A multi-parameter all-fiber well-logging system and method

Abstract

The application discloses a kind of multi-parameter all-optical fiber logging system and method, it is related to fiber-optic logging technical field, system includes optical fiber sensing group bundle and distributed optical fiber sensing demodulation system;Optical fiber sensing group bundle is used to: the measurement of multiple logging parameters in well is carried out, the optical signal corresponding to each logging parameter is obtained, and is sent to distributed optical fiber sensing demodulation system;Distributed optical fiber sensing demodulation system is used to: the optical signal corresponding to each logging parameter is demodulated, and the actual measurement data of each logging parameter is obtained.The application can realize the simultaneous acquisition of multiple parameters in wellbore by optical fiber sensing group bundle, and realizes the passive design in well, with the characteristics of multi-parameter acquisition, high sensitivity, high integration, high temperature resistance, while supporting high-speed large-capacity data transmission.

Description

Technical Field

[0001] This invention relates to the field of fiber optic logging technology, and in particular to a multi-parameter all-fiber optic logging system and method. Background Technology

[0002] Oil and gas exploration and development has entered a new stage, with increased difficulty in discovering oil and gas resources and low-grade newly discovered reserves. Developed oilfields are in a "double-high" stage of high water cut and high recovery rate, resulting in poor economic benefits. Exploration and development face key technological bottlenecks. The increased difficulty in oil and gas exploration and development has led to an extension of exploration areas into deeper / ultra-deep and complex reservoirs. New oil and gas reserves are mainly unconventional, represented by tight, low-permeability, heavy oil, and special lithological reservoirs. Breakthroughs in technologies such as ultra-deep / complex, concealed oil and gas reservoir exploration, enhanced oil recovery in old oilfields (displacement, fracturing, etc.), and unconventional oil and gas extraction have become crucial for stable production, increased reserves, and improved efficiency in oil and gas reservoirs.

[0003] As oil and gas exploration extends to deeper / ultra-deep and complex reservoirs, detailed characterization of unconventional oil and gas reservoirs has become crucial for reservoir development planning and subsequent enhanced production. In recent years, fiber optic sensing technology, sensitive to external environments, has enabled full lifecycle monitoring of the wellbore in well logging, monitoring different stages of wellbore and injection / production conditions through temperature, acoustic waves, and strain. Fiber optic logging leverages the advantages of optical fibers, such as high-temperature resistance, environmental friendliness, stable performance, long measurement distance, and long-term monitoring capabilities, and has been widely applied in well logging, demonstrating significant application potential.

[0004] Currently, the more mature distributed fiber optic logging systems include Distributed Fiber Optic Temperature Sensing System (DTS), Distributed Fiber Optic Acoustic Sensing System (DAS), and Distributed Fiber Optic Strain Sensing System (DSS). These systems have achieved certain applications in wellbore integrity, production profile monitoring, fracturing monitoring, and CCUS. However, due to limitations in construction technology, practical monitoring applications often only utilize one or two fiber optic monitoring technologies (e.g., the invention patent with publication number "CN108632516A" entitled "A Downhole Fiber Optic Imaging Camera"). This leads to multiple interpretations of formation information, often requiring various other information to constrain the interpretation model (e.g., the invention patent with publication number "CN116971761A" entitled "Design Method and System for DTS Logging Acquisition Scheme of Oil Well Based on Forward Model"). This results in interpretation lag, and the consistency between the interpretation results and actual formation information needs further improvement. These factors hinder the widespread application of distributed fiber optic logging technology. Therefore, developing a multi-parameter, highly sensitive, and highly integrated all-fiber optic logging system is crucial. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of existing technologies, specifically by providing a multi-parameter all-fiber logging system and method, as detailed below:

[0006] 1) In a first aspect, the present invention provides a multi-parameter all-fiber logging system, the specific technical solution of which is as follows:

[0007] This includes fiber optic sensing bundles and distributed fiber optic sensing demodulation systems;

[0008] The fiber optic sensing bundle is used to measure various logging parameters downhole, obtain the optical signal corresponding to each logging parameter, and send it to the distributed fiber optic sensing demodulation system.

