A high pressure energy storage device for producing a transient field through casing log for a well

Abstract

The utility model discloses a kind of high-pressure energy storage devices for producing well transient field through casing logging, including shell, skeleton assembly and connecting support are set respectively in the both ends of shell, install matching power module, switching circuit and capacitor module string in shell, the capacitor module string includes shaft and the several sections module of being sleeved on shaft.The high-pressure energy storage device disclosed in the utility model, several energy storage capacitors are clamped between the two modular supports to form module, realizes the capacitive modularization in small diameter range, and then several sections module containing more than 160 energy storage capacitors are used to form capacitor module string, to meet the current requirement of 800V, 100A of instantaneous transmitting signal of transmitting coil.In addition, it also has the characteristics of wide application range, and can be applied to other fields that require long-time continuous work with large short-time discharge current.

Description

Technical Field

[0001] This invention belongs to the field of transient field through-casing logging, and specifically relates to a high-pressure energy storage device for transient field through-casing logging in production wells. This high-pressure energy storage device has a high power supply voltage, a large short-time discharge current, and can work continuously for a long time. It can be used for high-temperature and high-pressure through-casing logging. Background Technology

[0002] Domestic and international oilfields primarily use nuclear logging and through-casing resistivity logging in casing wells for reservoir evaluation and saturation monitoring. Compared to nuclear logging, through-casing resistivity logging offers greater depth detection and is less affected by lower-layer porosity, making it advantageous for residual oil detection. Through-casing resistivity logging employs two methods: electrode logging and transient electromagnetic logging.

[0003] Although the electrode method for through-casing logging has a relatively complete theoretical approach and related instruments have been successfully applied in oilfields, it has the following limitations: well cleaning is required before logging; the logging process uses point measurements, and measuring a depth point involves pressurization and depressurization of the hydraulic system, resulting in a long logging time; the instrument probe is expensive, easily wears out during the logging process, and has high maintenance costs; and when encountering severe cases such as casing deformation or corrosion, poor contact between the electrode and the casing after pushing the probe in results in poor logging data. These limitations restrict its further promotion in oilfields.

[0004] The transient electromagnetic method is a time-domain artificial source electromagnetic detection method based on the theory of electromagnetic induction. It employs low-frequency electromagnetic signal transmission, which generates eddy currents in the casing and the surrounding medium. The secondary field generated by these eddy currents penetrates the casing and is received by the receiving coil. Transmitting and receiving coils are wound separately on a magnetic core. The probe is placed in the well, and a signal with a certain current and voltage is supplied to the transmitting coil. The transmitting coil emits an alternating primary electromagnetic field, which generates a secondary field in the eddy currents. This secondary field induces an electromotive force (EMF) in the receiving coil, carrying formation information. During through-casing formation resistivity testing, the electromagnetic signal can penetrate the casing and enter the formation, thus requiring a strong current transmission. The transmitting coil must withstand a large current surge and possess long-distance detection capabilities. Simultaneously, it receives telemetry commands, excites the transmitting antenna according to a prescribed sequence, collects the transmitted current, and uploads it.

[0005] Transient electromagnetic logging (TEM) employs non-contact measurement, eliminating the need for downhole push-in systems and significantly reducing the stringent requirements on wellbore conditions and depth structure. By using a non-time-harmonic field operating mode, it separates casing information from formation information in the time domain, obtaining formation information outside the metal casing. This enables more effective evaluation of water-flooded zones and residual oil saturation in the formation. TEM is an electromagnetic detection method based on a time-domain artificial source. It uses low-frequency electromagnetic signal transmission. For the electromagnetic signal from the transmitting coil to penetrate the casing and enter the formation, a strong current needs to be emitted. However, the through-casing TEM logging tools used in production wells are small-diameter instruments (only 43mm in diameter) using single-core thin cables. The current transmitted by the cable is approximately 200V, 2A, which is insufficient to meet the 800V, 100A current requirement of the through-casing TEM transmitting coil. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a high-pressure energy storage device with high power supply voltage, large short-time discharge current, and the ability to work continuously for a long time, which can be used for casing logging in transient fields of high-temperature and high-pressure production wells.

