WO2025079002A1 - Outil de fracture à double mode et procédés associés - Google Patents
Outil de fracture à double mode et procédés associés Download PDFInfo
- Publication number
- WO2025079002A1 WO2025079002A1 PCT/IB2024/059927 IB2024059927W WO2025079002A1 WO 2025079002 A1 WO2025079002 A1 WO 2025079002A1 IB 2024059927 W IB2024059927 W IB 2024059927W WO 2025079002 A1 WO2025079002 A1 WO 2025079002A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- fissure
- thermally conductive
- wellbore
- conductive material
- rock formation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24T—GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
- F24T10/00—Geothermal collectors
- F24T10/20—Geothermal collectors using underground water as working fluid; using working fluid injected directly into the ground, e.g. using injection wells and recovery wells
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/267—Methods for stimulating production by forming crevices or fractures reinforcing fractures by propping
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24T—GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
- F24T10/00—Geothermal collectors
- F24T2010/50—Component parts, details or accessories
- F24T2010/53—Methods for installation
Definitions
- the field of the disclosure is devices and methods for generating fractures in dry rock with controlled geometry, particularly as it relates to generation of fractures for thermal reach enhancement structures in geothermal wells for geoheat recovery.
- fractures can be formed in a hot rock formation and filled with a thermally conductive material to so help transfer thermal energy from the rock to a heat harvesting structure (typically a closed-loop system) in a geothermal well as is described in WO 2023/069703 and WO 2023/150466.
- a heat harvesting structure typically a closed-loop system
- the geometry of the fractures and, subsequently, the efficiency of heat transfer and harvest remain difficult to control.
- the disclosure is directed to various systems, devices, and methods of generating a fissure in a geothermal well in a rock formation in which the fissure has a controlled, typically wedge-shaped geometry.
- the inventors have now discovered that the geometries and methods presented herein are especially advantageous in the context of thermal energy transfer from a (typically hot dry rock) formation to a heat harvesting element located in the geothermal well, typically via a thermally conductive sheath surrounding the heat harvesting element and where a thermally conductive material present in the fissure and the sheath.
- the inventors contemplate a method of forming a fissure with controlled geometry in wellbore located within a rock formation that includes a step of placing a contact device in the wellbore at a target location, wherein the contact device has at least two movable contact elements, and a further step of using the contact elements at the target location to apply a stress force in the rock formation to thereby create an initial fissure. While maintaining the first stress force, the initial fissure is then expanded using hydraulic fracturing to thereby create an expanded fissure, wherein the expanded fissure has a mouth portion at a wall of the wellbore.
- Contemplated methods will further repeatedly perform steps (a) and (b) in sequence, wherein (a) uses the contact elements to apply a further stress force at the target location in the rock formation to thereby increase the width of the mouth portion; and (b) further applies hydraulic pressure at the target location to further expand the fissure.
- these repeated steps advantageously generate a wedge-shaped fissure in which the mouth portion at the wall of the wellbore is wider than a proximal portion of the fissure, and in which the proximal portion of the fissure is wider than a distal portion of the fissure.
- the inventors also contemplate a method of directionally fracturing rock in a wellbore that involves placing at a first downhole position a contact device in the wellbore at a target location, wherein the contact device has at least two movable contact elements, moving the contact elements in the wellbore at the first downhole position at the target location in a direction against a wall of the wellbore to apply a stress in the rock formation, thereby creating an initial fissure, and while maintaining the stress, expanding the initial fissure using the contact elements, thereby creating an expanded fissure, repeatedly performing steps (a) and (b) in sequence: (a) using the contact elements to apply a further stress force at the target location in the rock formation to thereby increase the width of the mouth portion and (b) using the contact elements at the target location to further expand the fissure.
- the above method may further comprise a step of placing the contact device at a second downhole position that is different from the first downhole position, wherein the contact device is placed such that the contact elements have a radial offset in the wellbore relative to the contact elements at the first downhole position, and further comprising applying stress in the rock formation at the second downhole position, thereby creating a second initial fissure, and while maintaining the stress, expanding the second initial fissure using the contact elements, thereby creating a second expanded fissure.
- the steps (a) and (b) may additionally be performed at the second downhole position.
- the radial offset is at least 30 degrees and the difference in distance between the first and second downhole positions is between 10 m and 100 m.
- the movable contact elements of the contact device are configured to conform to the wall of the wellbore and will typically be located on opposite sides of the contact device.
- the contact device will be configured such that the movable contact elements move using hydraulic force.
- the rock formation is a dry hot rock formation (e.g., intrusive igneous, granitic, basaltic, sedimentary, or metamorphous rock), for example, with a target location at a depth of between 150 m and 20,000 m and/or has a temperature of between about 120 °C to 600 °C.
- the stress is applied at a force of between about 10 and 100 MPa. (e.g., 10-50 MPa), and the further stress is between about 1.1-fold and 1.5-fold of the stress, (e.g., 1.1-1.3-fold).
- steps (a) and (b) are repeatedly performed in sequence between 2-6 times, but more frequent iterations are not excluded.
- the mouth portion at the wall of the wellbore has a width of between 1 mm and 100 mm
- the proximal portion of the fissure has a width of between 3 mm and 25 mm
- the distal portion of the fissure has a width of between 0.5 mm and 2 mm.
- the fissure has a length of between 1 m and 200 m as measured from the mouth portion to the distal end
- the fissure has a vertical orientation and a height of between 1 m and 40 m.
- the inventors also contemplate a wellbore with a fissure within a rock formation wherein the fissure has a controlled geometry, and wherein the fissure is formed in a manner as described above.
- the controlled geometry is such that a mouth portion of the fissure at a wall of the wellbore is wider than a proximal portion of the fissure, and that the proximal portion of the fissure is wider than a distal portion of the fissure.
- the fissure is filled with a first thermally conductive material, preferably having a k-value of at least 5 W/mK. Additionally, it is contemplated that the first thermally conductive material is thermally coupled to a second thermally conductive material surrounding a heat harvesting element, and that the thermal conductivity constants of the first and second thermally conductive materials differ by no more than 10% as measured by their respective k-values. Alternatively, the first and second thermally conductive materials can be the same.
