A controllable electromagnetic pulse detection system and method based on downhole real-time high-power

Abstract

The present invention relates to a controllable electromagnetic pulse detection system and method based on downhole real-time high power, which includes: a ground power supply control cabinet, which provides power to downhole equipment through a logging cable and performs control; the downhole equipment includes a downhole high-voltage DC power supply, a pulse energy storage device, and an energy converter; the downhole high-voltage DC power supply is connected to the ground power supply control cabinet via a logging cable and is powered and controlled by the ground power supply control cabinet; the pulse energy storage device is connected to the downhole high-voltage DC power supply for charging and energy storage; the energy converter is connected to the pulse energy storage device, is used to receive the electrical energy transmitted by the pulse energy storage device, and converts the electrical energy into shock wave energy before applying it to a load. The present invention can perform a controllable repetition frequency action on reservoir segments.

Description

Technical Field

[0001] The present invention relates to the technical field of oil reservoir development, and in particular to a downhole real-time high-power controllable electromagnetic pulse detection system and method. Background Art

[0002] Downhole electromagnetic exploration is commonly used to evaluate the distribution of remaining oil in developed reservoirs. Increasing the power supply source is an effective measure to improve the effectiveness of electromagnetic exploration. Traditional reservoir stimulation methods primarily rely on static pressure, which focuses its effects on weak areas. Regardless of any vertical heterogeneity, these methods generally treat the reservoir as a whole, with only a one-time success or failure. This method utilizes other media to apply pressure from surface equipment to the reservoir, making it a typical intrusive approach that cannot precisely control the pressure applied to the reservoir. Furthermore, hydraulic fracturing equipment is large, expensive, and energy-intensive.

[0003] Existing literature describes methods for fabricating a high-power electromagnetic pulse transmitter in a well. This device can achieve instantaneous, high-power pulsed magnetic field excitation in a cased wellbore and record the full-time data of the transmitted waveform and received signal. This provides an observation system for wellbore electromagnetic exploration methods used to evaluate the distribution of remaining oil in developed reservoir formations. However, existing literature describes a low-voltage, high-power transmitter circuit for transient electromagnetic logging. The transmitter circuit is designed using high-power, low-on-resistance transistors and MOS transistors, and connected to a high-power transmitter coil placed within the steel casing for transmission testing. A discharge resistor is used in the transmitter circuit to dissipate the idle work stored in the transmitter coil. The presence of the discharge resistor results in a very large peak voltage amplitude in the transmitter coil when transmission stops. During signal transmission, as the transmitter power voltage gradually increases, the voltage across the coil increases, resulting in a gradual increase in the transmission power. While these methods achieve high-power design, the transmission voltage during electromagnetic transmission is not adjustable, and their application in intelligent wellbore applications is not discussed.

[0004] Existing static pressure methods utilize other media to apply pressure from surface equipment to the reservoir. This is a typical intrusive modification and cannot precisely target the pressure acting on the reservoir. Furthermore, hydraulic fracturing equipment is large, expensive, and consumes significant energy. Existing downhole high-power electromagnetic pulse detection methods generate a relatively high peak voltage at the moment transmission stops, making the actual transmission power unadjustable. When intelligent well systems encounter complex well conditions in target layers, an adjustable transmission power system would facilitate more refined management of each layer. Summary of the Invention

[0005] In view of the above problems, the purpose of the present invention is to provide a controllable electromagnetic pulse setting system and method based on real-time high power downhole, which can perform controllable repetition frequency effects on reservoir segments.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions: a controllable electromagnetic pulse detection system based on real-time high power downhole, which includes: a ground power supply control cabinet, which provides power to downhole equipment through a logging cable and controls it; the downhole equipment includes a downhole high-voltage DC power supply, a pulse energy storage device and an energy converter; the downhole high-voltage DC power supply is connected to the ground power supply control cabinet via a logging cable, and is powered and controlled by the ground power supply control cabinet; the pulse energy storage device is connected to the downhole high-voltage DC power supply for charging and energy storage; the energy converter is connected to the pulse energy storage device, for receiving the electric energy transmitted by the pulse energy storage device, and converting the electric energy into shock wave energy before applying it to the load.

[0007] Furthermore, the load is a reservoir, and the shock wave energy acts on the reservoir by penetrating the casing and the perforating blastholes.

