CN112305622A

CN112305622A - Resistivity imaging device

Info

Publication number: CN112305622A
Application number: CN201910712798.5A
Authority: CN
Inventors: 李新; 米金泰; 倪卫宁; 闫立鹏
Original assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Current assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Priority date: 2019-08-02
Filing date: 2019-08-02
Publication date: 2021-02-02

Abstract

The present invention relates to a resistivity imaging device comprising: a cylindrical main body; a launching mechanism mounted on an exterior side of the tubular body, the launching mechanism configured to launch a current signal into a formation; and a receiving mechanism mounted outside the cylindrical body and spaced apart from the transmitting mechanism in an axial direction of the cylindrical body, the receiving mechanism including a plurality of receivers spaced apart from each other in a circumferential direction of the cylindrical body, the receivers configured to receive current signals from the earth formation. The operator can grasp the situation in the earth formation more accurately by the device.

Description

Resistivity imaging device

Technical Field

The invention relates to the technical field of petroleum and natural gas drilling, in particular to a resistivity imaging device.

Background

Resistivity measurements in wells are one of the primary means commonly used in the art to resolve conditions in earth formations. Resistivity imaging instruments are currently available for measuring the resistivity in the earth formation and imaging the earth formation environment accordingly.

Current resistivity imaging instruments typically include a signal transmitter and a signal receiver. The signal transmitter is used to transmit a signal into the formation, which is ultimately returned to the signal receiver. Resistivity in the formation is determined from the received signals. However, the existing instruments have difficulty in achieving high accuracy and high imaging resolution. This makes it difficult for the operator to accurately grasp the condition in the formation.

Accordingly, there is a need for a resistivity imaging device that facilitates a practitioner in more accurately mastering the condition of the earth formation.

Disclosure of Invention

In view of the above problems, the present invention proposes a resistivity imaging apparatus by which an operator can grasp the situation in the earth formation more accurately.

According to the present invention, there is provided a resistivity imaging apparatus comprising: a cylindrical main body; a launching mechanism mounted on an exterior side of the tubular body, the launching mechanism configured to launch a current signal into a formation; and a receiving mechanism mounted outside the cylindrical body and spaced apart from the transmitting mechanism in an axial direction of the cylindrical body, the receiving mechanism including a plurality of receivers spaced apart from each other in a circumferential direction of the cylindrical body, the receivers configured to receive current signals from the earth formation.

The resistivity imaging apparatus can transmit a current signal into the formation through the transmitting mechanism, and the current signal is transmitted to the receiving mechanism. By processing the received current signals, the resistivity in the earth formation may be determined and a corresponding image formed therefrom. By providing a plurality of receiving devices independent of each other in the circumferential direction of the cylindrical body, the current signals can be received in different directions, respectively. Thereby, the resistivity in different circumferential directions can be determined separately. This facilitates the operator to more accurately grasp the condition in the formation.

In one embodiment, the firing mechanism includes a firing assembly surrounding the cylindrical body in a circumferential direction of the cylindrical body, the firing assembly including: the accommodating sleeve is sleeved outside the cylindrical main body and provided with an accommodating groove at one end; the spiral ring is accommodated in the accommodating groove; and an end piece provided at least one end of the accommodation sleeve, wherein the end piece provided at the end of the accommodation sleeve at which the accommodation groove is provided is configured to be able to close the accommodation groove.

In one embodiment, the receiving sleeve includes a middle section of larger outer diameter and an end section of smaller outer diameter connected to the middle section, and the end piece includes a main body portion disposed at one end of the receiving sleeve and a snap portion extending away from the main body portion and snap-fitting over the end section.

In one embodiment, the receiving sleeve comprises: the shell body, the shell body is including setting up the metal part of tip section department, and set up and be in wear-resisting part of middle part section department, spiral wound ring insulating boot, insulating boot sets up the shell body with between the tube-shape main part form on the insulating boot the holding tank to and the elastic filling body, the elastic filling body is full of the shell body insulating boot with the space that surrounds between the tube-shape main part.

In one embodiment, the accommodating groove is filled with a sealing glue to seal the spiral ring in the accommodating groove.

In one embodiment, the receiver comprises: the receiving electrode extends in an outer groove of the cylindrical body along a radial direction of the cylindrical body, an outer end of the receiving electrode is exposed to the environment, an induction coil is arranged in the outer groove, an inner end of the receiving electrode is inserted into the induction coil, and a coil insulation sleeve surrounds the induction coil and separates the inner end of the receiving electrode from the induction coil.

In one embodiment, a positioning hole extending inward in a radial direction of the cylindrical body is configured at a bottom wall of the outer groove, and the coil insulating sleeve is configured with a positioning protrusion capable of extending inward in the radial direction of the cylindrical body to be inserted into the positioning hole to prevent the coil and the coil insulating sleeve from rotating relative to the receiving electrode.