- the inventors also contemplate a method of facilitating thermal energy transfer in a geothermal well having a wellbore with a thermal reach enhancement structure at a target location within a rock formation.
- Such methods will generally include a step of forming the thermal reach enhancement structure to include a fissure in which a mouth portion of the fissure at a wall of the wellbore is wider than a proximal portion of the fissure, and in which the proximal portion of the fissure is wider than a distal portion of the fissure, and a further step of filling the fissure with a first thermally conductive material.
- a heat harvesting element located in the wellbore is thermally coupled with the first thermally conductive material using a second thermally conductive material.
- the thermal conductivity constants of the first and second thermally conductive material differ by no more than 10% as measured by their respective k-values or are the same.
- the fissure in the thermal reach enhancement structure is formed using the method as described above.
- the fissure in the thermal reach enhancement structure is naturally occurring, formed using hydraulic fracking, formed using a contact device, or formed using mechanical fracking. Therefore, in at least some embodiments the thermal reach enhancement structure is configured as a longitudinal/lateral (bilateral or biwing) vertical structure. In other embodiments, the thermal reach enhancement structure may be configured as a radial/transverse structure.
- the fissure in the thermal reach enhancement structure is widened and/or propagated using a directionally controlled contact device to create a predictable structure.
- the mouth portion at the wall of the wellbore has a width of between 1 mm and 100 mm
- the proximal portion of the fissure has a width of between 3 mm and 25 mm
- the distal portion of the fissure has a width of between 0.5 mm and 2 mm
- the fissure has a length of between 1 and 200 m as measured from the mouth portion to the distal end.
- the first thermally conductive material has a thermal conductivity of between 50 W/mK and 400 W/mK, and/or the first and/or second thermally conductive materials are materials other than cementitious materials.
- the heat harvesting element comprises a closed loop circuit in which heat is transferred from the second thermally conductive material to a casing of the heat harvesting element.
- the second thermally conductive material is then configured as a sheath surrounding the casing of the heat harvesting element.
- the step of filling the fissure with the first thermally conductive material includes a step of compressing the first thermally conductive material using geostatic pressure and/or using mechanical compression (e.g., during placement of the heat harvesting element into the wellbore) to so ensure a continuous heat transfer path.
- the inventors also contemplate a wellbore with a fissure within a rock formation wherein the fissure has a controlled geometry, formed by hydraulic fracking or by using a contact device, wherein the controlled geometry is such that a mouth portion of the fissure at a wall of the wellbore is wider than a proximal portion of the fissure, and that the proximal portion of the fissure is wider than a distal portion of the fissure.
- the fissure is filled with a first thermally conductive material, preferably having a k-value of at least 5 W/mK.
- the first thermally conductive material may comprise a material selected from the group consisting of zinc, graphite, graphene, tungsten, aluminum, silicon carbide, aluminum nitride, silicon nitride, boron nitride, gold, copper, silver, diamond, aluminum alloys, aluminum oxides, rhodium, cobalt, copper alloys, nickel, iron, platinum, palladium, tin, steel, zirconium, titanium, carbon fiber, carbon black, Hastelloy, carbon-based inorganic, metal, metal oxides, metal nitrides, alloys, or hybrids.
- the first thermally conductive material is thermally coupled to a second thermally conductive material surrounding a heat harvesting element, and that the thermal conductivity constants of the first and second thermally conductive materials differ by no more than 10% as measured by their respective k-values.
- the first and second thermally conductive materials can be the same.
- the second thermally conductive material may also comprise a material selected from the group consisting of zinc, graphite, graphene, tungsten, aluminum, silicon carbide, aluminum nitride, silicon nitride, boron nitride, gold, copper, silver, diamond, aluminum alloys, aluminum oxides, rhodium, cobalt, copper alloys, nickel, iron, platinum, palladium, tin, steel, zirconium, titanium, carbon fiber, carbon black, Hastelloy, carbon-based inorganic, metal, metal oxides, metal nitrides, alloys, or hybrids.
- the contact device is involved in fissure formation, fissure widening, and/or fissure propagation. Most typically, the contact device is directionally controllable to allow rotation and application in a direction of choice.
- the mouth portion at the wall of the wellbore is contemplated to have a width of between 1 mm and 100 mm
- the proximal portion of the fissure is contemplated to have a width of between 3 mm and 25 mm
- the distal portion of the fissure is contemplated to have a width of between 0.5 mm and 2 mm
- the fissure is contemplated to have a length of between 1 and 200 m as measured from the mouth portion to the distal end.
- the wellbore may be a greenfield new well, a brownfield geothermal well, or a brownfield oil and gas well.
- the inventors additionally contemplate a system configured to initiate a fissure within a wellbore in a rock formation in a desired direction that includes a contact device that has at least two movable elements, wherein the contact elements are configured to allow application of mechanical stress in the rock formation at a target location to thereby create an initial fissure in the well bore in a direction that is substantially perpendicular to a direction in which the contact elements move, and a controller that is configured to maintain a pressure of a hydraulic fluid within the initial fissure while the contact device is expanding and/or propagating the fissure.
- the wellbore is a greenfield new well, a brownfield geothermal well, or a brownfield oil and gas well.
- the initial fissure is a dual fissure that extends longitudinally from the wellbore in opposite directions.
- the fissure within the rock formation does not follow a naturally occurring feature in the rock formation.
- a mouth portion at a wall of the wellbore is contemplated to have a width of between 1 mm and 100 mm, a proximal portion of the fissure a width of between 3 mm and 25 mm, a distal portion of the fissure a width of between 0.5 mm and 2 mm, and wherein the fissure is contemplated to have a length of between 1 m and 200 m as measured from the mouth portion to the distal end.
- the fissure has a controlled geometry such that a mouth portion of the fissure at a wall of the wellbore is wider than a proximal portion of the fissure, and wherein the proximal portion of the fissure is wider than a distal portion of the fissure.
