JPS60219581A - Device and method of measuring characteristic of bed adjacent to bore hole - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to measuring formation conditions during drilling of a borehole, and more particularly to measuring the slope of a formation using an aperture antenna.

PRIOR ART It is desirable to transmit an electrical signal through the earth's crust as a propagation medium and to receive this signal at a location remote from the transmitter for a number of reasons. Such signal propagation methods are used, for example, both for measurement and communication purposes of various conditions related to this propagation medium. These methods are often used to investigate the environment surrounding the borehole, especially the surrounding geological formations. Various borehole logging methods are available to accomplish these investigations. A group of these methods utilizes electromagnetic field phenomena to obtain data from the environment around the borehole.

One type of electromagnetic logging is electrode logging, which utilizes the electric field in the surrounding formation to generate power vehicles in the formation and make measurements. A conductive mud is required for successful implementation of the system. Inductive logging is another type of electromagnetic logging that utilizes magnetic fields in the formation to generate secondary currents in the formation. Part 2
The secondary current causes a secondary magnetic field that induces a current in the receiving coil placed in the borehole. The induced current in the receiver coil is proportional to the secondary current in the formation, which is directly proportional to the conductivity and inversely proportional to the resistivity of the surrounding formation. Electromagnetic wave propagation also provides another logging method for investigating the geological formations around a borehole and is also relevant for the purposes of the present invention. A typical electromagnetic logging method for electromagnetic wave propagation is Goui.
No. 3,551,797 to lloud et al. This patent discloses a wireline system having a transmitter and a pair of receivers disposed along the axis of the borehole. The transmitter propagates electromagnetic energy in a magnetic field uniformly spread radially (azimuthally) around the borehole, and
The signals received by the axially disposed receiving antennas are analyzed in terms of amplitude and phase difference as an indication of the conductivity of the formation surrounding the borehole.

A very useful parameter for measuring the condition of the underground strata penetrated by drilling is the thickness of the strata, which is the plane formed by the boundary of the characteristic stratum and the boundary of the adjacent strata with respect to the standard (standard) horizontal plane. is the angle of More specifically, the slope of the formation is determined by measuring the angle at which the wall of the borehole crosses the boundary surface of the formation. One of the problems of measuring the slope of a geological formation is to place three points in the sedimentary layer with respect to the horizontal plane, as the plane is determined by three points and the slope angle is the angle between the plane and the horizontal plane. be.

Traditional wireline methods used to measure formation orientation require three measurements to be made.

The first is the slope measurement of the formations associated with the drilling, which is carried out by recording three electrical logs oriented azimuthally spaced in the drilling and perpendicular to the axis of the instrument. This is done by including three identical sets of electrodes arranged on a plane and spaced around the perimeter of the device at 120'. The second is a measurement of the inclination angle and direction of the borehole, and the third is a measurement of the orientation of the borehole axis relative to magnetic north.

The inclination and orientation of the borehole are conventionally measured using an accelerometer, which uses the Earth's gravity and magnetic forces as a reference frame.
ometers) and/or magnetometers. However, the slope of the formation requires fairly accurate measurements of the properties of the several formations around the perforation in order to determine along the length of the perforation where a formation of one composition ends and another begins. It will be done.

One type of conventional inclinometer utilizes three self-potential (sp) curves to measure the slope of the formation relative to the drilling axis.

These devices require electrodes pressed against the sidewalls of the borehole to measure minute currents, ie, the potential in the formation relative to a reference potential at the ground surface. Another technique for measuring formation conditions to obtain the slope of a formation is disclosed in U.S. Pat. A wireline device is shown that performs inductive logging by measuring electrical conductivity and magnetic susceptibility.

U.S. Pat. No. 4,383,220 discloses a microwave electromagnetic drilling inclinometer that includes a wireline device with a plurality of radially extending arms having pads biased in tight engagement with the drilling wall. has been done.

Each pad has a microwave transmitting antenna and a microwave receiving antenna. Microwave energy having a frequency on the order of 1 to 3 GIIz is propagated through the formation by a transmitting antenna, and the energy received by the receiving antenna is determined by the relative Changes are treated as indicative of the properties of the strata, as they determine the slope of the strata.

