CA2804224A1 - Multiple sensor array seismic tool - Google Patents
Multiple sensor array seismic tool Download PDFInfo
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- CA2804224A1 CA2804224A1 CA2804224A CA2804224A CA2804224A1 CA 2804224 A1 CA2804224 A1 CA 2804224A1 CA 2804224 A CA2804224 A CA 2804224A CA 2804224 A CA2804224 A CA 2804224A CA 2804224 A1 CA2804224 A1 CA 2804224A1
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- 239000004593 Epoxy Substances 0.000 description 12
- 238000013461 design Methods 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 230000002706 hydrostatic effect Effects 0.000 description 7
- 238000005538 encapsulation Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000004382 potting Methods 0.000 description 6
- 229910001220 stainless steel Inorganic materials 0.000 description 6
- 239000010935 stainless steel Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 238000000465 moulding Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 238000003491 array Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- -1 FR4 PCBs Chemical class 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 239000004020 conductor Substances 0.000 description 3
- 239000008393 encapsulating agent Substances 0.000 description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 description 3
- 239000011707 mineral Substances 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 239000003208 petroleum Substances 0.000 description 3
- 238000003908 quality control method Methods 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000005382 thermal cycling Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 230000009477 glass transition Effects 0.000 description 2
- 238000005065 mining Methods 0.000 description 2
- 150000003071 polychlorinated biphenyls Chemical class 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- SPJOZZSIXXJYBT-UHFFFAOYSA-N Fenson Chemical compound C1=CC(Cl)=CC=C1OS(=O)(=O)C1=CC=CC=C1 SPJOZZSIXXJYBT-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000012938 design process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000013022 venting Methods 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/16—Receiving elements for seismic signals; Arrangements or adaptations of receiving elements
- G01V1/168—Deployment of receiver elements
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- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- Remote Sensing (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Measuring Fluid Pressure (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
A cartridge sub-assembly which acts as a primary seal for sensor elements with an external pod housing performing the function of a secondary seal.
Description
Multiple Sensor Array Seismic Tool Background:
Micro-seismic monitoring is increasingly used to understand the geophysics which occur in the mineral extraction industries when producing petroleum and when mining ores. By generating a seismic event through production activities, or through other sources, the monitoring of the propagation of micro-displacements through the earth, i.e. monitoring the source and direction of P-waves and 5-waves, will provide the mineral producers with insight into the geological formation, into its porosity, and into the structure of the earth surrounding the deposit. With this knowledge, petroleum producers can determine where to apply pressure in order to extract oil from a petroleum reservoir while minimizing the loss of reservoir pressure, while minimizing the leakage of oil product, and while minimizing the waste of extraction fluids. When mining an ore deposit, the seismic analysis of the earth surrounding the ore deposit will enable producers to decide where to drill as well as provide warning of structural instability.
Because S- and P-wave displacements provide the highest signal fidelity and the highest signal reliability when they are detected below the earth's surface, prior art has devised methods for deploying a string of geophones down a borehole.
Witness US patent (No. 5,860,483) "Method for Installing Electronic Equipment Below Soft Earth Surface", (Author Sven 0. Havig). Other Inventors have used similar deployment methods to deploy multiple sensor types in pursuit of seismic data.
Witness US Patent (No. 6,888,972 B2), "Multiple Component Sensor Array Mechanism" (Author Berg et al.); and witness US Patent (No. 6,724, 319) "Acoustic Sensing System for Downhole Seismic Application Utilizing an Array of Fiber Optic Sensors". Variations on these methods have been in use since the 1950s. All of these multiple sensor arrays have in common a length of cable used for transmitting signals interspersed with sensor pods which feature an impermeable pressure and temperature resistant housing. Differences, occur as to the type of sensor used to monitor seismic events, the format as to how the signal is transmitted to the surface (analog or digital), and the design of the seismic cable and sensor pods.
DETAILED DESCRIPTION
With the increased dependency placed upon micro-seismic analysis when extracting minerals, there is an ever-increasing need for multiple sensor arrays offering improved signal fidelity, as well as an ever-increasing need for improved sensor array reliability and durability when operating under severe pressure, temperature and environmental conditions.
The present document describes the design and manufacturing method for producing a multiple sensor array which fills the need for increased fidelity, reliability and durability. Emphasis is placed upon the innovative design and production of sub-assemblies whose performance and durability can be pre-qualified prior to final assembly and shipment for deployment.
