Look-ahead long-range electromagnetic wave detection-while-drilling instrument based on electric dipole antenna

Abstract

Disclosed in the present invention is a look-ahead long-range electromagnetic wave detection-while-drilling instrument based on an electric dipole antenna. A signal transmitting sub is used. The signal transmitting sub is equipped with three toroidal antennas, which are respectively responsible for transmitting electromagnetic wave signals in an axial direction and two horizontal directions. At least one signal receiving sub is matched with the signal transmitting sub, and each signal receiving sub comprises three magnetic dipole antenna receiving coils for capturing magnetic field signals reflected from a formation. The subs can be freely combined, and the spacing between the transmitting sub and the receiving sub is adjustable, thereby meeting different detection requirements. Each toroidal antenna is composed of an annular magnetic core and a copper wire, thereby improving the signal transmission efficiency. Compared with the prior art, the present invention can achieve detection of formations behind a drill bit, and can also achieve detection of formations ahead of the drill bit, and the maximum detection distance can reach 30 meters or more, and the detection distance for lateral formation boundaries is also significantly increased. In addition, the application of low-frequency electromagnetic waves further improves the performance of long-range detection, thereby reducing drilling risks, and facilitating an improvement to the efficiency and safety of petroleum drilling operations.

Description

Drilling Electromagnetic Wave Forward-Looking Instrument Based on Electric Dipole Antenna Technical Field

[0001] This invention relates to the field of geophysical exploration or oil drilling technology, and in particular to a forward-looking electromagnetic wave detection instrument based on an electric dipole antenna. Background Technology

[0002] In the field of oil exploration and development, drilling equipment is an indispensable tool. To improve the development efficiency of oil and gas wells, ensuring that the drill bit can drill towards oil and gas-bearing formations is particularly important. However, current technology has certain limitations in detecting formation information, especially in effectively obtaining formation information ahead of the drill bit.

[0003] Traditional azimuth-guided drilling instruments can provide information such as resistivity, wave velocity, and porosity of the formation behind the drill bit. However, this data primarily reflects the formation conditions behind the drill bit and cannot provide information about the formation in front of the drill bit. This information asymmetry limits the accuracy and safety of drilling to some extent.

[0004] Specifically, existing electromagnetic wave instruments used in drilling typically employ magnetic dipole antennas for signal detection. While these antennas can effectively detect formation information behind the drill bit, their detection principle and structure limit their ability to effectively detect formations in front of the drill bit. Therefore, during drilling, operators cannot accurately predict the formation conditions ahead, which increases the risk and uncertainty of the drilling process.

[0005] Therefore, how to effectively detect the formation information in front of the drill bit has become the technical problem to be solved by this invention. Summary of the Invention

[0006] The technical problem solved by this invention is to address the deficiencies in the prior art by providing a drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna, thereby solving the problem mentioned in the background art that traditional drilling azimuth electromagnetic wave instruments cannot detect formation information in front of the drill bit.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna, comprising:

[0009] A signal transmitting section contains three spiral antennas: an axial transmitting spiral antenna, a horizontal x-direction transmitting spiral antenna, and a horizontal y-direction transmitting spiral antenna, for transmitting electromagnetic wave signals with a frequency range from 1 kHz to 100 kHz.

[0010] At least one signal receiving section, each receiving section containing three magnetic dipole antenna receiving coils, namely an axial magnetic dipole coil, a horizontal x-direction coil, and a horizontal y-direction coil, for receiving magnetic field signals reflected from the strata;

[0011] The signal transmitting section and the signal receiving section can be freely combined, and the distance between them can be adjusted according to the formation detection needs within different detection ranges in front of the drill bit.

[0012] As a further embodiment of the present invention, the spiral antenna is composed of a circular magnetic core and copper wires wound around the magnetic core, forming an electric dipole.

[0013] As a further aspect of the present invention, a combination of one signal transmitting sub and two or more signal receiving subs is used to detect the formation resistivity, formation dip angle, and formation boundary in front of the drill bit.

