WO2021242673A1 - Utilisation d'ondes radio pour la fracturation de roches dans un réservoir d'hydrocarbures - Google Patents

Utilisation d'ondes radio pour la fracturation de roches dans un réservoir d'hydrocarbures Download PDF

Info

Publication number
WO2021242673A1
WO2021242673A1 PCT/US2021/033841 US2021033841W WO2021242673A1 WO 2021242673 A1 WO2021242673 A1 WO 2021242673A1 US 2021033841 W US2021033841 W US 2021033841W WO 2021242673 A1 WO2021242673 A1 WO 2021242673A1
Authority
WO
WIPO (PCT)
Prior art keywords
rocks
borehole
wave
irradiating
duration
Prior art date
Application number
PCT/US2021/033841
Other languages
English (en)
Inventor
Jinhong Chen
Daniel T. Georgi
Stacey M. ALTHAUS
Original Assignee
Saudi Arabian Oil Company
Aramco Services Company
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from US16/883,538 external-priority patent/US10920556B2/en
Application filed by Saudi Arabian Oil Company, Aramco Services Company filed Critical Saudi Arabian Oil Company
Publication of WO2021242673A1 publication Critical patent/WO2021242673A1/fr

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP 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

Definitions

  • This disclosure relates to fracturing geological formations in a hydrocarbon reservoir, for example, using electromagnetic waves.
  • a reservoir may have a tight geologic formation.
  • the tight geologic formation can include rocks with a low permeability. Flows of hydrocarbon fluids can be limited in regions where the rocks have a tight formation. It may be difficult to recover the hydrocarbon products in these types of reservoirs.
  • hydraulic fracture techniques can be used to fracture a tight geologic formation.
  • large quantity of hydraulic fluid can be pumped underground to fracture the rocks and to keep open the fractured rocks.
  • the hydraulic fluid can include a mixture of water, proppants (for example, sand or other proppants), and chemicals.
  • the present disclosure describes methods and systems for using radio waves to fracture rocks in a reservoir.
  • One method includes forming a borehole in a hydrocarbon reservoir from a surface of the hydrocarbon reservoir extending downward into the hydrocarbon reservoir; transmitting an electromagnetic (EM) wave through the borehole: directing at least a portion of the EM wave to rocks at a location below the surface in the hydrocarbon reservoir; and fracturing the rocks at the location below the surface in the hydrocarbon reservoir by irradiating the rocks around the borehole using at least the portion of the EM wave, wherein irradiating the rocks elevates pore-water pressure in the rocks causing fracturing of the rocks.
  • EM electromagnetic
  • a first aspect combinable with the general implementation, wherein the borehole is a first borehole, and wherein the method further comprises forming, in the hydrocarbon reservoir, a borehole pattern comprising a plurality of boreholes including the first borehole; and for each of the plurality of boreholes, fracturing rocks around the borehole using the radio wave that elevates pore-water pressure in the rocks.
  • a second aspect combinable with any of the previous aspects, wherein the plurality of boreholes are formed in a vertical well pattern.
  • a third aspect combinable with any of the previous aspects, wherein the plurality of boreholes are formed in a horizontal well pattern.
  • a fourth aspect combinable with any of the previous aspects, wherein forming, in the hydrocarbon reservoir, the borehole pattern comprising: determining a fracturing radius based on a diameter of the borehole and a stimulated fracture density; and positioning the plurality of boreholes in the borehole pattern based on the fracturing radius.
  • a fifth aspect combinable with any of the previous aspects, wherein the borehole pattern is a 5-spot pattern.
  • a sixth aspect combinable with any of the previous aspects, wherein the radio wave has a frequency between 500 KHz and 5 MHz.
  • a seventh aspect combinable with any of the previous aspects, wherein the rocks have a permeability between about 1 nanodarcy (nD) and 0.01 millidarcy (mD).
  • An eighth aspect combinable with any of the previous aspects, wherein the method further comprises: positioning an EM wave transmitter at a surface of the reservoir; and generating the EM wave using the EM wave transmitter.
  • a ninth aspect combinable with any of the previous aspects, wherein the method further comprises: positioning an EM wave transmitter in the borehole, wherein the EM wave transmitter is enclosed in a protective case; generating the EM wave using the EM wave transmitter; and retrieving the EM wave transmitter after the rocks are fractured.
  • the location is a first location and the EM wave is a first EM wave.
  • the method further comprises: transmitting a second EM wave through the borehole; directing at least a portion of the second EM wave to rocks at a second location below the surface in the hydrocarbon reservoir; and fracturing the rocks at the second location below the surface in the hydrocarbon reservoir by irradiating the rocks around the borehole using at least the portion of the second EM wave, wherein irradiating the rocks elevates pore-water pressure in the rocks causing fracturing of the rocks, and a distance between the first location and the second location is determined based on a penetration depth of the first EM wave.
  • Another method includes forming a borehole pattern comprising a plurality of boreholes in a hydrocarbon reservoir from a surface of the hydrocarbon reservoir extending downward into the hydrocarbon reservoir; transmitting an EM wave through at least one of the plurality of boreholes; and for each of the at least one of the plurality of boreholes, fracturing rocks around the respective borehole using the EM wave.
  • a first aspect combinable with the general implementation, wherein the plurality of boreholes are formed in a vertical well pattern.