Conventional methods for measuring formation conditions, such as conductive electrodes to measure the self-potential, inductive methods to measure conductivity and magnetic susceptibility, and wireline methods, which also utilize microwave propagation, are particularly important in the environment during excavation. There are certain drawbacks when used for measurements. In order to integrate the measuring device into the drill string of the borehole, the electrode system requires insulating the steel drill collar from some of the transmitting and receiving electrodes of the system. In this case, it is usually necessary to apply a special insulation coating to the steel drill collar near the electrode.
This is expensive and of questionable reliability. Inductive logging methods typically need to be carried out at frequencies on the order of 10 K) Iz and therefore require large diameter coils to obtain the necessary electromagnetic coupling with the formation. In the MWD arrangement, the induction logging coil must be mounted within the drill collar in the drill string, and the corresponding portion of the drill collar must be non-conductive. Non-conductive collars are difficult to maintain the structure and strength required for use in drill strings. Therefore, if the coil size is reduced, the operating frequency of the system must be increased to obtain the necessary coupling between the separated coils.

For fixed size antennas, the operating frequency is 10Kl
Since the wave propagation becomes a predetermined energy transfer mechanism, the standard inductive measurement method with conventional antennas is no longer valid.

As previously mentioned, inclinometers using wireline microwave propagation devices do not use acoustic assemblies that are sufficiently structured and strong to be incorporated into the drill string, and also engage the borehole wall and meet the required conditions. A radially extending appendage is required to enable measurements of , which is of course completely impractical for MWD measurements.

In the use of antenna structures in drilling, the measuring instruments are all actually concerned with the generation of an electromagnetic field to be propagated into the surrounding medium. The subject matter of the present invention operates at frequencies low enough to utilize the induced magnetic field component, but to allow the energy to be focused in a highly directional manner to investigate the properties of the formation surrounding the borehole. is a sufficiently high frequency, i.e.
The fluid dimension (fluid di
It teaches the use of slot antennas for men-tions. Such measurements provide a drilling operation of resistivity/conductivity values that are a signal indication of changing formations or slopes of formations. The essence of this measurement-while-drilling method is to provide the drilling operation with useful continuous data indicative of the conditions within the borehole. Drilling operations can thus anticipate and avoid potentially dangerous situations as well as detecting reliable data necessary to measure the formations that the drilled hole will penetrate. The antenna structure used in the apparatus of the present invention can be easily incorporated into a logging system during excavation.

The device of the present invention is capable of generating electromagnetic energy with a strong H magnetic field component perpendicular to the open end to induce a highly directional magnetic field in the formation adjacent to the drill hole, in order to measure the properties of the formation. The difficulties of the prior art are overcome by providing an aperture antenna device with an integrated structure.

<Configuration of the Invention> The present invention relates to an apparatus for measuring the properties of a subsurface stratum penetrated by a borehole. The device generates electromagnetic energy including a strong H magnetic field in the near field, highly focuses this field into an azimuthally narrow shape, and directs this field into the formation to Contains means for obtaining information regarding properties.

A drilling equipment is provided that includes three aperture antenna assemblies incorporated into a drill string of the drilling equipment and azimuthally evenly spaced about a longitudinal axis of the equipment. The instrument also includes means for receiving signals by means of a similar aperture antenna assembly for measuring properties of the formation.

The present invention provides a method for measuring a feature in a stratum adjacent to a borehole by installing a first aperture antenna in the borehole such that the wall of the opening lies on a plane extending parallel to the axis of the borehole. and equipment.

An electromagnetic field having a strong H magnetic field component and a frequency smaller than the wavelength 174 of the width of the aperture antenna is generated in the hot water at a short distance. The electromagnetic field is split through an aperture antenna to confine a narrow non-propagating induced magnetic field component to penetrate a substantial distance beyond the borehole wall and into the surrounding formation. With electromagnetic energy directed through an aperture antenna to measure properties of a formation oriented in a particular orientation, an electromagnetic signal corresponding to the penetration of the formation is received.

The present invention provides a method of penetrating the formation from the back side by installing a second open hole antenna in the borehole having side walls parallel to the first open hole antenna, and through the second open hole antenna to measure the properties of the formation. A method and apparatus for measuring properties of a formation adjacent to a borehole by receiving electromagnetic signals is included.

