flow path of the drill string into the lost circulation zone, where the UV curable material cures to fill the voids.
Patent Literature 1: WO2020/003551
Patent Literature 2: JP 2019-11612 A
Patent Literature 3: U.S. Pat. No. 7,931,091 B2
Patent Literature 4: US 2021/0238953 A1
Patent Literature 5: U.S. Pat. No. 10,865,620 B1
Non Patent Literature 1: Koji Yamamoto, “About the Second Offshore Production Test”, [online], Nov. 29, 2017, Methane Hydrate Forum 2017, [Retrieved Feb. 2, 2022]
The methane hydrate production method of Patent Literature 1 installs a casing in a drilled hole and applies cementing to the gap between the borehole wall and the casing. In addition, through holes are formed between the casing and cementing by gun perforation, thus enabling a material exchange between the reservoir and the inside of the mine. Although this production method provides excellent mechanical stability for the production well, it not only increases the construction costs of the production well, but also reduces the gas production efficiency, compared to an open hole without a casing. The same applies to the methods of Patent Literatures 2 and 4 that use a casing.
To cure the fluid composition over the entire circumference of the borehole wall of the open hole, the tool for producing a coating for open hole in Patent Literature 3 requires rotation of the tool having emitters on part of the circumferential surface in a circumferential direction. However, the rotation of the tool may be hindered by the partially cured fluid composition. It is also not practical to cure the fluid composition, which is supplied from the injectors to the outer periphery of the tool, by the light irradiated from the emitters from the borehole wall side without allowing it to settle in the open hole. The method of Patent Literature 5 includes irradiating the UV curable material in the fluid flow path of the drill string with UV light for activation, and then feeding the UV material into cavities of the strata to allow it to cure. The feasibility of this method, however, is questionable.
The present disclosure provides a joint assembly that selectively isolates an isolation target layer in an open hole drilled in the strata including a hydrocarbon-bearing reservoir and the isolation target layer, and provides a production well manufacturing method and gas production method using the joint assembly.
A joint assembly according to one aspect of the present disclosure is used in an open hole drilled in strata including a hydrocarbon-bearing reservoir and an isolation target layer and is configured to selectively isolate the isolation target layer. The joint assembly includes: a tubular body to be inserted into the open hole to be positioned to penetrate the isolation target layer; and a light source disposed over entire circumference of an outer periphery of the body and configured to emit light to cure uncured photo-curable resin that is introduced between the body and a borehole wall of the open hole.
The joint assembly according to the above aspect of the present disclosure is used having the tubular body inserted into the open hole to be placed at a position penetrating the isolation target layer in the strata and then introducing uncured photo-curable resin between the body and the borehole wall of the open hole. The joint assembly in this state lets the light source, which is placed over the entire circumference of an outer periphery of the body, emit light to cure the photo-curable resin. This allows the annular or cylindrical photo-curable resin cured between the body and the borehole wall of the open hole to cover the borehole wall of the open hole at a portion that penetrates the isolation target layer of the open hole, thus enabling selective isolation of the isolation target layer from the open hole.
The joint assembly according to the above aspect of the present disclosure may further include an actuator configured to contract the outer periphery from an expanded position outside in the radial direction of the body to a contracted position inside in the radial direction.
The joint assembly according to this aspect allows, in response to the operation of the actuator, to contract the outer periphery of the body from an expanded position outside in the radial direction of the body to a contracted position inside in the radial direction. This allows the outer circumferential surface of the outer periphery of the body to be separated from the inner circumferential surface of the cured photo-curable resin covering the borehole wall of the open hole at the part penetrating the isolation target layer, and thus enables the removal of the body from the open hole having the isolation target layer separated by the cured photo-curable resin.
The joint assembly according to the above aspect of the present disclosure may further include an anti-adhesion layer on the outer surface of the body, the anti-adhesion layer preventing adhesion of the photo-curable resin after curing and the body.