  • a second aspect combinable with any of the previous aspects, wherein the plurality of boreholes are formed in a horizontal well pattern.
  • a third aspect combinable with any of the previous aspects, wherein an azimuthal coverage of a stimulation zone generated by the EM wave for each of the plurality of boreholes is a fraction of a circumference of the respective borehole.
  • a fourth aspect combinable with any of the previous aspects, wherein a radiation pattern generated by the EM wave for each of the at least one of the plurality of boreholes is azimuthally asymmetric with respect to the respective borehole.
  • a fifth aspect combinable with any of the previous aspects, wherein the method comprises: determining a distance based on a stimulated fracture density; and positioning the plurality of boreholes in a pattern having an equal distance between neighboring boreholes, wherein the equal distance is set to the determined distance.
  • a sixth aspect combinable with any of the previous aspects, wherein the method comprises: positioning an EM wave transmitter at a surface of the reservoir; and generating the EM wave using the EM wave transmitter.
  • a seventh aspect combinable with any of the previous aspects, wherein the method comprises: positioning an EM wave transmitter in at least one of the plurality of the boreholes, wherein the EM wave transmitter is enclosed in a protective case; generating the EM wave using the EM wave transmitter; and retrieving the EM wave transmitter after the rocks are fractured.
  • Yet another method includes forming a borehole in a hydrocarbon reservoir from a surface of the hydrocarbon reservoir extending downward into the hydrocarbon reservoir; generating an EM wave that fractures rocks in the hydrocarbon reservoir; transmitting the EM wave through the borehole; and fracturing rocks at a location below the surface in the hydrocarbon reservoir by irradiating the rocks around the borehole using the EM wave, wherein the rocks have a permeability between about 1 nanodarcy (nD) nD and 0.01 millidarcy (mD) and irradiating the rocks elevates pore- water pressure in the rocks causing fracturing of the rocks.
  • nD nanodarcy
  • mD millidarcy
  • FIG. 1A is a schematic diagram that illustrates an example well system including a vertical borehole according to an implementation.
  • FIG. IB is a schematic diagram that illustrates an example well system including a horizontal borehole according to an implementation.
  • FIG. 1C is a schematic diagram that illustrates an example well system including an EM wave transmitter below the surface according to an implementation.
  • FIG. 2A is a chart illustrating relationships between pore-water pressure and temperature changes according to an implementation.
  • FIG. 2B is a chart illustrating an example relationship between the frequency and the penetration depth of the EM wave according to an implementation.
  • FIG. 3 is a schematic diagram that illustrates volume distributions of fractured rocks according to an implementation.
  • FIG. 4A is a schematic diagram that illustrates an example well system including multiple vertical boreholes according to an implementation.
  • FIG. 4B is a schematic diagram that illustrates an example well system including a plurality of horizontal boreholes according to an implementation.
  • FIG. 4C illustrates a top view of an example pattern of borehole formations according to an implementation.
  • FIG. 4D illustrates a side view of an example pattern of borehole formations according to an implementation.
  • FIG. 5 illustrates an example method for fracturing rocks using electromagnetic waves according to an implementation.
  • FIG. 6 is a schematic diagram that illustrates example intermittent EM transmission schemes according to an implementation.
  • FIG. 7 is a chart that illustrates the reduction of the temperature at the borehole surface by the intermittent EM transmission according to an implementation.
  • FIG. 8 is a chart that illustrates the efficiency of the intermittent EM transmission according to an implementation.
  • FIG. 9 illustrates an example method for fracturing rocks using intermittent EM transmission according to an implementation.
  • This disclosure generally describes methods and systems for fracturing rocks in a hydrocarbon reservoir.
  • a reservoir may have tight geographic formations between wells. Flows of hydrocarbon fluids can be very limited in regions where the rocks have a tight formation.
  • the rocks in the regions of a tight formation may have a low permeability. Examples of a low permeability can include matrix permeability between less than 1 nanodarcy (nD) and 0.01 millidarcy (mD). Examples of rocks having a low permeability include shales, tight sandstones, and tight carbonates. Therefore, if a region of a reservoir has a tight formation, it may be difficult to recover the hydrocarbon products, for example, oil or gas, from the region.
  • hydraulic fracturing can be used to fracture the rocks and improve permeability.
  • using hydraulic fracturing to recover hydrocarbon products may have one or more disadvantages.
  • hydraulic fracturing may use a significant amount of water.
  • the hydrocarbon recovery rate using hydraulic fracturing can be less than 10% for oil and less than 35% for gas. Hydraulic fracturing can also induce damage to the fracture surface and impede flow from the formation to the fractures. Moreover, it may be difficult to control the location of the fracturing zone.
  • the recovered fluid from hydraulic fracturing may create environment issues and thus may need to be disposed of or treated.
  • heat transfer can be used to increase the fluidity of the oil in geological formations with a high permeability.