In one embodiment, the middle of receiving electrode is constructed with along the joint that the radial direction of receiving electrode outwards extended is protruding, the inner and the outer end of receiving electrode are in respectively the bellied both sides of joint, the receiver still includes the apron, the apron structure is for covering the outside of receiving electrode, wherein, the bellied lateral surface of joint with the apron cooperatees, the bellied medial surface of joint with coil insulation cover cooperatees.

In one embodiment, the resistivity imaging device includes a plurality of receiving mechanisms spaced apart from each other in an axial direction of the cylindrical body, and receivers in different receiving mechanisms are staggered from each other in a circumferential direction of the cylindrical body.

In one embodiment, the resistivity imaging device includes a plurality of transmitting mechanisms spaced apart from each other in an axial direction of the cylindrical body, at least two of the plurality of transmitting mechanisms being different in distance from the corresponding receiving mechanism.

Compared with the prior art, the invention has the advantages that: the resistivity imaging apparatus can transmit a current signal into the formation through the transmitting mechanism, and the current signal is transmitted to the receiving mechanism. By processing the received current signals, the resistivity in the earth formation may be determined and a corresponding image formed therefrom. By providing a plurality of receiving devices independent of each other in the circumferential direction of the cylindrical body, the current signals can be received in different directions, respectively. Thereby, the resistivity in different circumferential directions can be determined separately. This facilitates the operator to more accurately grasp the condition in the formation.

Drawings

The invention is described in more detail below with reference to the accompanying drawings. Wherein:

FIG. 1 shows a schematic block diagram of a resistivity imaging apparatus according to one embodiment of the invention;

FIG. 2 shows a projection of the resistivity imaging device of FIG. 1 in direction B;

FIG. 3 shows a cross-sectional view of the resistivity imaging device of FIG. 1 along line A-A;

FIG. 4 shows an axial cross-sectional view of a first receiving mechanism in the resistivity imaging apparatus of FIG. 1;

FIG. 5 shows a cross-sectional view of the resistivity imaging device of FIG. 2 along line C-C;

FIG. 6 shows a cross-sectional view of the resistivity imaging device of FIG. 1 along line D-D;

FIG. 7 shows a cross-sectional view of the resistivity imaging device of FIG. 1 along line E-E;

FIG. 8 shows a cross-sectional view of the resistivity imaging device of FIG. 1 along line F-F;

FIG. 9 shows a cross-sectional view of the resistivity imaging device of FIG. 1 along line G-G;

FIG. 10 shows a cross-sectional view of the resistivity imaging device of FIG. 1 taken along line H-H;

FIG. 11a shows an axial cross-sectional view of a first emitting mechanism in the resistivity imaging apparatus of FIG. 1;

11 b-11 d show enlarged partial views of other firing mechanisms engaged with the tubular body;

fig. 12 shows a schematic structural view of an embodiment of the receiving sleeve in the first launching mechanism of fig. 11 a.

In the drawings, like parts are provided with like reference numerals. The figures are not drawn to scale.

Detailed Description

The invention will be further explained with reference to the drawings.

Fig. 1 schematically shows a resistivity imaging device (hereinafter simply referred to as "device") 100 according to an embodiment of the present invention. The device 100 comprises a cylindrical body 101 which can be installed as a sub in a drill string. The cylindrical body 101 is configured with upper and lower connector links 104 and 103 (see figure 3) for connection with other subs or devices in the drill string. Thus, the device 100 may be used as a resistivity imaging while drilling device. The cylindrical body 101 is generally configured in a cylindrical shape, and a slurry passage 102 is configured along an axial middle portion thereof. The cylindrical body 101 may be made of a non-magnetic stainless steel material (e.g., P550, P530, etc.). The upper and

lower connector links

104 and 103 may be, for example, NC50 button type of API standard.

As shown in fig. 1, at least one

transmitting mechanism

200, 300, and 400, and at least one

receiving mechanism

500 and 600 are provided on the cylindrical body 101. The device 100 may also include a processing mechanism 700 for processing the current signal. At least one of the

launching mechanisms

200, 300, and 400 may be used to launch a current signal into the formation as the apparatus 100 is lowered into the well. The transmitted current signal is in turn returned from the formation to at least one

receiving mechanism

500 and 600 of the apparatus 100 where it is received by them. The received current signal is then transmitted to the processing mechanism 700. The processing mechanism 700 processes the received current signal to obtain data for the corresponding resistivity.

In the embodiment shown in fig. 1, 3 transmitting mechanisms and 2 receiving mechanisms are provided. For ease of understanding and distinction, firing

mechanisms

200, 300, and 400 are hereinafter referred to as first firing mechanism 200, second firing mechanism 300, and third firing mechanism 400, respectively; similarly, the receiving

mechanisms

500 and 600 are referred to as a first receiving mechanism 500 and a second receiving mechanism 600, respectively. It should be understood that other numbers of transmitting and receiving mechanisms may be provided, as desired.