[0007] The present invention adopts the following technical solution:

[0008] A high-pressure energy storage device for through-casing logging in transient fields of production wells includes a housing. The improvement lies in the following: a skeleton assembly and a connecting bracket are respectively provided at both ends of the housing; a matching power module, a converter circuit, and a capacitor module string are installed inside the housing. The capacitor module string includes a mandrel and several modules sleeved on the mandrel. Each module includes two opposing modular supports with a central opening allowing the modular supports to fit onto the mandrel. Several capacitor cavities are arranged around the central opening on one side of each modular support, allowing several energy storage capacitors to be sandwiched between the two opposing modular supports. A circuit board is provided on the other side of the modular supports, with each energy storage capacitor electrically connected to the circuit board of its respective module. The circuit board of each module is electrically connected to the matching power module via the converter circuit.

[0009] Furthermore, one end of the spindle is fixedly connected to the connecting bracket by fasteners, and the other end is electrically connected to the adapter circuit through a connecting end, which is also electrically connected to the circuit board of each module.

[0010] Furthermore, the radial cross-sectional shape of the mandrel is non-circular, and the shape of the central opening of the modular bracket corresponds to the shape of the radial cross-section of the mandrel, so that the modular bracket can be fitted onto the mandrel but cannot rotate around the mandrel.

[0011] Furthermore, several wiring channels are set around the central opening on the surface of the modular bracket, and notches corresponding to the positions of these wiring channels are set on the circuit board.

[0012] Furthermore, the cable trays are evenly distributed circumferentially on the surface of the modular bracket.

[0013] Furthermore, adjacent modules are separated by non-metallic insulating pads.

[0014] Furthermore, non-metallic insulating pads are nested on the mandrel.

[0015] Furthermore, notches corresponding to the wiring channels of the modular bracket are also provided on the non-metallic insulating pads.

[0016] The beneficial effects of this invention are:

[0017] The high-voltage energy storage device disclosed in this invention forms a module by sandwiching several energy storage capacitors between two opposing modular supports, achieving capacitor modularization within a small diameter range. A capacitor module string is then formed from several modules containing more than 160 energy storage capacitors to meet the instantaneous 800V, 100A current requirement of the transmitting coil. Furthermore, it has a wide range of applications and can be extended to other fields requiring large short-term discharge currents and long-term continuous operation.

[0018] The high-voltage energy storage device disclosed in this invention features several wiring grooves on the surface of a modular support frame. Wiring is routed through the gaps between the energy storage capacitors, making efficient use of limited space while ensuring the safety and reliability of the wiring. Notches corresponding to the wiring grooves are also provided on the circuit board, allowing the wiring between modules to be designed outside the capacitor module strings for easier wiring and future maintenance.

[0019] The high-voltage energy storage device disclosed in this invention uses non-metallic insulating pads to separate adjacent modules, ensuring safety between modules during instantaneous high-current charging and discharging. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the high-voltage energy storage device disclosed in this invention;

[0021] Figure 2 This is a schematic diagram of the structure of the capacitor module string disclosed in this invention;

[0022] Figure 3 This is a schematic diagram of the module disclosed in this invention.

[0023] Reference numerals: 1-Skeleton assembly, 2-Matching power module, 3-Adapter circuit, 4-Capacitor module string, 5-Connecting bracket, 6-Modular bracket, 61-Center opening, 62-Wire routing channel, 7-Energy storage capacitor, 8-Circuit board, 9-Module, 10-Mandrel, 11-Fastener, 12-Connecting end. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] Example 1: This example discloses a high-pressure energy storage device for through-casing logging in transient fields of production wells, such as... Figure 1 As shown, the device includes a housing (not shown in the figure), with a frame assembly 1 and a connecting bracket 5 respectively installed at both ends of the housing. Inside the housing, a matching power module 2, an adapter circuit 3, and a capacitor module string 4 are installed, as shown. Figure 2 As shown, the capacitor module string includes a core 10 and several module sections 9 sleeved on the core 10, such as... Figure 3 As shown, the module includes two opposing modular brackets 6, with a central opening 61 in the modular brackets to allow the modular brackets to fit onto the mandrel. Several capacitor cavities are arranged around the central opening on one side of the modular brackets, allowing several energy storage capacitors 7 to be sandwiched between the two opposing modular brackets (one end of the energy storage capacitor is inserted into the capacitor cavity of one modular bracket, and the other end is inserted into the capacitor cavity of the other modular bracket). A circuit board 8 is arranged on the other side of the modular brackets, and each energy storage capacitor is electrically connected to the circuit board of its respective module. The circuit board of each module is electrically connected to the matching power supply module through an adapter circuit.