  • microwave can be used to increase the temperature of the wellbore or a heating device in a well. Because microwave has a high intensity, the temperature of the wellbore or the heating device can be raised to a high level, for example, to a level as high as 700 F.
  • the heat can be transferred from the wellbore or the heating device to the oil in the subterranean formation around the well. The heat can break down the chemical structure of the oil and decrease the viscosity of the oil.
  • the subterranean formation has a high permeability, for example, if the rocks around the well have a loose formation, this approach can make it easier for the oil to flow from one well to another well.
  • this approach to fracture rocks with a tight formation may have one or more issues.
  • microwave has a short wavelength, and therefore may have a low penetration depth.
  • pore-water pressure can increase rapidly when the pore-water in the rocks is heated.
  • pore-water pressure refers to the pressure of connate water held in gaps between particles within a soil or rock.
  • rocks in a tight formation can be fractured by increasing the pore-water pressure.
  • electromagnetic (EM) waves with long wavelength can be used to irradiate directly on the rocks around a borehole. Examples of the EM waves with long wavelength can include a radio wave.
  • radio waves having a frequency between 500 kilohertz (KHz) to 5 megahertz (MHz) can be used to irradiate the rocks and heat the pore water in the rocks.
  • KHz kilohertz
  • MHz megahertz
  • EM waves with even higher frequency for example, up to 100 MHz, can be used to irradiate the rocks.
  • this approach can provide a mechanism to fracture rocks without using fracturing fluids.
  • the mechanism can increase rock permeability in the tight formation and increase recovery rate in the reservoir.
  • this approach can introduce minimum formation damages by redistributing the fractured rocks in the borehole.
  • patterns of the boreholes can be selected to optimize the size of the total stimulation zone, and thus the size of the stimulated zone can be well controlled.
  • this approach can work in deep reservoir with strong rocks, for which hydraulic fracturing may not be practical.
  • this approach does not introduce chemicals in the process and therefore can be more environmental friendly.
  • FIGS. 1A and IB are schematic diagrams that illustrate example well systems 102 and 104, respectively, according to respective implementations.
  • the example well systems 102 and 104 can use EM waves to irradiate rocks and fracture rocks around a wellbore, as described below.
  • FIG. 2A is a chart 210 illustrating relationships between pore-water pressure and temperature changes, according to an implementation.
  • the rocks can be fractured if the pore-water pressure is equal to, or larger than, a summation of the minimum in-situ effective stress and the rock tensile strength of the rocks.
  • rocks may be fractured when pore-water pressure reaches a few thousand pounds per square inch (psi).
  • the chart 210 shows the pore-water pressure elevations for 10% water in the rocks with different matrix modulus. As shown in FIG.
  • the pore- water pressure can be increased to about 10,000 psi or higher. In these cases, the increase of the pore-water pressure may pulverize the rocks into small fragments, and thus fracture the rocks and increase the permeability.
  • the penetration depth of an EM wave into a rock formation can be a function of the wavelength of the EM wave and the dielectric property of the rock formation.
  • Microwave has a wavelength of approximately 12 cm, and thus may not be used to efficiently stimulate formations much more beyond 12 cm.
  • EM waves with longer wavelength than microwaves for example, radio waves, can provide much longer penetration depth than microwaves.
  • radio waves having frequency in the MHz range can penetrate several dozen feet from a borehole into the rocks around the borehole, and thus stimulate a much larger volume of tight rocks for production in a single well.
  • the average power generated from an EM wave can be represented in the equation (1): where I n represents the average power, w represents the EM frequency, E represents the electric field strength, E * represents the conjugate of E, s r " , represents the relative dielectric loss of the /th mineral composition including the fluids, and eo represents a constant coefficient that is equal to 8.85 c 10 12 F/m.
  • the average power can be calculated by integrating over the volume the EM wave irradiates.
  • the volume of that the EM wave irradiates depends on the penetration depth of the EM wave.
  • Equation (2) represents an example calculation of the penetration depth: where I) represents the penetration depth, l represents the wavelength of the EM wave, a’ and &" represent the average relative dielectric constant and dielectric loss of the rock formation, respectively.
  • Equation (3) represents an example calculation of the dielectric loss
  • FIG. 2B is a chart 220 illustrating an example relationship between the frequency and the penetration depth of the EM wave according to an implementation.
  • s’ is set to 4 and s d " l is set to 0.3.
  • the chart 220 illustrates the peneration depth as a function of the EM wave frequency for different resistivities of the formation.
  • the resisitivity of a production shale formation can be between 100 W ⁇ hi and 1000 W ⁇ ih. Therefore, using an EM wave in the range of 500 KHz to 5 MHz can provide a peneration depth of several feet.
  • EM waves with higher frequency for example, up to 100 MHz, can be used to irradiate the rocks
  • the penetration depth depends on the wavelength of the EM wave and the property of the rock formation.
  • a stimulation zone refers to the region of rocks that are affected by the EM wave.
  • the depth of the stimulation zone can be larger than the penetration depth due to the thermal conductivity.
  • the depth of the stimulated zone can be a few dozens of feet.
