CN116696334A - Stratum interface remote detection system and method - Google Patents
Stratum interface remote detection system and method Download PDFInfo
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- CN116696334A CN116696334A CN202210191669.8A CN202210191669A CN116696334A CN 116696334 A CN116696334 A CN 116696334A CN 202210191669 A CN202210191669 A CN 202210191669A CN 116696334 A CN116696334 A CN 116696334A
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/02—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with propagation of electric current
- G01V3/06—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with propagation of electric current using ac
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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Abstract
The application discloses a stratum interface remote detection system, which is characterized by comprising the following components: a transmitting device for continuously transmitting a probe current to the formation during while drilling; the receiving device is positioned between the transmitting device and the drill bit and is arranged outside the drill rod, and is used for measuring electromotive force parameters of a plurality of directions; the signal processing device is used for integrating electromotive force parameters of a plurality of directions to form corresponding stratum interface boundary information; and the boundary generation device is used for obtaining the complete boundary distribution characteristics of the current stratum interface according to the stratum interface boundary information generated by the receiving device in real time. The application realizes the remote detection of the boundary of the stratum interface under the conditions of shorter source distance and non-rotation, and effectively improves the stratum description precision of the front, the back and the side of the underground drilling tool.
Description
Technical Field
The application belongs to the field of petroleum exploration and development, and particularly relates to a stratum interface remote detection system and method.
Background
While-drilling geosteering technology is an important means for oil and gas reservoir exploration and development, and is critical to achieving accurate targeting of a target layer, avoiding drilling risks in real time, and obtaining maximized oil and gas productivity of a horizontal well. The key point of the while-drilling geosteering technology is that whether logging forward vision can be realized or not, and a stratum interface or an abnormal body can be found in time. In the process of implementing the application, the inventor finds that the electromagnetic wave-front-view logging instrument related to the prior art usually has the detection range of tens of meters by means of multi-component magnetic field signal combination and modularized structural design. However, the prior art also has the following problems: (1) The source distance between the transmitting antenna and the receiving antenna of the forward-looking logging instrument is too long, so that certain difficulty exists in signal synchronization between different pup joints; (2) The scattered signal of the measured magnetic field caused by the front stratum interface is weak and the signal to noise ratio is low.
Currently, forward looking remote detection is mainly based on tilted or orthogonally closed transmit and receive antennas, the essence of which is to measure the magnetic field component excited by a magnetic dipole source. The remote detection instrument designed based on the forward-looking remote detection principle has the problems of weak measurement signals, overlong source distance, poor azimuth sensitivity and the like. In addition, some remote detecting instruments use semicircular antennas (open loop half coils) as transmitting antennas, response information corresponding to the method is easy to be influenced by environment, and the obtained measuring effect is poor. Meanwhile, the magnetic field information is related to the measurement result obtained by using the semicircular antenna, and the information is required to be extracted depending on the rotation direction of the instrument.
Therefore, how to adopt a shorter instrument size (less than 5 m) to realize the remote detection of geological anomalies in front of the drill bit (more than 15 m) is a necessary requirement for the development of logging while drilling, and is a key problem to be solved urgently at present. At the same time, solving this problem is of great importance for widening the geosteering field of view.
Disclosure of Invention
In order to solve the above problems, an embodiment of the present application provides a far detection system for a formation interface, including:
a transmitting device for continuously transmitting a probe current to the formation during while drilling; the receiving device is positioned between the transmitting device and the drill bit and is arranged outside the drill rod, and is used for measuring electromotive force parameters of a plurality of directions; the signal processing device is used for integrating the electromotive force parameters of the plurality of directions to form corresponding stratum interface boundary information; and the boundary generation device is used for obtaining the complete boundary distribution characteristics of the current stratum interface according to the stratum interface boundary information generated by the receiving device in real time.
Preferably, the receiving device includes: a measurement module, wherein the measurement module comprises: an axially closed measuring antenna which surrounds the outside of the drill rod in a direction perpendicular to the axis of the drill rod and is used for measuring a first electromotive force of the longitudinal position of the receiving device; and a plurality of electromagnetic sensors mounted on the axial closing measuring antenna for measuring a second electromotive force of a plurality of circumferential orientations of the receiving device.
Preferably, the plurality of electromagnetic sensors are disposed at intervals of 90 ° in the circumferential direction.
Preferably, the signal processing means is further configured to calculate potential differences between two pairs of sensors having symmetrical positional relationships, respectively, and obtain an intermediate electromotive force representing the electromotive force of the receiving means by using the following expression, thereby generating the formation interface boundary information in accordance with the intermediate electromotive force in combination with the first electromotive force:
Ve＝sqrt(△V 1 2 +△V 2 2 )
wherein Ve represents an intermediate electromotive force, deltaV 1 And DeltaV 2 Respectively two sets of potential differences, sqrt represents a square root sign.