The joint assembly according to this aspect lets the light source emit light to the uncured photo-curable resin through the light-transmissive anti-adhesion layer placed on the outer surface of the body, so that the photo-curable resin cures while being in contact with the anti-adhesion layer. Thus, the anti-adhesion layer prevents the cured photo-curable resin from adhering to the outer surface of the body, and when the actuator is operated to contract the outer periphery of the body radially inward, the outer circumferential surface of the outer periphery is easily separated from the inner circumferential surface of the cured photo-curable resin.
A production well manufacturing method according to one aspect of the present disclosure includes: drilling the open hole into the strata; locating the hydrocarbon-bearing reservoir and the isolation target layer in the strata; inserting the body into the open hole to place the body at a position penetrating the isolation target layer; introducing the uncured photo-curable resin between the body and the borehole wall of the open hole; emitting the light from the light source to cure the uncured photo-curable resin between the body and the borehole wall of the open hole over the entire circumference of the body, thus forming a production well having the isolation target layer of the open hole selectively isolated by the cured photo-curable resin; and collecting the uncured photo-curable resin and remains in a portion of the open hole where the hydrocarbon-bearing reservoir is exposed.
The production well manufacturing method according to the above aspect of the present disclosure allows the drilling of an open hole into strata that contains a hydrocarbon-bearing reservoir and an isolation target layer, and the locating of the hydrocarbon-bearing reservoir and the isolation target layer in the strata. Then, the method inserts the body of the joint assembly according to the above aspect into the open hole to be placed at a position penetrating the isolation target layer in the strata, and emits light from the light source placed over the entire circumference of the outer periphery of the body to uncured photo-curable resin that is introduced between the body and the borehole wall of the open hole. This selectively cures the uncured photo-curable resin, which is in contact with the isolation target layer exposed to the borehole wall of the open hole, over the entire circumference of the borehole wall, thus forming a production well having the isolation target layer selectively isolated from the open hole by the cured photo-curable resin. After that, the method collects uncured photo-curable resin that remains in the portion of the open hole where the hydrocarbon-bearing reservoir is exposed, thereby manufacturing a production well that is capable of yielding hydrocarbon from the hydrocarbon-bearing reservoir selectively exposed to the borehole wall of the open hole.
In the production well manufacturing method according to the above aspect, the production well may be formed while leaving the uncured photo-curable resin above the cured photocurable resin.
Although the cured photo-curable resin may contract and create a gap between the borehole wall of the open hole and the cured photo-curable resin, the uncured photo-curable resin remaining above the cured photo-curable resin will flow into the gap and cure to fill the gap. This prevents the formation of a gap between the cured photo-curable resin and the isolation target layer exposed to the borehole wall of the open hole, thereby isolating the isolation target layer from the open hole more reliably.
In the production well manufacturing method according to the above aspect, the hydrocarbon-bearing reservoir may include a gas hydrate-bearing layer, and the isolation target layer may include a water-bearing layer.
The manufacturing method of this aspect allows the drilling of an open hole into strata that contains a gas hydrate-bearing layer that bears hydrocarbon such as methane hydrate and a water-bearing layer to form a production well having the water-bearing layer selectively isolated from the open hole. Therefore, the method manufactures a production well that is capable of efficiently producing hydrocarbon gas such as methane gas from the gas hydrate-bearing layer selectively exposed to the borehole wall of the open hole.
A gas production method according to another aspect of the present disclosure includes the production well manufacturing method according to the above aspect, and the method includes following the collecting of the uncured photo-curable resin, reducing pressure of the production well to collect gas released from the gas hydrate-bearing layer to the production well.
The gas production method according to the above aspect of the present disclosure uses the production well having the water-bearing layer exposed to the borehole wall of the open hole and selectively isolated, and being capable of efficiently producing hydrocarbon gas such as methane gas from the gas hydrate-bearing layer selectively exposed to the borehole wall of the open hole, thus efficiently producing the gas by the depressurization method.