As shown in fig. 3, 5 and 11a, the first launching mechanism 200 includes a first launching assembly. The first transmitting assembly includes a receiving sleeve 202 disposed outside the cylindrical body 101, and a receiving groove is formed in the receiving sleeve 202 for disposing a spiral ring 206 therein. As shown in fig. 11a, the receiving groove is opened at the lower end (i.e., the end toward the bottom of the well) of the receiving sleeve. However, a receiving groove may also be opened at the upper end of the receiving sleeve (i.e., the end toward the wellhead) as desired.

End pieces

203 and 201 are provided at upper and lower ends of the receiving sleeve 202, respectively. The receiving sleeve 202 may be configured, for example, as shown in fig. 11a as a "dogbone" configuration having a larger outer diameter middle section and smaller outer diameter end sections adjacent to and joined to the middle section. Accordingly, the

end pieces

201, 203 comprise a main body portion at one end of the receiving sleeve 202, and a snap-fit portion extending from the main body portion to outside the end section of the receiving sleeve 202, which snap-fit portion is snap-fit with the end section, preferably sealingly by a seal 208, thereby avoiding fluid flow therethrough. Further, the main body portions of the

end members

201 and 203 are also sealingly connected to the cylindrical main body 101 by a seal 208. In this case, the

end pieces

201, 203 effectively block the opening of the receiving groove, on the one hand, preventing the toroid 206 from being unintentionally pulled out, and on the other hand, preventing the fluid in the well from flowing into the receiving groove unintentionally and contacting the toroid. This effectively ensures that the toroid 206 can operate effectively to emit a current signal. The

end pieces

201, 203 here may be made of a non-magnetic metal, such as non-magnetic stainless steel, titanium alloy, etc.

In one embodiment, the receiving groove may be filled with a sealing glue 207 to seal the opening of the receiving groove. Such an arrangement may be provided as an alternative to the end piece described above, preferably in combination with the end piece. In a preferred embodiment, the sealing glue 207 may fill the entire space between the receiving groove and the winding ring, thereby additionally serving as a fixing and shock absorbing function. The sealing compound 207 here should be insulating and may be, for example, a high temperature resistant RTV silicone, a high temperature resistant epoxy, or the like.

As shown in fig. 11a, the end of the

end piece

201, 203 facing away from the receiving sleeve may be provided with a bevel 210, which bevel 210 forms a smooth transition between the tubular body 101 and the largest outer diameter portion of the

end piece

201, 203. The angle of inclination 211 of the ramp 210 is preferably between 30 ° and 60 °. In addition, the maximum outer diameter of the

end pieces

201, 203 is flush with the outside of the middle section of the receiving sleeve. As shown in fig. 1, wear strips 204 are embedded outside the largest outer diameter portions of the

end pieces

201, 203 for enhancing the wear resistance of the

end pieces

201, 203. For example, a plurality of wear strips 204 spaced apart from each other may be arranged in the circumferential direction of the tubular main body 101 at the maximum outer diameter portions of the

end pieces

201, 203, each wear strip 204 being configured with a strip-shaped profile extending along the axial direction of the tubular main body 101. It should be understood that the wear strips 204 may have a rectangular, circular, or triangular profile, as desired. The outer ends of the wear strips 204 are flush with the outside of the largest outer diameter portion of the

end pieces

201, 203. The wear strips 204 may be made of non-magnetic, high temperature resistant, wear resistant materials, such as alumina ceramics, zirconia ceramics, and the like.

Mounting holes 212 are also formed in the

end pieces

201, 203, said mounting holes extending in the radial direction thereof. The tubular main body 101 is provided with a stepped hole 213 corresponding to the mounting hole 212. Threaded fixing pins 810 may be inserted into the mounting holes 212 and the stepped holes 213 to fix the

end pieces

201, 203 to the tubular body 101 and thereby fix the receiving sleeve 202 to the tubular body 101. The threaded retaining pin 810 includes a larger diameter portion 8101, which is a smooth cylinder, and a smaller diameter portion 8102, which mates with the threads of the stepped bore 213. The top of the threaded fixation pin 810 is preferably configured with a hexagonal socket 8103 to facilitate tightening of the threaded fixation pin 810 with a socket wrench during installation. Preferably, before the threaded fixing pin 810 is installed, a thread fastening glue may be applied to the thread of the smaller diameter portion 8102 for preventing the thread fit from being loosened. For example, 8 threaded fixing pins 810 may be evenly distributed in the circumferential direction of the cylindrical body 101. Other numbers (preferably in the range of 2-30) of threaded retaining pins 810 may be provided as desired.

In addition, in a preferred embodiment, as shown in fig. 11a, a retainer ring 811 is provided on the top of the threaded fixing pin 811, and the retainer ring 811 is used to prevent the threaded fixing pin 810 from falling out due to vibration of the downhole tool. Preferably, the retainer ring 811 may be made of a non-magnetic metal (e.g., 316 stainless steel or brass), and may be a circlip for a bore, for example. The card slot may be configured at a corresponding location within the mounting hole 212. The retainer ring 811 may be engaged in the engaging groove.

