UNTETHERED LOGGING DEVICES AND RELATED METHODS OF LOGGING A WELLBORE
An untethered device includes a housing, a magnetic actuator that is coupled to the housing, and a buoyancy device. The buoyancy device includes an attachment plate that is securable to the magnetic actuator, a degradable ballast weight that is coupled to the attachment plate, and a buoyancy-enhancing feature that is positioned adjacent to the attachment plate.
This disclosure relates to untethered devices, such as untethered logging devices that include a buoyancy device with a relatively buoyant attachment plate and a degradable ballast weight.
BACKGROUNDUntethered devices in oil and gas applications refer to untethered logging, intervention, stimulation, or other devices that are unattached to a wellbore surface and are deposited in a wellbore to descend in a downhole direction. Such an untethered device may include a release mechanism whereby an exposed ballast weight degrades or is released at a downhole depth along the wellbore to reduce a density of untethered device for allowing the untethered device to float back upward to the surface. The release mechanism may include an attachment plate that, owing to its weight, settles permanently in a bottomhole region of the wellbore. An accumulation of such attachment plates at the bottomhole region (e.g., especially because the attachment plates do not erode quickly) can lead to wellbore cluttering, which is hinders various wellbore interventions and bottomhole operations. Furthermore, heat produced by the highly exothermic reaction undergone by the exposed ballast weight can permanently damage the other components of the untethered device while attached to the ballast weight.
SUMMARYThis disclosure relates to untethered logging devices that include a buoyancy device with a relatively buoyant attachment plate and a degradable ballast weight. Upon release of the buoyancy device from a remaining functional module of the untethered logging device, the functional module floats in an uphole direction towards the surface. Upon sufficient degradation of the degradable ballast weight of the buoyancy device, the attachment plate floats in the uphole direction towards the surface. The functional module of the untethered logging devices are designed to log the wellbore while flowing in both downhole and uphole directions within the wellbore.
In one aspect, an untethered device includes a housing, a magnetic actuator that is coupled to the housing, and a buoyancy device. The buoyancy device includes an attachment plate that is securable to the magnetic actuator, a degradable ballast weight that is coupled to the attachment plate, and a buoyancy-enhancing feature that is positioned adjacent to the attachment plate.
Embodiments may provide one or more of the following features.
In some embodiments, the buoyancy-enhancing feature includes a buoyant material layer.
In some embodiments, the buoyant material layer is disposed between the attachment plate and the degradable ballast weight.
In some embodiments, the buoyant material layer includes a syntactic foam.
In some embodiments, the degradable ballast weight is attached directly to the buoyant material layer.
In some embodiments, the buoyancy device is separable as an entire unit from the magnetic actuator.
In some embodiments, components of the buoyancy device are secured to one another via one or more mechanical fasteners.
In some embodiments, components of the buoyancy device are secured to one another via one or more adhesive substances.
In some embodiments, the buoyancy-enhancing feature includes void regions within the attachment plate.
In some embodiments, the attachment plate is attached directly to the degradable ballast weight.
In some embodiments, the degradable ballast weight is non-magnetic.
In some embodiments, the untethered device further includes one or more sensors configured to measure one or more properties within a surrounding wellbore.
In some embodiments, the untethered device is configured to continuously log the surrounding wellbore while the untethered device flows in a downhole direction and while the untethered device flows in an uphole direction.
In some embodiments, the untethered device is an untethered logging device.
In another aspect, a method of logging a wellbore includes dropping an untethered logging device in a downhole direction through the wellbore. In some embodiments, the untethered logging device includes a functional module including a magnetic actuator, an attachment plate that is equipped with a buoyancy-enhancing feature and coupled to the magnetic actuator, and a degradable ballast weight that is attached to the attachment plate. The method further includes releasing the attachment plate from the magnetic actuator to reduce a bulk density of the untethered logging device and flowing the functional module of the untethered logging device in an uphole direction through the wellbore.
Embodiments may provide one or more of the following features.