The above aspects of the present disclosure provide a joint assembly that selectively isolates an isolation target layer in an open hole drilled in the strata including a hydrocarbon-bearing reservoir and the isolation target layer, and provides a production well manufacturing method and gas production method using the joint assembly.
Referring to
The joint assembly 110 of this embodiment is inserted into an open hole 210 drilled into strata GS including a hydrocarbon-bearing reservoir HCL and an isolation target layer ITL. The joint assembly 110 is configured to selectively isolate the isolation target layer ITL exposed to the borehole wall 211 of the open hole 210 by cured photo-curable resin CR. The open hole 210 refers to a portion of the production well 200 drilled in the strata GS where the casing 201 is not inserted.
For instance, the strata GS having the production well 200 drilled therein is seabed strata at a depth of 500 m or more, and includes an upper ground layer UG including the seabed surface, and hydrocarbon-bearing reservoirs HCL and isolation target layers ITL that are deposited alternately below the upper ground layer UG. The production well 200 has a part penetrating the upper ground layer UG, and a casing 201 is inserted in this part. The lower part of the production well 200 below the upper ground layer UG is the open hole 210, where the casing 201 is not inserted. That is, the strata GS through which the open hole 210 is drilled includes the hydrocarbon-bearing reservoirs HCL and the isolation target layers ITL.
Each hydrocarbon-bearing reservoir HCL is a gas hydrate-bearing layer GHL that bears a hydrocarbon gas, for example. Each gas hydrate-bearing layer GHL is a methane hydrate-bearing layer MHL or natural gas hydrate-bearing layer NGL, for example. Each isolation target layer ITL is a water-bearing layer SWL, for example. The strata GS through which the open hole 210 is drilled is not limited to seabed strata, and may be land strata containing permafrost, for example. In this embodiment, each hydrocarbon-bearing reservoir HCL is a methane hydrate-bearing layer MHL, and each isolation target layer ITL is a water-bearing layer SWL.
For instance, tubular joint assemblies 110 are alternately connected with tubular sand filters 120 to configure a tubular sand control assembly (SCA) 100 that extends from the upper end to the bottom of the open hole 210. That is, the sand control assembly 100 includes a plurality of joint assemblies 110 and a plurality of sand filters 120 that are connected in a straight line in the depth direction of the open hole 210 and is inserted and installed in the open hole 210.
The sand control assembly 100 is configured so that one or more joint assemblies 110 are each placed at a position of the corresponding isolation target layer ITL and one or more sand filters 120 are each placed at a position of the corresponding hydrocarbon-bearing reservoir HCL, these joint assemblies 110 and sand filters 120 being alternately connected in the depth direction of the open hole 210.
In other words, when being inserted and installed in the open hole 210, the sand control assembly 100 has one or more joint assemblies 110 at overlapping positions with their corresponding isolation target layers ITL, and one or more sand filters 120 at overlapping positions with their corresponding hydrocarbon-bearing reservoirs HCL. The joint assemblies 110 and the sand filters 120 may be prepared in several different lengths in accordance with the thicknesses of the isolation target layers ITL and of the hydrocarbon-bearing reservoirs HCL, respectively.
For instance, as shown in
A pump 205 is placed below the liquid level LL inside the casing 201. The pump 205 is connected to a water production tube 301 that extends above sea surface OS. When the water in the casing 201 is pumped up by the pump 205 to a floating production facility 300 above the sea surface OS, the open hole 210 is depressurized so that decomposition of methane hydrate is accelerated in the methane hydrate bearing layer MHL that is a hydrocarbon-bearing reservoir HCL near the open hole 210, and methane gas, together with water, flows into the sand control assembly 100 through the sand filter 120.
The water and methane gas flowing into the sand control assembly 100 inserted into the open hole 210 flows into the perforation 204p at the tip of the inner tubing 204 inserted into the sand control assembly 100, and rises within the inner tubing 204 to 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.