Preferably, the signal processing device is further configured to combine the first electromotive force with the intermediate electromotive force by using the following expression, thereby obtaining an amplitude variation relationship feature between the first electromotive force and the intermediate electromotive force, and then obtain the formation interface boundary information according to the amplitude variation relationship feature:
Att＝abs(Ve/Vh)
where Att represents an amplitude ratio, vh represents a first electromotive force, and abs represents an absolute value sign.
Preferably, the signal processing device further adopts a fast forward inversion algorithm to carry out pixelation processing on the amplitude variation relation, so that the amplitude variation relation is converted into the stratum interface boundary information.
Preferably, the system further comprises: and the excitation device is used for providing a time harmonic current required for emission for the emission device.
Preferably, the system is further configured with a number of transmitting means and a number of receiving means.
Preferably, the system further comprises: and the resistivity measurement module is used for measuring the formation apparent resistivity of the drilling tool at the real-time arrival position.
In addition, the application provides a stratum interface remote detection method, which utilizes the system to realize remote detection of the stratum interface, and comprises the following steps: continuously transmitting a detection current to the stratum in the drilling process; measuring electromotive force parameters of a plurality of directions by using a receiving device arranged between the transmitting device and the drill bit; integrating the electromotive force parameters of the plurality of directions to form corresponding stratum interface boundary information; and obtaining the complete boundary distribution characteristics of the current stratum interface according to the stratum interface boundary information generated by the receiving device in real time.
One or more embodiments of the above-described solution may have the following advantages or benefits compared to the prior art:
the application provides a stratum interface remote detection system and a stratum interface remote detection method. The system comprises a transmitting device, a receiving device, a signal processing device and a boundary generating device. Firstly, arranging a transmitting device and a receiving device on the outer side of a drill rod, then continuously transmitting detection current to a stratum in the while-drilling process, measuring electromotive force parameters of a plurality of directions in real time by the receiving device, integrating the electromotive force parameters of the plurality of directions measured by the receiving device by a signal processing device to form corresponding stratum interface boundary information, and finally collecting the stratum interface boundary information generated by the receiving device in real time by a boundary generating device to generate complete boundary distribution characteristics of a current stratum interface. The application solves the contradiction between the detection depth and the source distance (the distance between each transmitting device and each receiving device) of the existing detecting instrument, realizes the purpose of carrying out stratum interface remote detection under the conditions of shorter source distance and non-rotation, effectively improves the stratum description precision of the front, the back and the side of the underground drilling tool, and improves the oil and gas exploration and development benefits.
Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application. The objectives and other advantages of the application will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification, illustrate the application and together with the embodiments of the application, serve to explain the application, without limitation to the application. In the drawings:
FIG. 1 is a schematic diagram of the overall structure of a far-formation-interface detection system according to an embodiment of the present application.
FIG. 2 is a schematic diagram of a specific structure of a far-formation-interface detection system according to an embodiment of the present application.
FIG. 3 is a schematic diagram of a single-interface computational model in a far-formation-interface detection system according to an embodiment of the present application.
FIG. 4 is a schematic diagram of a change in rotational orientation of two sets of potential differences based on four orientations in a far formation interface detection system in accordance with an embodiment of the present application.
FIG. 5 is an exemplary graph of electromotive force parameters of a far detection system for formation interface as a function of measurement depth according to an embodiment of the present application.
FIG. 6 is an exemplary plot of amplitude ratio versus depth of measurement for a far formation interface detection system in accordance with an embodiment of the present application.
FIG. 7 is a schematic diagram of a trend of a maximum edge detection distance under different conditions in a far detection system for a formation interface according to an embodiment of the present application.
FIG. 8 is a diagram of one example of an arrayed transmitting and receiving device in a far-formation-interface detection system according to an embodiment of the present application.
FIG. 9 is a view of a formation window covering of a far-formation-interface detection system according to an embodiment of the present application.
FIG. 10 is a step diagram of a method of remotely detecting a formation interface in accordance with an embodiment of the present application.
Detailed Description
The following will describe embodiments of the present application in detail with reference to the drawings and examples, thereby solving the technical problems by applying technical means to the present application, and realizing the technical effects can be fully understood and implemented accordingly. It should be noted that, as long as no conflict is formed, each embodiment of the present application and each feature of each embodiment may be combined with each other, and the formed technical solutions are all within the protection scope of the present application.
Additionally, the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer executable instructions, and although a logical order is illustrated in the flowcharts, in some cases the steps illustrated or described may be performed in an order other than that herein.