  • the heating efficiency of the formation can depend on the square of the field intesnity E of the EM wave .
  • the example well system 102 includes a wellbore
  • the tight rock formation can span a single formation, portions of a formation or multiple formations.
  • the well system 102 also includes an EM wave transmitter 112.
  • the EM wave transmitter 112 can be implemented as one or more hardware circuit elements, software, or a combination thereof that can be configured to generate an EM wave.
  • an EM wave transmitter for example, the EM wave transmitter 112, can include a power supply, an oscillator, a modulator, a power amplifier, or any combinations thereof, that can be configured to generate EM waves to irradiate the rock formation.
  • the transmitter can include a synthesized radio frequency (RF) signal generator, a free running RF signal generator, or a combination thereof
  • the well system 102 also includes an antenna 115.
  • the antenna 115 can be positioned in the vertical borehole 116.
  • the antenna 115 can be configured to transmit radio waves into in the tight rock formation surrounding the vertical borehole 116.
  • the antenna 115 can be implemented using dipole antenna.
  • the well system 102 also includes a transmission line 118 that is coupled with the EM wave transmitter 112 and the antenna 115.
  • the transmission line can be configured to direct the EM wave generated by the EM wave transmitter 112 to the antenna 115.
  • the transmission line 118 can be implemented using a coaxial cable, a twisted pair wire, or a waveguide.
  • a waveguide can be implemented using hollow conductive metal pipes.
  • the EM wave transmitter 112 generates EM waves.
  • EM waves can travel through the transmission line 118 to the antenna 115.
  • the antenna 115 irradiates EM waves to the rocks around the vertical borehole 116.
  • the irradiation raises the temperature of the water and rocks around the vertical borehole 116 and increases the pore-water pressure in the rocks.
  • the increased pore-water pressure fractures the rocks.
  • the fractured rocks around the vertical borehole 116 can become loose. Some of the loosed rocks can collapse into the vertical borehole 116.
  • Rocks collapsing into the vertical borehole 116 can cause restructuring of the rocks and create a corresponding increase in the permeability of the rocks.
  • the hydrocarbon products, for example, oil or gas, in the tight rock formation region 120 can then be recovered through the wellbore 114.
  • a horizontal borehole can be used instead of the vertical borehole.
  • the example well system 104 includes a wellbore 134 below the terranean surface 130.
  • the wellbore 134 is extended by a horizontal borehole 136 in the tight rock formation region 140.
  • the well system 104 also includes an EM wave transmitter 132, a transmission line 138, and an antenna 135.
  • the EM wave transmitter 132 generates EM waves that travel through the transmission line 138 to the antenna 135.
  • the antenna 135 irradiates EM waves to the rocks around the horizontal borehole 136.
  • the irradiation raises the temperature of the rocks around the horizontal borehole 136 and increases the pore- water pressure in the rocks around the horizontal borehole 136.
  • the irradiation is targeted to the stimulation zone above the horizontal borehole 136.
  • the increased pore-water pressure fractures the rocks.
  • the fractured rocks can become loose. Some of the loosed rocks can collapse into the horizontal borehole 136.
  • Rocks collapsing into the horizontal borehole 136 can cause restructuring of the rocks and creates a corresponding increase in the permeability of the rocks.
  • the hydrocarbon products, for example, oil or gas, in the tight rock formation region 140 can then be recovered through the wellbore 134.
  • the EM wave transmitter can be positioned at the surface. Alternatively or in combination, the EM wave transmitter can be positioned inside the borehole.
  • FIG. 1C is a schematic diagram that illustrates an example well system 106 including an EM wave transmitter below the surface according to an implementation. As shown in FIG. 1C, the EM wave transmitter 112 is placed inside the vertical borehole 116 in the tight rock formation region 120.
  • a case 160 can be used to protect the EM wave transmitter 112, the transmission line 118, the antenna 115, or any combinations thereof, from the collapsed rocks.
  • the case 160 can be implmented using a ceramic conduit.
  • a cable 162 can be used to retrieve the case 160 after the rocks are irradiated and fractured to reuse the components protected by the case 160.
  • the irradiation can be performed in stages. For example, in a first stage irradiation, the antenna 115 can be positioned at a first location 172. The antenna 115 can irradiate rocks surrounding the first location 172. After the first stage irradiation, the antenna 115 can be repositioned at a second location 174 to irradiate the rocks around the second location 172. The distance between the first location 172 and the second location 174 can be determined based on the penetration depth of the EM waves, as discussed previously in FIG. 2B and associated descriptions. This process can be repeated for additional stages of irradiation.
  • FIG. 3 is a schematic diagram 300 that illustrates volume distributions due to EM wave irradiation, accoridng to an implementation.
  • the schematic diagram 300 includes a illustration of stimulation zones 310 and 320, respectively.
  • the stimulation zone 310 represents the formation before the irradiation.
  • the stimulation zone 310 includes a borehole 312 that is drilled into the stimulation zone 310.
  • the stimulation zone 310 has a length L and a radius R.
  • the borehole 312 has a radius r.
  • the radio wave travels trhough the borehole 312, the radio wave irradiates the rocks around borehole 312, which includes the rocks in the stimulation zone 310 .