"Sensor Cartridge" Sub-Assembly:
A novel sub-assembly design and manufacturing process ensures that the modular sub-assembly, dubbed the "sensor cartridge", has complete standalone functionality, and can pass a rigorous quality control procedure which features a check for hydrostatic pressure-resistance through pressurization as well as checks for the quality and fidelity of the sensor signal by running proprietary sensor excitation and response analysis. Because the sub-assembly is complete in its functionality, the above quality control checks guarantee complete end-use functionality of the sensor array prior to its final assembly. Therefore, one of the advantages of this design is that it permits a sensor array which can be over meters in length to be completely checked for hydrostatic pressure resistance prior to deployment. Due to the cumbersome length of the sensor array, completely checking the final tool array assembly for hydrostatic pressure resistance is impossible.
Not only was the sub-assembly design chosen to be modular, but it uses, in a novel way, the materials employed to make the "sensor cartridge" subcomponents.
These materials are chosen and treated in such a way that bonding occurs between the individual sub-components which ensures a pressure and temperature resistant encapsulation of the sensor elements. In the preferred embodiment, seen in Fig.1,
Micro-seismic monitoring is increasingly used to understand the geophysics which occur in the mineral extraction industries when producing petroleum and when mining ores. By generating a seismic event through production activities, or through other sources, the monitoring of the propagation of micro-displacements through the earth, i.e. monitoring the source and direction of P-waves and 5-waves, will provide the mineral producers with insight into the geological formation, into its porosity, and into the structure of the earth surrounding the deposit. With this knowledge, petroleum producers can determine where to apply pressure in order to extract oil from a petroleum reservoir while minimizing the loss of reservoir pressure, while minimizing the leakage of oil product, and while minimizing the waste of extraction fluids. When mining an ore deposit, the seismic analysis of the earth surrounding the ore deposit will enable producers to decide where to drill as well as provide warning of structural instability.
Because S- and P-wave displacements provide the highest signal fidelity and the highest signal reliability when they are detected below the earth's surface, prior art has devised methods for deploying a string of geophones down a borehole.
Witness US patent (No. 5,860,483) "Method for Installing Electronic Equipment Below Soft Earth Surface", (Author Sven 0. Havig). Other Inventors have used similar deployment methods to deploy multiple sensor types in pursuit of seismic data.
Witness US Patent (No. 6,888,972 B2), "Multiple Component Sensor Array Mechanism" (Author Berg et al.); and witness US Patent (No. 6,724, 319) "Acoustic Sensing System for Downhole Seismic Application Utilizing an Array of Fiber Optic Sensors". Variations on these methods have been in use since the 1950s. All of these multiple sensor arrays have in common a length of cable used for transmitting signals interspersed with sensor pods which feature an impermeable pressure and temperature resistant housing. Differences, occur as to the type of sensor used to monitor seismic events, the format as to how the signal is transmitted to the surface (analog or digital), and the design of the seismic cable and sensor pods.
DETAILED DESCRIPTION
With the increased dependency placed upon micro-seismic analysis when extracting minerals, there is an ever-increasing need for multiple sensor arrays offering improved signal fidelity, as well as an ever-increasing need for improved sensor array reliability and durability when operating under severe pressure, temperature and environmental conditions.
The present document describes the design and manufacturing method for producing a multiple sensor array which fills the need for increased fidelity, reliability and durability. Emphasis is placed upon the innovative design and production of sub-assemblies whose performance and durability can be pre-qualified prior to final assembly and shipment for deployment.
"Sensor Cartridge" Sub-Assembly:
A novel sub-assembly design and manufacturing process ensures that the modular sub-assembly, dubbed the "sensor cartridge", has complete standalone functionality, and can pass a rigorous quality control procedure which features a check for hydrostatic pressure-resistance through pressurization as well as checks for the quality and fidelity of the sensor signal by running proprietary sensor excitation and response analysis. Because the sub-assembly is complete in its functionality, the above quality control checks guarantee complete end-use functionality of the sensor array prior to its final assembly. Therefore, one of the advantages of this design is that it permits a sensor array which can be over meters in length to be completely checked for hydrostatic pressure resistance prior to deployment. Due to the cumbersome length of the sensor array, completely checking the final tool array assembly for hydrostatic pressure resistance is impossible.