Additionally, the present invention involves the use of a pair of remotely located receive aperture antennas and the measurement of the phase difference between the electromagnetic signals received by the two antennas as a measure of the properties of a geological formation oriented in a particular orientation. intended. In addition, the present invention includes a plurality of pairs of transmitting and receiving aperture antennas spaced azimuthally from one side to the other to simultaneously measure properties of formations oriented in different orientations.

The invention further provides a method and apparatus for measuring the properties of a geological formation adjacent to a borehole, wherein the side wall of the aperture antenna is rectangular with its long side parallel to the axis of the borehole, and the frequency of the electric order magnetic field is 2M1lz frame. and the size of the aperture antenna is 0.5 to 6 inches (0.12 to 15.24c+
n).

In other respects, the present invention provides an apparatus for measuring the thickness and slope of a formation penetrated by a borehole during measurements, the invention comprising: a drill collar spaced around a cross section; Includes having a conductive cylindrical portion of a drill collar having a plurality of first cavities formed in a cross-sectional body. The drill collar also includes electromagnetic field generating means attached to each of the first cavities together with a plurality of first open antennas formed on the outer wall of the body of the portion and communicating with each of the first cavities, the electromagnetic field generating means being attached to each of the first cavities. A frequency having a magnetic field strength H component and having a long wavelength relative to the size of the aperture antenna for directing a narrowly limited lobe of induced electromagnetic energy through the aperture antenna into the perforated wall at a predetermined distance. have The drill collar further includes a plurality of second cavities axially spaced apart from, but coincident with, each of the first cavities and formed in the body of the portion of the drill string and an outer wall of the portion. and a plurality of second open antennas formed in and communicating with each of the second cavities. The device is mounted in each of the second cavities, and includes means for receiving electromagnetic energy from the formation surrounding the borehole in response to energy directed into the formation through the first open antenna; means for measuring the formation condition of the borehole along the length of the borehole in response to the energy applied and for measuring the slope and thickness of the formation penetrated by the borehole.

Referring to FIG. 1, a drilling rig 11 is illustrated located at the top of a borehole 12. As shown in FIG. System (device) for measuring the slope of underground strata during drilling 10 One specific example is drilling 12
Sub 1 including the part of the drill collar 15 placed in the
Retained by 4.

The water system 10 is used to measure parameters (factors) related to the geological structure around the borehole and the slope of the stratum through which the borehole penetrates during measurements.

Still referring to FIG. 1, a drill bit 22 is located at the lower end of drill string 18.

The borehole 12 in the formation 24 is drilled while the drilling mud 26 is pumped through the valve head 28. Metal surface casing 2
9 is shown positioned within the borehole 12 above the drill bit 22 to protect the borehole 12 near the surface. As described below, the present invention makes it possible to accurately measure the inclination angle of the stratum through which the perforation penetrates by measuring during the perforation. The annular cavity 16 between the drill string 18 and the drilling wall 20 essentially becomes a flow path filled with return mud. The muddy water is supplied to the pump device 30 through a muddy water supply pipe 31 connected to the drill string 18.
It is pumped in from the valve head 28 by. Drilling mud is thus forced down the axial passageway of the drill string 18 and directed from the drill bit toward the surface for transporting cuttings, including rock and crustal cuttings and related materials. It flows upward from 22. A conduit 32 is provided in the valve head for directing mud from the borehole 18 to the mud bit 34. The drilling mud is typically handled and treated by various devices W (not shown) such as a degasser and a circulation tank to maintain a selected viscosity and consistency of the mud. This device included in Sub 14 is capable of detecting R, which has a magnetic field strength H component near the stratum around the drilling hole.
F. Allows directional control of electromagnetic energy and allows measurement of the properties and composition of the surrounding formation while pumping drilling fluid through the drill pipe.

Continuing to refer to FIG. 1, a sub 14 and drill collar 15 are shown containing a portion of the apparatus 10 of the present invention in a lower drilling environment. This device is capable of handling adjacent strata (multiple)
It is configured to generate signals for recording at the bottom of the borehole and for telemetry from the valve head, information about the composition of the formation and the angle of inclination of the formation relative to the axis of the borehole. The information includes the electromagnetic antenna and sub-14 as described in more detail below.
obtained by a device placed inside. The essential telemetry and analysis equipment is of conventional construction and is not specifically described.