- the contact device is configured to allow successive movement in the same direction to thereby promote fissure widening, and/or fissure propagation.
- the contact device is directionally controllable to allow rotation relative to a direction of the initial fissure and application of further mechanical stress in a different direction.
- controller is further configured to control movement of the contact elements and maintains pressure within the fissure hydraulically or mechanically.
- the inventors contemplate a method of expanding an existing fissure in a wellbore that includes, placing at a first downhole position a contact device in the wellbore at a target location proximal to the existing fissure, wherein the contact device has at least two movable contact elements, and moving the contact elements in the wellbore at the first downhole position at the target location in a direction against a wall of the wellbore to expand the existing fissure using the contact elements, thereby creating an expanded fissure.
- the existing fissure is naturally occurring, initiated using hydraulic fracturing, initiated using mechanical fracturing, or initiated using the contact device.
- the contact elements are used to apply a further stress force at the target location in the rock formation to thereby increase the width of the mouth portion. This further applied stress force is most typically repeatedly performed between 2-6 times.
- FIGS.1A-1F are schematic and exemplary illustrations depicting selected steps in the deployment and operation of a contact device.
- the inventors have now developed various systems and methods of fissure generation in a geological formation, and particularly in a hot dry rock formation, in which the geometry of the fissure can be controlled to produce a wedge-shaped fissure.
- Such geometry is especially advantageous in the context of thermal energy transfer from a (typically hot dry rock) formation to a heat harvesting element located in the geothermal well where thermal energy is transferred through thermally conductive materials placed in the fissure and wellbore.
- the rock formation at the target location is a dry hot rock formation such as an intrusive igneous or metamorphous rock formation.
- the target location may also be in hot wet rock, a “greenfield”, a “brownfield”, the ocean floor, and/or oil/gas wells.
- the rock formation may be permeable or impermeable and additional rock types may include granitic, basaltic, or sedimentary rock.
- geothermal energy may be harnessed through the retrofitting of inactive or unproductive wells and co-production on active wells.
- a complete geothermal system could be placed at or near seafloor spreading rifts. Drilling on the ocean floor may also be anywhere else that geothermal energy can be extracted, such as major tectonic plate boundaries or rift zones.
- the target location (or target production zone) has a target temperature of at least 100 °C, at least 200 °C, at least 300 °C, at least 350 °C, at least 400 °C, at least 450 °C, or at least 500 °C, or at least 600 °C and/or the target location may be below ground at a depth of at least 100 m, at least 200 m, at least 300 m, at least 500 m, at least 600 m, at least 700 m, at least 800 m, at least 900 m, at least 1,000 m, at least 1,250 m, at least 1,500 m, at least 1,750 m, at least 2,000 m, at least 2,500 m, at least 3,000 m, at least 4,000 m, at least 5,000 m, at least 10,000 m, or at least 20,000 m.
- suitable target temperature will be between 150 °C and 350 °C, or between 200 °C and 400 °C, or between 250 °C and 450 °C, or between 300 °C and 600 °C.
- contemplated depths of between 100 m and 300 m, or between 200 m and 800 m, or between 500 m and 1,500 m, or between 1,000 m and 3,000 m, or between 2,000 m and 6,000 m.
- a contact device is configured to allow deployment of the device to a target location within a wellbore at which the fissure is to be generated.
- Preferred contact devices have at least two movable contact elements that are movably coupled to opposite sides of the contact device such that the contact elements will move from a retracted position (typically used during deployment) into an extended contact position in which the contact elements have increased radial distance from a hypothetical central axis of the contact device.
- the contact device may be part of a system that is configured to initiate a fissure within a wellbore in a rock formation in a desired direction.
- the contact device is directionally controllable to allow rotation relative to a direction of the initial fissure and application of further mechanical stress in a difference direction.
- the contact elements may be configured to allow application of mechanical stress in the rock formation at a target location to thereby create an initial fissure in the wellbore in a direction that is substantially perpendicular to a direction in which the contact elements move.
- the movable contact elements of the contact device are configured to conform at least in part to the wall of the wellbore (e.g., will have a curved contact surface).
- a controller may be used that is configured to maintain a pressure of a hydraulic fluid within the initial fissure while the contact device is expanding and/or propagating the fissure.
- the controller maintains pressure within the hydraulically or mechanically, but is nonetheless configured to control movement of the contact elements.
- the initial fissure may be a dual fissure that extends longitudinally from the wellbore in opposite directions.
- the contact device may also be configured to allow successive movement in the same direction to thereby promote fissure widening and/or fissure propagation.
- the contact elements in the contact device will be movable by mechanic or hydraulic actuation such that upon contact of the contact elements with the wall of the wellbore, continued actuation will result in an increasing stress in the rock surrounding the well bore. Therefore, where two contact elements are oppositely forced by mechanic or hydraulic actuation against the wall of a wellbore, increasing force will ultimately lead to a fracture in the rock formation that is approximately between and perpendicular to the direction of the movement of the contact elements.
- the fracture may be initiated/created in such method by continued increase of mechanic or hydraulic actuation of the contact elements to exert stress beyond the fracture stress of the rock, or by a combination of mechanic or hydraulic actuation of the contact elements to a point below the fracture stress of the rock followed additional pressure provided to the target area using conventional hydraulic fracturing.
- hydraulic fracturing it is then contemplated to use hydraulic fracturing to thereby expand the initial fissure to an expanded fissure.
- use of the contact device in combination with hydraulic fracturing will produce an expanded fissure in the rock.
- a fracture may instead be naturally occurring or created by any other engineered fracking approaches. Nonetheless, the contact device may be used to also (or only) widen or propagate the fracture. As will be readily appreciated, the contact device also can provide directional control. For example, the contact device can be rotated to create/widen/propagate natural or engineered fractures in the direction of choice to thereby allow for more predictable fracturing in rock formations. Indeed, the contact device may be place at a first downhole position in a wellbore at a target location, where the contact device has at least two movable contact elements.