While-drilling geosteering technology is an important means for oil and gas reservoir exploration and development, and is critical to achieving accurate targeting of a target layer, avoiding drilling risks in real time, and obtaining maximized oil and gas productivity of a horizontal well. The key point of the while-drilling geosteering technology is that whether logging forward vision can be realized or not, and a stratum interface or an abnormal body can be found in time. In the process of implementing the application, the inventor finds that the electromagnetic wave-front-view logging instrument related to the prior art usually has the detection range of tens of meters by means of multi-component magnetic field signal combination and modularized structural design. However, the prior art also has the following problems: (1) The source distance between the transmitting antenna and the receiving antenna of the forward-looking logging instrument is too long, so that certain difficulty exists in signal synchronization between different pup joints; (2) The scattered signal of the measured magnetic field caused by the front stratum interface is weak and the signal to noise ratio is low.
Currently, forward looking remote detection is mainly based on tilted or orthogonally closed transmit and receive antennas, the essence of which is to measure the magnetic field component excited by a magnetic dipole source. The remote detection instrument designed based on the forward-looking remote detection principle has the problems of weak measurement signals, overlong source distance, poor azimuth sensitivity and the like. In addition, some remote detecting instruments use semicircular antennas (open loop half coils) as transmitting antennas, response information corresponding to the method is easy to be influenced by environment, and the obtained measuring effect is poor. Meanwhile, the magnetic field information is related to the measurement result obtained by using the semicircular antenna, and the information is required to be extracted depending on the rotation direction of the instrument.
Therefore, how to adopt a shorter instrument size (less than 5 m) to realize the remote detection of geological anomalies in front of the drill bit (more than 15 m) is a necessary requirement for the development of logging while drilling, and is a key problem to be solved urgently at present. At the same time, solving this problem is of great importance for widening the geosteering field of view.
In order to solve the above problems, the present application provides a system and a method for detecting a formation boundary, the system includes a transmitting device, a receiving device, a signal processing device, and a boundary generating device. The transmitting device continuously transmits a probe current to the formation during while-drilling, thereby creating a varying potential field in the current formation. The receiving device is arranged between the transmitting device and the drill bit and is arranged outside the drill rod and used for measuring electromotive force parameters of a plurality of directions. The signal processing device integrates the electromotive force parameters measured by the receiving device to form corresponding stratum interface boundary information (stratum layering interface information). And finally, summarizing the stratum interface boundary information generated in real time by the receiving device by the boundary generating device to generate the complete boundary distribution characteristics of the current stratum interface.
The application solves the contradiction between the detection depth and the source distance (the distance between each transmitting device and each receiving device) of the existing detecting instrument, realizes the purpose of remotely detecting the stratum interface under the condition of shorter source distance and non-rotation, effectively improves the stratum description precision of the front, the back and the side of the underground drilling tool, and improves the oil and gas exploration and development benefits.
Example 1
FIG. 1 is a schematic diagram of the overall structure of a far-formation-interface detection system according to an embodiment of the present application. FIG. 2 is a schematic diagram of a specific structure of a far-formation-interface detection system according to an embodiment of the present application. The formation interface remote detection system according to the present application is described in detail below with reference to fig. 1 and 2.
As depicted in fig. 1, the formation interface remote detection system comprises at least: transmitting means 11, receiving means 12, signal processing means 13 and boundary generating means 14. The transmitting means 11 is used to continuously transmit a probe current to the formation during the while drilling process. The receiving means 12 are located between the transmitting means 11 and the drill bit and mounted outside the drill rod. The receiving device 12 is used to measure electromotive force parameters for a plurality of orientations. The signal processing device 13 is configured to integrate electromotive force parameters of a plurality of directions measured by the receiving device 12 to form corresponding formation boundary information. The boundary generation device 14 is configured to obtain a complete boundary distribution characteristic of the current formation boundary according to the formation boundary information generated by the receiving device 12 in real time.
In the measurement while drilling process, the transmitting device 11 and the receiving device 12 of the far detection system of the stratum interface are arranged at the drill rod close to the drill bit, so that the combination of the transmitting device 11 and the receiving device 12 forms a probe of the far detection system of the stratum interface in the embodiment of the application.
The structure and function of the far-reaching detection system for a formation interface according to the embodiments of the present application are described in detail below.
As shown in fig. 2, in the embodiment of the present application, the transmitting device 11 and the receiving device 12 are both disposed outside the drill pipe. The receiving means 12 is located between the transmitting means 11 and the drill bit. Referring to fig. 2, the drill bit is located on the right side of the drill pipe (not shown). The transmitting means 11 mainly comprise a transmitting coil. The transmitter coil is used to excite current into the formation. The receiving means 12 mainly comprise a receiving coil. The receiving coil is used for measuring the current returned by the stratum after the exciting current enters the stratum, so that the resistivity information of the stratum at a certain distance from the drill bit is obtained according to the returned current.