However, methods and apparatus for the measurement of formation conditions are explained in detail below and are the subject of the present invention.

The basic principle of the system (device) according to the present invention incorporates a structure conventionally called a slot antenna. Slot antennas are typically constructed such that L=Nλ/2. That is, the length of the antenna is an integer multiple of half the wavelength of the electromagnetic radiation produced by the antenna. A further important consideration is the energy radiated and propagated to distant locations by such antenna devices. However, for use in measurements during excavation, it is quite practical to design an antenna structure that is exactly half a wavelength in length in the desired operating environment! A'uN,
.

The measuring machine number at the bottom of the borehole is operated in the formation, where the conditions of composition of the propagation medium can change, and the wavelength, and therefore the distance that constitutes a half-wavelength, can also vary widely. Thus, it is not possible to operate a slot antenna under varying resonances in the surrounding transmission medium.

What is required to effectively make azimuthally definitive measurements by electromagnetic radiation is the construction of an aperture antenna that generates a highly directional, strong magnetic field H in the nearby magnetic field environment. As used herein, the term strong H magnetic field means that the vector magnitude of the magnetic field H of electromagnetic radiation is large relative to the vector magnitude of the magnetic field E at a particular distance away from the antenna. Similarly, a strong local magnetic field E means that the vector quantity of the magnetic field E is larger than the vector quantity of the magnetic field H. A strong local H magnetic field is desired. This is because an antenna producing a strong local magnetic field H can produce a strong local magnetic field E in inducing a current at a point away from the borehole without being overly sensitive to the geometry of the borehole or local structural conditions. This is because they are much more effective than conventional antennas.

The ability to induce currents in the formation is essential in order to be able to subsequently measure the signal produced by the induced current, which is proportional to the composition of the formation. Furthermore, the ability to induce electrical currents at some distance from the perforation, the mud cake region and the penetrated site is an essential factor in determining the composition of the undisturbed formation. The present proposal thus includes a method for exciting an aperture antenna in a manner effective for producing strong local H magnetic fields and inducing currents in remote formations.

As shown in FIG. 2, the shape of the aperture used in such a measurement method is quite conventional, and a specially shaped hole is not necessarily required. As shown in FIG. 2, the wall of drill collar 41 defines an opening 42 whose outer periphery defines an irregular periphery 43. As shown in FIG. In the body of the drill pipe 41 an electromagnetic field is excited to produce an H magnetic field in the direction of the arrow 44 perpendicular to the opening edge 43 of the opening 42 . With the Ha field directed in this way, a current is induced to flow around the edge of the aperture and energy is radiated in a direction perpendicular to the aperture edge 43 towards the external environment.

Still referring to FIG. 3, a rectangular opening 45 having generally straight sidewalls 46 is formed in the wall of the drill collar 47. Immediately adjacent the aperture 45 and towards the interior of the drill collar there is a loop antenna of one or more turns of wire 48 which allows the current to flow in the direction of arrow 49 so as to produce a local H magnetic field in the direction of arrow 50. RoF, energy actuated to flow in the direction. To create the desired radially directed H magnetic field, the slot or aperture 45 is excited by R, F energy whose size in the sidewalls 46 of the aperture 45 is at a frequency greater than the wavelength of the energy. is preferred. Thus, the slot or aperture antenna taught by the present invention is not operated at or near its resonant frequency to propagate energy into the surrounding formations, but rather in the near field directed radially away from the aperture 45. It can be seen that the R,F induced field is operated well below its resonant frequency to produce an R,F induced magnetic field with a strong H component.

As further shown in FIG. 4, the aperture or slot antenna used in the present invention is constructed in a manner and frequency selected such that the energy is directed to the formation in a highly selective manner. As shown, the illustrated drill collar 51 has a plurality of slots 52 formed at 90° angles to each other and located in a common plane transverse to the axis of the drill collar 51. The antenna aperture or slot has a collimating or focusing effect in the horizontal plane illustrated by the near field pattern 53 shown extending into the formation 54.
ing or focusing effect). Furthermore, it is understood that similar vertical focusing effects are necessary to provide the vertical resolution (accuracy) necessary for high performance formation logging capable of measuring formation slope. Several openings 52 formed in the circumference of the drill collar 51 allow for multiple measurements at the same time. However, it is understood that a single aperture or aperture arrangement can be used to make multiple measurements in different directions and in relation to orientation while monitoring equipment to measure the slope of the formation. be done.