In some embodiments, the method further includes allowing the degradable ballast weight to degrade to reduce a bulk density of an assembly of the degradable ballast weight and the attachment plate and flowing the attachment plate in the uphole direction through the wellbore.
In some embodiments, the buoyancy-enhancing feature includes a buoyant material layer.
In some embodiments, the buoyant material layer includes a syntactic foam.
In some embodiments, the buoyancy-enhancing feature includes void regions within the attachment plate.
In some embodiments, the method further includes measuring one or more properties within the wellbore while the functional module flows in the downhole direction and in the uphole direction.
The details of one or more embodiments are set forth in the accompanying drawings and description. Other features, aspects, and advantages of the embodiments will become apparent from the description, drawings, and claims.
The buoyancy device 106 includes an attachment plate 116, a buoyant layer 118, and a ballast weight 132. The attachment plate 116 is a metal plate that is made of one or more ferromagnetic materials, such as high-permeability, soft ferromagnetic materials (e.g., carbon steels or nickel-iron alloys). The resulting attractive force between the attachment plate 116 and the magnetic actuator 110 ensures that the attachment plate 116 remains secured to the magnetic actuator 110 until the magnetic actuator 110 is operated to release the entire buoyancy device 106 as a unit from the electromagnetic activation unit 104 of the untethered logging device 100 (e.g., refer to 100b in
While the remaining functional module of untethered logging device 100 floats upward, the buoyancy device 106 continues to descend as a unit toward the bottomhole end 113 of the wellbore 101 (e.g., refer to 100d in
In this way, a state of the ballast weight 132 (e.g., the extent to which the ballast weight 132 has degraded) governs whether the buoyancy device 106 descends in the downhole direction 105 or ascends in the uphole direction 107 through the wellbore fluid 109. For example, when the state of the ballast weight 132 is such that the bulk density of the buoyancy device 106 is greater than the density of the wellbore fluid 109, there is a positive differential in density that renders the buoyancy device 106 relatively non-buoyant, causing the buoyancy device 106 to descend through the wellbore fluid 109 in the downhole direction 105. In contrast, when the state of the ballast weight 132 is such that the overall density of the buoyancy device 106 is less than the density of the wellbore fluid 109, there is a negative differential in density that renders the buoyancy device 106 relatively buoyant, causing the buoyancy device 106 to ascend through the wellbore fluid 109 in the uphole direction 107 for retrieval at the surface 103.
Referring still to
The buoyant layer 118 is positioned between the attachment plate 116 and the ballast weight 132. The buoyant layer 118 is made of one or more relatively low-density materials to lower an overall density of the buoyancy device (e.g., an effective density of the attachment plate 116). The buoyant layer 118 accordingly increases an overall buoyancy of the buoyancy device 106. For example, the effect of the buoyant layer 118 is that, once the ballast weight 132 has sufficiently degraded (e.g., by about 10% or more), the overall density of the buoyancy device 106 (e.g., an assembly of the attachment plate 116, the buoyant layer 118, and any small volume of remaining ballast weight 132) is low enough (e.g., less than that of the wellbore fluid 109) to cause the buoyancy device 106 to float in the uphole direction 107 back to the surface 103.
In some embodiments, the buoyant layer 118 is made a syntactic foam. In some embodiments, the buoyant layer 118 has a density between about 0.5 g/cm 3 and 0.7 g/cm 3, a hydrostatic crush pressure resistance between about 2,000 psi and about 30,000 psi, a compressive modulus between about 100,000 psi and about 900,000 psi, a glass transition point above about 150° C., and a thermal conductivity between about 0.05 W/m-K and about 0.5 W/m-K. In some embodiments, the buoyancy layer has a thickness (e.g., a vertical height) between about 0.5 cm and about 5 cm.