[0008] Furthermore, the pulse energy storage device includes a high-energy storage capacitor C, a resistor R, a transmitting coil inductor L and a trigger switch;

[0009] One end of the high-energy storage capacitor C is connected to the downhole high-voltage DC power supply via the trigger switch, and the other end of the high-energy storage capacitor C is respectively connected to one end of the resistor R and the energy converter; the other end of the resistor R is connected in series with the transmitting coil inductor L and then connected to the trigger switch.

[0010] Furthermore, the trigger switch includes a first contact a, a second contact b and a switch k; the connection end of the switch k is connected to one end of the high-energy storage capacitor C, the first contact a is connected to the downhole high-voltage DC power supply, and the second contact b is connected to the transmitting coil inductor L.

[0011] Furthermore, the action direction, pulse width and frequency of the shock wave can be adjusted by a battery management system arranged in a ground power control cabinet.

[0012] Furthermore, the pulse width of the shock wave is adjustable within 0.5 ms.

[0013] Furthermore, the direction of the shock wave is determined by adjusting the electrode shape of the high-energy storage capacitor C through the battery management system; the transmission frequency is changed by changing the width of the current pulse through the battery management system; and the frequency can be controlled by controlling the parameters of the resistor R, the transmitting coil inductance L, and the high-energy storage capacitor C.

[0014] Furthermore, the controllable electromagnetic pulse detection system also includes an intelligent well excitation energy storage device;

[0015] The intelligent well excitation energy storage device includes a casing, a single-core steel pipe cable and an excitation probe;

[0016] The casing corresponding to the reservoir is set as a multi-layer structure, the casing located on the top layer is provided with a top seal, the casing at the bottom and the middle is provided with an interlayer seal, and each layer is separated by a seal; each layer of the casing is provided with the trigger switch, the energy converter and the excitation probe, and the upper casing of the top seal is provided with the high-energy storage capacitor C, the high-energy storage capacitor C is connected to each trigger switch, the energy converter and the excitation probe via the single-core steel pipe cable; the single-core steel pipe cable is connected to the battery management system in the ground power control cabinet to realize power supply and control.

[0017] Furthermore, a plurality of the excitation probes are placed on each layer of the casing, and the discharge after the combination is controlled by a switching circuit so that the excitation position within the layer can be adjusted; the excitation probes between layers are connected by controlling the single-core steel pipe cable to realize single-layer discharge to generate shock waves acting on a single reservoir, or multi-layer combined discharge to generate shock waves acting on multiple reservoirs at the same time.

[0018] A method for using the above-mentioned downhole real-time high-power controllable electromagnetic pulse detection system includes:

[0019] Pull out all pipes from the well;

[0020] Run the well gauge, fill the wellbore with water, and maintain the liquid level at the wellhead during the entire operation;

[0021] Send the pulse energy storage device to the perforation section of the coal seam to be treated underground;

[0022] Divide the oil reservoir into multiple treatment sections;

[0023] The pulse energy storage device operates repeatedly at the set operating frequency at each operating point;

[0024] After the treatment is completed, the underground equipment is removed;

[0025] Install the production string and complete the well according to the set requirements.

[0026] The present invention has the following advantages due to the adoption of the above technical solution:

[0027] 1. This invention is the first to propose a downhole high-power electromagnetic pulse setting device. By varying the R, L, and C parameters, the electromagnetic pulse frequency, and thus the pulse width, can be altered to produce electromagnetic pulses of varying power. These pulses achieve high peak pressures with short durations, without damaging the casing or cement sheath.

[0028] 2. The energy converter of the present invention can discharge in real time.

[0029] 3. The present invention can perform a controllable repetitive frequency action on reservoir segments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the pulse power detection principle in one embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of a high-power controllable electromagnetic pulse in a well according to an embodiment of the present invention;

[0032] Figure 3 This is a topological diagram of a battery management system according to an embodiment of the present invention;

[0033] Figure 4 It is a schematic structural diagram of an intelligent well excitation energy storage device in one embodiment of the present invention. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0036] The present invention utilizes a method and device for setting controllable, high-power, downhole electromagnetic pulses. This method applies high-power electromagnetic pulse pressure to each layer of an intelligent well. The shockwave's direction is determined by adjusting the electrode shape. The shockwave charging time and excitation intensity can be controlled and adjusted according to actual needs, allowing the electromagnetic pulse device to discharge in real time. A single-core steel cable can be used to control the connection and disconnection of excitation probes between any layers of the intelligent well. This method achieves high peak pressure and short duration, without damaging casing or cement sheaths, and can apply controlled repetition rates to reservoir segments.