Not only was the sub-assembly design chosen to be modular, but it uses, in a novel way, the materials employed to make the "sensor cartridge" subcomponents.
These materials are chosen and treated in such a way that bonding occurs between the individual sub-components which ensures a pressure and temperature resistant encapsulation of the sensor elements. In the preferred embodiment, seen in Fig.1,
2 the encapsulation material is an epoxy (1 ) with ceramic additives, and has a glass transition temperature of 105 C, however, other embodiments may use a high temperature epoxy which has a glass transition temperature in the 200 C range.
FR4 PCBs (2) and (3) are used as structural elements to hold the sensors elements.
Because the epoxy will bond to the PCBs made from FR4 material if these are treated properly, a pressure-resistant, water impermeable seal will be made between these structural elements and the epoxy encapsulant. Moreover, internal traces inside PCBs conduct the sensor response signals from inside the encapsulation to the outside of the "cartridge sensor". Because these traces are internal to the FR4 boards, they are physically sealed and prevent water which is under hydrostatic pressure from migrating from outside into the encapsulation, using these electrical traces on the PCBS as conduits to reach the sensor elements.
In the preferred embodiment, the sensor elements are geophones (4) which are prone to failure if they become wet.
Other embodiments to this cartridge sensor may include thermistors as sensor-elements and the inclusion of amplifiers in order to provide gain to the sensors signals as they are transmitted to the surface.
In the preferred embodiment, the structural FR4 PCBs are designed to lock together and locate the geophone pairs (4) in a mutually orthogonal concentric cylinder.
This orthogonality improves accuracy when detecting the source and direction of P-and S-waves because the dip and azimuth of the seismic pulses can be more accurately calculated.
Sub-components (2), (3) and (4) are over-moulded in a split cavity mould. The mould is designed to minimize cavity pressure when injecting epoxy, in order that the sensor elements do not deform or are penetrated by the moulded encapsulant.
Subsequent to moulding, the "cartridge sensor" is removed from the mould and post-treated using a heat schedule designed to minimize residual stresses which results from the thermal expansion of the diverse sub-components.
A) DH Sensor Pod Assembly
FR4 PCBs (2) and (3) are used as structural elements to hold the sensors elements.
Because the epoxy will bond to the PCBs made from FR4 material if these are treated properly, a pressure-resistant, water impermeable seal will be made between these structural elements and the epoxy encapsulant. Moreover, internal traces inside PCBs conduct the sensor response signals from inside the encapsulation to the outside of the "cartridge sensor". Because these traces are internal to the FR4 boards, they are physically sealed and prevent water which is under hydrostatic pressure from migrating from outside into the encapsulation, using these electrical traces on the PCBS as conduits to reach the sensor elements.
In the preferred embodiment, the sensor elements are geophones (4) which are prone to failure if they become wet.
Other embodiments to this cartridge sensor may include thermistors as sensor-elements and the inclusion of amplifiers in order to provide gain to the sensors signals as they are transmitted to the surface.
In the preferred embodiment, the structural FR4 PCBs are designed to lock together and locate the geophone pairs (4) in a mutually orthogonal concentric cylinder.
This orthogonality improves accuracy when detecting the source and direction of P-and S-waves because the dip and azimuth of the seismic pulses can be more accurately calculated.
Sub-components (2), (3) and (4) are over-moulded in a split cavity mould. The mould is designed to minimize cavity pressure when injecting epoxy, in order that the sensor elements do not deform or are penetrated by the moulded encapsulant.
Subsequent to moulding, the "cartridge sensor" is removed from the mould and post-treated using a heat schedule designed to minimize residual stresses which results from the thermal expansion of the diverse sub-components.
A) DH Sensor Pod Assembly
3 In the final assembly of the sensor pod, the "sensor cartridge" is positioned along a length of seismic cable at the desired location for the sensor pod. 3 twisted-pair conductors are cut and attached to the 3 terminals on the "cartridge sensor"
PCB.