As shown in fig. 11a, the cylindrical body 110 includes a first diameter section 111, a second diameter section 112 and a third diameter section 113 connected in sequence from bottom to top, wherein the first diameter section 111 has an outer diameter smaller than that of the second diameter section 112 to form a step therebetween, and the second diameter section 112 has an outer diameter smaller than that of the third diameter section 113 to form a step therebetween. The

end pieces

201 and 203 together with the receiving sleeve 202 are mounted on the second diameter section 112 and cover substantially the entire second diameter section 112. The relatively upper end section 203 abuts against the step between the second and

third diameter sections

112, 113 to achieve positioning.

The outer diameter of the second diameter section 112 matches the inner diameter of the

end pieces

201 and 203 and the receiving sleeve 202, providing a clearance fit. The

end pieces

201 and 203 and the receiving sleeve 202 may be sleeved from the first diameter section 111 to the second diameter section 112. Due to the smaller outer diameter of the first diameter section 111, the clearance between the

end pieces

201 and 203 and the receiving sleeve 202 and the first diameter section 111 is larger, and friction between the

end pieces

201 and 203 and the receiving sleeve 202 and the first diameter section 111 can be avoided as much as possible.

Fig. 12 shows a preferred embodiment of the receiving sleeve 202. As shown in fig. 12, the receiving sleeve 202 includes a spiral-wound ring insulation sleeve 2021. The helicon insulating sleeve 2021 may be made of non-metallic materials such as PEEK, glass reinforced plastic, etc. The accommodating groove for accommodating the spiral ring 206 is formed on the spiral ring insulating sleeve 2021. In addition, the containment sleeve 202 further comprises an outer shell comprising metal portions (

e.g. metal pads

2022 and 2024 in fig. 12) provided at the end sections and a wear portion (e.g. wear layer 2023 in fig. 12) provided at the middle section. The

metal pads

2022 and 2024 are used to cooperate with the engaging portions of the

end members

201 and 203 to form sealing surfaces by using excellent rigidity and toughness of metal, which is advantageous for improving sealing effect. The

metal pads

2022 and 2024 may be made of non-magnetic metals such as non-magnetic stainless steel, copper, titanium alloys, and the like. The wear resistant layer 2023 is made of a high temperature resistant, wear resistant non-metallic material such as glass fiber reinforced plastic, PEEK, ceramic, etc. As shown in fig. 12, the spiral-wound ring insulation sleeve 2021, the wear-resistant layer 2023, and the

metal pads

2022 and 2024 surround and define the outer contour of the receiving sleeve 202. They can be connected to one another by an elastic connecting layer 2025. The connection layer 2025 may be made of rubber, for example. Such a tie layer 2025 allows for some flexibility of the overall containment sleeve 202, further allowing for a tight, sealed engagement between the containment sleeve 202 and the

end pieces

201, 203.

In addition, as shown in fig. 5, the first transmission mechanism 200 further includes a first circuit 251. The first circuit 251 may be connected to an antenna wound around the toroid 206 for delivering a current signal to the toroid 206. As shown in fig. 5, a string passing hole 150 extending in the axial direction of the cylindrical body 101, and a string passing hole 152 extending in the radial direction of the cylindrical body 101 are configured in the cylindrical body 101. Electrical connections for connecting the first circuit 251 and the antenna on the toroid 206 may extend within the

vias

150 and 152.

As shown in fig. 5, the first circuit 251 is embedded in the cylindrical body 101 below the first radiator module. The first circuit 251 is enclosed in the tubular main body 101 by the first circuit cover 205. The first circuit cover plate 205 may be made of, for example, a high strength non-magnetic stainless steel (e.g., P550). The first circuit cover plate 205 is sealingly engaged with the cylindrical body 101 by a seal 253 to seal the first circuit 251 therebetween from external mud contacting the first circuit 251. Preferably, the first circuit 251 is surrounded by a first circuit insulating layer 252. The first circuit insulating layer 252 prevents the first circuit 251 from being electrically connected to the first circuit cover 205 and the tubular main body 101, and also plays a role of vibration reduction.

In addition, as shown in fig. 1, a second launching mechanism 300 is further provided above the first launching mechanism 200. The second transmission mechanism 300 is similar in structure to the first transmission mechanism 200, and is configured with a solenoid 306, a sealing glue 307, a housing sleeve 302,

end pieces

301, 303, a seal 308, a second circuit 351, a second circuit insulating layer 352, a seal 353, and a second circuit cover 305, respectively. A wire through hole 153 extending in the radial direction is configured on the cylindrical body 101, and an electrical connection for connecting the antenna on the solenoid 306 with the second circuit 351 passes through the wire through

holes

153 and 150. Preferably, wear strips 304 are also provided on the

end pieces

301, 303.