[0014] As a further aspect of the invention, the distances from the forward and lateral stratigraphic boundaries are represented by the attenuation of data at different frequencies observed by antennas in corresponding directions on the two receiving sub-sections.

[0015] As a further embodiment of the present invention, the instrument is directly connected to the rear of the drill bit for detecting the formation information in front of the drill bit, and when the drill bit changes its drilling direction, the instrument changes its drilling direction accordingly.

[0016] As a further aspect of the present invention, the received observation data is processed by an inversion method to derive the parameter information of the formation, including the formation resistivity and formation boundaries.

[0017] As a further embodiment of the present invention, the spiral antenna is fixed on the drill collar, and there is no space for movement between the coil and the drill collar.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. It not only provides formation information behind the drill bit but also effectively detects formation conditions in front of the drill bit, thus providing more comprehensive and accurate data support for drilling operations. This solves the problem that current drilling-while-drilling azimuth electromagnetic wave instruments cannot detect formation boundaries in front of the drill bit. Its detection distance can reach over 30 meters, providing unprecedented forward-looking information for oil drilling operations and significantly reducing uncertainties and risks during the drilling process.

[0020] 2. Significant improvement in detection range at lateral formation boundaries. Traditional drilling azimuth electromagnetic wave instruments have a lateral formation boundary detection range of approximately 6 meters. This invention, through the independent design of the transmitting and receiving antenna sections, allows for flexible combinations of transmission and reception distances according to target detection requirements, typically employing transmission and reception distances of 10 meters or even longer, thereby further enhancing long-range detection capabilities.

[0021] 3. Flexible transmission and reception distance adjustment: In this invention, the transmitting antenna section and the receiving antenna section are independent, and their spacing can be freely combined according to the target detection requirements. This not only improves the flexibility and adaptability of the instrument, but also enables the instrument to be optimally configured according to the specific drilling environment and requirements, thereby improving detection efficiency and accuracy.

[0022] 4. Low-frequency electromagnetic waves enable long-distance detection: The electromagnetic wave frequency used in this invention is lower than that of existing technologies, which helps to achieve detection over longer distances. Low-frequency electromagnetic waves experience less attenuation during propagation in the strata, allowing them to penetrate deeper layers and thus provide richer and more accurate stratum information.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 is a schematic diagram of the spiral-wound antenna of the present invention.

[0026] Figure 2 is a schematic diagram of the structure of the transmitting section of the present invention, wherein T1 is an axial transmitting spiral antenna, T2 is a horizontal x-direction transmitting spiral antenna, and T3 is a horizontal y-direction transmitting spiral antenna.

[0027] Figure 3 is a schematic diagram of the receiving section of the present invention, wherein R1 is an axial receiving coil, R2 is a horizontal x-direction receiving coil, and R3 is a horizontal y-direction receiving coil. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please refer to Figures 1-3. In this embodiment of the invention, a drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna includes:

[0030] A signal transmitting sub-section contains three helical antennas: an axial transmitting helical antenna, a horizontal x-axis transmitting helical antenna, and a horizontal y-axis transmitting helical antenna. These antennas are used to transmit electromagnetic wave signals in a frequency range from 1 kHz to 100 kHz. The sub-section's design, with its three directional helical antennas, allows the electromagnetic waves to penetrate the formation effectively and return useful reflected signals.

[0031] At least one signal receiving section, each receiving section containing three magnetic dipole antenna receiving coils: an axial magnetic dipole coil, a horizontal x-direction coil, and a horizontal y-direction coil, for receiving magnetic field signals reflected from the strata; the receiving section is equipped with receiving coils corresponding to the transmitting antenna, which can capture magnetic field signals reflected back from different directions, providing rich information for subsequent data analysis.

[0032] The signal transmitting and receiving sections can be freely combined, and the distance between them can be adjusted according to the formation detection needs within different detection ranges in front of the drill bit. This design provides flexibility, allowing the distance between the transmitting and receiving sections to be adjusted to achieve optimal detection results based on different detection requirements.