[0009] The distributed fiber optic sensing demodulation system is used to demodulate the optical signal corresponding to each logging parameter to obtain the actual measurement data of each logging parameter.

[0010] The beneficial effects of the multi-parameter all-fiber logging system provided by this invention are as follows:

[0011] Through fiber optic sensor bundles, multiple parameters can be acquired simultaneously within the wellbore, achieving a passive design downhole. It features multi-parameter acquisition, high sensitivity, high integration, and high temperature resistance, while also supporting high-speed, high-capacity data transmission.

[0012] Based on the above scheme, the multi-parameter all-fiber logging system of the present invention can be further improved as follows.

[0013] Furthermore, it also includes fiber optic image transmission bundles and illumination fibers, and various logging parameters including: images of the target area;

[0014] Illumination optical fibers are used to: direct a light beam into a target area to illuminate the target area;

[0015] The fiber optic image bundle is used to acquire the optical signal corresponding to the image of the target area downhole.

[0016] Furthermore, it also includes a laser, with the illumination fiber specifically used to transmit the laser beam to the target area.

[0017] Furthermore, the laser is a white light laser.

[0018] Furthermore, the fiber optic sensing bundle also includes DAS sensing fiber, and various logging parameters include: acoustic and vibration information along the DAS sensing fiber.

[0019] DAS sensing fiber is used to: collect optical signals induced by acoustic waves and vibrations along the DAS sensing fiber.

[0020] Furthermore, the fiber optic sensing bundle also includes: DTS sensing fiber; and various logging parameters include: temperature information along the DTS sensing fiber.

[0021] DTS sensing fiber is used to: collect optical signals induced by temperature changes along the DTS sensing fiber.

[0022] Furthermore, the fiber optic sensing bundle also includes: DSS sensing fiber, and various logging parameters include: strain information along the DSS sensing fiber;

[0023] DSS sensing fiber is used to: acquire optical signals induced by strain along the DSS sensing fiber.

[0024] Furthermore, it also includes a ground imaging system, which is used to receive and image the actual measurement data of each logging parameter.

[0025] Furthermore, it also includes an industrial control computer, which is used to control the fiber optic sensor bundle, the distributed fiber optic sensor demodulation system, and the ground imaging system.

[0026] 2) In a second aspect, the present invention also provides a multi-parameter all-fiber logging method, employing any of the above-mentioned multi-parameter all-fiber logging systems, the method comprising:

[0027] Multiple logging parameters in the well are measured by fiber optic sensing bundles to obtain the optical signal corresponding to each logging parameter, and then sent to the distributed fiber optic sensing demodulation system.

[0028] The optical signal corresponding to each logging parameter is demodulated by a distributed optical fiber sensing demodulation system to obtain the actual measurement data of each logging parameter.

[0029] It should be noted that the beneficial effects of the technical solution of the second aspect of the present invention and the corresponding possible implementation can be found in the above description of the technical effects of the first aspect and its corresponding possible implementation, and will not be repeated here. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below:

[0031] Figure 1 This is one of the structural schematic diagrams of a multi-parameter all-fiber logging system according to an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the cross-section of an optical fiber sensing bundle;

[0033] Figure 3 This is a second schematic diagram of the structure of a multi-parameter all-fiber logging system according to an embodiment of the present invention;

[0034] Figure 4 This is one of the flowcharts of a multi-parameter all-fiber logging method according to an embodiment of the present invention;

[0035] Figure 5 This is a second schematic flowchart of a multi-parameter all-fiber logging method according to an embodiment of the present invention. Detailed Implementation

[0036] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0037] The technical solution of the present invention and how the technical solution of the present invention solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0038] like Figure 1 and Figure 3 As shown, an embodiment of the present invention provides a multi-parameter all-fiber logging system, which includes a fiber optic sensor bundle and a distributed fiber optic sensor demodulation system.