Referring to
Advantageously, as compared to conventional logging devices with ballast-release systems, the design aspects of the buoyant layer 118 avoid multiple interventions that may otherwise need to be performed at the wellbore 101 to recover the attachment plate 116 from the bottomhole region 113 of the wellbore 101 In this manner, the buoyant layer 118 prevents clutter resulting from attachment plates 116 that may otherwise accumulate at the bottomhole end region 113. Accordingly, the buoyant layer 118 provides the untethered logging device 100 with a zero-waste feature that results in safer and cleaner well operations. Additional advantages arise from the buoyant layer 118 as well. For example, the buoyant layer 118 serves as a shock absorber for the other components of the untethered logging device 100 while the untethered logging device 100 descends through the wellbore 101. The buoyant layer 118 also serves as a thermal shield that protects the other components of the untethered logging device 100 from the highly exothermic degradation (e.g., dissolving) process gradually undergone by the ballast weight 132.
Referring again to
The untethered logging device 100 includes also one or more sensors 140 that are continuously powered by the battery 130 and designed to measure one or more physical, chemical, geological, or structural properties along the wellbore 101 to log the wellbore 101 continuously and in real time. Example properties include elapsed time, temperature, pressure, fluid density, fluid viscosity, fluid flow rate, magnetic field, gamma ray intensity, tool acceleration, tool rotation, and other parameters. The continuous measurements are acquired while the untethered logging device 100 both descends and ascends through the wellbore fluid 109. During the logging operation, the transmitter 124 sends data carrying the real-time measurements to one or more devices located at the surface 103 for further processing of the data.
In some embodiments, a weight of the untethered logging device 100, excluding the ballast weight 132, is in a range of about 25 g to about 500 g. In some embodiments, the ballast weight 132 weighs between about 10 g and about 300 g. Measured to the downhole end 114 of the protective wall 108, the untethered logging device 100 typically has a total height of about 5 cm to about 30 cm. The untethered logging device 100 typically has a width (e.g., determined by a diameter of the main housing 102) of about 5 cm to about 10 cm. Each of the main housing 102, the closed wall 112, and the protective wall 108 may be made of one or more materials, such as metals (e.g., steel, titanium, or nickel-chromium-based alloys), syntactic foam, thermoplastics, and carbon fiber materials.
Additionally, there are at least two other important parameters that should be considered with respect to the design of the untethered logging device 100. These parameters include a thickness of the attachment plate 116 and an effective density of an assembled combination of the attachment plate and the buoyant layer 118 (e.g., a combined layer 148). The thickness of the attachment plate 116 determines a holding force that can be exerted by a combined effect of the magnetic actuator 110, a magnetic field strength of the magnet 142, and a magnetic permeability of the ferromagnetic material from which the attachment plate 116 is made. If the attachment plate 116 is thinner than a critical thickness, then the magnetic field saturates the attachment plate 116, thereby greatly reducing its magnetic permeability. As a result, a reluctance of the attachment plate 116 increases, and an affinity that allows the magnetic field to remain inside of the attachment plate 116 is reduced. This reduced affinity causes the magnetic field to leak such that the holding force applied to the attachment 116 plate is reduced.
In order for the untethered logging device 100 to reach the target depth 111, the combined layer 148 should be less buoyant than the wellbore fluid 109 (e.g., having a density of about 1.0 g/cm 3 for water and a density of about 0.75-0.9 cm 3 for oil). For example, for the combined layer 148 to have an effective density of about 0.85 g/cm 3, a steel attachment plate 116 of about 2 cm 3 (e.g., having a density of about 7.85 g/cm 3) would require a buoyant layer 118 of about 70 cm 3 (e.g., having a density of about 0.65 g/cm 3) or about 16 cm 3 of trapped air.
While the untethered logging device 100 has been described and illustrated with respect to certain dimensions, sizes, shapes, arrangements, materials, and methods 200, in some embodiments, an untethered logging device that is similar in construction and function to the untethered logging device 100 may include one or more different dimensions, sizes, shapes, arrangements, configurations, and materials or may be utilized according to different methods.