[0033] The solenoid antenna consists of a circular magnetic core and copper wires wound around it, forming an electric dipole. The structure of the solenoid antenna includes a circular magnetic core around which copper wires are tightly wound, enabling the antenna to effectively transmit and receive electromagnetic wave signals.

[0034] A combination of one signal transmitting sub and two or more signal receiving subs is used to probe formation resistivity, dip angle, and formation boundaries in front of the drill bit. By using multiple receiving subs, formation information such as formation resistivity, dip angle, and formation boundaries can be analyzed more accurately because multiple receiving points can provide more data for comparison and analysis.

[0035] The distances to the forward and lateral formation boundaries are represented by the attenuation of data at different frequencies observed by antennas in corresponding directions on the two receiving sub-sections. By analyzing the attenuation of signals at different frequencies on the two receiving sub-sections, the distances to the formation boundaries can be estimated, which is crucial for decision-making during drilling operations.

[0036] The instrument is directly connected to the rear of the drill bit and is used to detect formation information in front of the drill bit. When the drill bit changes its drilling direction, the instrument changes its drilling direction accordingly. The instrument is designed to closely follow the drill bit, ensuring real-time acquisition of formation information in front of the drill bit. Furthermore, its directional design allows it to turn with the drill bit, always maintaining synchronization with it.

[0037] The received observation data is processed using inversion methods to derive stratigraphic parameters, including stratigraphic resistivity and boundaries. The received data requires specialized processing methods to extract useful stratigraphic information. Inversion methods are an effective data processing tool that can help us derive important parameters such as stratigraphic resistivity and boundaries.

[0038] The spiral-wound antenna is fixed to the drill collar, with no space between the coil and the collar. This design ensures the antenna's stability during drilling, avoiding signal distortion or data errors caused by vibration or movement. The tight fixation between the antenna and the drill collar makes data collection more accurate and reliable.

[0039] Example 1:

[0040] This embodiment provides a specific application of a drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna. The instrument is directly connected to the rear of the drill bit to detect formation information in front of the drill bit in real time during drilling.

[0041] The instrument's signal transmission section contains three helical antennas, responsible for transmitting electromagnetic signals in the axial, horizontal (x-axis), and horizontal (y-axis) directions, respectively. These signals range in frequency from 1 kHz to 100 kHz, ensuring effective detection at different depths. The helical antennas consist of a circular magnetic core and copper wire wound around it, forming an electric dipole; this structure enhances signal transmission and reception capabilities.

[0042] During drilling, electromagnetic waves emitted by the signal transmitting section penetrate the formation and are reflected when they encounter formations with different resistivities. These reflected signals are then captured by the magnetic dipole antenna receiving coils in the signal receiving section. Each receiving section also contains receiving coils in three directions, corresponding to the axial, horizontal x-axis, and horizontal y-axis, respectively, thus enabling comprehensive reception of reflected signals from different directions.

[0043] To accurately detect formation information ahead of the drill bit, a combination of one signal transmitting section and two signal receiving sections was used. This configuration not only improves the sensitivity of the detection but also allows for accurate calculation of the distances to the forward and lateral formation boundaries by comparing the attenuation of different frequency data observed by antennas in corresponding directions on the two receiving sections.

[0044] When the drill bit changes its drilling direction, the instrument can flexibly adjust its detection direction to ensure that it always remains consistent with the drill bit's direction. This flexibility enables the instrument to provide continuous and accurate formation information in complex drilling environments.

[0045] The received observation data is processed using inversion methods to derive detailed formation parameters, including formation resistivity and formation boundaries. This information is crucial for guiding drilling operations and improving drilling efficiency and safety.

[0046] In addition, the spiral antenna is firmly fixed to the drill collar to ensure that it will not move or be damaged during drilling, thereby ensuring the stability and reliability of the detection data.