[0039] The fiber optic sensing bundle is used to measure various logging parameters downhole, obtain the optical signal corresponding to each logging parameter, and send it to the distributed fiber optic sensing demodulation system.

[0040] The fiber optic sensing bundles need to be armored, have a certain degree of flexibility, and at the same time meet the tensile requirements during construction.

[0041] The distributed fiber optic sensing demodulation system is used to demodulate the optical signal corresponding to each logging parameter to obtain the actual measurement data of each logging parameter.

[0042] Optionally, the above technical solution also includes an optical fiber image transmission bundle and an illumination optical fiber.

[0043] Multiple logging parameters include: images of the target area;

[0044] Illumination optical fibers are used to: direct a light beam into a target area to illuminate the target area;

[0045] The lighting fiber includes multiple high-temperature resistant lighting fibers, which can be combined and deployed to meet the full-range lighting needs of the target area.

[0046] The fiber optic image bundle is used to acquire the optical signal corresponding to the image of the target area downhole.

[0047] The fiber optic image bundle is composed of a specific number of high-temperature resistant optical fibers, ranging from several thousand to hundreds of thousands, which can be set according to the actual situation. The specific number of high-temperature resistant optical fibers are bundled in a specific way, which can be set according to the actual situation to obtain a larger fill ratio. One high-temperature resistant optical fiber is one pixel, realizing high-resolution imaging of the target area downhole. For example, 200,000 2,000-meter quartz optical fibers are prepared into a fiber optic image bundle by acid dissolution or stacking in a hexagonal close-packed manner.

[0048] Optionally, the above technical solution also includes a laser, and the illumination fiber is specifically used to transmit the beam emitted by the laser to the target area.

[0049] Optionally, in the above technical solution, the laser is a white light laser.

[0050] The brightness of the white light beam in the target area can be set according to the actual situation (specifically by adjusting the lumens of the white light) to achieve high-resolution imaging of different target areas downhole.

[0051] Optionally, in the above technical solution, the fiber optic sensing bundle also includes DAS sensing fiber, and various logging parameters include: acoustic wave and vibration information along the DAS sensing fiber.

[0052] DAS sensing fiber is an acoustic wave sensing fiber. It can be a regular single-mode fiber, a single-mode fiber with an etched grating, a scattering-enhanced fiber, or a microstructured single-mode fiber. The number of acoustic wave sensing fibers can be set according to the actual situation.

[0053] DAS sensing fiber is used to: collect optical signals induced by acoustic waves and vibrations along the DAS sensing fiber.

[0054] Optionally, in the above technical solution, the fiber optic sensing bundle also includes: DTS sensing fiber; and various logging parameters include: temperature information along the DTS sensing fiber.

[0055] DTS sensing fiber is a temperature sensing fiber, which can be a regular multimode fiber, an etched grating multimode fiber, a scattering-enhanced fiber, or a microstructured multimode fiber. The number of temperature sensing fibers can be set according to the actual situation.

[0056] DTS sensing fiber optic cable is used to collect the optical signal corresponding to the temperature within a target area.

[0057] Optionally, in the above technical solution, the fiber optic sensing bundle also includes: DSS sensing fiber, and various logging parameters include: strain information along the DSS sensing fiber.

[0058] DSS sensing fiber is a strain sensing fiber, which can be ordinary fiber, fiber with etched gratings, fiber with scattering enhancement, or microstructure fiber. The number of strain sensing fibers can be set according to the actual situation.

[0059] DSS sensing fiber is used to: acquire optical signals induced by strain along the DSS sensing fiber.

[0060] Optionally, when the DTS sensing fiber, DSS sensing fiber, and DAS sensing fiber can return optical signals to the distributed optical fiber sensing demodulation system through the same communication fiber, the DTS sensing fiber, DSS sensing fiber, DAS sensing fiber, and the communication fiber can be connected by fusion splicing or by patch cord plugging and unplugging.