As shown in fig. 11b, the cylindrical body 101 is further configured with a fourth diameter section 114, the fourth diameter section 114 being connected to and above the third diameter section 113. The outer diameter of the fourth diameter section 114 is greater than the outer diameter of the third diameter section 113 forming a step therebetween. The second emitting component of the second emitting mechanism 300 is sleeved on the third diameter section 113, and the end member 303 thereof is clamped at the step between the third diameter section 113 and the fourth diameter section 114 for positioning.

As shown in fig. 1, 3 and 5, a first receiving mechanism 500 is also provided above the second transmitting mechanism 300. As shown in fig. 4 and 8, the first receiving mechanism 500 includes a plurality of receivers arranged spaced apart from each other in the circumferential direction of the cylindrical body. For example, there are 4 receivers in this embodiment, i.e., a first receiver, a second receiver, a third receiver, and a fourth receiver. Each receiver is embedded within the cylindrical body 101. The following is a detailed description of the structure of one of the receivers.

As shown in fig. 4, a groove, referred to herein as an outer groove, is formed on the outer side wall of the cylindrical body 101. The first receiver includes a receiving electrode 511, which is substantially configured in a cylindrical shape, inserted into the outer groove in the radial direction of the cylindrical body 101. Preferably, a mounting hole 5112 extending inward in the radial direction of the cylindrical body 101 is configured at the bottom wall of the outer groove, and the inner end of the receiving electrode 511 (i.e., the end toward the central axis of the cylindrical body) is inserted into this mounting hole 5112 to achieve positioning of the receiving electrode 511. The inner end of the receiving electrode 511 is in direct contact with and electrically connected to the cylindrical body 101 so as to form a circuit. The first receiver further includes an induction coil 512, and the inner end of the receiving electrode 511 is inserted into the induction coil 512. A coil insulation sleeve 514 is sleeved on the outside of the receiving electrode 511 and separates the induction coil 512 from the inner end of the receiving electrode 511. Preferably, as shown in fig. 4, at the bottom wall of the outer groove, there is also configured a positioning hole 5142 extending inward in the radial direction of the cylindrical body 101; accordingly, the coil insulating sleeve 514 is configured with a positioning projection 5141 extending inward in the radial direction of the cylindrical body 101. The positioning protrusion 5141 can be inserted into the positioning hole 5142, so as to fix the coil insulation sleeve 514 and the induction coil 512 surrounded thereby, and prevent them from rotating relative to the receiving electrode 511. Preferably, the positioning hole 5142 may be filled with RTV silicone to facilitate fixing the positioning protrusion 5141.

In addition, the middle of the receiving electrode 511 is configured with a catching protrusion 5111 (see fig. 8) extending outward in the radial direction of the receiving electrode 511. The cover plate 501 covers the outer groove of the cylindrical body 101 to enclose the receiving electrode 511 and the induction coil 512 in the outer groove. An opening is formed in the middle of the cap plate 501, allowing the outer end of the receiving electrode 511 (i.e., the end facing away from the central axis of the cylindrical body 101) to extend through the opening to be exposed to the formation. The catching projection 5111 can be caught between the cap plate 501 and the coil insulation cover 514 to fix the receiving electrode 511. Meanwhile, the cover 501 can protect the receiving electrode 511 and the induction coil 512. The cover plate 501 may be rectangular as shown in fig. 1, for example, and is fastened to the tubular body 101 by bolts. The cover plate 501 may be made of, for example, a high temperature resistant non-magnetic stainless steel (e.g., P550). Preferably, an electrode insulating sleeve 513 is further disposed between the cover plate 501 and the receiving electrode 511 for spacing the cover plate 501 from the receiving electrode 511. The electrode insulating sheath 513 may be formed in a "convex" configuration as shown in fig. 4, for example.

In a preferred embodiment, shown in fig. 1, wear posts 507 are embedded on the outside of the cover plate 501. The outer ends of the wear columns 507 are preferably flush with the outer ends of the cover plate 501. The wear columns 507 may be used to improve the wear resistance of the coverplate 501. The wear pillars 507 may be cylindrical, for example, made of a non-magnetic, wear resistant material (e.g., ceramic).

Sealing members 515 are provided between the cover plate 501 and the tubular body 101 and between the cover plate 501 and the electrode insulating sheath 513, so that sealing is performed to prevent short circuit caused by contact of external cement paste with the induction coil 512.

As shown in fig. 8, the second receiver, the third receiver, and the fourth receiver in the first receiving mechanism are configured similarly to the first receiver. The four receivers are evenly arranged in the circumferential direction at intervals of 90 °. The second receiver includes a receiving electrode 521 and an induction coil 522; the third receiver comprises a receiving electrode 531 and an induction coil 532; the fourth receiver includes a receiving electrode 541 and an induction coil 542.