It is clear that a series of azimuth measurements are repeated as the drill string descends through the formation to obtain all the information necessary to measure the slope of the formation as well as the thickness of the single layer. Will.

Subresonant frequency
It should be understood that the slot or aperture antennas used in the perforations may be arranged in transmitter pairs as other shapes of perforation arrays form patterns of energy directed during the perforations.

Indeed, the relationship between the electrical conditions and the physical configuration of the formation adjacent to the borehole is known such that from the combination of the clearly measured electrical conditions the slope of the formation can be determined. Therefore, it is rather essential to the invention that the axial and azimuthal positions in the drilling where the electrical conditions change can be easily determined as an indication of the transition zone between one formation and the next adjacent formation. It is possible to determine the electrical conditions of the strata.

Referring to FIG. 5, there is shown a schematic, partially cutaway cross-sectional view of sub 14 carrying a device constructed in accordance with the teachings of the present invention.

Sub 14 preferably includes a drill collar coupled between sections of drill pipe containing drill string 18 located in borehole 12 . The borehole 12 penetrates a formation that includes a shale layer 61 and a clay layer 62 with a boundary illustrated by reference numeral 63 therebetween for purposes of illustration. The operation of the method and apparatus (system) of the invention is to measure several points along the wall of the borehole 12 where the boundary layer 63 crosses the borehole 12 in order to determine the slope angle of the boundary layer of the formation. It is. Note that layers 61 and 6
It should be understood that the relationship between 2 and boundary layer 63 is shown for illustrative purposes only. In fact, instead of clear boundaries of the illustrated area, the geological structure transitions are more gradual.

The sub 14 has a cylindrical copper body (drill collar) 71 having an axial passage 72. The passage hole 72 allows the drilling fluid to flow down the drill string and into the drill bit 22, and the sub 14
The annular cavity 16 between the sides of the borehole 12 and the wall of the borehole 12 allows the flow to flow back to the surface. The annular cavity 16 is filled with conductive drilling fluid. One formed end of the cylindrical drill collar 71 adjacent to the hole 72 is a step 73 forming an equipment compartment 74 , the compartment 74 being a generally cylindrical drill collar 71 having an inner diameter that is the same as the inner diameter of the axial passageway 72 . The insert 75 and a radial funnel-shaped upper end member 76 for closing the equipment chamber 74 are sealed to prevent drilling fluid from penetrating.

Equipment room 74 includes both a radio frequency transmitter and a radio frequency receiver along with a power source, and includes recorders and/or instruments that communicate data to the surface by means not shown.

The embodiment of the invention illustrated illustratively in FIG. 5 includes three sets of aperture or slot antennas mounted at 120 degrees from one to the other. The transmitter slot 81 is rectangular with its longitudinal direction extending parallel to the axis of the drill collar. The transmitter hole is, for example, one and a half inches (3.8 cm) in diameter.
) and 4 to 6 inches (10 to 15 cm) long.

Each slot 81 is located radially from the antenna mounting recess 82 to the outside in the drill collar, and the recess 8
2, an elliptical loop transmission antenna 83 is located in which the longitudinal direction of the slot 81 and the longitudinal direction of the loop are in the same direction. Each loop 83 has one or more turns of conductive material, the end of which is connected to the output end of the radio frequency transmitter through a recess 82 for antenna attachment through the steel body of the drill collar 81. It is guided by conduit 84.

Similarly, immediately below the first transmitting antenna 81 is an identical first receiving slot or aperture antenna 91 having a first receiving antenna mounting cavity 92 formed radially inward.

The first slot receive antenna 91 is disposed axially a distance on the order of several inches from the transmit antenna 81 and is aligned with the axis. Attached to each cavity 92 is a loop-type receiving antenna 93, the end of which is guided by means of a tubular guide 94 for connection to a receiver located within the equipment chamber 74.