[0061] Optionally, multiple fiber optic fusion splicing areas are determined, and a target laser of preset intensity is applied to the fiber optic fusion splicing areas using a laser. The preset intensity and the frequency of the target laser can be set according to the actual situation. The returned optical signal from the fiber optic fusion splicing area is collected, and the spectrum of the optical signal is converted into a spectral image. Multiple peaks, including the maximum peak, are marked at equal intervals in the spectral image. The equal interval can be understood as sampling points with equal intervals. Thus, multiple marked spectral images are obtained. A preset neural network model is trained using the multiple marked spectral images to obtain a trained preset neural network model. The trained preset neural network model is used to identify the maximum peak and multiple equally spaced peaks, including the maximum peak.

[0062] When different levels of fiber optic sensing units are connected by fiber optic fusion splicing, a target laser of preset intensity is applied to any actual fiber optic fusion splice area (the actual fiber optic fusion splice area refers to the fiber optic fusion splice area obtained when connecting DTS sensing fiber, DSS sensing fiber, DAS sensing fiber, and communication fiber by fiber optic fusion splicing in this invention; the number of actual fiber optic fusion splice areas can be multiple) by a laser. The returned optical signal from the actual fiber optic fusion splice area is collected, and the spectrum of the optical signal is converted into a spectrum diagram. A pre-trained preset neural network model is used to identify the maximum peak value corresponding to the actual fiber optic fusion splice area and multiple equally spaced peak values, including the maximum peak value. The deviation between the maximum peak value corresponding to the actual fiber optic fusion splice area and the standard maximum peak value is calculated, as well as the deviation between the corresponding peak value corresponding to the actual fiber optic fusion splice area and the standard peak value. It is determined whether the proportion exceeding the preset deviation threshold exceeds the preset proportion threshold. If so, the fiber optic fusion splice is deemed unqualified; otherwise, it is deemed qualified.

[0063] in, Figure 2The diagram shows a cross-section of an optical fiber sensing bundle. The central component is an optical fiber imaging bundle composed of a specific number of high-temperature resistant optical fibers. Surrounding this bundle are illumination fibers, within which are embedded steel tubes. These steel tubes contain six optical fibers: two DAS sensing fibers, two DTS sensing fibers, and two DSS sensing fibers. In another embodiment, 12 illumination fibers are evenly distributed around the outer ring of the optical fiber imaging bundle, housed within a stainless steel tube. This stainless steel tube contains two DAS sensing fibers, two DTS sensing fibers, and two DSS sensing fibers. The tube is then sheathed and armored to provide tensile strength and flexibility. It should be noted that the arrangement of the optical fiber sensing bundle can be customized according to specific requirements.

[0064] Optionally, the above technical solution also includes a ground imaging system, which is used to receive and image the actual measurement data of each logging parameter.

[0065] Optionally, the DAS sensing fiber, DTS sensing fiber, and DSS sensing fiber in the fiber optic sensing bundle are connected to a distributed fiber optic sensing demodulation system, and the illumination fiber is connected to a white light laser.

[0066] Optionally, the above technical solution also includes an industrial control computer, which is used to control the fiber optic sensor bundle, the distributed fiber optic sensor demodulation system, and the ground imaging system, specifically:

[0067] 1) The industrial control computer controls whether the white laser emits white light and controls the lumens of the emitted white light.

[0068] 2) The industrial control computer controls whether the distributed optical fiber sensing demodulation system demodulates the optical signal corresponding to each logging parameter.

[0069] 3) The industrial control computer sends instructions to the distributed optical fiber sensing demodulation system, enabling the system to control the optical fiber image bundle, DAS sensing fiber, DTS sensing fiber, and DSS sensing fiber in the optical fiber sensing bundle to acquire optical signals corresponding to the well logging parameters. It should be noted that the optical fiber image bundle, DAS sensing fiber, DTS sensing fiber, and DSS sensing fiber are all passive and can respond to the corresponding well logging parameters in real time, obtaining the optical signal corresponding to each well logging parameter. In real time, the distributed optical fiber sensing demodulation system can acquire and analyze the corresponding optical signals as needed. Therefore, the industrial control computer can control the measurement frequency of the optical fiber image bundle, DAS sensing fiber, DTS sensing fiber, and DSS sensing fiber to obtain the optical signal corresponding to each well logging parameter.