- steps (a) and (b) are repeatedly performed in sequence: (a) using the contact elements to apply a further stress force at the target location in the rock formation to thereby increase the width of the mouth portion, and (b) using the contact elements at the target location to further expand the fissure. Steps (a) and (b) may be repeated between 2-6, including at least once, at least twice, at least three times, at least four times, at least five times, and at least six times.
- the contact device may also be placed at a second downhole position that is different from the first downhole position.
- the contact device may also be placed at a third, fourth, or fifth downhole position.
- the contact device may be placed at more than five downhole positions. Nonetheless, the contact device may be placed such that the contact elements have a radial offset in the wellbore relative to the contact elements at the first downhole position, and further comprising applying stress in the rock formation at the second, third, fourth, or fifth downhole positions to thereby create a second, third, fourth, or fifth initial fissure. While maintaining the stress, the contact elements may also expand the subsequent initial fissure thereby creating a second, third, fourth, or fifth expanded fissure. Most typically, aforementioned steps (a) and (b) will be repeated at the second, third, fourth, or fifth downhole position.
- the radial offset is at least 30 degrees, at least 45 degrees, or at least 90 degrees.
- the difference in distance between the first and second, or second and third, or third and fourth downhole positions is between 10 m and 100 m.
- the differences in distance may be the same between each downhole position, or they may be different.
- the difference in distance between the first and second downhole position may be 50 m
- the difference in distance between the third and fourth downhole position may be 80 m.
- the difference in distance between the first and second downhole position and the difference in distance between the third and fourth downhole position may bother be 40 m.
- the contact device may be placed in a vertical position within the wellbore, or it may be placed in a lateral or horizontal position within a fissure or wellbore depending on the construction of the wellbore and/or corresponding fissures.
- the contact device may be placed vertically within a wellbore to initiate a fissure, then subsequently placed horizontally within a fissure to further expand and/or propagate the fissure.
- the pressure of the hydraulic fracturing fluid will be maintained at the target location to thereby maintain the expanded fissure in the rock, while the contact elements are further actuated into a position and to a degree at which the contact elements exert additional stress to the rock formation.
- the so applied stress will open the fissure mouth portion and/or assist in opening of the fissure mouth portion once further hydraulic fracturing is performed at the same location.
- the further hydraulic fracturing will once more expand the fissure.
- these further steps can be repeatedly performed to thereby generate a fissure in which the mouth portion at the wall of the wellbore is significantly wider than a proximal portion of the fissure, and in which the proximal portion of the fissure is wider than a distal portion of the fissure.
- the contact device may also be used to expand existing fissures in a wellbore.
- the contact device may be placed at a first downhole position at a target location proximal to the existing fissure, wherein the contact device has at least two movable contact elements. Subsequently, the contact elements are moved in the wellbore at the first depth at the target location in a direction against a wall of the wellbore to expand the existing fissure using the contact elements, thereby creating an expanded fissure.
- the existing fissure is most typically naturally occurring, initiated using hydraulic fracturing, initiated using mechanical fracturing, or initiated using the contact device.
- the contact elements are generally used to apply a further stress force at the target location in the rock formation to thereby increase the width of the mouth portion.
- Application of this further stress force is contemplated to be repeatedly performed between 2- 6 times. However, it may also be performed less than 2 or more than 6 times.
- FIG.1A-1F Selected steps of such method are exemplarily depicted in FIG.1A-1F in which the top portion depicts a side view of an exemplary contact device, and in which the bottom portion depicts a horizontal cross section of the above depicted contact device in a wellbore. More specifically, in FIG.1A shows the contact device in a retracted position in which the contact elements are substantially flush with the remainder of the device. The device can be placed into the wellbore at a target location having a desired depth and the contact elements are then actuated to move into contact with the wall of the wellbore as is exemplarily shown in FIG.1B. Continued actuation of the contact elements will progressively produce stress in the rock formation as schematically indicated by the arrows in FIG.1C.
- the actuation of the contact elements may be to a point below, at, or above fracture stress of the rock at the target location. Therefore, it should be appreciated that the actuation of the contact elements can results in a stressed location, micro-fissures, or an initial fissure (all of which are referred to herein as an “initial fissure”).
- the contact elements can then be further advanced (typically, but not necessarily in the same direction as the previous advance) to engage with the walls of the wellbore and to apply further stress to the rock as is schematically shown in FIG. IE.
- this stress and additional hydraulic fluid pressure in the fracturing fluid will then further open the fissure as schematically shown in FIG. IF.
- the sequential steps of FIGS.1E-F can be repeated multiple times (e.g., between 1-3 times, or 2-6 times, or 4-8 times, or 5-10 times, and even more) to so increase the width of the fissure at the mouth portion and to also deepen the fissure, thereby creating a wedge-shaped fissure in which the mouth portion at the wall of the wellbore is wider than a proximal portion of the fissure, and in which the proximal portion of the fissure is wider than a distal portion of the fissure.
- incremental repetitive application of stress force and subsequent hydraulic fracturing will produce a geometry of the fissure that would otherwise not be achieved in a conventional single-step fracking operation.
- the methods presented herein make use of repeated steps of stress induction and hydraulic fracturing in which the stress and hydraulic fracture pressure are incrementally increased to so form a wedge-shaped fissure in the rock.
- such fissure is then filled with a first thermally conductive material to produce a continuous pathway for thermal energy transfer from the rock into the first thermally conductive material, and from the first thermally conductive material at the mouth portion of the fissure to a second thermally conductive material.
- Such filling may be performed at the last pressure level by replacing the fracking fluid with a slurry comprising a thermally conductive material.
- the geostatic pressure in the formation will then advantageously express the carrier fluid in the slurry, resulting in a compacted thermally conductive material in the fissure.
- the specific geometry of the fissure will reduce or even entirely avoid a ‘backing up’ of heat flux otherwise encountered by a fissure having substantially uniform thickness as is common with fissures that have been produced in conventional manner.
- thermally conductive materials in conventional fissures having substantially uniform thickness will not have the capacity to receive and transmit thermal energy received form the formation and so create a heat flux bottleneck.