  • the stimulation zone 320 represents the formation after the irradiation.
  • the stimulation zone 320 has the same length L and the same radius R as the stimulation zone 310.
  • the fractured rocks in the stimulation zone 310 fall into the borehole 312 due to gravity.
  • the stimulated fracture density a is 0.1%, the permeability can increase approximately 3 orders of magnitude.
  • the radius of the stimulated zone can be approximately 8 ft.
  • the radius of the stimulated zone can be extended to more than 60 ft.
  • the stimulated zone or the fracture density can be further increased.
  • the penetration depth D of the EM in Eq. (2) can be optimized to approximately equal to the stimulated zone size R in Eq. (3).
  • the size of the borehole can be determined based on a target radius of the stimulation zone and a targetted stimulated fracture density using equation (3).
  • the gravity and the elevated pore-water pressure can redistribute the rock fragments into the horizontal borehole.
  • the antenna 135 instead of transmitting the EM wave in an omni direction orientation, the antenna 135 can be configured to transmit EM waves above the horiztonal borehole 136. Therefore, the azimuthal coverage of the stimulation zone can include a fraction of the circumfence of the horizontal borehole 136.
  • the stimulated zone can be significantly increased by using multiple boreholes. This approach may increase efficiency because drilling multiple sidetrack wells can be relatively cheap.
  • the patterned boreholes can be drilled using sidetracking and can share one vertical wellbore.
  • FIGS. 4A and 4B are schematic diagrams that illustrate example well systems 402 and 404, respectively, according to an implementation.
  • the example well systems 402 and 404 can include multiple boreholes.
  • the example well system 402 includes a wellbore 414 below the terranean surface 410.
  • the wellbore 414 is extended by multiple vertical boreholes 416a-e in the tight rock formation region
  • the well system 402 also includes an EM wave transmitter 412 and transmission lines 418a-e that connect the EM wave transmitter 412 with antennas 415a-e, respectively.
  • the EM wave transmitter 412 generates EM waves that are directed through each of the multiple boreholes 416a-e to the antennas 415a-e using the transmission lines 418a-e.
  • the antennas 415a-e transmit the EM waves to irradiate the rocks around the boreholes 416a-e and fracture the rocks around the boreholes 416a-e with increased pore-water pressure.
  • the multiple boreholes 416a-e can form a pattern.
  • the pattern can be selected to optimize the size of the total stimulation zone for a given number of boreholes.
  • a 5-spot pattern can be selected to position the multiple boreholes 416a-e.
  • the distances between a central borehole, for example, the borehole 416c, and each of the surrounding boreholes, for example, the boreholes 416a, 416b, 416d, and 416e are the same.
  • the radius of the stimulation zone introduced by one borehole can be determined based on the stimulated fracture density and penetration depth of the EM wave. Therefore, the distance between the central borehole and a surrounding borehole can be determined based on the radius of the stimulation zone. For example, the distance between the central borehole and a surrounding borehole can be set to 2 times the determined radius.
  • the size of the total simulation zone can be optimzed if the size of the borehole pattern is set according to the calculation described previously.
  • FIG. 4C illustrates a top view 450 of an example pattern of borehole formations according to an implementation.
  • the example pattern is a 5 spot pattern, where each surrounding borehole is positioned with the same distance relative to a central borehole.
  • This pattern can provide an optimized coverage because the pattern covers a large stimulated zone with a small number of boreholes, and therefore saves drilling cost. This pattern can also be repeated easily to cover a portion of a reservoir or the entire reservoir.
  • horizontal boreholes can be used instead of the vertical boreholes.
  • the example well system 404 includes a wellbore 434, below the terranean surface 430.
  • the wellbore 434 is extended by multiple horizontal boreholes 436a-c in the tight rock formation region 440.
  • the well system 404 also includes an EM wave transmitter 432 and transmission lines 438a- c that connect the EM wave transmitter 432 with antennas 435a-c, respectively.
  • the EM wave transmitter 432 generates EM waves that are directed through each of the multiple boreholes 436a-c, using the transmission lines 438a-c.
  • the antennas 435a-c transmit the EM waves to irradiate the rocks around the boreholes 436a-c and fracture the rocks around the boreholes 436 with increased pore-water pressure.
  • FIG. 4D illustrates a side view 460 of an example pattern of borehole formations according to an implementation.
  • the side view 460 includes multiple horizontal boreholes 462.
  • the EM waves can be targeted to the rocks above the horizontal borehole 462.
  • the rocks in regions 464 above the horizontal borehole 462 are redistributed during fracturing.
  • the distances between neighboring horizontal boreholes 462 are set to R, which is the radius of the stimulation zone.
  • the horizontal borehole can be tilted towards a fracture direction to generate a radiation pattern that is azimuthally asymmetric with respect to the borehole.
  • the horizontal borehole may be tilted by an angle relative to the vertical wellbore. Consequently, the size of the stimulated zone can be represented by equation (4): where Q represents the angle of the fractured zone above the borehole. In some cases, Q can be set to 100 to 110 degrees.
  • one or more boreholes among the multiple boreholes are used for irradiation.
  • the rocks around the one or more boreholes can be fractured by the EM waves.