For example,
Referring to
The upper and lower portions 350, 352 and the columns 354 together form multiple void regions 358 (e.g., air pockets) that reduce an overall weight (e.g., and therefore an effective density) of the attachment plate 316 as a result of material removal. The columns 354 together provide an internal truss structure that can resist relatively high crush pressures while still allowing for a relatively low density of the attachment plate 316. In some embodiments, the attachment plate 316 may be made by bring multiple pieces together or by employing additive manufacturing. A thickness and an effective density of the attachment plate 316 are critical factors for proper functioning of the attachment plate 316, as discussed above with respect to the attachment plate 116, the combined layer 148, and relationship shown in
While the device 100 has been described as an untethered logging device, in some embodiments, another type of untethered device that is otherwise similar in construction and function to the device 100 can include the ballast weight-release mechanisms described above. Such devices include intervention devices, stimulation devices, and other types of untethered devices.
Other embodiments are also within the scope of the following claims.
Claims
1. An untethered device comprising:
- a housing;
- a magnetic actuator that is coupled to the housing; and
- a buoyancy device comprising: an attachment plate that is securable to the magnetic actuator, wherein the attachment plate is equipped with a buoyancy-enhancing feature, and a degradable ballast weight that is coupled to the attachment plate, wherein the degradable ballast weight degrades to reduce a bulk density of the buoyancy device such that the attachment plate floats towards a surface.
2. The untethered device of claim 1, wherein the buoyancy-enhancing feature comprises a buoyant material layer.
3. The untethered device of claim 2, wherein the buoyant material layer is disposed between the attachment plate and the degradable ballast weight.
4. The untethered device of claim 2, wherein the buoyant material layer comprises a syntactic foam.
5. The untethered device of claim 2, wherein the degradable ballast weight is attached directly to the buoyant material layer.
6. The untethered device of claim 5, wherein the buoyancy device is separable as an entire unit from the magnetic actuator.
7. The untethered device of claim 1, wherein components of the buoyancy device are secured to one another via one or more mechanical fasteners.
8. The untethered device of claim 1, wherein components of the buoyancy device are secured to one another via one or more adhesive substances.
9. The untethered device of claim 1, wherein the buoyancy-enhancing feature comprises void regions within the attachment plate.
10. The untethered device of claim 9, wherein the attachment plate is attached directly to the degradable ballast weight.
11. The untethered device of claim 1, wherein the degradable ballast weight is non-magnetic.
12. The untethered device of claim 1, further comprising one or more sensors configured to measure one or more properties within a surrounding wellbore.
13. The untethered device of claim 1, wherein the untethered device is configured to continuously log a surrounding wellbore while the untethered device flows in a downhole direction and while the untethered device flows in an uphole direction.
14. The untethered device of claim 1, wherein the untethered device comprises an untethered logging device.
15. A method of logging a wellbore, the method comprising:
- dropping an untethered logging device in a downhole direction through the wellbore, the untethered logging device comprising: a functional module comprising a magnetic actuator, an attachment plate that is equipped with a buoyancy-enhancing feature and coupled to the magnetic actuator, and a degradable ballast weight that is attached to the attachment plate;
- releasing the attachment plate from the magnetic actuator to reduce a bulk density of the untethered logging device;
- flowing the functional module of the untethered logging device in an uphole direction through the wellbore
- allowing the degradable ballast weight to degrade to reduce a bulk density of an assembly of the degradable ballast weight and the attachment plate; and
- flowing the attachment plate in the uphole direction through the wellbore.
16. (canceled)
17. The method of claim 15, wherein the buoyancy-enhancing feature comprises a buoyant material layer.
18. The method of claim 17, wherein the buoyant material layer comprises a syntactic foam.
19. The method of claim 15, wherein the buoyancy-enhancing feature comprises void regions within the attachment plate.
20. The method of claim 15, further comprising measuring one or more properties within the wellbore while the functional module flows in the downhole direction and in the uphole direction.
Type: Application
Filed: Sep 21, 2022
Publication Date: Mar 21, 2024
Inventors: Mohamed Larbi Zeghlache (Dhahran), Huseyin Rahmi Seren (Houston, TX)
Application Number: 17/949,819