The device of the present invention is intended to have a second open antenna 101 disposed directly below the first open receiving antenna 91 and spaced apart from each other on the same axis. The second receiving antenna 10
1 is disposed at a distance of about 2 to 3 inches from the first antenna 91 in the axial direction. Each second open antenna 101
is connected to the second receiving antenna mounting cavity 102. A second oval-shaped loop receive antenna 103 having one or more turns of conductive wire is mounted in each cavity 102, the end of which is tubular for connection to a receiver located within the equipment compartment 74. It is guided by a guide 104.

The interior of the antenna mounting cavity and opening or slot antenna is filled with a strong elastic insulation material to secure the transmitting and receiving antennas, protect them from the harsh environment during drilling progress, and to protect the outer periphery of the drill collar. It closes against the ingress of drilling fluids and forms a continuous outer surface.

The size of an aperture antenna is much smaller than a quarter to half a wavelength at that frequency. Rather than operating as a resonator to propagate electromagnetic energy to the surrounding formations, the slot antenna is a columnnator (coLL, mnators). The loop antenna 83 is operated in such a way that the induced electromagnetic field pattern has a very strong H field component in a close range field that maximizes the penetration and visibility of the magnetic field within the formation. Similarly, the slot or aperture receiving antenna acts to confine a narrow electromagnetic field pattern, which excites the oval loop receiving antenna 93 in response to the received signal caused by the conductivity of the formation changing in response to the induced magnetic field.

Three transmitting antennas 81 are arranged around the circumference of the drill collar 15a, and R, which has a strong H magnetic field component in the near field,
F, and when the receive slot antennas 91 are each used simultaneously, these received signals are indicative of the conductivity of the formation adjacent to each respective receive antenna slot 91. The drill stem 18 is axially lowered through the drilling hole, and subsequent transmissions are made from each of the three slot transmission antennas 81 disposed around the circumference,
If the received signals at the three receiving slot antennas 91 arranged around the circumference are compared with the previous readings, an indication is now given of the change in the strata around the borehole with distance along the borehole. More specifically, the variation in conductivity as a function of both longitudinal and azimuth along the borehole can be performed by conventional software to display the slope of the formation through which the borehole penetrates.

In another preferred mode of operation, the signal induced into the formation through the emitted aperture antenna 81 is transmitted through the array of first receive aperture antennas 91 and the second receive aperture antenna 10.
1 array. First antenna 91
The phase difference between the signals received by the second antenna 101 and the second antenna 101 is indicative of the nature of the formation adjacent to the borehole. This phase difference is measured between the outputs of the two received signals by a phase comparator located in the equipment room 74 containing the receiver. By moving the instrument down the borehole to measure the phase difference movement several times, the slope of the formation and the thickness of the monolayer can be determined by conventional signal analysis techniques.

An essential feature of the invention is that a slot or aperture antenna in combination with a highly directional, large amplitude non-propagating electromagnetic wave energy, i.e., a non-propagating magnetic field component of an induced magnetic field, penetrates a substantial depth in the formation surrounding the borehole. is to use. The induced-field modes of the excitation signal can penetrate deeper distances outside the perforation wall than is possible with resonantly propagating microwaves taught by the prior art.

As can be understood from the foregoing disclosure, the apparatus and method of the present invention, as one of the measurement methods during drilling, accurately measure numerical values of formation conditions determined with vertical and azimuth accuracy during drilling. Allows you to measure.

The operation and structure of the invention will be apparent from the foregoing description. It will be obvious that the methods and apparatus illustrated and described are shown as preferred and that various changes and modifications may be made thereto without departing from the spirit and spirit of the invention as claimed. Probably.