Each terminal corresponds to one of 3 seismic channels inside the pod. The remaining twisted pairs in the seismic cable are tied to along the length of the "cartridge sensor". These remaining seismic twisted pairs pass through the pod to consecutive sensor pods lower down in the array. This corresponds to item (1), seen in Fig.2. A stainless steel sleeve, (2) in Fig (2), is placed over the "cartridge sensor" (3) and the pass-through seismic cable. End-caps, (4) in Fig.2, are fed over the seismic cable and attached to the stainless steel sleeve. These end-caps are in-turn overmoulded, (5) in Fig (2), using polyurethane, to the seismic cable, providing a watertight bond. Because the primary wartertight seal is created at the "cartridge sensor" sub-assembly, external seals for the sensor pods, created by using o-rings to seal the end-caps to the stainless steel sleeve and by using an overmould to seal the end-caps to the seismic cable, are redundant, secondary seals.
Any voids which are formed inside the pod housing and the "cartridge sensor"
are filled with the same encapsulant material used to mould the cartridge sub-assembly. In this way, good transmissibility of seismic events is ensured from the outside of the sensor pod, through the "cartridge sensor", into the sensor elements.
Havig et al. describes a sensor pod assembly with a pass-through seismic cable, however the primary seal of the geophone elements is performed by the external pod housing. The design disclosed herein describes a cartridge sub-assembly which acts as a primary seal for the sensor elements, while the external pod housing performs the function of a secondary seal. Unlike the design presently disclosed, Havig et at. does not describe a modular sub-assembly which is standalone, complete in its functionality and which can be pre-qualified or tested in order to guarantee the final end-use functionality of the entire sensor array prior to final assembly. Moreover, unlike Havig et at, the disclosed design features a structure in which all sensor elements are concentric.
PCB.
Each terminal corresponds to one of 3 seismic channels inside the pod. The remaining twisted pairs in the seismic cable are tied to along the length of the "cartridge sensor". These remaining seismic twisted pairs pass through the pod to consecutive sensor pods lower down in the array. This corresponds to item (1), seen in Fig.2. A stainless steel sleeve, (2) in Fig (2), is placed over the "cartridge sensor" (3) and the pass-through seismic cable. End-caps, (4) in Fig.2, are fed over the seismic cable and attached to the stainless steel sleeve. These end-caps are in-turn overmoulded, (5) in Fig (2), using polyurethane, to the seismic cable, providing a watertight bond. Because the primary wartertight seal is created at the "cartridge sensor" sub-assembly, external seals for the sensor pods, created by using o-rings to seal the end-caps to the stainless steel sleeve and by using an overmould to seal the end-caps to the seismic cable, are redundant, secondary seals.
Any voids which are formed inside the pod housing and the "cartridge sensor"
are filled with the same encapsulant material used to mould the cartridge sub-assembly. In this way, good transmissibility of seismic events is ensured from the outside of the sensor pod, through the "cartridge sensor", into the sensor elements.
Havig et al. describes a sensor pod assembly with a pass-through seismic cable, however the primary seal of the geophone elements is performed by the external pod housing. The design disclosed herein describes a cartridge sub-assembly which acts as a primary seal for the sensor elements, while the external pod housing performs the function of a secondary seal. Unlike the design presently disclosed, Havig et at. does not describe a modular sub-assembly which is standalone, complete in its functionality and which can be pre-qualified or tested in order to guarantee the final end-use functionality of the entire sensor array prior to final assembly. Moreover, unlike Havig et at, the disclosed design features a structure in which all sensor elements are concentric.
4 Berg et al. and Knaack et al. describe multiple sensor arrays for deployment in a well bore, but the sensor elements are hydrophones instead of geophones , and the sensor signal transmitted to the surface is digital instead of analog, Moreover, the primary sealing of the pods in both cases is performed at the sensor housing.
Accordingly, described herein is an improved downhole (DH) micro-seismic sensor, which features increased performance and reliability. In this design, a new sub-assembly, dubbed the "geophone cartridge" is created prior to the final assembly of the sensor pods. The geophone cartridge allows a more controlled epoxy-potting process which offers improved sealing, increased impact resistance, and which resists the development of cracks in the cartridge assembly. Moreover the cartridge assembly makes possible, the pressure testing of 100% of the micro-seismic sensors prior to customer delivery. This step makes the DH tool manufacturing process more rigorous and is designed to offer improved reliability for deployment at depth under hydrostatic pressure. See Figures 3 and 4.
The PCB boards were chosen as a structural member to contain the geophones, because of the well -known adhesion of epoxy potting compounds to these boards.