A blow out protection (BOP) 206, installed at the upper end of the casing 201 above the seabed surface, has the water production tube 301 passing therethrough to extend to the floating production facility 300 at the sea surface OS. The BOP 206 also has a gas production tube 302 attached thereto, which communicates with the space above the liquid level LL within the casing 201 and extends to the floating production facility 300. For instance, the floating production facility 300 includes a platform 303 floating above the sea surface OS, a produced water tank 304 on the platform 303, a switching device 305, and a photocurable-resin tank 306.
The gas production method GPM of this embodiment shown in
In step S1 shown in
In the open-hole drilling and logging step S11, while the bottom hole assembly 400 is rotated, seawater or drilling mud is supplied for circulation to the tip of the drill bit 402 through the drill pipes 401 to drill the open hole 210 in the strata GS. Another drill pipe 401 will be connected as the drilling of the open hole 210 progresses. The open-hole drilling and logging step S11 may include a step of installing a casing 201 at the upper end of the open hole 210.
In the open-hole drilling and logging step S11, logging is also performed simultaneously with drilling of the strata GS using a physical logging method such as logging while drilling (LWD) and measurement while drilling (MWD). Drilling and logging of the open hole may be performed sequentially. In this case, wireline logging may follow the drilling of the open hole. These logging techniques accurately specify the position, i.e., depth, of each of the hydrocarbon-bearing reservoirs HCL and isolation target layers ITL in the depth direction of the open hole 210.
After the completion of the open-hole drilling and logging step S11, the bottom hole assembly 400 is extracted from the open hole 210. Then, step S12 is performed to determine whether or not the strata GS having the open hole 210 drilled contains any isolation target layer ITL, such as a water-bearing layer SWL. If it is determined in step S12 that the strata GS includes an isolation target layer ITL (YES), step S13 of attaching a joint assembly 110 to the sand control assembly 100 and step S14 of attaching a sand filter 120 are performed. Then, step S15 is performed to install the sand control assembly (SCA) 100 in the open hole 210.
The tubular joint assemblies 110 are inserted into the open hole 210 to be each positioned to penetrate the corresponding isolation target layer ITL. That is, each joint assembly 110 is installed at the position or depth of the corresponding isolation target layer ITL in the depth direction of the open hole 210. Each of the tubular sand filters 120 is installed at the position or depth of the corresponding hydrocarbon-bearing reservoir HCL in the depth direction of the open hole 210.
Each joint assembly 110 has a tubular body 111 that is inserted into the open hole 210 to be positioned to penetrate the isolation target layer ITL, and a luminescence device 112 that is placed around the entire perimeter of the body 111. Each sand filter 120 has a tubular body 121 similar to the bodies 111 of the joint assemblies 110, and a filter 122 around the periphery of the body 121.
Each sand filter 120 has a plurality of through holes 123 penetrating the wall of the body 121. The flow path inside the sand filter 120 communicates with the open hole 210 surrounding the sand filter 120 via the through holes 123 and a filter 122. For instance, the sand filters 120 may be a commercially available sand filter such as EXCLUDER2000 manufactured by Baker Hughes, Inc. or GeoFORM.
For instance, the body 111 has an external thread on the outer circumferential surface at one end in the longitudinal direction, and an internal thread on the inner circumferential surface at the other end in the longitudinal direction. This allows the plurality of joint assemblies 110 to be connected in a straight line in the axial direction. For instance, the body 111 is 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 allows the light emitted from the luminescence device 112 to pass through. The luminescence device 112 is placed between the outer tube and the inner tube on the outer periphery 111o of the body 111, around the entire perimeter of the outer periphery 111o.