[0070] In another embodiment, such as Figure 3As shown, the multi-parameter all-fiber logging system of the present invention includes: an industrial control computer, a white light laser, a fiber optic sensing bundle, and a distributed fiber optic sensing demodulation system. The fiber optic sensing bundle includes a fiber optic image transmission bundle, an illumination fiber, a DAS sensing fiber, a DTS sensing fiber, and a DTS sensing fiber. The industrial control computer controls the white light laser to emit white light, which is transmitted to the target area downhole via the illumination fiber to meet the illumination requirements of the target area downhole. The fiber optic image transmission bundle acquires images of the target area downhole and transmits them to the surface imaging system to achieve high-resolution imaging of the target area downhole. The optical signals induced by acoustic waves and vibration along the DAS sensing fiber, the optical signals induced by temperature along the DTS sensing fiber, and the optical signals induced by strain along the DTS sensing fiber are acquired by the DTS sensing fiber and transmitted via their own sensing fibers to the distributed fiber optic sensing demodulation system to acquire multiple parameters such as downhole acoustic waves, temperature, strain, and images.

[0071] The beneficial effects of this invention are as follows:

[0072] High-brightness imaging of the target area in the wellbore is achieved through illumination optical fiber; a three-dimensional image of the entire wellbore is acquired through high-resolution optical fiber image transmission, enabling "seeing far"; acoustic information of the entire wellbore is acquired through DAS sensing technology, enabling "hearing clearly"; temperature and strain information of the entire wellbore is acquired through DTS and DSS sensing technologies, enabling "touching"; by organically combining illumination optical fiber, optical fiber image transmission bundle, DAS sensing optical fiber, DTS sensing optical fiber, and DSS sensing optical fiber, multiple parameters such as wellbore image, temperature, acoustic wave, and strain are acquired simultaneously, achieving a passive design for downhole operation. It features multi-parameter acquisition, high sensitivity, high integration, and high temperature resistance, while also supporting high-speed and high-capacity data transmission.

[0073] like Figure 4 As shown, an embodiment of the present invention provides a multi-parameter all-fiber logging method, employing any of the aforementioned multi-parameter all-fiber logging systems. The method includes:

[0074] S1. Measure various logging parameters downhole through fiber optic sensing bundles, obtain the optical signal corresponding to each logging parameter, and send it to the distributed fiber optic sensing demodulation system.

[0075] S2. The optical signal corresponding to each logging parameter is demodulated by a distributed optical fiber sensing demodulation system to obtain the actual measurement data of each logging parameter.

[0076] In another embodiment, such as Figure 5 As shown, a multi-parameter all-fiber logging method of the present invention includes the following steps:

[0077] S11. Turn on the industrial control computer, distributed fiber optic sensing demodulation system, white light laser, and ground imaging system in sequence, and check on the ground whether the industrial control computer, fiber optic sensing demodulation system, white light laser, fiber optic image bundle, ground imaging system, and fiber optic sensing bundle are working properly.

[0078] S12. Use a winch to lower the fiber optic sensor bundle to the target area in the well. The target area can be set according to the actual situation.

[0079] S13. Turn on the white light laser. The white light generated is transmitted to the target area in the well through the illumination fiber to achieve downhole illumination.

[0080] S14. The ground imaging system acquires images and videos of the target area downhole to achieve high-resolution downhole imaging.

[0081] S15. Turn on the distributed optical fiber sensing demodulation system, collect and demodulate the optical signals induced by sound waves and vibration along the DAS sensing fiber, the optical signals induced by temperature along the DTS sensing fiber, and the optical signals induced by strain along the DSS sensing fiber, to obtain the sound wave and vibration information along the DAS sensing fiber, the temperature information along the DTS sensing fiber, and the strain information along the DSS sensing fiber.