[0037] In one embodiment of the present invention, Figure 1 As shown, a controllable electromagnetic pulse detection system based on real-time high power downhole detection is provided. In this embodiment, the system includes:

[0038] The ground power control cabinet provides power to and controls downhole equipment through the logging cable. The downhole equipment includes a downhole high-voltage DC power supply, a pulse energy storage device, and an energy converter.

[0039] The underground high-voltage DC power supply is connected to the ground power control cabinet via the logging cable, and is powered and controlled by the ground power control cabinet;

[0040] The pulse energy storage device is connected to the underground high-voltage DC power supply to charge and store energy;

[0041] The energy converter is connected to the pulse energy storage device, and is used to receive the electrical energy transmitted by the pulse energy storage device, and convert the electrical energy into mechanical energy (shock wave energy), and then act on the load to realize the pulsation detection function.

[0042] In this embodiment, the load is the reservoir, and the mechanical energy can be applied to the reservoir by penetrating the casing and perforating the blastholes.

[0043] In the above embodiment, the downhole equipment is transported to the reservoir location by a cable car and connected to the ground power control cabinet.

[0044] In the above embodiment, Figure 2 As shown, the pulse energy storage device adopts a damped oscillation circuit, including a high-energy storage capacitor C, a resistor R, a transmitting coil inductor L and a trigger switch Q.

[0045] One end of the high-energy storage capacitor C is connected to the downhole high-voltage DC power supply via the trigger switch Q. The other end of the high-energy storage capacitor C is connected to one end of the resistor R and the energy converter. The other end of the resistor R is connected in series with the transmitting coil inductor L and then to the trigger switch Q, forming a damped oscillation circuit.

[0046] Among them, the trigger switch Q includes a first contact a, a second contact b and a switch k; the connection end of the switch k is connected to one end of the high-energy storage capacitor C, the first contact a is connected to the underground high-voltage DC power supply, and the second contact b is connected to the transmitting coil inductor L.

[0047] During use, when the selection end of the switch k is connected to the first contact a, the underground high-voltage DC power supply charges and stores energy for the high-energy storage capacitor C to a very high preset voltage; when the selection end of the switch k is connected to the second contact b, the high-energy storage capacitor C, the resistor R, and the transmitting coil inductor L form a damped oscillation circuit, which discharges, and the high-energy storage capacitor C discharges to the energy converter, transmitting electrical energy to the energy converter.

[0048] In the above embodiment, after the pulse energy storage device discharges to the energy converter, the energy converter converts the electrical energy into mechanical energy, that is, shock wave energy. The direction, pulse width and frequency of the shock wave can be adjusted by the battery management system set in the ground power control cabinet.

[0049] Among them, the battery management system can adjust the electrode shape of the high-energy storage capacitor C in the pulse energy storage device to determine the direction of the shock wave; by changing the width of the current pulse through the battery management system, the emission frequency can be changed, and the frequency can be controlled by controlling the parameters of R, L, and C.

[0050] Preferably, the pulse width of the shock wave of the present invention is adjustable within 0.5 ms.

[0051] Specifically, such as Figure 2 As shown, when the high-energy storage capacitor C discharges to the energy converter, in the discharge circuit, R is the resistance of the damping circuit oscillation, and L is the inductance of the transmitting coil. According to Kirchhoff's law, there is:

[0052]

[0053] Wherein, t represents the test time, Uc represents the voltage of the high-energy storage capacitor C, and C is the capacitance value of the high-energy storage capacitor.

[0054] The boundary conditions and initial conditions are:

[0055] U C (0 + )=U C (0 - )=U0 (2)

[0056]

[0057]

[0058] Among them, U C (0 + ) is the voltage flowing into the capacitor, U C (0 - ) is the voltage flowing out of the capacitor, and i(t) is the current at time t.

[0059] Assuming that the capacitor is already charged, its voltage is U0, and the initial current in the inductor is I0=0, the discharge switch is turned on under the set voltage and current reference direction, and we can get:

[0060] When , it is in over-damping state;

[0061] It is in critical damping state;

[0062] It is in underdamped state.