In the embodiment of the application, the excitation device is used for providing the time harmonic current required for emission for the emission device 11. Firstly, a current excitation source is utilized to emit low-frequency alternating current, and the current is injected into a downhole metal sleeve, so that a conductive metal sleeve is obtained. Thereafter, the conductive metal sleeve is used as a quasi-steady state excitation source. Further, the present quasi-steady state excitation source is used as the excitation device of the present application to provide the time-harmonic current required for emission to the emission device 11, so that the excitation position of the excitation device in the present formation is near the downhole electrical anomaly (formation interface). Wherein the formation interface is characterized by a high conductivity as compared to the non-formation interface region of the current formation.
In addition, the method and the device for detecting the electromagnetic signals of the metal sleeve have the characteristics of high conductivity of the stratum interface, and the stratum interface area is preliminarily determined according to the characteristics of the stratum interface, so that the ground multi-component electromagnetic receivers distributed in an array mode are arranged right above the stratum interface area, and the influence rule of the metal sleeve on the electromagnetic signals of different components is analyzed by utilizing the electromagnetic signals generated by the exciting device received by the multi-component electromagnetic receivers, so that the influence of the metal sleeve on the electromagnetic signals generated by the exciting device is eliminated, and then accurate electromagnetic signals are obtained. It should be noted that, the embodiment of the present application does not specifically limit the intensity of the harmonic current, and a person skilled in the art may set various parameters of the excitation device according to actual needs, so as to obtain the actually required current intensity.
Further, the transmitting means 11 is used for continuously transmitting a detection current to the formation during the while drilling process. Specifically, a closed multi-turn coil is used as the transmitting coil of the transmitting device 11, wherein the closed multi-turn coil surrounds the outside of the drill rod in a direction perpendicular to the axis of the drill rod (refer to fig. 2). During measurement while drilling, the closed multi-turn coil continuously emits a time-harmonic current (probe current) provided by the excitation device to the formation, thereby creating a varying potential field in the current formation. In an embodiment of the application, the transmitting means 11 is preferably a closed axial magnetic source antenna comprising a closed coil. It should be noted that, in the embodiment of the present application, the number of turns of the closed coil in the transmitting device 11 and the orientation of the closed axial magnetic source antenna are not particularly limited, and may be set by those skilled in the art according to actual needs.
Next, the receiving device 12 is used to measure electromotive forces in a plurality of directions. The receiving device 12 moves with the movement of the drill pipe during measurement while drilling and measures electromotive force parameters of a plurality of directions around itself in real time during the movement.
Further, the receiving means 12 comprise a measuring module. The measurement module includes: the measuring antenna and the plurality of electromagnetic sensors are axially closed. The axial closing measuring antenna surrounds the outside of the drill rod in a direction perpendicular to the axis of the drill rod and is used for measuring a first electromotive force at the longitudinal position of the receiving device. The electromagnetic sensors are uniformly arranged on the axial closed measuring antenna. The plurality of electromagnetic sensors are for measuring a second electromotive force of the plurality of circumferential orientations. In the embodiment of the present application, the receiving coil of the receiving device 12 adopts an axial closed measuring antenna, and the direction of the axial closed measuring antenna perpendicular to the axis of the drill rod surrounds the outside of the drill rod, namely: the axially closed measuring antenna is parallel to the closed multi-turn coil in the transmitting means 11. Wherein the axially closed measuring antenna is used for measuring a first electromotive force of the longitudinal position of the receiving device 12, namely an electromotive force V of the receiving coil h . One end of each electromagnetic sensor is fixedly connected with the drill rod, the other end of each electromagnetic sensor penetrates out of the outer side of the axial closed measuring antenna, and one end of each electromagnetic sensor, which is positioned on the outer side of the axial closed measuring antenna, is provided with a corresponding measuring electrode. The electromagnetic sensor converts the potential intensity information to generate corresponding electromotive force parameters, so that second electromotive forces of a plurality of circumferential directions are obtained. In an embodiment of the present application, the receiving device 12 has a glass fiber reinforced plastic housing, and the axially closed measuring antenna and the plurality of electrical measuring sensors are all located in the glass fiber reinforced plastic housing.