[Brief explanation of the drawing]

FIG. 1 is a schematic side cross-sectional view of a borehole drilling operation illustrating electromagnetic interrogation of the formation penetrated by the borehole. FIG. 2 is an enlarged partial perspective view of a drill pipe with an aperture antenna formed to generate an electromagnetic field; FIG. FIG. 4 is a top view of an aperture antenna array mounted on a drill collar, illustrating the induced electromagnetic field emanating from each aperture. FIG. 5 shows the method of the present invention 8. for measuring the slope of the subsurface strata along the perforation. FIG. 3 is a diagram showing a partial cross section along the longitudinal direction of the excavation width measuring device integrated with the aperture antenna device of FIG. . In the drawings, II...Drilling rig, 12...Drilling, 14.
... Sub, 15 ... Drill collar, 16 ... Annular cavity, 18 ... Drill string, 20 ... Perforation wall, z
2... Drill bit, 26... Mud water, 28... Casing, 30... Pump, 31... Mud water supply pipe, 32... Conduit, 34... Mud water pit, 42.45
...Opening, 46...Side wall, 51...Drill collar, 52...Opening, 71...Drill collar, 72...
・Axis passageway, 73...Stepped portion, 74...Control room, 81
... slot, 82 ... recess, 83 ... transmitting antenna, 91 ... receiving antenna. Patent applicant N.L. Industries, Inc. Representative Patent attorney Masahiro Matsui

Claims (1)