- the heat transfer capacity of thermally conductive materials in fissures having a wedge-shaped geometry increases from a distal portion to a proximal portion, and again from the proximal portion to the mouth of the fissure, thereby avoiding heat flux impedance and backing up of heat into the rock formation.
- a mouth portion with relatively large width will reduce or even entirely avoid potential issues associated with a draining proppant and inadvertent fissure closure.
- a mouth portion with relatively large width generates a relatively large (and typically continuous) thermal heat transfer interface from the first thermally conductive materials in the fissure to a second thermally conductive materials in the wellbore (which typically surrounds the heat harvesting element located in the wellbore).
- a mouth portion with relatively large width will allow for an improved thermal energy flux from the first thermally conductive materials in the fissure to the second thermally conductive material and ultimately the working fluid in the heat harvesting element. Consequently, it should be appreciated that the fissure geometries and methods for generating such fissures greatly reduce bottlenecks in heat transfer otherwise encountered with conventionally generated fissures that have substantially the same width along the length of the fissure.
- the mouth portion of the fissure has a width of between 1 mm and 100 mm, that the proximal portion of the fissure has a width of between 3 mm and 25 mm, and that the distal portion of the fissure has a width of between 0.5 mm and 2 mm.
- the fissure has a length of between 1 m and 200 m as measured from the mouth portion to the distal end, and that the fissure has a vertical orientation with a height of between 1 m and 40 m.
- the term “mouth portion” of a fissure refers to the portion of the fissure that terminates at the wellbore. Viewed from a different perspective, the mouth portion will typically include the opening and the first 1-20 cm, or 1-10 cm, or 1-5 cm of the fissure as measured from the opening in direction to the distal end of the fissure.
- the term “proximal portion” of a fissure refers to a portion of the fissure located between the mouth portion and a distal end of the fissure. Therefore, the proximal portion of the fissure will be around a middle third section as measured along the length of the fissure.
- distal portion refers to the end portion of the fissure, and most typically the terminal third or terminal quarter of the fissure.
- the mouth portion of the fissure can have a width of between 2 mm and 4 mm, or between 4 mm and 6 mm, or between 6 mm and 8 mm, or between 2 mm and 10 mm, or between 6 mm and 10 mm, or between 8 mm and 10 mm, or between 10 mm and 14 mm, or between 12 mm and 18 mm, or between 16 mm and 22 mm, or between 12 mm and 24 mm, or between 15 mm and 25 mm, or between 20 mm and 30 mm, or between 25 mm and 35 mm, or between 30 mm and 40 mm, or between 35 mm and 45 mm, or between 40 mm and 50 mm, or between 40 mm and 75 mm, or between 60 mm and 90 mm, or between 75 mm and 150 mm, and even wider.
- the proximal portion of the fissure can have a width of between 1 mm and 2 mm, or between 2 mm and 3 mm, or between 3 mm and 5 mm, or between 1 mm and 6 mm, or between 6 mm and 8 mm, or between 7 mm and 9 mm, or between 10 mm and 12 mm, or between 12 mm and 14 mm, or between 12 mm and 16 mm, or between 13 mm and 17 mm, or between 15 mm and 20 mm, or between 20 mm and 30 mm, or between 25 mm and 35 mm, or between 30 mm and 40 mm, or between 35 mm and 60 mm, or between 50 mm and 75 mm, and even wider.
- the distal portion of the fissure can have a width of between 0 mm and 0.2 mm, or between 0.2 mm and 0.5 mm, or between 0.3 mm and 0.6 mm, or between 0.6 mm and 0.8 mm, or between 0.5 mm and 1 mm, or between 0.7 mm and 1.2 mm, or between 1.2 mm and 1.5 mm, or between 1.2 mm and 1.6 mm, or between 1.5 mm and 1.7 mm, or between 1.5 mm and 1.9 mm, or between 1.5 mm and 2.0 mm, or between 2.0 mm and 2.5 mm, and even wider.
- the width of the mouth portion will be larger than the width at a proximal portion, and that the width at the proximal portion is larger than the width at a distal portion.
- contemplated fissures will have an increasing capacity to transfer thermal energy along the length of the fissure (as seen from the distal portion to the mouth portion).
- the fissure will have a generally wedge-shaped geometry.
- the fissure will be filled with a first thermally conductive material, which may be installed into the fissure in form of a (typically compactable) slurry, cementitious or otherwise flowable composition that may harden or otherwise cure over time.
- a first thermally conductive material which may be installed into the fissure in form of a (typically compactable) slurry, cementitious or otherwise flowable composition that may harden or otherwise cure over time.
- the first thermally conductive material will have (upon curing, compaction, or otherwise settling) a thermal conductivity that is greater than 1 W/mK, or greater than 5 W/mK, or greater than 10 W/mK, or greater than 25 W/mK, or greater than 50 W/mK, or greater than 75 W/mK, or greater than 100 W/mK, or greater than 150 W/mK, or greater than 250 W/mK, but less than 600 W/mK, or less than 400 W/mK, or less than 300 W/mK, or less than 200 W/mK.
- the first thermally conductive material can have a thermal conductivity of 10-50 W/mK, or of about 30-90 W/mK, or of about 50-150 W/mK, or of about 100-300 W/mK, or of about 300-600 W/mK, and in some cases even higher.
- the first thermally conductive material can include various carbon allotropes, metal particles or metal fibers (e.g., graphite powder, exfoliated graphite, flaked graphite, pyrolytic graphite, desulfurized petroleum coke, graphene, fly ash, copper powder, boron nitride, aluminum nitride, and silicon carbide), which may or may not be surface modified to increase hydrophilicity and homogenous distribution in an aqueous or cementitious phase.
- various carbon allotropes e.g., graphite powder, exfoliated graphite, flaked graphite, pyrolytic graphite, desulfurized petroleum coke, graphene, fly ash, copper powder, boron nitride, aluminum nitride, and silicon carbide
- thermally conductive materials include zinc, graphene, tungsten, aluminum, silicon nitride, gold, copper, silver, diamond, aluminum alloys, aluminum oxides, rhodium, cobalt, copper allows, nickel, iron, platinum, palladium, tin, steel, zirconium, titanium, carbon fiber, carbon black, and Hastelloy.