[0047] Through the application of the above embodiments, the electromagnetic wave forward-looking detection instrument for drilling of the present invention has demonstrated great potential and practical value in the field of oil exploration and development. It can not only provide formation information ahead of the drill bit, but also guide drilling operations based on this information, improving drilling accuracy and safety. The successful implementation of this technical solution provides an effective and practical method for solving the problems raised in the background art.

[0048] Example 2:

[0049] In this embodiment, we will describe in detail the practical application of the electromagnetic remote sensing instrument for drilling proposed in this invention in oil drilling, especially how it can achieve accurate detection of formation information ahead of the drill bit through specific short section combinations and data processing methods.

[0050] First, our instrument consists of a signal transmitting section and multiple signal receiving sections. The transmitting section is equipped with three solenoid antennas (i.e., electric dipole antennas), which are responsible for transmitting electromagnetic wave signals in the axial, horizontal x-axis, and horizontal y-axis directions, respectively, with a frequency range from 1 kHz to 100 kHz. These antennas are uniquely designed, consisting of a circular magnetic core and copper wire tightly wound around the core, forming a highly efficient electric dipole structure.

[0051] Before drilling operations, a combination of one launch sub and two receiver subs may be configured based on the characteristics of the target formation. This configuration provides richer data for more accurate formation inversion. These subs are directly connected to the drill bit and maintain a fixed configuration throughout the drilling process to ensure data consistency and comparability.

[0052] During drilling, the transmitting sub continuously emits electromagnetic wave signals. These signals penetrate the formation and are reflected back when they encounter formation boundaries or changes in resistivity. The magnetic dipole antenna receiving coils in the receiving sub are responsible for capturing these reflected signals. Importantly, these coils are fixed to the drill collar, with no space between them and the collar, ensuring the stability and accuracy of the data.

[0053] When the drill bit changes its drilling direction, the instrument also flexibly adjusts its direction to ensure that it always remains consistent with the drill bit's direction of travel. This flexibility allows the instrument to provide accurate formation information in various complex drilling environments.

[0054] The received observational data is processed using advanced inversion methods. This method takes the observational data as input and, through extensive mathematical calculations, ultimately derives detailed formation parameters, including formation resistivity and formation boundaries. This information is crucial for guiding drilling operations, optimizing drilling strategies, and improving drilling efficiency and safety.

[0055] Specifically, by comparing the attenuation of different frequency data observed by antennas in corresponding directions on two receiving sections, the distances to the forward and lateral formation boundaries can be accurately calculated. This quantitative analysis method provides valuable formation information, helping us to more accurately predict and assess the drill bit's path and potential formation conditions.

[0056] In summary, the drilling electromagnetic remote sensing instrument of this invention achieves accurate detection of formation information ahead of the drill bit through a unique combination of short sections, flexible direction adjustment, and advanced inversion methods. This technical solution demonstrates enormous application potential and practical value in the field of oil exploration and development.

[0057] Example 3:

[0058] This embodiment will describe in detail the advantages of the drilling electromagnetic wave remote sounding instrument in detecting lateral formation boundaries, flexibly adjusting the transmission and reception distance, and achieving long-distance detection using low-frequency electromagnetic waves.

[0059] I. Improved detection range of lateral stratigraphic boundaries.

[0060] Traditional drilling azimuth electromagnetic wave instruments have a limited detection range of only about 6 meters for lateral formation boundaries, due to their antenna design and signal processing technology. However, this invention significantly improves this detection range through innovative design.

[0061] Specifically, the transmitting and receiving antenna sections of this invention are designed independently, allowing for flexible combinations of transmission and reception distances based on target detection requirements. In practical applications, we typically use transmission and reception distances of 10 meters or even longer for detection. This design not only increases the penetration capability of electromagnetic waves but also improves the signal-to-noise ratio, thereby further enhancing long-range detection capabilities.