For instance, the luminescence device 112 has a strip-shaped light emitting section 112s with a plurality of LEDs 112l. The strip-shaped light emitting section 112s is wound spirally around the outer circumferential surface of the inner tube of the body 111, for example. For instance, the luminescence device 112 has a battery and a switch built into one end of the outer periphery 111o of the body 111 to let the LEDs 112l of the light emitting section 112s emit light.
The luminescence device 112 emits light to cure uncured photo-curable resin LCR (see
As shown in
This allows the photo-curable 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. The photo-curable resin LCR, such as a UV curing resin, has a higher specific gravity than the fluid, such as seawater, in the open hole 210. Therefore, the uncured photo-curable resin LCR discharged from the check valve 130 at the tip of the sand control assembly 100 into the bottom of the open hole 210 gradually accumulates upward from the bottom of the open hole 210, filling the space between the body 111 of each joint assembly 110 and the borehole wall 211 of the open hole 210.
In this step S16 of introducing the photo-curable resin LCR, the supply of photo-curable resin LCR is continued until the photo-curable resin LCR is introduced between the bodies 111 of all joint assemblies 110 that constitute the sand control assembly 100 and the borehole wall 211 of the open hole 210. Thereafter, the supply of the photo-curable resin LCR from the photo-curable resin tank 306 to the sand control assembly 100 is stopped, and step S17 of curing the resin shown in
Specifically, UV light is emitted from the plurality of LEDs 112l of the light emitting section 112s in the luminescence device 112 placed over the entire circumference of the outer periphery 111o of the body 111 of the joint assembly 110, for example. This cures the uncured UV-curing resin, the photo-curable resin LCR, between the body 111 and the borehole wall 211 of the open hole 210, so that the cured photo-curable resin CR covers the isolation target layers ITL exposed to the borehole wall 211 of the open hole 210.
As a result of the resin curing step S17 by light irradiation, a production well 200 is formed, having the isolation target layers ITL of the open hole 210 that are selectively isolated by the cured photo-curable resin CR. In the production well manufacturing method WPM of this embodiment, the resin curing process S17 is to form the production well 200 having the isolation target layers ITL selectively isolated by light irradiation. In this step, the photo-curable resin LCR still remains uncured above the cured photocurable resin CR.
Next, as shown in
This causes the uncured photo-curable resin LCR remaining in the portion of the open hole 210 where the hydrocarbon-bearing reservoirs HCL are exposed to flow into the internal flow path of the sand filters 120 through the filters 122 and multiple through holes 123 of the sand filters 120. The uncured photo-curable resin LCR that flows into the inner flow path of the sand filters 120 is then pumped up by the pump 205 in the casing 201 to be collected in the photo-curable resin tank 306 of the floating production facility 300 via the inner tubing 204 and water production tube 301, for example.
If it is determined that there is no isolation target layer ITL (NO) in step S12 that determines whether any isolation target layer ITL exists in
This completes step S1 of manufacturing the production well 200 shown in
This reduces the pressure in the open hole 210 around the sand filters 120 and promotes the decomposition of gas hydrates such as methane hydrate in the hydrocarbon-bearing reservoirs HCL around the open hole 210. As a result, gas G, such as methane gas and natural gas, along with seawater and groundwater, flows from the hydrocarbon-bearing reservoirs HCL into the open hole 210, and then flows from the open hole 210 into the flow path within the sand control assembly 100 via the filters 122 and multiple through holes 123 in the sand filters 120. The gas G, such as methane gas and natural gas, which flows into the flow path within the sand control assembly 100 along with seawater and groundwater, is then pumped up by the pump 205 in the casing 201, and the gas and liquid are separated in the casing 201.
As shown in
The following describes the advantageous effects of the joint assembly 110, production well manufacturing method WPM, and gas production method GPM according to the present embodiment.
The strata GS into which the production well 200 is drilled includes an isolation target layer ITL, such as a water-bearing layer SWL, between the hydrocarbon-bearing reservoirs HCL, including gas hydrate-bearing layers GHL such as methane hydrate-bearing layers MHL and natural gas hydrate-bearing layers NGL. This isolation target layer ITL, such as a water-bearing layer SWL, is presumed to be one of the causes of the production of water that hinders depressurization in the open hole 210 during gas production, and also of the production of sand.