[0082] S16. Display and save the acoustic waves and vibrations along the DAS sensing fiber, the temperature along the DTS sensing fiber, the strain along the DSS sensing fiber, and the images and videos of the target area on the imaging system to achieve multi-parameter, high-sensitivity, and highly integrated all-fiber logging in downhole.

[0083] It should be noted that the beneficial effects of the multi-parameter all-fiber logging method provided in the above embodiments are the same as the beneficial effects of the multi-parameter all-fiber logging system described above, and will not be repeated here. In addition, the method and system embodiments provided in the above embodiments belong to the same concept, and their specific implementation process can be found in the method embodiments, which will not be repeated here.

[0084] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this invention is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this invention.

[0085] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and represent a limitation on a specific order or sequence. Where appropriate, the order of use for similar objects can be interchanged so that the embodiments of this application described herein can be implemented in an order other than that shown or described.

[0086] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A multi-parameter all-fiber optic logging system, characterized in that, This includes fiber optic sensing bundles and distributed fiber optic sensing demodulation systems; The fiber optic sensing bundle is used to measure various logging parameters downhole, obtain the optical signal corresponding to each logging parameter, and send it to the distributed fiber optic sensing demodulation system. The distributed optical fiber sensing demodulation system is used to demodulate the optical signal corresponding to each logging parameter to obtain the actual measurement data of each logging parameter.

2. The multi-parameter all-fiber logging system according to claim 1, characterized in that, It also includes fiber optic image transmission bundles and illumination fibers, and various logging parameters including: images of the target area; The illumination fiber is used to: guide a light beam into the target area to illuminate the target area; The optical fiber image bundle is used to acquire the optical signal corresponding to the image of the target area downhole.

3. The multi-parameter all-fiber logging system according to claim 2, characterized in that, It also includes a laser, and the illumination fiber is specifically used to transmit the beam emitted by the laser to the target area.

4. The multi-parameter all-fiber logging system according to claim 3, characterized in that, The laser is a white light laser.

5. The multi-parameter all-fiber logging system according to claim 1, characterized in that, The fiber optic sensing bundle also includes a DAS sensing fiber, and various logging parameters include: acoustic wave and vibration information along the DAS sensing fiber. The DAS sensing fiber is used to: collect the optical signals induced by acoustic waves and vibrations along the DAS sensing fiber.

6. The multi-parameter all-fiber logging system according to claim 1, characterized in that, The fiber optic sensing bundle also includes: DTS sensing fiber; multiple logging parameters include: temperature information along the DTS sensing fiber; The DTS sensing fiber is used to: collect the optical signal induced by temperature changes along the DTS sensing fiber.

7. The multi-parameter all-fiber logging system according to claim 1, characterized in that, The fiber optic sensing bundle also includes: DSS sensing fiber, and various logging parameters include: strain information along the DSS sensing fiber; The DSS sensing fiber is used to: acquire the optical signal induced by strain along the DSS sensing fiber.

8. The multi-parameter all-fiber logging system according to claim 1, characterized in that, It also includes a ground imaging system, which is used to receive and image actual measurement data for each logging parameter.

9. A multi-parameter all-fiber logging system according to claim 8, characterized in that, It also includes an industrial control computer, which is used to control the fiber optic sensing bundle, the distributed fiber optic sensing demodulation system, and the ground imaging system.

10. A multi-parameter all-fiber logging method, characterized in that, The method of using a multi-parameter all-fiber logging system according to any one of claims 1 to 9 includes: Multiple logging parameters in the well are measured by fiber optic sensing bundles to obtain the optical signal corresponding to each logging parameter, and then sent to the distributed fiber optic sensing demodulation system. The optical signal corresponding to each logging parameter is demodulated by a distributed optical fiber sensing demodulation system to obtain the actual measurement data of each logging parameter.

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