[0026] In order to axially position the mandrel, one end of the mandrel is fixedly connected to the connecting bracket by fastener 11, and the other end is electrically connected to the adapter circuit by connecting end 12. The connecting end is also electrically connected to the circuit board of each module.

[0027] The radial cross-sectional shape of the mandrel is non-circular (e.g., a circle missing a section of arc). The shape of the central opening of the modular bracket corresponds to the shape of the radial cross-section of the mandrel, so that the modular bracket can be fitted onto the mandrel but cannot rotate around the mandrel, thereby achieving radial positioning of the module within a limited space.

[0028] Several wiring grooves 62 are arranged around the central opening on the surface of the modular bracket. These wiring grooves are evenly distributed circumferentially on the surface of the modular bracket. The wiring is routed using the mating gaps between the energy storage capacitors, which not only makes reasonable use of the limited space but also ensures the safety and reliability of the wiring. Notches corresponding to the positions of the wiring grooves are provided on the circuit board, so that the wiring between modules is designed on the outside of the capacitor module string, which facilitates wiring and later maintenance.

[0029] Adjacent modules are separated by non-metallic insulating pads. These non-metallic insulating pads are nested on the mandrel. Notches corresponding to the wiring channels of the modular bracket are also provided on the non-metallic insulating pads.

[0030] In one embodiment, the high-voltage energy storage device has an outer diameter Φ=43mm and an effective length of approximately 1700mm. To better provide the instantaneous current required by the transient measurement transmitting coil, theoretical simulation calculations show that more than 160 energy storage capacitors need to be connected in series and parallel multiple times. Each module needs to be equipped with an appropriate number of energy storage capacitors. At the same time, to prevent overcharging and over-discharging, a matching power supply module needs to be set inside the device to ensure normal and safe use and meet the 800V, 100A current requirement of the transient electromagnetic transmitting coil through the bushing.

Claims

1. A high-pressure energy storage device for through-casing logging in transient fields of production wells, comprising a casing, characterized in that: A frame assembly and a connecting bracket are respectively set at both ends of the outer shell. A matching power module, an adapter circuit, and a capacitor module string are installed inside the outer shell. The capacitor module string includes a core shaft and several modules sleeved on the core shaft. Each module includes two opposing modular brackets with a central opening in the modular brackets so that the modular brackets can be sleeved on the core shaft. Several capacitor cavities are arranged around the central opening on one side of the modular brackets so that several energy storage capacitors can be sandwiched between the two opposing modular brackets. A circuit board is set on the other side of the modular brackets. Each energy storage capacitor is electrically connected to the circuit board of its respective module. The circuit board of each module is electrically connected to the matching power module through the adapter circuit.

2. The high-pressure energy storage device for through-casing logging in transient fields of production wells according to claim 1, characterized in that: One end of the spindle is fixedly connected to the connecting bracket by fasteners, and the other end is electrically connected to the adapter circuit through the connecting end. The connecting end is also electrically connected to the circuit board of each module.

3. The high-pressure energy storage device for through-casing logging in transient fields of production wells according to claim 1, characterized in that: The radial cross-sectional shape of the mandrel is non-circular, and the shape of the central opening of the modular bracket corresponds to the shape of the radial cross-section of the mandrel, so that the modular bracket can be fitted onto the mandrel but cannot rotate around the mandrel.

4. The high-pressure energy storage device for through-casing logging in transient fields of production wells according to claim 1, characterized in that: Several wiring channels are set around the central opening on the surface of the modular bracket, and notches corresponding to the positions of these wiring channels are set on the circuit board.

5. The high-pressure energy storage device for through-casing logging in transient fields of production wells according to claim 4, characterized in that: Cable trays are evenly distributed circumferentially on the surface of the modular bracket.

6. The high-pressure energy storage device for through-casing logging in transient fields of production wells according to claim 1, characterized in that: Adjacent modules are separated by non-metallic insulating pads.

7. The high-pressure energy storage device for through-casing logging in transient fields of production wells according to claim 6, characterized in that: Non-metallic insulating pads are nested on the mandrel.

8. The high-pressure energy storage device for through-casing logging in transient fields of production wells according to claim 6, characterized in that: Notches corresponding to the wiring channels of the modular bracket are also provided on the non-metallic insulating pads.

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