A known technique for isolating a particular area within the open hole 210 is a packing device called a packer or tubing packer. Hydrocarbon-bearing reservoirs HCL, such as methane hydrate-bearing layers MHL, and isolation target layers ITL, such as water-bearing layers SWL, are relatively brittle and prone to collapse, and the use of a packer may expand the borehole wall 211 of the open hole 210. In the open hole 210 drilled in such collapsible strata GS, a packer cannot be used, thus failing to effectively isolate the isolation target layers ITL.
Meanwhile, the joint assembly 110 of this embodiment is configured to selectively isolate an isolation target layer ITL in an open hole 210 drilled in strata GS including hydrocarbon-bearing reservoirs HCL and isolation target layers ITL. The joint assembly 110 includes a tubular body 111 that is inserted into the open hole 210 to be positioned to penetrate the isolation target layer ITL, and a luminescence device 112 placed over the entire circumference of the outer periphery 111o of the body 111. The luminescence device 112 is configured to emit light to cure uncured photo-curable resin LCR that is introduced between the body 111 and the borehole wall 211 of the open hole 210.
With this configuration, the joint assembly 110 of the present embodiment is placeable at a position penetrating the isolation target layer ITL of the strata GS while having the tubular body 111 inserted into the open hole 210. The joint assembly 110 of this embodiment has the luminescence device 112 placed over the entire circumference of the outer periphery 111o of the body 111, the luminescence device 112 being capable of irradiating uncured photo-curable resin LCR introduced between the body 111 and the borehole wall 211 of the open hole 210 with light to cure this photo-curable resin LCR.
This allows, as shown in
The production well manufacturing method WPM of this embodiment manufactures a production well 200 using the joint assembly 110 of this embodiment. The production well manufacturing method WPM has an open hole drilling and logging step S11 of drilling an open hole 210 in strata GS, and locating hydrocarbon-bearing reservoirs HCL and isolation target layers ITL in the strata GS. The production well manufacturing method WPM also includes step S15 of inserting a body 111 of a joint assembly 110 into the open hole 210 and positioning it at a position penetrating the isolation target layer ITL, and step S16 of introducing an uncured photo-curable resin LCR between the body 111 and the borehole wall 211 of the open hole 210. The production well manufacturing method WPM also includes step S17 of emitting light from the luminescence device 112 to cure the uncured photo-curable resin LCR between the body 111 and the borehole wall 211 of the open hole 210 over the entire circumference of the body 111, thus forming a production well 200 having the isolation target layer ITL of the open hole 210 selectively isolated by the cured photo-curable resin CR. The production well manufacturing method WPM also includes step S18 of collecting uncured photo-curable resin LCR that remains in the portion of the open hole 210 where the hydrocarbon-bearing reservoirs HCL are exposed.
With this configuration, the production well manufacturing method WPM of the present embodiment allows the drilling of an open hole 210 into strata GS that contains a hydrocarbon-bearing reservoir HCL and an isolation target layer ITL, and the locating of the hydrocarbon-bearing reservoir HCL and the isolation target layer ITL in the strata GS. Then, the method inserts the body 111 of the joint assembly 110 according to the present embodiment into the open hole 210 to be placed at a position penetrating the isolation target layer ITL in the strata GS, and emits light from the luminescence device 112 placed over the entire circumference of the outer periphery 111o of the body 111 to uncured photo-curable resin LCR that is introduced between the body 111 and the borehole wall 211 of the open hole 210.