- the second thermally conductive material will be disposed in the wellbore and typically surrounds the heat harvesting element (most typically a closed loop system in a casing) to assist in thermal energy transfer into the working fluid.
- the second thermally conductive material will be thermally coupled to the first thermally conductive material by direct contact with the first thermally conductive material at the mouth portion to thereby form a continuous heat transfer interface. Most preferably, thermal transfer at the interface is ensured by compaction or other manner of compression of the second thermally conductive material against the first thermally conductive material.
- the thermal conductivity of the first thermally conductive material is similar or identical to that of the second thermally conductive material.
- the thermal conductivity of the first thermally conductive material will deviate by no more than 25%, or no more than 20%, or no more than 15%, or no more than 10%, or no more than 8%, or no more than 5% from the thermal conductivity of the second thermally conductive material. Therefore, it is also contemplated that the first and second thermally conductive materials may be the same.
- the thermally conductive materials may be combined with void space or an “inactive” material (e.g., sand).
- an “inactive” material is one that exceeds an aggregate thermal conductivity of at least 5 W/mK once placed, to thereby create a thermal energy transfer pathway or conduit between the rock formation and casing.
- the thermally conductive material may be comprised of various shapes.
- suitable shapes include a platelet, a flake, a sphere, an irregular shape, a cube, a rod, a disc, a prism, a needle, a tube, a fiber, an angular shape, a subangular shape, a rounded shape, a subrounded shape, a dumbbell shape, and a star shape.
- Contemplated contact devices will typically have two contact elements that will be movable in opposite direction to so create stress in a formation at a controllable position (which is typically located between the contact elements). However, in further embodiments, more than two contact elements can also be used to thereby produce more than two areas of stress in the formation. As will be readily appreciated, the contact elements will generally be longitudinally oriented (e.g., parallel to the direction of the wellbore) to so generate a stress pattern that will result in fissures that extend along the longitudinal axis of the wellbore.
- preferred contact elements will typically have a length of at least 20 cm, or at least 50 cm, or at least 100 cm, or at least 150 cm, or at least 200 cm, such as for example, between 20 and 40 cm, or between 25-75 cm, or between 50 and 100 cm, or between 150 and 200 cm, and even longer.
- multiple sequentially arranged contact elements may result in a contact device that can create longitudinal fissures over significant lengths, such as at between 1 m and 5 m, or between 3 m and 10m, or between 5 m and 25 m, and even more.
- the manner of actuation of the contact elements may vary considerably so long as the contact elements can exert a stress on the rock formation that is at about or above fracture stress in the rock. Therefore, mechanical and hydraulic actuation are particularly preferred.
- the contact elements can produce a stress of at least 5 MPa, or at least 10 MPa, or at least 20 MPa, or at least 30 MPa, or at least 40 MPa, or at least 50 MPa, such as for example, between 5-25 MPa, or between 15-40 MPa, or between 30-60 MPa, and even higher.
- So applied stress forces will be incremental and the additional stress forces may be incrementally increased (between successive rounds of operation as shown in FIGS.1E-F) by about 1.1-fold, or about 1.2-fold, or about 1.3-fold, or about 1.4-fold, or about 1.5-fold, or about 1.6-fold, or about 1.8-fold of the prior stress force, or even higher.
- the contact elements will be configured to at least partially conform to the wall of the wellbore to so maximize application of the stress over an extended area on wall of the wellbore. Therefore, curved plate shaped contact elements are especially contemplated. However, other configurations such as pistons and bars are also deemed suitable for use herein. As will be readily appreciated, contemplated contact devices can further comprise various data logging tools, including one or more stress sensors, pressure sensors, temperature sensors, sonic imaging sensors, flow sensors, etc.
- the contact device will be configured to allow delivery of a hydraulic fracturing fluid to the target location at which the contact device is deployed while the contact elements are in an extended position.
- the contact elements during such operation will maintain the mouth portion in an open state and prevent inadvertent closure while hydraulic fracturing will expand the fissure.
- the contact elements Upon termination of the hydraulic fracturing, the contact elements will be advanced further against the wall of the wellbore to apply further stress in preparation for a subsequent hydraulic fracturing step. Therefore, exemplary contemplated contact devices suitable for use herein include those described in US 9664024, US 8875790, US 2015/0322760, and US 2776014, each incorporated by reference in their entirety herein.
- a method of forming a fissure with controlled geometry in wellbore located within a rock formation comprising: placing a contact device in the wellbore at a target location, wherein the contact device has at least two movable contact elements; using the contact elements at the target location to apply a stress force in the rock formation, thereby creating an initial fissure, and while maintaining the first stress force, expanding the initial fissure using hydraulic fracturing, thereby creating an expanded fissure, wherein the expanded fissure has a mouth portion at a wall of the wellbore; repeatedly performing steps (a) and (b) in sequence, wherein (a) is using the contact elements to apply a further stress force at the target location in the rock formation to thereby increase the width of the mouth portion; and (b) is further applying hydraulic pressure at the target location to further expand the fissure; to thereby generate a fissure in which the mouth portion at the wall of the wellbore is wider than a proximal portion of the fissure, and in which the proximal portion
- steps (a) and (b) are repeatedly performed in sequence between 2-6 times.
- a method of facilitating thermal energy transfer in a geothermal well having a wellbore with a thermal reach enhancement structure at a target location within a rock formation comprising: forming the thermal reach enhancement structure to include a fissure in which a mouth portion of the fissure at a wall of the wellbore is wider than a proximal portion of the fissure, and in which the proximal portion of the fissure is wider than a distal portion of the fissure; filling the fissure with a first thermally conductive material; thermally coupling a heat harvesting element located in the wellbore with the first thermally conductive material in the fissure using a second thermally conductive material; and wherein thermal conductivity constants of the first and second thermally conductive material differ by no more than 10% as measured by their respective k-values.
- thermal reach enhancement structure is configured as a bilateral or bi-wing vertical structure.