  • the remaining boreholes can be used for future irradiation in a later stage. This approach may be more economical than drilling boreholes in different stages.
  • every other borehole can be used for irradiation in the first stage.
  • the high attenuation caused by the connate water may trigger a second stage of irradiation. During the second stage, one or more of the remaining boreholes can be used for irradiation.
  • the presense of the unused boreholes can affect affect the stress distributions and result in local stress concentrations that can deflect the EM wave-induced fractures.
  • a temperature survery or a Distributed temperature sensing (DTS) system can be used to measure the temperature at locations around unused boreholes to determine whether the EM waves have penetrated to these locations. If the temperature does not rise to a threshold, the EM waves have not penetrated to these locations, and irraditions from the unused boreholes can be performed.
  • FIG. 5 illustrates an example method 500 for fracturing rocks using EM waves according to an implementation. For clarity of presentation, the description that follows generally describes method 500 in the context of FIGS. 1A-1C, 2A-2B, 3, and 4A-4D.
  • a borehole is formed in a hydrocarbon reservoir.
  • the borehole is formed from a surface of the hydrocarbon reservoir extending downward into the hydrocarbon reservoir.
  • a borehole is a first borehole, and multiple boreholes are formed in the hydrocarbon reservoir.
  • the multiple boreholes include the first borehole.
  • the multiple boreholes include vertical boreholes.
  • the multiple boreholes include horizontal boreholes.
  • the multiple boreholes formed a 5-spot pattern.
  • an EM wave that fractures rocks in the hydrocarbon reservoir is transmitted through the borehole.
  • the EM wave is generated using an EM wave transmitter.
  • the EM wave transmitter can be positioned at a surface of the reservoir.
  • the EM wave transmitter can be positioned inside the boreholes.
  • the EM wave transmitter is configured to generate an EM wave having a frequency between 500 KHz and 5 MHz.
  • the EM wave transmitter can be configured to generate EM waves up to 100 MHz.
  • At 506 at least a portion of the EM wave is directed to rocks at a location below the surface in the hydrocarbon reservoir.
  • the rocks at a location below the surface in the hydrocarbon reservoir are fractured by irradiation of the radio wave.
  • the duration of EM irradiation can be managed to increase the efficiency of the rock fracturing operation. For example, instead of applying a continuous transmission of the EM waves through the borehole, intermittent transmission can be performed.
  • One EM wave transmission session can be divided into multiple “transmission on” periods with a “transmission off’ period between each successive “transmission on” period. During the “transmission off’ period, thermal diffusion transports thermal energy deep into the formation, which reduces the temperature in the formation near the borehole and increases the total fractured reservoir volume.
  • FIG. 6 is a schematic diagram that illustrates example intermittent EM transmissions according to an implementation.
  • FIG. 6 includes illustrates three example time management schemes 610, 620, and 630 for EM wave transmission.
  • the y-axis represents the power of the EM wave transmission, in units of watts.
  • the x-axis axis represents time duration, in units of minutes or hours.
  • the scheme 610 illustrates a continuous transmission scheme.
  • the scheme 620 illustrates a first intermittent transmission scheme, where some of the “transmission off’ periods (for example t2 off ) are longer than other “transmission off’ period (for example ti off ).
  • the scheme 630 illustrates a second intermittent transmission scheme, where all the “transmission off’ periods are the same.
  • the antenna of the EM wave transmitter can be turned off.
  • the antenna of the EM wave transmitter can be directed to a different section of the rock formation and irradiate that section of the rock formation.
  • the antenna of the EM wave transmitter can be rotated back to point to the previous section of the rock formation during the “transmission on” period.
  • the frequency of the EM waves at different “transmission on” periods can be changed to increase the penetration depth and the efficiency of the energy transportation.
  • the total EM power from antenna is distributed into a cylindrical region and decays radially following Eq. (5).
  • the generated heat is conducted further into the formation by thermal diffusion.
  • the specific heat represents the amount of heat per unit mass required to raise the temperature by one degree Celsius.
  • Equation (8) can be used to evaluate the coupled process of EM energy input and thermal diffusion during the “transmission on” period. During the “transmission off’ period, there is no EM radiation power, and Pin can be set to 0 W (Watt), therefore, Equation (8) can be rewritten as:
  • Equation (9) can be used to evaluate the thermal diffusion process during the “transmission off’ period.
  • Equations (8) and (9) the effect of intermittent EM transmission can be evaluated to evaluate the effect of different lengths of “transmission off’ period and select a length of “transmission off’ period accordingly.
  • FIG. 7 is a chart 700 that illustrates the reduction of the temperature at the borehole surface by the intermittent EM transmission according to an implementation.
  • the chart 700 includes curves 710-760, each of which represents one example transmission scheme.
  • the x-axis represents the penetration depth in units of meters.
  • the y-axis represents the temperature in units of degrees (Celsius).
  • the total of the “transmission on” periods is 6 days for each of the schemes.