[0063] The excitation current is different under different damping states. Therefore, by changing the parameters of R, L, and C, the frequency of the electromagnetic pulse can be changed, and then the width of the electromagnetic pulse can be changed to obtain electromagnetic pulses of different powers.

[0064] On this basis, according to the power and voltage requirements of the pulse energy storage device, charge and discharge management can be achieved through the batteries connected in series in the ground power control cabinet, such as Figure 3 Figure 2 shows a topology diagram of a battery management system.

[0065] The battery management system includes a BMS with a balancer, battery modules, sampling resistors, discharge MOSFETs, charge MOSFETs, and a short-circuit protection circuit. Multiple battery modules are provided, all connected to the BMS for management and control. Each battery module is connected in parallel with a discharge MOSFET, a charge MOSFET, and an energy storage inductor. The discharge MOSFET and charge MOSFET are connected to the BMS, and the BMS controls the operation of the MOSFETs to charge and discharge the stored energy to the battery module. The lines connecting the discharge and charge MOSFETs are also connected to a sampling resistor and a short-circuit protection circuit. The pulse signals that control the MOSFET switching transistors enable high and low voltage charging management and overcurrent detection for the MOSFETs.

[0066] In the above embodiment, the downhole real-time high-power controllable electromagnetic pulse detection system also includes an intelligent well excitation energy storage device, and the excitation connection between the reservoirs is achieved through the single-core steel pipe cable in the intelligent well excitation energy storage device.

[0067] Take the three-layer reservoir as an example, Figure 4 As shown, the intelligent well excitation energy storage device includes casing 1, a single-core steel pipe cable 2, and an excitation probe 3. The casing 1 is set as a three-layer structure corresponding to the reservoir. The casing 1 at the top layer is provided with a top packer 4, and the casing 1 at the bottom and middle is provided with an interlayer packer 5. The layers are separated by packers. Each layer of casing 1 is provided with a trigger switch Q, an energy converter, and an excitation probe 3. The casing 1 above the top packer 4 is provided with a high-energy storage capacitor C. The high-energy storage capacitor C is connected to each trigger switch Q, energy converter, and excitation probe 3 via a single-core steel pipe cable 2. At the same time, the single-core steel pipe cable 2 is connected to the battery management system in the ground power control cabinet to achieve power supply and control.

[0068] Among them, the high-voltage energy storage capacitor C is separated from the trigger switch Q and the excitation probe 3. The high-voltage energy storage capacitor C is arranged on the top of the top packer 4, and the trigger switch and the excitation probe 3 are placed in each layer, which can avoid the high-voltage energy storage capacitor C being too large to be installed in each layer.

[0069] In the above embodiment, since the excitation probes are typically small (<500mm), multiple excitation probes 3 can be placed on each layer of casing as needed. Switch circuits are used to control the combined discharge, allowing for adjustable excitation positions within the layer. By controlling the interlayer connectivity of the excitation probes 3 via a single-core steel pipe cable 2, the discharge conditions in each layer can be flexibly controlled. For example, a single-layer discharge can generate a shock wave affecting a single reservoir, or a multi-layer combined discharge can generate shock waves affecting multiple reservoirs simultaneously. Multiple layers can be discharged simultaneously, and switches can be freely combined. However, excitation of a single layer alone produces less power, while simultaneous excitation of multiple layers produces greater power.

[0070] In summary, when the present invention is used, the real-time high-power controllable electromagnetic pulse operation process includes the following steps:

[0071] 1) Pull out all pipes underground;

[0072] 2) Run the well gauge to ensure unobstructed passage of downhole instruments;

[0073] 3) Fill the wellbore with water and maintain the liquid level at the wellhead during the entire operation;

[0074] 4) Sending the pulse energy storage device to the perforation section of the coal seam to be treated underground;

[0075] 5) Divide the oil layer into multiple treatment stages, for example, the oil layer is divided into a treatment section of 30 to 50 cm;

[0076] The pulse energy storage device repeats the operation 50 to 80 times at each operating point at the set operating frequency;

[0077] 6) After the treatment is completed, remove the underground equipment;

[0078] 7) Install production tubing and complete the well according to set requirements.