The adhesion creates a primary seal between the geophones and the external hydrostatic pressure from the well. In the final assembly, a secondary seal is created when the cartridge is inserted into the stainless steel pod housing which has end-caps which are over-moulded onto the polyurethane jacket. In order to fix the cartridge within the housing, a second epoxy potting is done to surround the cartridge in the housing. In the primary seal created by the "geophone cartridge", water cannot migrate from the outside of the board, along the electrical conductors to the geophones because the electrical conductors which lead from the geophones to the edge of the PCB board are embedded and are concealed. The PCB boards also have a strain relief attachment for the micro-seismic cables. In this way the risks of breaking the electrical connections to the geophones due to impact are mitigated.
In the secondary seal, when epoxy is potted over the cartridge inside the stainless steel tube, the individual twisted pairs which are connected to the cartridge have epoxied sections of magnet wire which are strain-relieved by the PCB board.
Epoxy bonds well to magnet wire and as such, a block is created which eliminates the potential for water to migrate from the twisted pairs into the cartridge.
In order to mould the geophone cartridge, the inventors tested and verified the performance of many epoxy potting compounds. The final selection was made based on the epoxy's tensile strength, its low moisture absorption, its temperature stability, its impact resistance as well as its low shrinkage during moulding.
During the moulding process, the moulding parameters of temperature and humidity can be better controlled in an enclosed chamber, because the carridge is moulded as a standalone unit, free of the sensor housing and the associated seismic cable. The shot fill is better assured because of the improved benefits of a dedicated mould which has better venting and optimal location of the injection gates. This validated potting process will ensure that there are no air-bubbles trapped within the potting which can create a conduit for water to migrate through in the event that the secondary seal is breached.
Moreover, once moulded, the cartridge can be inspected and tested as a standalone unit free of the external stainless steel housing. Visual inspection can be made for air bubbles and cracks due to mould shrinkage. As a second step in the quality control procedure, pressure testing can be done on 100% of the cartridges, and each unit can be checked for electrical resistance, sensitivity and frequency response after pressure testing.
These added controls to the manufacturing of DH tools enable a sensor pod which has redundant sealing, and is more robust against impact, crushing and thermal cycling. The perpendicularity of the PCB boards assures not only improved orthogonality of the sensor signals, but also ensures that the geophones are surrounded by a uniform and controlled amount of impact resistant epoxy. In this way resistance to impact and crushing is better assured. Moreover mould shrinkage can be better controlled, because of the improved moulding process, which thus eliminates residual stresses and better resists the development of cracking in the encapsulation. The sensor will better resist impact and thermal cycling when under hydrostatic pressure, since it is devoid of cracks in the encapsulation.
Through the adoption of the geophone cartridge sub-assembly, the presently described embodiments mitigate the risks associated with the common failure modes for DH sensor arrays, which include (1) breach of the seals (2) breaks in the electrical connections to the geophones, (3) cracks developing due to thermal cycling (4) loss of operation of the geophones due to impact.
Accordingly, described herein is an improved downhole (DH) micro-seismic sensor, which features increased performance and reliability. In this design, a new sub-assembly, dubbed the "geophone cartridge" is created prior to the final assembly of the sensor pods. The geophone cartridge allows a more controlled epoxy-potting process which offers improved sealing, increased impact resistance, and which resists the development of cracks in the cartridge assembly. Moreover the cartridge assembly makes possible, the pressure testing of 100% of the micro-seismic sensors prior to customer delivery. This step makes the DH tool manufacturing process more rigorous and is designed to offer improved reliability for deployment at depth under hydrostatic pressure. See Figures 3 and 4.
The PCB boards were chosen as a structural member to contain the geophones, because of the well -known adhesion of epoxy potting compounds to these boards.
The adhesion creates a primary seal between the geophones and the external hydrostatic pressure from the well. In the final assembly, a secondary seal is created when the cartridge is inserted into the stainless steel pod housing which has end-caps which are over-moulded onto the polyurethane jacket. In order to fix the cartridge within the housing, a second epoxy potting is done to surround the cartridge in the housing. In the primary seal created by the "geophone cartridge", water cannot migrate from the outside of the board, along the electrical conductors to the geophones because the electrical conductors which lead from the geophones to the edge of the PCB board are embedded and are concealed. The PCB boards also have a strain relief attachment for the micro-seismic cables. In this way the risks of breaking the electrical connections to the geophones due to impact are mitigated.