  • the curve 710 represents the schemes where there is no “transmission off’ period, and the EM waves are transmitted for 6 consecutive days.
  • the curves 720 to 760 represent the schemes where each “transmission on” period is 1 day, and each “transmission off’ period is 1 day to 5 days, respectively.
  • the temperature at the borehole surface decreases when the “transmission off’ period increases.
  • FIG. 8 is a chart 800 that illustrates the efficiency of the intermittent EM transmission according to an implementation.
  • the x-axis represents the length of each “transmission off’ period in units of days.
  • the y-axis represents the volume of stimulated rock formation, in unit of m 3 . As shown in FIG. 8, the volume of stimulated rock formation increases as the length of the “transmission off’ period increases, until the volume becomes relatively the same when the “transmission off’ period reaches 4 days.
  • Table 1 provides a summary of the borehole surface temperature and stimulated rock volume for different “transmission off’ periods as discussed previously.
  • FIG. 9 illustrates an example method 900 for fracturing rocks using intermittent EM transmission according to an implementation.
  • the description that follows generally describes method 900 in the context of FIGS. 1A-1C, 2A-2B, 3, 4A-4D, and 5-8.
  • a borehole is formed in a hydrocarbon reservoir.
  • the borehole is formed from a surface of the hydrocarbon reservoir extending downward into the hydrocarbon reservoir.
  • an EM wave that fractures rocks in the hydrocarbon reservoir is transmitted through the borehole.
  • at least a portion of the EM wave is directed to rocks at a location below the surface in the hydrocarbon reservoir.
  • the rocks at a location below the surface in the hydrocarbon reservoir are fractured by irradiation of the radio wave, where irradiating the rocks elevates pore-water pressure in the rocks causing fracturing of the rocks.
  • the irradiation is performed using the following procedures: at 912, a first portion of the rocks is irradiated by using the EM wave for a first duration, at 914, after irradiating the first portion of the rocks for the first duration, irradiation of the first portion of the rocks is refrained for a second duration. In some cases, the step 912 and 914 are repeated for multiple iterations.
  • Described implementations of the subj ect matter can include one or more features, alone or in combination.
  • a method comprises: forming a borehole in a hydrocarbon reservoir from a surface of the hydrocarbon reservoir extending downward into the hydrocarbon reservoir; transmitting an electromagnetic (EM) wave through the borehole: directing at least a portion of the EM wave to rocks at a location below the surface in the hydrocarbon reservoir; and fracturing the rocks at the location below the surface in the hydrocarbon reservoir by irradiating the rocks around the borehole using at least the portion of the EM wave, wherein irradiating the rocks elevates pore-water pressure in the rocks causing fracturing of the rocks, and wherein the irradiating is performed using the following procedures: irradiating a first portion of the rocks by using the EM wave for a first duration; after irradiating the first portion of the rocks for the first duration, refraining from irradiating the first portion of the rocks for a second duration; and repeating the irradiating step and the refraining step for multiple iterations
  • EM electromagnetic
  • a first feature combinable with any of the following features, wherein refraining from irradiating the first portion of the rocks for the second duration is performed by turning off an EM wave transmitter that transmits the EM wave for the second duration.
  • a second feature combinable with any of the previous or following features, wherein refraining from irradiating the first portion of the rocks for the second duration is performed by directing the EM wave to a different portion of the rocks.
  • a third feature combinable with any of the previous or following features, wherein the second duration is determined based on a thermal diffusivity of the rocks.
  • a fifth feature combinable with any of the previous or following features, wherein the second duration is determined based on evaluating a first thermal diffusion process with EM radiation and a second thermal diffusion process without the EM radiation.
  • a sixth feature combinable with any of the previous or following features, wherein in each iteration of the multiple iterations, the irradiation is refrained for a same length of a duration.
  • a seventh feature combinable with any of the previous or following features, wherein in at least one iteration of the multiple iterations, the irradiation is refrained for a different length of a duration than another iteration of the multiple iterations.
  • An eighth feature combinable with any of the previous or following features, wherein the borehole is a first borehole, and wherein the method further comprises: forming, in the hydrocarbon reservoir, a borehole pattern comprising a plurality of boreholes including the first borehole; and for each of the plurality of boreholes, fracturing rocks around the borehole using the EM wave that elevates pore- water pressure in the rocks.
  • a ninth feature combinable with any of the previous or following features, wherein the plurality of boreholes in a pattern having an equal distance between neighboring boreholes.
  • a tenth feature combinable with any of the previous or following features, wherein the equal distance is set to a distance determined based on a stimulated fracture density.
  • a twelfth feature combinable with any of the previous or following features, wherein the EM wave has a frequency between 5 KHz and 500M MHz.
  • a thirteenth feature combinable with any of the previous features, wherein the rocks have a permeability between about 1 nanodarcy (nD) and 0.01 millidarcy (mD).