[0062] To verify this, the detection performance at different transmission and reception distances was simulated in a laboratory environment. Experimental results show that when the transmission and reception distance is increased to 10 meters, the instrument can still clearly detect the existence of lateral stratigraphic boundaries, and the signal quality is significantly better than that of traditional instruments. This result fully demonstrates the effectiveness of this invention in improving the detection range of lateral stratigraphic boundaries.

[0063] 2. Flexible adjustment of transmit and receive distance.

[0064] Another significant advantage of this invention is the flexibility in transmission and reception distances. Because the transmitting and receiving antenna sections are independent, they can be optimally configured according to specific drilling environments and requirements. This flexibility allows the instrument to adapt to different drilling scenarios, thereby improving detection efficiency and accuracy.

[0065] For example, in complex drilling environments, if more detailed detection data is required, the transmit and receive distance can be appropriately reduced to improve signal resolution and sensitivity. Conversely, in scenarios requiring long-distance detection, the transmit and receive distance can be increased to achieve detection over greater distances. This flexible capability to adjust the transmit and receive distance makes this invention more widely applicable and of greater practical value in real-world applications.

[0066] III. Low-frequency electromagnetic waves enable long-distance detection.

[0067] The electromagnetic wave frequency used in this invention is lower than that of existing technologies, which is key to achieving long-distance detection. Low-frequency electromagnetic waves experience less attenuation during propagation in the strata, allowing them to penetrate deeper layers and thus provide richer and more accurate stratum information.

[0068] To verify the advantages of low-frequency electromagnetic waves in long-distance detection, a series of field tests were conducted. The test results show that when using low-frequency electromagnetic waves for detection, the signal can penetrate deeper into the earth's strata, and the attenuation rate is significantly slower than that of high-frequency electromagnetic waves. This means that using low-frequency electromagnetic waves can obtain information from more distant strata, thereby improving the depth and accuracy of detection.

[0069] In summary, this embodiment demonstrates the beneficial effects of the present invention in improving the detection range of lateral stratigraphic boundaries, flexibly adjusting the transmit and receive distances, and achieving long-distance detection using low-frequency electromagnetic waves. These advantages make the present invention more practical and applicable in real-world situations.

[0070] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0071] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna, characterized in that, Include: A signal transmitting section contains three spiral antennas: an axial transmitting spiral antenna, a horizontal x-direction transmitting spiral antenna, and a horizontal y-direction transmitting spiral antenna, for transmitting electromagnetic wave signals with a frequency range from 1 kHz to 100 kHz. At least one signal receiving section, each receiving section containing three magnetic dipole antenna receiving coils, namely an axial magnetic dipole coil, a horizontal x-direction coil, and a horizontal y-direction coil, for receiving magnetic field signals reflected from the strata; The signal transmitting section and the signal receiving section can be freely combined, and the distance between them can be adjusted according to the formation detection needs within different detection ranges in front of the drill bit.

2. The drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna according to claim 1, characterized in that, The spiral antenna consists of a circular magnetic core and copper wires wound around the magnetic core, forming an electric dipole.

3. The drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna according to claim 1, characterized in that, The formation resistivity, formation dip angle, and formation boundary in front of the drill bit are detected by using a combination of one signal transmitting sub and two or more signal receiving subs.

4. The drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna according to claim 1, characterized in that, The distances from the forward and lateral stratigraphic boundaries are represented by the attenuation of data at different frequencies observed by antennas in the corresponding directions on the two receiving sub-sections.

5. A drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna according to claim 1, characterized in that, The instrument is directly connected to the rear of the drill bit and is used to detect the formation information in front of the drill bit. When the drill bit changes its drilling direction, the instrument changes its drilling direction accordingly.

6. The drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna according to claim 1, characterized in that, The received observation data is processed by inversion methods to derive the formation parameters, including formation resistivity and formation boundaries.

7. A drilling electromagnetic wave forward-looking detection instrument based on an electric dipole antenna according to claim 1, characterized in that, The spiral antenna is fixed to the drill collar, and there is no space for movement between the coil and the drill collar.

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