In the secondary seal, when epoxy is potted over the cartridge inside the stainless steel tube, the individual twisted pairs which are connected to the cartridge have epoxied sections of magnet wire which are strain-relieved by the PCB board.
Epoxy bonds well to magnet wire and as such, a block is created which eliminates the potential for water to migrate from the twisted pairs into the cartridge.
In order to mould the geophone cartridge, the inventors tested and verified the performance of many epoxy potting compounds. The final selection was made based on the epoxy's tensile strength, its low moisture absorption, its temperature stability, its impact resistance as well as its low shrinkage during moulding.
During the moulding process, the moulding parameters of temperature and humidity can be better controlled in an enclosed chamber, because the carridge is moulded as a standalone unit, free of the sensor housing and the associated seismic cable. The shot fill is better assured because of the improved benefits of a dedicated mould which has better venting and optimal location of the injection gates. This validated potting process will ensure that there are no air-bubbles trapped within the potting which can create a conduit for water to migrate through in the event that the secondary seal is breached.
Moreover, once moulded, the cartridge can be inspected and tested as a standalone unit free of the external stainless steel housing. Visual inspection can be made for air bubbles and cracks due to mould shrinkage. As a second step in the quality control procedure, pressure testing can be done on 100% of the cartridges, and each unit can be checked for electrical resistance, sensitivity and frequency response after pressure testing.
These added controls to the manufacturing of DH tools enable a sensor pod which has redundant sealing, and is more robust against impact, crushing and thermal cycling. The perpendicularity of the PCB boards assures not only improved orthogonality of the sensor signals, but also ensures that the geophones are surrounded by a uniform and controlled amount of impact resistant epoxy. In this way resistance to impact and crushing is better assured. Moreover mould shrinkage can be better controlled, because of the improved moulding process, which thus eliminates residual stresses and better resists the development of cracking in the encapsulation. The sensor will better resist impact and thermal cycling when under hydrostatic pressure, since it is devoid of cracks in the encapsulation.
Through the adoption of the geophone cartridge sub-assembly, the presently described embodiments mitigate the risks associated with the common failure modes for DH sensor arrays, which include (1) breach of the seals (2) breaks in the electrical connections to the geophones, (3) cracks developing due to thermal cycling (4) loss of operation of the geophones due to impact.
Claims
1. A multiple Sensor Array Seismic Tool comprising a cartridge sub-assembly which acts as a primary seal for sensor elements with an external pod housing performing the function of a secondary seal.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2804224A CA2804224C (en) | 2013-01-25 | 2013-01-25 | Multiple sensor array seismic tool |
| CA 2828543 CA2828543A1 (en) | 2013-01-25 | 2013-09-26 | Sealed sensor assembly |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2804224A CA2804224C (en) | 2013-01-25 | 2013-01-25 | Multiple sensor array seismic tool |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2804224A1 true CA2804224A1 (en) | 2014-07-25 |
| CA2804224C CA2804224C (en) | 2019-06-04 |
Family
ID=51221005
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2804224A Active CA2804224C (en) | 2013-01-25 | 2013-01-25 | Multiple sensor array seismic tool |
| CA 2828543 Abandoned CA2828543A1 (en) | 2013-01-25 | 2013-09-26 | Sealed sensor assembly |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2828543 Abandoned CA2828543A1 (en) | 2013-01-25 | 2013-09-26 | Sealed sensor assembly |
Country Status (1)
| Country | Link |
|---|---|
| CA (2) | CA2804224C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111197481A (en) * | 2018-10-31 | 2020-05-26 | 中石化石油工程技术服务有限公司 | Bearing drilling tool of measurement and control instrument while drilling |
| US12031397B2 (en) | 2018-08-03 | 2024-07-09 | Interra Energy Services Ltd. | Device and method for actuating downhole tool |
-
2013
- 2013-01-25 CA CA2804224A patent/CA2804224C/en active Active
- 2013-09-26 CA CA 2828543 patent/CA2828543A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US12031397B2 (en) | 2018-08-03 | 2024-07-09 | Interra Energy Services Ltd. | Device and method for actuating downhole tool |
| CN111197481A (en) * | 2018-10-31 | 2020-05-26 | 中石化石油工程技术服务有限公司 | Bearing drilling tool of measurement and control instrument while drilling |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2804224C (en) | 2019-06-04 |
| CA2828543A1 (en) | 2014-07-25 |
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