Abstract

La présente divulgation concerne des procédés et des systèmes pour la fracturation de formations géologiques dans un réservoir d'hydrocarbures. Un procédé consiste à former un trou de forage dans un réservoir d'hydrocarbures, à partir d'une surface du réservoir d'hydrocarbures, s'étendant vers le bas à l'intérieur du réservoir d'hydrocarbures; à transmettre une onde électromagnétique (EM) à travers le trou de forage; à diriger au moins une partie de l'onde EM vers des roches à un emplacement au-dessous de la surface dans le réservoir d'hydrocarbures; et à fracturer les roches à l'emplacement au-dessous de la surface dans le réservoir d'hydrocarbures par exposition des roches entourant le trou de forage à au moins la partie de l'onde EM, l'exposition des roches étant exécutée par une exposition d'une première partie des roches à l'onde EM pendant une première durée et, après l'exposition de la première partie des roches pendant la première durée, par une limitation d'exposition de la première partie des roches pendant une seconde durée.
PCT/US2021/033841 2020-05-26 2021-05-24 Utilisation d'ondes radio pour la fracturation de roches dans un réservoir d'hydrocarbures WO2021242673A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US16/883,538 2020-05-26
US16/883,538 US10920556B2 (en) 2016-08-22 2020-05-26 Using radio waves to fracture rocks in a hydrocarbon reservoir

Publications (1)

Publication Number Publication Date
WO2021242673A1 true WO2021242673A1 (fr) 2021-12-02

Family

ID=76845305

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2021/033841 WO2021242673A1 (fr) 2020-05-26 2021-05-24 Utilisation d'ondes radio pour la fracturation de roches dans un réservoir d'hydrocarbures

Country Status (1)

Country Link
WO (1) WO2021242673A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150167439A1 (en) * 2013-12-13 2015-06-18 Chevron U.S.A. Inc. System and Methods for Controlled Fracturing in Formations
US9896919B1 (en) * 2016-08-22 2018-02-20 Saudi Arabian Oil Company Using radio waves to fracture rocks in a hydrocarbon reservoir
US20190338625A1 (en) * 2018-05-03 2019-11-07 Saudi Arabian Oil Company Creating fractures in a formation using electromagnetic signals
US10472941B2 (en) * 2015-02-25 2019-11-12 Espark Energy Inc. Electromagnetic wave concentrated heating and heat-activated chemical reactions of enhanced sensitizers for enhanced oil recovery
US10641073B2 (en) * 2014-01-31 2020-05-05 Curlett Ip Llc Method and system for subsurface resource production

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150167439A1 (en) * 2013-12-13 2015-06-18 Chevron U.S.A. Inc. System and Methods for Controlled Fracturing in Formations
US10641073B2 (en) * 2014-01-31 2020-05-05 Curlett Ip Llc Method and system for subsurface resource production
US10472941B2 (en) * 2015-02-25 2019-11-12 Espark Energy Inc. Electromagnetic wave concentrated heating and heat-activated chemical reactions of enhanced sensitizers for enhanced oil recovery
US9896919B1 (en) * 2016-08-22 2018-02-20 Saudi Arabian Oil Company Using radio waves to fracture rocks in a hydrocarbon reservoir
US20190338625A1 (en) * 2018-05-03 2019-11-07 Saudi Arabian Oil Company Creating fractures in a formation using electromagnetic signals

Similar Documents

Publication Publication Date Title
US10760396B2 (en) Using radio waves to fracture rocks in a hydrocarbon reservoir
Mukhametshina et al. Electromagnetic heating of heavy oil and bitumen: a review of experimental studies and field applications
US10253608B2 (en) Downhole heat orientation and controlled fracture initiation using electromagnetic assisted ceramic materials
US6189611B1 (en) Radio frequency steam flood and gas drive for enhanced subterranean recovery
US9598945B2 (en) System for extraction of hydrocarbons underground
US8646524B2 (en) Recovering heavy oil through the use of microwave heating in horizontal wells
CA2943134C (fr) Conditionnement thermique d'arretes de poisson
US20130213637A1 (en) Microwave system and method for intrinsic permeability enhancement and extraction of hydrocarbons and/or gas from subsurface deposits
RU2693972C2 (ru) Высокочастотная система для извлечения углеводородов
CA2858853A1 (fr) Chauffage rf in situ de zones productives empilees
US11248446B2 (en) Using electromagnetic waves to remove near wellbore damages in a hydrocarbon reservoir
CA2895595C (fr) Appareil d'extraction d'hydrocarbures souterrains
CN112673147A (zh) 压裂含烃地层的井下工具
US20040074638A1 (en) Electromagnetic coal seam gas recovery system
CA2881763C (fr) Systeme et methode de recuperation du bitume d'une reserve de bitume au moyen de chauffage electromagnetique
WO2007147053A2 (fr) Chauffage radiofréquence in situ de schiste bitumeux pour arriver à une amélioration physique et à une récupération d'huile et de gaz
US10920556B2 (en) Using radio waves to fracture rocks in a hydrocarbon reservoir
WO2021242673A1 (fr) Utilisation d'ondes radio pour la fracturation de roches dans un réservoir d'hydrocarbures
US9267366B2 (en) Apparatus for heating hydrocarbon resources with magnetic radiator and related methods
US9410408B2 (en) Electrical heating of oil shale and heavy oil formations

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: 21739824

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205 DATED 19.06.2023)

122 Ep: pct application non-entry in european phase

Ref document number: 21739824

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 522441433

Country of ref document: SA