In the receiving device 12, a plurality of electromagnetic sensors are provided at intervals of 90 ° in the drill pipe circumferential direction. As shown in fig. 2, the plurality of electromagnetic sensors are distributed in such a manner as to be mutually orthogonal in the circumferential direction, and each electromagnetic sensor is located at a position of 0 degrees, 90 degrees, 180 degrees, and 270 degrees in the circumferential direction, respectively. In the embodiment of the application, the second electromotive forces corresponding to the circumferential directions of 0 degree, 90 degrees, 180 degrees and 270 degrees are respectively denoted as V 1 、V 2 、V 3 And V 4 。
Further, the signal processing device 13 is configured to integrate electromotive force parameters of a plurality of directions to form corresponding boundary information of the formation interface. Specifically, the signal processing device 13 firstly obtains the first electromotive force measured by the axial closed measuring antenna of the receiving device 12 and the second electromotive force measured by the plurality of electromagnetic sensors, then processes the second electromotive force measured by the plurality of electromagnetic sensors, and finally integrates the second electromotive force processing result with the first electromotive force to obtain an integration result capable of extracting the azimuth information and the distance information of the formation interface boundary from the second electromotive force processing result, and further forms corresponding formation interface boundary information according to the extracted azimuth information and the distance information.
Next, the signal processing device 13 is also configured to calculate potential differences between two pairs of sensors having a symmetrical positional relationship, respectively, to obtain an intermediate electromotive force representing the electromotive force of the reception device 12, thereby generating formation boundary information from the intermediate electromotive force in combination with the first electromotive force. Specifically, according to the rule of axial symmetry, a plurality of pairs of electromagnetic sensors symmetrical about the axis of the drill are determined, and potential information corresponding to each pair of electromagnetic sensors is divided into a group, and the signal processing device 13 recognizes the potential signal corresponding to each electromagnetic sensor, and calculates a potential difference corresponding to each group of potential information. After that, the signal processing device 13 integrates the potential differences corresponding to each set of potential information to obtain an intermediate electromotive force representing the electromotive force of the reception device 12. Finally, the signal processing device 13 combines the intermediate electromotive force and the first electromotive force to obtain boundary information of the formation interface.
FIG. 3 is a schematic diagram of a single-interface computational model in a far-formation-interface detection system according to an embodiment of the present application. As shown in fig. 3, the resistivities of the upper and lower strata are 10 Ω m and 1 Ω m, respectively, and the far-strata boundary detection system (detection instrument) according to the present application is parallel to the strata boundary shown in fig. 3. The rotation detection process of the far detection system of the stratum interface is simulated by using the calculation model shown in fig. 3, so that the relation between the potential difference and the rotation angle is obtained for the potential difference corresponding to each set of potential information, and the potential difference change characteristics shown in fig. 4 (fig. 4 is a schematic diagram of rotation orientation change of two sets of potential differences based on four orientations in the far detection system of the stratum interface) are obtained. By analyzing the change characteristics of the potential difference, the far detection system is positioned on the high-resistance layer at the stratum interface, the distance from the stratum interface boundary is 1.0m, the number of turns of the coil of the transmitting device 11 is 10 turns, the working frequency is 100kHz, and under the condition of rotation detection, the potential difference between two groups of sensors with symmetrical position relation respectively meets the change rules of cosine and sine in the drilling process, so that the detection of the stratum interface can be realized by utilizing each group of potential difference. Meanwhile, the numerical relation that the sum of squares is constant is also obtained through further calculation.
In one embodiment of the application, the signal processing means 13 is calculated to obtain the following two sets of potential differences: deltaV 1 ＝(V 3 -V 1 ) And DeltaV 2 ＝(V 4 -V 2 ). The intermediate electromotive force Ve is extracted according to the periodic variation law satisfied by the two sets of potential differences. Wherein the intermediate electromotive force representing the electromotive force of the reception device 12 is obtained using the following expression:
Ve＝sqrt(△V 1 2 +△V 2 2 ) (1)
wherein Ve represents an intermediate electromotive force, deltaV 1 And DeltaV 2 Respectively two sets of potential differences, sqrt represents a square root sign.
Further, the signal processing device 13 is further configured to combine the first electromotive force with the intermediate electromotive force, thereby obtaining an amplitude variation relationship feature between the first electromotive force and the intermediate electromotive force, and then obtain the boundary information of the formation interface according to the amplitude variation relationship feature. Specifically, the signal processing device 13 combines the first electromotive force with the intermediate electromotive force, and converts the electromotive force into the amplitude ratio Att characterizing the amplitude variation relationship therebetween by synthesizing the two. After the amplitude ratio is obtained, the signal processing device 13 uses the change in the amplitude ratio to represent the distance between the receiving device 12 and the boundary of the formation. Wherein the change of the amplitude ratio indicates the distance between the drill bit and the boundary of the stratum interface at the front, the rear and the side of the drill bit, and the orientation of the boundary of the stratum interface is indicated by the positive and negative of the amplitude ratio. Wherein the first electromotive force is combined with the intermediate electromotive force using the following expression:
Att＝abs(Ve/Vh) (2)
where Att represents an amplitude ratio, vh represents a first electromotive force, and abs represents an absolute value sign.