This selectively cures the uncured photo-curable resin LCR, which is in contact with the isolation target layer ITL exposed to the borehole wall 211 of the open hole 210, over the entire circumference of the borehole wall 211, thus forming a production well 200 having the isolation target layer ITL selectively isolated from the open hole 210 by the cured photo-curable resin CR. After that, the method collects uncured photo-curable resin LCR that remains in the portion of the open hole 210 where the hydrocarbon-bearing reservoirs HCL are exposed, thereby manufacturing a production well 200 that is capable of yielding hydrocarbon from the hydrocarbon-bearing reservoir HCL selectively exposed to the borehole wall 211 of the open hole 210.
In this production well manufacturing method WPM of this embodiment, in step S17 to cure the uncured photo-curable resin LCR to form the production well 200 having the isolation target layers ITL selectively isolated, uncured photo-curable resin LCR still remains above the cured photocurable resin CR.
Although the cured photo-curable resin CR may contract and create a gap between the borehole wall 211 of the open hole 210 and the cured photo-curable resin CR, the uncured photo-curable resin LCR remaining above the cured photo-curable resin CR will flow into the gap and cure to fill the gap. This prevents the formation of a gap between the cured photo-curable resin CR and the isolation target layer ITL exposed to the borehole wall 211 of the open hole 210, thereby isolating the isolation target layer ITL from the open hole 210 more reliably.
In the production well manufacturing method WPM of this embodiment, each hydrocarbon-bearing reservoir HCL is a gas hydrate-bearing layer GHL, and each isolation target layer ITL is a water-bearing layer SWL.
With this configuration, the production well manufacturing method WPM of the present embodiment allows the drilling of an open hole 210 into strata GS that contains a gas hydrate-bearing layer GHL that bears hydrocarbon such as methane hydrate and a water-bearing layer SWL to form a production well 200 having the water-bearing layer SWL selectively isolated from the open hole 210. Therefore, the method manufactures a production well 200 that is capable of efficiently producing hydrocarbon gas such as methane gas from the gas hydrate-bearing layer GHL selectively exposed on the borehole wall 211 of the open hole 210.
The gas production method GPM of this embodiment includes the production well manufacturing method WPM of this embodiment. The gas production method GPM of this embodiment includes step S2, following step S18 of collecting the uncured photo-curable resin LCR. In step S2, the pressure of the production well 200 is reduced to collect the gas G released from the gas hydrate-bearing layer GHL to the production well 200.
With this configuration, the gas production method GPM of this embodiment uses the production well 200 having the water-bearing layer SWL exposed to the borehole wall 211 of the open hole 210 and selectively isolated, and being capable of efficiently producing hydrocarbon gas such as methane gas from the gas hydrate-bearing layer GHL selectively exposed to the borehole wall 211 of the open hole 210, thus efficiently producing the gas G by the depressurization method.
As described above, the present embodiment provides the joint assembly 110 that selectively isolates the isolation target layer ITL in the open hole 210 drilled in the strata GS including the hydrocarbon-bearing reservoir HCL and the isolation target layer ITL, and provides the production well manufacturing method WPM and gas production method GPM using the joint assembly 110.
Referring to
The joint assembly 110 of this embodiment emits light from the luminescence device 112 when the outer periphery 111o of the body 111 is in the expanded position shown in
The contraction mechanism 113 of the joint assembly 110 is not limited to the configuration shown in
In the strata GS, isolation target layers ITL, such as water-bearing layers SWL, more easily collapse than hydrocarbon-bearing reservoirs HCL, such as methane hydrate-bearing reservoirs MHL, and the borehole wall 211 may be scooped out to have a concave shape during the drilling of the open hole 210. In this case, as shown in
Thereafter, as shown in
The joint assembly 110 of this embodiment may include an anti-adhesion layer 114 on the outer surface of the body 111 to prevent adhesion of the cured photo-curable resin CR and the body 111. The anti-adhesion layer 114 may include grease that transmits the light emitted from the luminescence device 112, or a polytetrafluoroethylene (PTFE) sheet.