As shown in fig. 4, the first receiving mechanism further includes

electrode circuits

551, 561 disposed under the respective receivers. The current received by the receiver may be passed to electrode circuits 551,561 for processing. The electrode circuit 551 is disposed under the first receiver, embedded in the cylindrical body 101, and covered by the cover plate 505. The cover plate 505 is sealed with the cylindrical body 101 by a seal 553 to prevent the cement paste from contacting the electrode circuit 551. Preferably, an electrode circuit insulating layer 552 is surrounded on the outside of the electrode circuit 551. A wire passage hole 554 (fig. 4) extending in an axial plane and a wire passage hole 573 (fig. 8) extending in a radial plane are configured in the cylindrical body 101. Electrical connections for connecting the electrode circuit 551 with the antenna of the first induction coil 512 and for connecting the electrode circuit 551 with the antenna of the second induction coil 522 may pass through the wire through

holes

554, 573.

Similarly, electrode circuit 561 is disposed below the third receiver, circumferentially 180 ° from electrode circuit 551. A cover 506, an electrode circuit insulating layer 562, and a sealing member 563 are provided for the electrode circuit 561, respectively. A wire passage hole 564 (fig. 4) extending in an axial plane and a wire passage hole 574 extending in a radial plane are configured in the cylindrical body 101. Electrical connections for connecting the antenna of the electrode circuit 561 and the third induction coil 532 and for connecting the antenna of the electrode circuit 561 and the fourth induction coil 542 may pass through the wire through

holes

564, 574.

As shown in fig. 3 and 6, the processing mechanism 700 includes a control circuit 711 and a data processing circuit 721. The control circuit 711 and the data processing circuit 721 are embedded in the cylindrical body 101 at a distance of 120 ° from each other in the circumferential direction. The control circuit 711 is covered by the cover plate 710. The cover plate 710 forms a seal with the cylindrical body 101 by a seal 713 to seal the control circuit 711 therebetween. A control circuit insulating layer 712 is surrounded outside the control circuit 711. Similarly, the data processing circuit 721 is covered by the cover plate 720. A seal is formed between the cover plate 720 and the cylindrical body 101 by a seal 723. A data processing circuit insulating layer 722 is surrounded outside the data processing circuit 721.

As shown in fig. 6, the tubular body 101 is configured with

wire passing holes

714 and 724 extending in a radial plane. The wire through hole 714 is communicated between the control circuit 711 and the wire through hole 150; the via hole 724 communicates between the data processing circuit 721 and the via hole 150. Electrical connections may be made between control circuit 711 and first circuit 251 or second circuit 351 through

wire vias

714 and 150 to allow control circuit 711 to signal first circuit 251 or second circuit 351 to control them to generate and output corresponding current signals. Additional electrical connections may be made between the electrode circuits 551,561 and the data processing circuit 721 through the vias 724,150, 571 and 572 to allow the data processing circuit 721 to receive the current signals from the electrode circuits 551,561 and process them accordingly to obtain the resistivity of the earth formation.

It is understood that one of the wire through

holes

571 and 572 may be omitted, if necessary.

A second receiving means 600 is also provided above the handling means 700. As shown in fig. 10, the second receiving mechanism 600 includes 4 receivers, i.e., a fifth receiver, a sixth receiver, a seventh receiver, and an eighth receiver. As shown in fig. 10, the fifth receiver includes a receiving electrode 611 and an induction coil 612; the sixth receiver includes a receiving electrode 621 and an induction coil 622; the seventh receiver includes a receiving electrode 631 and an induction coil 632; the eighth receiver includes a receiving electrode 641 and an induction coil 642. The receivers are evenly distributed circumferentially at 90 ° to each other. It should be noted that the 4 receivers in the second receiving mechanism 600 and the 4 receiving mechanisms in the first receiving mechanism 500 are circumferentially offset from each other. If the circumferential position at which the first receiver is disposed is defined as a 0 ° position, the second receiver, the third receiver, and the fourth receiver are disposed at-90 °, 180 °, and +90 °, respectively; the fifth receiver, the sixth receiver, the seventh receiver, and the eighth receiver are disposed at-45 °, -135 °, +135 °, and +45 °, respectively. Such an arrangement enables the apparatus 100 to measure formation resistivity in more directions in order to improve the measurement accuracy and imaging resolution of the apparatus 100. It should be understood that more or fewer receivers may be provided, as desired. However, setting up 8 receivers in two groups is a preferred arrangement. This arrangement takes into account both the measurement accuracy and the structural stability of the device.

As shown in fig. 9, the second receiving mechanism 600 further includes

electrode circuits

651 and 661. The electrode circuit 651 is electrically connected with the antenna of the fifth induction coil 612 and the antenna of the sixth induction coil 622 through electrical connections passing through the wire through

holes

150, 673. The electrode circuit 661 is electrically connected with the coils of the seventh induction coil 632 and the antennas of the eighth induction coil 642 by the electrical connection through the wire through

holes

150, 674. The

electrode circuits

651, 661 are in turn electrically connected to the data processing circuit 721 by electrical connections through the

wire vias

671, 672, 150 and 724.