Further, the signal processing device 13 also adopts a fast forward and backward algorithm to carry out pixelation processing on the amplitude variation relationship, so as to convert the amplitude variation relationship into stratum interface boundary information. In the embodiment of the present application, the signal processing device 13 extracts the azimuth information and the distance information of the boundary of the formation interface by using the amplitude ratio data in real time based on the conversion relationship between the amplitude ratio and the boundary of the formation interface by adopting a fast forward-reverse algorithm, so as to perform one-dimensional pixelation processing on the amplitude ratio data, thereby achieving the purpose of converting the amplitude variation relationship between the first electromotive force and the intermediate electromotive force into the boundary information of the formation interface.
After the signal processing device 13 generates the boundary information of the formation interface, the boundary generating device 14 is configured to obtain the complete boundary distribution characteristic of the current formation interface according to the boundary information of the formation interface generated by the receiving device 12 in real time. The boundary generating device 14 collects the formation boundary information generated by the signal processing device 13 in real time during the measurement while drilling process, and integrates all the formation boundary information in the whole measurement while drilling process into a two-dimensional curtain map comprising each formation boundary information, so that the complete boundary distribution characteristics of the current formation boundary can be intuitively reflected by utilizing the two-dimensional curtain map.
Further, the formation interface remote detection system is also provided with a plurality of transmitting devices and a plurality of receiving devices. The device comprises a drill rod, a plurality of transmitting devices, a plurality of receiving devices, a plurality of connecting rods and a plurality of connecting rods, wherein the transmitting devices and the receiving devices are distributed on the outer side of the drill rod in an array mode, and the transmitting devices and the receiving devices are sequentially arranged along the axial direction of the drill rod according to a preset penetrating arrangement sequence. Therefore, the stratum interface remote detection system can obtain an arrayed detection range.
Next, a detailed description will be given of a configuration method of the transmitting apparatus and the receiving apparatus according to the embodiment of the present application.
Specifically, in the far-formation-interface detection system of the present application, multiple sets of first combinations including a transmitting device and a receiving device are generated for the current formation. Wherein the number ratio of transmitting devices and receiving devices in each group of first combinations is different, and each transmitting device and each receiving device in each first combination forms a corresponding arrayed probe instance. Further, the number of receiving means that can be provided between the respective transmitting means in the different first combinations is different. And then, continuously setting a corresponding source distance array (the distance between each transmitting device and each receiving device) for each first combination to form a plurality of source distance setting schemes for each first combination, setting corresponding working frequencies for the transmitting devices in each source distance setting scheme according to the source distance setting schemes of all the first combinations, and forming a plurality of working frequency configuration schemes for each source distance setting scheme, thereby forming corresponding transmitting and receiving setting schemes for each working frequency configuration scheme.
Next, a numerical simulation technology is utilized to calculate the threshold value (including the intermediate electromotive force threshold value, the first electromotive force threshold value and the amplitude ratio threshold value) of the measurement data for converting into the formation interface boundary information for each group of transmission and reception setting schemes respectively, so that the detection range corresponding to each working frequency configuration scheme is obtained by utilizing the threshold value of the measurement data, and the transmission and reception setting scheme corresponding to the maximum detection range is determined to be the optimal setting scheme, so that the current optimal setting scheme is put into the actual logging while drilling process.
Further, the stratum interface remote detection system provided by the application also utilizes a single-interface calculation model shown in fig. 3 to simulate the change relation between the intermediate electromotive force and the first electromotive force in the measured data along with the detection depth point. Under a non-rotation condition, a single-interface calculation model shown in fig. 3 is utilized to simulate a detection process of a stratum interface remote detection system penetrating through a single interface from top to bottom, a change relation between an intermediate electromotive force and a first electromotive force in measurement data along with a detection depth point is obtained, and a change relation shown in fig. 5 (fig. 5 is an example diagram of an electromotive force parameter of the stratum interface remote detection system changing along with the measurement depth) is obtained, so that the closer the intermediate electromotive force is to the stratum interface, the larger the amplitude change is, the highest value is reached at the stratum interface, the intensity of the intermediate electromotive force is far higher than that of the first electromotive force near the interface, the intermediate electromotive force is also obtained to be attenuated more slowly on the side of a low-resistance layer, the change of the first electromotive force in the high-resistance layer and the low-resistance layer is gentle, and the value of the first electromotive force in the low-resistance layer is slightly reduced. Accordingly, the far-boundary detection system determines the threshold values of the intermediate electromotive force and the first electromotive force in the measured data as the measurement threshold values for acquiring boundary characteristics of the formation boundary according to the rule that the attenuation in the high-resistance layer and the low-resistance layer is different from each other in the intermediate electromotive force and the first electromotive force in the measured data obtained by the numerical simulation technology.