With this configuration, the joint assembly 110 of this embodiment lets the luminescence device 112 emit light to the uncured photo-curable resin LCR through the light-transmissive anti-adhesion layer 114 placed on the outer surface of the body 111, so that the photo-curable resin CR after curing is in contact with the anti-adhesion layer 114. Thus, the anti-adhesion layer 114 prevents the cured photo-curable resin CR from adhering to the outer surface of the body 111, and when the contraction mechanism 113 is operated to contract the outer periphery 111o of the body 111 radially inward, the outer circumferential surface of the outer periphery 111o is easily separated from the inner circumferential surface of the cured photo-curable resin CR.
As described above, the present embodiment provides the joint assembly 110 that selectively isolates the isolation target layer ITL in the open hole 210 drilled in the strata GS including the hydrocarbon-bearing reservoir HCL and the isolation target layer ITL, and provides the production well manufacturing method WPM and gas production method GPM using the joint assembly 110.
That is a detailed description of the embodiments of the joint assembly, production well manufacturing method, and gas production method according to the present disclosure, with reference to the drawings. The specific configuration of the present disclosure is not limited to the above-stated embodiments, and the design may be modified variously without departing from the spirits of the present disclosure. The present disclosure also covers such modified embodiments. For instance, hydrocarbon-bearing reservoirs are not limited to gas hydrate-bearing layers, such as methane hydrate-bearing layers, as mentioned above, but may also include layers containing oil, natural gas, shale gas and oil.
The following is a description of experiments conducted to verify the effectiveness of the joint assembly according to the present disclosure.
Water W was then supplied between the container C1 and the container C2 to let the water W permeate into the hydrocarbon-bearing reservoirs HCL and isolation target layer ITL through the through holes in the side wall of the container C2 by hydraulic head pressure. Uncured photo-curable resin LCR was further introduced between the hole simulating the open hole 210 and the pipe P, and light was irradiated from the luminescence device 112 to cure all introduced uncured photo-curable resin LCR. As a result, the photo-curable resin CR after curing contracted, thus forming a gap g between the cured photo-curable resin CR and the hole simulating the open hole 210.
Thereafter, water W that had permeated the hydrocarbon-bearing reservoirs HCL and the isolation target layer ITL and accumulated in the hole simulating the open hole 210 was pumped up, and the water production amount ΔQ was measured. The result shows that the water production amount ΔQ was reduced to about one-third compared to the configuration without isolating the isolation target layer ITL by the cured photo-curable resin CR. This demonstrates that the isolation of the isolation target layer ITL was effective.
Thereafter, light was emitted from the luminescence device 112 to cure the uncured photo-curable 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 photo-curable resin CR and the hole simulating the open hole 210. Presumably, this is because uncured photo-curable resin LCR remaining outside the portion of pipe P covered with the aluminum foil AF was supplied to the gap g between the cured photo-curable resin CR and the hole simulating the open hole 210, and the resin cured to fill the gap g.
Thereafter, water W that had permeated the hydrocarbon-bearing reservoirs HCL and the isolation target layer ITL and accumulated in a hole simulating the open hole 210 was pumped up, and the water production amount ΔQ was measured. The result shows that the water production amount ΔQ was substantially zero. This demonstrates that the isolation of the isolation target layer ITL was effective. In this experiment, resin A (UV resin High transparency manufactured by NOVA3D) and resin B (Alpha Resin LV8-1 manufactured by Alpha Kaken) were used as the photo-curable resin LCR, and similar results were obtained from both.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-030057 | Feb 2022 | JP | national |
The present application is a continuation application of PCT International Application No. PCT/JP2023/006952 filed on Feb. 27, 2023, designating the United States of America, which is based on and claims priority to Japanese patent application JP 2022-030057, filed Feb. 28, 2022. The entire disclosures of the above-identified applications, including the specifications, the drawings, and the claims are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2023/006952 | Feb 2023 | WO |
| Child | 18815889 | US |