The structure of the second receiving mechanism 600 is similar to that of the first receiving mechanism 500, and is not described in detail herein.

As shown in fig. 1, a third transmitting mechanism 400 is further disposed above the second receiving mechanism 600. The structure of the third launching mechanism 400 is similar to that of the first launching mechanism 200. The third firing mechanism 400 includes a third firing assembly that includes a threaded collar 406, a closure glue 407, a containment sleeve 402,

end pieces

401, 403, and a seal 408. Preferably, corresponding wear strips 404 are also provided on the

end pieces

401, 403.

As shown in fig. 11c and 11d, the cylindrical body 101 further comprises a fifth diameter section 115 connected to the fourth diameter section 114 and a sixth diameter section 116 connected to the fifth diameter section 115. The outer diameter of the fourth diameter section 114 is greater than the outer diameter of the fifth diameter section 115, forming a step therebetween. The outer diameter of the fifth diameter section 115 is greater than the outer diameter of the sixth diameter section 116, forming a step therebetween. The third emitting component is sleeved at the fifth diameter section, and the end part 401 thereof abuts against the step between the fourth diameter section 114 and the fifth diameter section 115 to realize positioning. The third emission assembly covers substantially the entire fifth diameter section 115 with an end piece 403 thereof positioned substantially at the step between the fifth diameter section 115 and the sixth diameter section 116.

The third firing mechanism 400 also includes a third circuit 451 disposed over the third firing component, a third circuit insulating layer 452, a seal 453, and a cap plate 405. The third circuit 451 is electrically connected to the antenna of the spiral loop 406 by electrical connections passing through the wire through

holes

150 and 154. The third circuit 451 is also electrically connected to the control circuit 711 by electrical connections passing through the

wire passing holes

150, 714.

As shown in fig. 3, a fitting hole 730 is provided in the cylindrical body 101 above the third launching mechanism 400. The debug hole 703 is provided with a debug interface which communicates with a circuit to be debugged (for example, the control circuit 711 described above or other circuits) provided inside the tubular main body 101. The debugging hole 730 is covered and protected by a cover plate 732. A sealing member 733 is provided between the cover 732 and the cylindrical body 101 to seal therebetween and prevent external cement paste from contacting the fitting hole 730.

As shown in fig. 5, a wire hole plug 159 is provided in an upper end of the wire hole 150. The wire through hole 150 is communicated to the wire through holes in other upper short joints through an inclined wire through hole 151.

With the above arrangement and configuration, the following operation of the apparatus 100 can be achieved.

The control circuit 711 sends an electrical signal to at least one of the first circuit 251, the second circuit 351, and the third circuit 451 to control it to generate a corresponding current signal. The first circuit 251, the second circuit 351, and the third circuit 451 may be mounted with a band pass filter and a power amplifier. The band pass filter can band pass filter the signal sent from the control circuit 711. The filtered signal can be amplified by a power amplifier.

The generated current signal is delivered to the

respective toroid

206, 306, 406.

The

toroids

206, 306, 406 carry current signals to the formation, which are then transmitted back to the corresponding receivers to be received by the receiving

electrodes

511, 521, 531, 541, 611, 621, 631, 641.

The current signals received by the receiving electrodes excite the corresponding induction coils 512, 522, 532, 542, 612, 622, 632, 642 to generate corresponding induced current signals.

The induced current signals are transmitted to the corresponding

electrode circuits

551, 561, 651, 661. These

electrode circuits

551, 561, 651, 661 process the current signal, and transmit the processed current signal to the data processing circuit 721. The

electrode circuits

551, 561, 651, 661 can be mounted with an amplification filter, an analog signal converter, and a waveform collector. The amplifying filter can amplify the power of the transmitted induced current signal and filter out noise. One end of the analog signal converter is connected with the amplifying filter to receive the amplified and filtered current signal; the other end is connected with the waveform collector to transmit the analog signal to the waveform collector. The waveform collector can collect data of the analog signal transmitted from the analog signal converter and transmit the collected data to the data processing circuit 721.

The data processing circuit 721 determines the corresponding formation resistivity from the processed current data signal.

In the above embodiment, the first receiving mechanism 500 is used for receiving the current signals transmitted by the first transmitting mechanism 200 and the second transmitting mechanism 300; the second receiving means 600 is used for receiving the current signal transmitted by the third transmitting means 400. However, if necessary, the first receiving mechanism 500 may receive the current signal transmitted by the third transmitting mechanism 400, or the second receiving mechanism 600 may receive the current signals transmitted by the first transmitting mechanism 200 and the second transmitting mechanism 300.

In addition, one of the first, second or

third transmitting mechanisms

200, 300 or 400 may also be caused to receive current signals transmitted by the other transmitting mechanism to measure lateral formation resistivity, as desired.