- step of filling the fissure with the first thermally conductive material includes a step of compressing the first thermally conductive material using geostatic pressure and/or using mechanical compression.
- a system configured to initiate a fissure within a wellbore in a rock formation in a desired direction, comprising: a contact device that has at least two movable elements; wherein the contact elements are configured to allow application of mechanical stress in the rock formation at a target location to thereby create an initial fissure in the well bore in a direction that is substantially perpendicular to a direction in which the contact elements move; and a controller that is configured to maintain a pressure of a hydraulic fluid within the initial fissure while the contact device is expanding and/or propagating the fissure.
- a mouth portion at a wall of the wellbore has a width of between 1 mm and 100 mm
- a proximal portion of the fissure has a width of between 3 mm and 25 mm
- a distal portion of the fissure has a width of between 0.5 mm and 2 mm
- the fissure has a length of between 1 m and 200 m as measured from the mouth portion to the distal end.
- controller is further configured to control movement of the contact elements.
- a method of directionally fracturing rock in a wellbore comprising: placing at a first downhole position a contact device in the wellbore at a target location, wherein the contact device has at least two movable contact elements; moving the contact elements in the wellbore at the first downhole position at the target location in a direction against a wall of the wellbore to apply a stress in the rock formation, thereby creating an initial fissure, and while maintaining the stress, expanding the initial fissure using the contact elements, thereby creating an expanded fissure; repeatedly performing steps (a) and (b) in sequence (a) using the contact elements to apply a further stress force at the target location in the rock formation to thereby increase the width of the mouth portion; and (b) using the contact elements at the target location to further expand the fissure.
- [00130] 64 The method of aspect 62, wherein the first thermally conductive material is thermally coupled to a second thermally conductive material surrounding a heat harvesting element, and wherein thermal conductivity constants of the first and second thermally conductive materials differ by no more than 10% as measured by their respective k-values or wherein the first and second thermally conductive materials are the same.
- the first thermally conductive material comprises a material selected from the group consisting of zinc, graphite, graphene, tungsten, aluminum, silicon carbide, aluminum nitride, silicon nitride, boron nitride, gold, copper, silver, diamond, aluminum alloys, aluminum oxides, rhodium, cobalt, copper alloys, nickel, iron, platinum, palladium, tin, steel, zirconium, titanium, carbon fiber, carbon black, Hastelloy, carbon-based inorganic, metal, metal oxides, metal nitrides, alloys, or hybrids.
- the method of aspect 44 further comprising a step of filling the expanded fissure with a second thermally conductive material.
- the second thermally conductive material comprises a material selected from the group consisting of zinc, graphite, graphene, tungsten, aluminum, silicon carbide, aluminum nitride, silicon nitride, boron nitride, gold, copper, silver, diamond, aluminum alloys, aluminum oxides, rhodium, cobalt, copper alloys, nickel, iron, platinum, palladium, tin, steel, zirconium, titanium, carbon fiber, carbon black, Hastelloy, carbon-based inorganic, metal, metal oxides, metal nitrides, alloys, or hybrids.
- a method of expanding an existing fissure in a wellbore comprising: placing at a first downhole position a contact device in the wellbore at a target location proximal to the existing fissure, wherein the contact device has at least two movable contact elements; and moving the contact elements in the wellbore at the first downhole position at the target location in a direction against a wall of the wellbore to expand the existing fissure using the contact elements, thereby creating an expanded fissure.
- the first thermally conductive material comprises a material selected from the group consisting of zinc, graphite, graphene, tungsten, aluminum, silicon carbide, aluminum nitride, silicon nitride, boron nitride, gold, copper, silver, diamond, aluminum alloys, aluminum oxides, rhodium, cobalt, copper alloys, nickel, iron, platinum, palladium, tin, steel, zirconium, titanium, carbon fiber, carbon black, Hastelloy, carbon-based inorganic, metal, metal oxides, metal nitrides, alloys, or hybrids.
- the second thermally conductive material comprises a material selected from the group consisting of zinc, graphite, graphene, tungsten, aluminum, silicon carbide, aluminum nitride, silicon nitride, boron nitride, gold, copper, silver, diamond, aluminum alloys, aluminum oxides, rhodium, cobalt, copper alloys, nickel, iron, platinum, palladium, tin, steel, zirconium, titanium, carbon fiber, carbon black, Hastelloy, carbon-based inorganic, metal, metal oxides, metal nitrides, alloys, or hybrids.
- the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.”
- the terms "about” and “approximately”, when referring to a specified, measurable value is meant to encompass the specified value and variations of and from the specified value, such as variations of +/-10% or less, alternatively +/-5% or less, alternatively +/-1% or less, alternatively +/-0.1% or less of and from the specified value, insofar as such variations are appropriate to perform in the disclosed embodiments.