[Scope of Claims] (1) An apparatus for measuring characteristics of a stratum adjacent to a drilling hole. an electrically conductive cylindrical housing; a cavity formed within the housing; an aperture formed in the outer wall of the housing, communicating the cavity with an annular gap between the housing and the perforated wall; mounted in the cavity. the dimensions of said aperture antenna, said electromagnetic field generating means, said electromagnetic field having a strong H field component and directing a narrowly confined beam of induced electromagnetic energy a substantial distance into the wall of the perforation at that frequency; a means installed in the cavity for receiving energy from the strata around the perforation wall corresponding to the emitted energy; a stratum containing the perforation in response to the received energy; means for measuring the properties of; (2. A device for measuring the characteristics of a stratum adjacent to a borehole as set forth in claim 1, wherein the aperture antenna is rectangular, and the size of the aperture antenna is equal to the wavelength of the induced electromagnetic energy. integral fraction
ction). (3) A device for measuring the characteristics of a geological formation as set forth in claim 1, comprising: a second cavity formed in the housing; a second cavity formed in the housing and communicating with the second cavity; A second aperture antenna in which the signal receiving means is disposed within a second cavity. (4) The device for measuring the characteristics of a geological formation as set forth in claim 3, wherein the first and second open antennas are both rectangular, and the long sides thereof are parallel to the central axis of the housing. These two aperture antennas are vertically spaced apart from each other in a row. (5) An apparatus for measuring the characteristics of a stratum as set forth in claim 1, which includes means for monitoring the orientation of the aperture antenna during measurement. (6) An apparatus for measuring the characteristics of a geological formation as set forth in claim 1, wherein the electromagnetic field has a frequency of about 2 MHz, and the aperture antenna has a size of 0.5 inches to 6 inches ( 0.12 to 15.24 cm). (7) An apparatus for measuring the characteristics of a geological formation as set forth in claim 1, wherein the cavity and the aperture antenna are filled with an insulating material. (8) A device for measuring the characteristics of a geological formation as set forth in claim 1, wherein the conductive cylindrical portion of the drill collar is formed at intervals on the circumference of the body of the portion of the nitrile collar. a plurality of first cavities; formed on the outer wall of the portion;
a plurality of first aperture antennas communicating with each of the first cavities; an electromagnetic field generating means attached to each of the first cavities, wherein the electromagnetic field has a strong H magnetic field component and whose wavelength at the frequency is the same as that of the apertures; of a frequency that is long relative to the dimensions of the antenna and directs a narrow, confined lobe of induced electromagnetic energy through said aperture antenna and into the perforated wall a substantial distance; axially from each of said first cavities; a plurality of axially spaced second cavities formed in the body of the portion of the drill string; a plurality of second cavities formed in the outer wall of the portion and communicating with each of the second cavities; a second aperture antenna of: a means for receiving electromagnetic energy from the formation surrounding the borehole in response to energy directed into the formation through the first open antenna, mounted in each of the second cavities; 1. Measuring the formation conditions of the borehole along the length of the borehole in response to received energy and measuring the slope and thickness of the strata penetrated by the borehole; Measures the slope and thickness of the strata penetrated by. (9) The device for measuring the characteristics of a stratum as set forth in claim 8, wherein the first and second open antennas have a rectangular cross section in the longitudinal direction parallel to the fine details of the portion of the drill collar. something that is. (10) The device for measuring the characteristics of a stratum as set forth in claim 8, wherein the first and second cavities and the first and second open antennas close the drill collar and are continuous. An outer surface filled with a durable elastic insulating material. (11) An apparatus for measuring characteristics of a geological formation as set forth in claim 8, wherein the electromagnetic field generating means is arranged on a plane substantially parallel to the plane of an aperture antenna and a transmitter coupled to the antenna. Consisting of a loop-shaped antenna located at (12. An apparatus for measuring the characteristics of a geological formation as set forth in claim 8, wherein the electromagnetic field has a frequency of about 2 MHz, and the size of the aperture antenna is 0.5 inches to 6 inches ( 0.12 to 15.24 cm), and the antenna is operated in a non-resonant mode. (13) An apparatus for measuring the characteristics of a geological formation as set forth in claim 8, comprising: a drill; a plurality of third cavities formed in the body of said portion of the collar at intervals around the circumference; a plurality of third openings formed in the outer wall of said portion and communicating with said third vagina; an antenna; means for receiving electromagnetic energy from the formation surrounding the perforation in response to energy directed into the formation through the first open antenna; and means for responding to the received energy; including means for comparing the phase difference between the signals received by the second and third open antennas in order to measure the formation conditions of the drilling. (14) Measuring the properties of the formation adjacent to the drilling. A first open antenna is installed in a borehole so that the opening wall is located on a plane extending parallel to the axis of the borehole, and the first open antenna has a strong H magnetic field component in hot water at a short distance, and the antenna has a strong H magnetic field component. through said aperture antenna for generating an electromagnetic field having a frequency small to 174 wavelengths in width and confining the narrow non-propagating induced magnetic field component to penetrate beyond the borehole wall and into the surrounding formations a substantial distance; Direct the electromagnetic field to the surrounding strata,
A method comprising receiving an electromagnetic signal corresponding to penetration of a formation by electromagnetic energy directed through the aperture antenna to measure properties of the formation. (15) A method for measuring the characteristics of a stratum adjacent to a borehole according to claim 14, wherein the receiving step includes a second opening in the borehole having a side wall parallel to the first open antenna. and receiving electromagnetic signals penetrating from behind the formation through a second open antenna to measure properties of the formation. (16) A method for measuring the characteristics of a stratum adjacent to a borehole according to claim 14, wherein the side wall of the aperture antenna has a rectangular shape with a long side parallel to the axis of the borehole. (17) A method for measuring the characteristics of a stratum adjacent to a borehole according to claim 14, wherein the frequency of the electromagnetic field is on the order of 2 MHz, and the size of the aperture antenna is between 0.5 and 6 MHz. inch (0.12~15.24cm
). (18) A device for measuring the characteristics of a stratum adjacent to a borehole, wherein the first open antenna is installed in the borehole so that the aperture wall is located on a plane extending parallel to the axis of the borehole; short distance 1 of the open antenna which has a strong H magnetic field component in hot water.
Means for generating an electromagnetic field having a frequency small relative to 1 to 174 wavelengths; through an aperture antenna to confine a narrow non-propagating induced magnetic field component to penetrate into the surrounding strata at a substantial distance beyond the borehole wall; means for directing said electromagnetic field into surrounding formations; means for receiving electrode signals corresponding to penetration of the formation by electromagnetic energy directed through said aperture antenna to measure properties of the formation; (19) An apparatus for measuring the characteristics of a stratum adjacent to a borehole as set forth in claim 18, wherein the receiving portion has a second opening in the borehole having a side wall parallel to the first open antenna. means for installing an antenna; means for receiving electromagnetic signals penetrating from behind the formation through a second open antenna for measuring properties of the formation; (2. An apparatus for measuring the characteristics of a stratum adjacent to a borehole according to claim 18, wherein the side wall of the aperture antenna has a rectangular shape with a long side parallel to the axis of the borehole. (2) , an apparatus for measuring the characteristics of a geological formation adjacent to a borehole as claimed in claim 18, wherein the frequency of the electromagnetic field is on the order of 2 MHz and the size of the aperture antenna is between 0.5 and 6 inches ( 0.12~15.24cm)
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