Next, the stratum interface remote detection system according to the present application further uses a single interface calculation model as shown in fig. 3 to simulate the variation relationship of the amplitude ratio in the measurement data with the detection depth point. Under the non-rotation condition, the single-interface calculation model shown in fig. 3 is utilized to simulate the detection process of the formation interface remote detection system penetrating through the single interface from top to bottom, the change relation of the amplitude ratio in the measured data along with the detection depth point is obtained, and the change relation shown in fig. 6 (an example graph of the change of the amplitude ratio of the formation interface remote detection system along with the measurement depth in the embodiment of the application shown in fig. 6) is obtained, so that when the formation interface remote detection system is far away from the interface, the amplitude ratio is basically 0, and when the formation interface remote detection system is close to the formation interface, the amplitude ratio is sharply increased, and meanwhile, the abnormal range of the formation interface remote detection system in the high-resistance layer is also obtained to be far greater than that of the formation interface remote detection system in the low-resistance layer. Accordingly, the current stratum interface remote detection system is determined to have stronger detection capability in the high-resistance layer.
In a specific embodiment of the application, under the condition that the potential intensity corresponding to the measurement threshold value is 0.2dB, the detection edge distances of the current stratum interface far detection system in the high-resistance stratum and the low-resistance stratum are respectively 2.5m and 1.75m.
Next, under the condition that the potential intensity corresponding to the measurement threshold is 0.2dB, further assume that the resistivities at two sides of the formation interface are 100m and 10m respectively, so as to simulate the relationship between the source distance and the working frequency of the transmitting device 11 and the maximum edge detection distance, and obtain the correlation as shown in fig. 7 (schematic diagram of the variation trend of the maximum edge detection distance under different conditions in the far detection system of the formation interface in the embodiment of the present application in fig. 7). Analysis shows that the larger the source distance is, the stronger the edge detection capability of the stratum interface far detection system is; the higher the frequency, the shorter the edge detection distance of the formation interface far detection system.
Therefore, the embodiment of the present application designs a multi-transmitting multi-receiving antenna combination with four source distance arrays (0.4 m, 0.6m, 0.8m and 1.8 m) and three operating frequencies (100 kHz, 500kHz and 2 MHz) as shown in fig. 8 (fig. 8 is an exemplary diagram of an arrayed transmitting device and a receiving device in the far-detecting system for a formation interface in the embodiment of the present application), so that the far-detecting system for a formation interface has a wider edge detection range in the current formation, and the edge detection range can fully cover all the formation interface boundaries in the current formation.
Further, the formation interface remote detection system further comprises a resistivity measurement module for measuring formation apparent resistivity of the drilling tool at the real-time arrival location. Because the topography in the stratum is uneven and the underground medium is uneven in the actual logging while drilling operation, various rocks are overlapped with each other, the fault cracks are crisscrossed, or the stratum is filled with ore bodies. The resistivity measuring module is used for assisting in detecting the boundary of a stratum interface by measuring the apparent resistivity of the stratum at the position where the drilling tool arrives in real time and reflecting the electric non-uniformity and the topographic relief characteristic in the stratum in real time.
In one embodiment of the present application, the far-formation-interface detection system is based on the array structure shown in fig. 8, resulting in a formation curtain map as shown in fig. 9 (fig. 9 is a formation curtain map of the far-formation-interface detection system according to an embodiment of the present application). Wherein, the bright color is a high-resistance layer, and the dark color is a low-resistance layer. The current two-dimensional curtain diagram shows that the stratum interface far detection system can accurately position the boundary of the stratum interface when being far away from the bottom layer interface.
Example two
On the other hand, based on the stratum interface remote detection system, the embodiment of the application also provides a stratum interface remote detection method, and the stratum interface remote detection function is effectively realized by using the stratum interface remote detection system. FIG. 10 is a step diagram of a method of remotely detecting a formation interface in accordance with an embodiment of the present application. As shown in fig. 10, the method for remotely detecting the stratum interface according to the application comprises the following steps: step S101, continuously emitting detection current to the stratum in the while-drilling process; step S102, using a receiving device arranged between a transmitting device and a drill bit to measure electromotive force parameters of a plurality of directions; step S103, integrating the electromotive force parameters of the plurality of directions measured in the step S102 to form corresponding stratum interface boundary information; step S104 is to obtain the complete boundary distribution characteristics of the current stratum interface according to the stratum interface boundary information generated in real time by the receiving device in step S103.