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Earth Drilling (AREA)
Abstract
Selon l'invention, une fissure à géométrie contrôlée est formée dans une roche sèche chaude par application itérative de contraintes mécaniques et hydrauliques croissantes, la contrainte mécanique étant appliquée par un dispositif de contact avec typiquement des éléments de contact opposés pour ouvrir de manière incrémentielle une partie d'embouchure de la fissure tandis que la contrainte hydraulique est utilisée pour ensuite étendre la fissure. Cependant, il est également envisagé que le dispositif de contact puisse également être utilisé pour l'expansion et/ou la propagation de fissures existantes qui se produisent naturellement ou qui sont créées par fracturation hydraulique. Des fissures créées avec les dispositifs et les procédés présentés ici évitent des goulots d'étranglement thermiques dans des matériaux thermoconducteurs placés à l'intérieur de telles fissures. En outre, la large partie d'embouchure de telles fissures aide à assurer un transfert de chaleur continu à partir des matériaux thermoconducteurs placés à l'intérieur de telles fissures vers un matériau thermoconducteur placé à l'intérieur d'un puits de forage duquel les fissures proviennent.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US202363590379P | 2023-10-13 | 2023-10-13 | |
| US63/590,379 | 2023-10-13 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2025079002A1 true WO2025079002A1 (fr) | 2025-04-17 |
| WO2025079002A4 WO2025079002A4 (fr) | 2025-06-05 |
Family
ID=93430515
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IB2024/059927 Pending WO2025079002A1 (fr) | 2023-10-13 | 2024-10-10 | Outil de fracture à double mode et procédés associés |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2025079002A1 (fr) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN120273716A (zh) * | 2025-06-09 | 2025-07-08 | 北京中矿创新联盟能源环境科学研究院 | 胀裂器及胀裂装置 |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2776014A (en) | 1953-12-14 | 1957-01-01 | Socony Mobil Oil Co Inc | Tool for fracturing earth formations |
| US3062294A (en) * | 1959-11-13 | 1962-11-06 | Gulf Research Development Co | Apparatus for fracturing a formation |
| US7320221B2 (en) | 2004-08-04 | 2008-01-22 | Oramt Technologies Inc. | Method and apparatus for using geothermal energy for the production of power |
| US8875790B2 (en) | 2011-05-11 | 2014-11-04 | Baski, Inc. | Method and system for fracking and completing wells |
| US20150322760A1 (en) | 2012-12-13 | 2015-11-12 | Schlumberger Technology Corporation | Mechanically assisted fracture initiation |
| US20170211849A1 (en) | 2014-03-07 | 2017-07-27 | Greenfire Energy Inc | Process and method of producing geothermal power |
| WO2023069703A1 (fr) | 2021-10-21 | 2023-04-27 | Geothermic Solution, Llc | Amélioration de récupération de chaleur géothermique |
| WO2023150466A1 (fr) | 2022-02-01 | 2023-08-10 | Geothermic Solution, Inc. | Systèmes et procédés d'amélioration de la portée thermique |
-
2024
- 2024-10-10 WO PCT/IB2024/059927 patent/WO2025079002A1/fr active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2776014A (en) | 1953-12-14 | 1957-01-01 | Socony Mobil Oil Co Inc | Tool for fracturing earth formations |
| US3062294A (en) * | 1959-11-13 | 1962-11-06 | Gulf Research Development Co | Apparatus for fracturing a formation |
| US7320221B2 (en) | 2004-08-04 | 2008-01-22 | Oramt Technologies Inc. | Method and apparatus for using geothermal energy for the production of power |
| US8875790B2 (en) | 2011-05-11 | 2014-11-04 | Baski, Inc. | Method and system for fracking and completing wells |
| US9664024B2 (en) | 2011-05-11 | 2017-05-30 | Henry A. Baski | Method for fracking wells using a packer to form primary and secondary fracs and seal intervals for hydraulic fracturing |
| US20150322760A1 (en) | 2012-12-13 | 2015-11-12 | Schlumberger Technology Corporation | Mechanically assisted fracture initiation |
| US20170211849A1 (en) | 2014-03-07 | 2017-07-27 | Greenfire Energy Inc | Process and method of producing geothermal power |
| WO2023069703A1 (fr) | 2021-10-21 | 2023-04-27 | Geothermic Solution, Llc | Amélioration de récupération de chaleur géothermique |
| WO2023150466A1 (fr) | 2022-02-01 | 2023-08-10 | Geothermic Solution, Inc. | Systèmes et procédés d'amélioration de la portée thermique |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN120273716A (zh) * | 2025-06-09 | 2025-07-08 | 北京中矿创新联盟能源环境科学研究院 | 胀裂器及胀裂装置 |
| CN120273716B (zh) * | 2025-06-09 | 2025-09-05 | 北京中矿创新联盟能源环境科学研究院 | 胀裂器及胀裂装置 |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2025079002A4 (fr) | 2025-06-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4892147A (en) | Hydraulic fracturing utilizing a refractory proppant | |
| CA2596773C (fr) | Amorcage de plans d'injection dans un puits | |
| JP7624559B1 (ja) | 熱到達を強化させるシステムおよび方法 | |
| US7886823B1 (en) | Well remediation using downhole mixing of encapsulated plug components | |
| US4817717A (en) | Hydraulic fracturing with a refractory proppant for sand control | |
| US9732561B2 (en) | Method and apparatus for increasing well productivity | |
| CA2615972C (fr) | Procedes et appareil permettant de completer un puits | |
| MX2014004338A (es) | Fracturamiento hidraulico con emisión de impulsos de agentes de apuntalamiento a traves de perforaciones abrasivas conglomeradas. | |
| CN107313762A (zh) | 一种页岩水力压裂方法 | |
| WO2025079002A1 (fr) | Outil de fracture à double mode et procédés associés | |
| US20160237530A1 (en) | Material processing for components | |
| CA3047609A1 (fr) | Amelioration de la conductivite thermique dans un trou de forage | |
| CN111255428A (zh) | 一种套管水平井井筒重建重复压裂方法 | |
| CN107339091B (zh) | 一种人工建造油页岩地下破碎体的方法 | |
| Zou et al. | Laboratory investigation on fracture initiation and propagation behaviors of hot dry rock by radial borehole fracturing | |
| CN110388214A (zh) | 一种巷道围岩高温加热强化的支护方法和装置 | |
| TWI888232B (zh) | 熱到達增強防回流組合物和方法 | |
| WO2018236643A1 (fr) | Fracture hydraulique à impulsions de plasma avec suspension carbonée | |
| CN112324418A (zh) | 一种地下岩石水力破碎工艺方法 | |
| CN87100890A (zh) | 传导加热地下油页岩以赋予其渗透性并随后采油 | |
| US20250251176A1 (en) | Compositions and Methods to Form a Thermally Conductive Sheath | |
| CN114427414B (zh) | 一种提高盐间泥质白云岩油藏压裂有效期的方法及其应用 | |
| WO2025101536A1 (fr) | Structures d'amélioration de portée thermique à transfert d'énergie amélioré | |
| WO2025194108A1 (fr) | Structures de transfert de chaleur hétérogènes pour récupération d'énergie géothermique | |
| Wang | Description of high-pressure compressed stratum form |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 24801981 Country of ref document: EP Kind code of ref document: A1 |
|
| DPE1 | Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101) |