The distance between the receiving means and the transmitting means can be determined as desired. The distance between the first transmitting mechanism 200 and the first receiving mechanism 500 is shorter, while the distance between the second transmitting mechanism 300 and the first receiving mechanism 500 is longer. Thus, the first transmitter mechanism 200 and the first receiver mechanism 500 cooperate to measure the resistivity of formations that are relatively close to the device 100, while the second transmitter mechanism 300 cooperates with the first receiver mechanism 500 to measure the resistivity of formations that are relatively far from the device 100.

Additionally, the device 100 may rotate with the string of tubulars while being used as a measurement-while-drilling device. Thus, each receiver can measure data at different angular orientations. By overlapping the data measured at the same angle by different electrodes, more accurate measurement results can be obtained, and the signal-to-noise ratio is improved. At the same time, the measurable angular orientation of the receiver is increased by the rotation, so that the imaging resolution in the circumferential direction can be increased.

The apparatus 100 described above is capable of measuring resistivity in the formation with a high degree of accuracy, thereby facilitating the operator to more accurately grasp the conditions in the formation. Meanwhile, the device 100 also has the advantages of simple structure, easy assembly and convenient maintenance. Therefore, the device 100 can realize safe and reliable resistivity measurement when an unconventional oil and gas reservoir is drilled, and provides high-definition borehole images for geosteering and later development.

While the invention has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. It is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A resistivity imaging device comprising:

a cylindrical main body;

a launching mechanism mounted on an exterior side of the tubular body, the launching mechanism configured to launch a current signal into a formation; and

a receiving mechanism mounted outside the cylindrical body and spaced apart from the transmitting mechanism in an axial direction of the cylindrical body, the receiving mechanism including a plurality of receivers spaced apart from each other in a circumferential direction of the cylindrical body, the receivers configured to receive current signals from the earth formation.

2. The resistivity imaging device of claim 1 wherein the launching mechanism includes a launching assembly surrounding the cylindrical body in a circumferential direction of the cylindrical body, the launching assembly including:

the accommodating sleeve is sleeved outside the cylindrical main body and provided with an accommodating groove at one end;

the spiral ring is accommodated in the accommodating groove; and

an end piece disposed at least one end of the receiving sleeve, wherein the end piece disposed at the end of the receiving sleeve at which the receiving groove is disposed is configured to close the receiving groove.

3. The resistivity imaging device of claim 2 wherein the containment sleeve includes a middle section of larger outer diameter and an end section of smaller outer diameter connected to the middle section, the end piece including a main portion disposed at one end of the containment sleeve and a snap-fit portion extending out relative to the main portion and snap-fit over the end section.

4. The resistivity imaging device of claim 3 wherein the containment sleeve comprises:

an outer shell comprising a metal portion provided at the end section, and a wear portion provided at the middle section,

a toroidal insulation sleeve disposed between the outer shell and the tubular body, the insulation sleeve forming the receiving slot thereon, and

and the elastic filling body is filled in a space surrounded among the outer shell, the insulating sleeve and the cylindrical main body.

5. The resistivity imaging device according to any one of claims 2 to 4, wherein a sealing glue is filled in the receiving groove to seal the spiral ring in the receiving groove.

6. The resistivity imaging device of any one of claims 1 to 5 wherein the receiver comprises:

a receiving electrode extending within the outer groove of the cylindrical body in a radial direction of the cylindrical body, an outer end of the receiving electrode being exposed to an environment,

an induction coil disposed within the outer groove, an inner end of the receive electrode extending through the induction coil, and

a coil insulation sleeve surrounding the induction coil and spacing an inner end of the receive electrode from the induction coil.

7. The resistivity imaging device according to claim 6, wherein a positioning hole extending inward in a radial direction of the cylindrical body is configured at a bottom wall of the outer groove, and the coil insulating sleeve is configured with a positioning protrusion that can extend inward in the radial direction of the cylindrical body to be inserted into the positioning hole to prevent the coil and the coil insulating sleeve from rotating relative to the receiving electrode.

8. The resistivity imaging device according to claim 6 or 7, wherein a clamping protrusion extending outwards along a radial direction of the receiving electrode is formed in the middle of the receiving electrode, the inner end and the outer end of the receiving electrode are respectively arranged at two sides of the clamping protrusion,

the receiver still includes the apron, the apron structure is for covering receiving electrode's the outside, wherein, the bellied lateral surface of joint with the apron cooperatees, the bellied medial surface of joint with coil insulation cover cooperatees.

9. The resistivity imaging device of any one of claims 1 to 8 comprising a plurality of receiving mechanisms spaced from each other in an axial direction of the cylindrical body, receivers in different receiving mechanisms being staggered from each other in a circumferential direction of the cylindrical body.

10. The resistivity imaging device according to any one of claims 1 to 9, comprising a plurality of emitting mechanisms spaced apart from each other in an axial direction of the cylindrical body, at least two of the plurality of emitting mechanisms being different in distance from a corresponding receiving mechanism.