[0079] In summary, the downhole real-time high-power controllable electromagnetic pulse detection method uses shock pressure to act on the reservoir, which is different from traditional static pressure reservoir reconstruction technology; the shock wave pulse width is adjustable within 0.5ms, with a high pressure peak and short duration, which will not damage the casing and cement sheath; the repetition frequency can be controlled to act on the reservoir segment; the direction of shock wave action can be selected by designing the electrode shape; and the device relies on a high-power mechanism to save energy (single well operation consumes 2 degrees of electricity).

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A controllable electromagnetic pulse detection system based on downhole real-time high power, characterized in that: include: A ground power control cabinet provides power to and controls downhole equipment via logging cables; the downhole equipment includes a downhole high-voltage DC power supply, a pulse energy storage device, and an energy converter; The downhole high-voltage DC power supply is connected to the surface power control cabinet via a logging cable and is powered and controlled by the surface power control cabinet; The pulse energy storage device is connected to the underground high-voltage DC power supply to charge and store energy; The energy converter is connected to the pulse energy storage device, and is used to receive the electrical energy transmitted by the pulse energy storage device, and convert the electrical energy into shock wave energy, and then act on the load, which is the reservoir. The shock wave energy acts on the reservoir by penetrating the casing and the perforation hole; The pulse energy storage device includes a high-energy storage capacitor C, a resistor R, a transmitting coil inductor L, and a trigger switch; one end of the high-energy storage capacitor C is connected to the downhole high-voltage DC power supply via the trigger switch, and the other end of the high-energy storage capacitor C is connected to one end of the resistor R and the energy converter respectively; the other end of the resistor R is connected in series with the transmitting coil inductor L and then connected to the trigger switch; The trigger switch includes a first contact a, a second contact b, and a switch k; the connection end of the switch k is connected to one end of the high-energy storage capacitor C, the first contact a is connected to the downhole high-voltage DC power supply, and the second contact b is connected to the transmitting coil inductor L; The controllable electromagnetic pulse detection system also includes an intelligent well excitation energy storage device; The intelligent well excitation energy storage device includes a casing, a single-core steel pipe cable and an excitation probe; The casing corresponding to the reservoir is set to a multi-layer structure, the casing located at the top layer is provided with a top packer, the casing at the bottom and the middle is provided with an interlayer packer, and each layer is separated by a packer; each layer of the casing is provided with the trigger switch, the energy converter and the excitation probe, the upper casing of the top packer is provided with the high-energy storage capacitor C, the high-energy storage capacitor C is connected to each of the trigger switches, the energy converter and the excitation probe via the single-core steel pipe cable; the single-core steel pipe cable is connected to the battery management system in the ground power control cabinet to realize power supply and control; A plurality of excitation probes are placed on each layer of the casing, and the discharge after combination is controlled by a switch circuit so that the excitation position within the layer can be adjusted; the excitation probes between layers are connected by controlling the single-core steel pipe cable to realize single-layer discharge to generate shock waves acting on a single reservoir, or multi-layer combined discharge to generate shock waves acting on multiple reservoirs at the same time.

2. The downhole real-time high-power controllable electromagnetic pulse detection system according to claim 1, characterized in that: The action direction, pulse width and frequency of the shock wave can be adjusted by a battery management system arranged in a ground power control cabinet.

3. The downhole real-time high-power controllable electromagnetic pulse detection system according to claim 2, characterized in that: The shock wave pulse width is adjustable within 0.5ms.

4. The downhole real-time high-power controllable electromagnetic pulse detection system according to claim 2, characterized in that: The direction of the shock wave is determined by adjusting the electrode shape of the high-energy storage capacitor C through the battery management system; the transmission frequency is changed by changing the width of the current pulse through the battery management system; and the frequency can be controlled by controlling the parameters of the resistor R, the transmitting coil inductance L, and the high-energy storage capacitor C.

5. A method for using the downhole real-time high-power controllable electromagnetic pulse detection system according to any one of claims 1 to 4, comprising: Pull out all pipes from the well; Run the well gauge, fill the wellbore with water, and maintain the liquid level at the wellhead during the entire operation; Send the pulse energy storage device to the perforation section of the coal seam to be treated underground; Divide the oil reservoir into multiple treatment sections; The pulse energy storage device operates repeatedly at the set operating frequency at each operating point; After the treatment is completed, the underground equipment is removed; Install the production string and complete the well according to the set requirements.

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