The application provides a stratum interface remote detection system and a stratum interface remote detection method. Firstly, arranging a transmitting device and a receiving device on the outer side of a drill rod, then continuously transmitting detection current to a stratum in the while-drilling process by the transmitting device, measuring electromotive force parameters of a plurality of directions by the receiving device in real time, integrating the electromotive force parameters of the plurality of directions measured by the receiving device by a signal processing device to form corresponding stratum interface boundary information, and finally summarizing the stratum interface boundary information generated by the receiving device in real time by a boundary generating device to generate complete boundary distribution characteristics of a current stratum interface. The application solves the problems of short detection distance of the detection instrument, dependence of the detection instrument on rotation of the drill collar and the like in the prior art, achieves the purpose of carrying out far detection on a stratum interface under the conditions of shorter source distance and non-rotation, effectively improves the stratum description precision of the front, the rear and the side of the underground drilling tool, and improves the oil and gas exploration and development benefits. Meanwhile, the array acquisition mode is adopted, so that the signal strength and the signal-to-noise ratio are improved effectively.
The present application is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the scope of the present application are intended to be included in the scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
It is to be understood that the disclosed embodiments are not limited to the specific structures, process steps, or materials disclosed herein, but are intended to extend to equivalents of these features as would be understood by one of ordinary skill in the relevant arts. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.
Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Thus, the appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.
While the embodiments of the present application have been described above, the embodiments are presented for the purpose of facilitating understanding of the application and are not intended to limit the application. Any person skilled in the art can make any modification and variation in form and detail without departing from the spirit and scope of the present disclosure, but the scope of the present disclosure is still subject to the scope of the appended claims.
Claims (10)
1. A far-reaching formation interface detection system, comprising:
a transmitting device for continuously transmitting a probe current to the formation during while drilling;
the receiving device is positioned between the transmitting device and the drill bit and is arranged outside the drill rod, and is used for measuring electromotive force parameters of a plurality of directions;
the signal processing device is used for integrating the electromotive force parameters of the plurality of directions to form corresponding stratum interface boundary information;
and the boundary generation device is used for obtaining the complete boundary distribution characteristics of the current stratum interface according to the stratum interface boundary information generated by the receiving device in real time.
2. The system of claim 1, wherein the receiving means comprises: a measurement module, wherein the measurement module comprises:
an axially closed measuring antenna which surrounds the outside of the drill rod in a direction perpendicular to the axis of the drill rod and is used for measuring a first electromotive force of the longitudinal position of the receiving device; and
a plurality of electromagnetic sensors mounted on the axially closed measuring antenna for measuring a second electromotive force of a plurality of circumferential orientations of the receiving device.
3. The system of claim 2, wherein the plurality of electromagnetic sensors are disposed 90 ° apart in the circumferential direction.
4. A system according to claim 2 or 3, wherein,
the signal processing device is further configured to calculate potential differences between two pairs of sensors having symmetrical positional relationships, respectively, and obtain an intermediate electromotive force representing the electromotive force of the receiving device by using the following expression, thereby generating the formation interface boundary information in accordance with the intermediate electromotive force in combination with the first electromotive force:
Ve＝sqrt(△V 1 2 +△V 2 2 )
wherein Ve represents an intermediate electromotive force, deltaV 1 And DeltaV 2 Respectively two sets of potential differences, sqrt represents a square root sign.
5. The system of claim 4, wherein the signal processing device is further configured to combine the first electromotive force with the intermediate electromotive force using the following expression to obtain an amplitude variation relationship feature therebetween, and then obtain the formation interface boundary information according to the amplitude variation relationship feature:
Att＝abs(Ve/Vh)
where Att represents an amplitude ratio, vh represents a first electromotive force, and abs represents an absolute value sign.
6. The system of claim 5, wherein the signal processing device further employs a fast forward inversion algorithm to pixelate the amplitude variation relationship to convert the amplitude variation relationship to the formation interface boundary information.
7. The system of claim 1, wherein the system further comprises:
and the excitation device is used for providing a time harmonic current required for emission for the emission device.
8. The system according to any one of claims 1-7, characterized in that the system is further configured with a number of transmitting means and a number of receiving means.
9. The system of claim 8, wherein the system further comprises:
and the resistivity measurement module is used for measuring the formation apparent resistivity of the drilling tool at the real-time arrival position.
10. A method of remotely detecting a formation interface, the method being implemented using the system of any one of claims 1-9, the method comprising:
continuously transmitting a detection current to the stratum in the drilling process;
measuring electromotive force parameters of a plurality of directions by using a receiving device arranged between the transmitting device and the drill bit;
integrating the electromotive force parameters of the plurality of directions to form corresponding stratum interface boundary information;
and obtaining the complete boundary distribution characteristics of the current stratum interface according to the stratum interface boundary information generated by the receiving device in real time.
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