Title:
DATA-SIGNALING APPARATUS FOR WELL DRILLING TOOLS
United States Patent 3711825
Abstract:
In the preferred embodiments of the invention disclosed herein, a well tool having new and improved data-signaling apparatus and carrying a drill bit on its lower end is dependently coupled from a drill string and lowered into a borehole being excavated. During the drilling operation, measurements are successively made of selected borehole conditions, formation properties, or the like, which are converted by the data-signaling apparatus into coded electrical signal for repetitively initiating the operation of a valve of unique design operatively arranged on the tool to be selectively actuated by the drilling fluid interrupting the flow of the drilling fluid being circulated through the drill string. In this manner, the valve functions to produce a series of encoded pressure pulses in the drilling fluid which are representative of the measurements being obtained. These pressure pulses are transmitted through the drilling fluid to the surface where they are sensed and converted into meaningful indications of the measurements.


Inventors:
CLAYCOMB J
Application Number:
05/059395
Publication Date:
01/16/1973
Filing Date:
07/30/1970
Assignee:
Schlumberger Technology Corporation (New York, NY)
Primary Class:
Other Classes:
36/18
International Classes:
E21B47/18; (IPC1-7): G01V1/14
Field of Search:
340/18LD,18NC
View Patent Images:
US Patent References:
2787759Apparatus for logging wells1957-04-02Arps
2759143Earth borehole investigation-signaling system1956-08-14Arps
2700131Measurement system1955-01-18Otis et al.
2435934Signalling clinograph1948-02-10Jarney et al.
2300823Indicating device for well drills1942-11-03Whitman
1963090Apparatus for detecting excessive deviation of drill holes1934-06-19Jakosky
Primary Examiner:
Borchelt, Benjamin A.
Assistant Examiner:
Moskowitz N.
Claims:
What is claimed is

1. Apparatus adapted for transmitting data to the surface during the drilling of a borehole and comprising: a tubular drill string having a borehole-drilling device dependently coupled thereto and defining a flow passage for circulating drilling fluids between the surface and said borehole-drilling device; data-signaling means on said drill string adapted for producing electrical signals indicative of at least one downhole condition; and pressure-signalling means on said drill string adapted for producing pressure pulses in drilling fluids flowing through said drill string which are representative of the electrical signals produced by said data-signaling means, said pressure-signaling means including valve means adapted for movement between a passage-opening position and a passage-obstructing position for obstructing the flow of drilling fluids through said flow passage, a valve actuator adapted for movement between an inactive position and first and second spaced positions in said flow passage, said valve actuator having a fluid-impingement surface thereon adapted to be moved into the path of drilling fluids passing through said flow passage upon movement of said valve actuator to its said first position and operatively arranged for utilizing such fluids for carrying said valve actuator to its said second position, means on said valve actuator operatively arranged to engage said valve means only after said valve actuator is moved to its said first position and then shift said valve means to said passage-obstructing position as said valve actuator is carried to its said second position, first means responsive to said electrical signals adapted for moving said valve actuator to its said first position, and second means adapted for returning said valve actuator to its said inactive position and returning said valve means to said passage-opening position.

2. The apparatus of claim 1 further including means adapted to be located at the surface and responsive to said pressure pulses transmitted to the surface for providing indications of said pressure pulses.

3. The apparatus of claim 1 wherein said first means include an electrical solenoid coupled to said data-signaling means operatively associated with said valve actuator and adapted for initiating movement thereof to its said first position upon energization of said solenoid by said data-signaling means.

4. The apparatus of claim 1 wherein said second means include means adapted for reducing pressure differentials across said valve means after said valve means are in said passage-obstructing position, and biasing means operable only upon movement of said valve actuator to its said second position for returning said valve actuator to its said inactive position and returning said valve means to said passage-opening position once such pressure differentials across said valve means are reduced.

5. Apparatus adapted for transmitting data to the surface during the drilling of a borehole and comprising: a body adapted for connection in a tubular drill string and having a flow passage arranged to carry drilling fluids between the surface and a borehole-drilling device dependently coupled therebelow; and pressure-signaling means on said body and including means defining a valve seat in said flow passage, an annular valve member operatively arranged in said flow passage and adapted for longitudinal movement into and out of engagement with said valve seat, a valve actuator coaxially arranged within said valve member and operatively adapted for longitudinal movement in relation to said body and said valve member between first and second spaced positions on opposite sides of said valve seat, an enlarged portion on said valve actuator adapted to pass through said valve seat as said valve actuator is moved between its said first and second positions, means on said enlarged portion defining a fluid-impingement surface adapted to be struck by drilling fluids entering said valve seat once said valve actuator is moved away from it said first position and operatively arranged for such fluids to carry said valve actuator on to its said second position, electrical means operable in response to electrical signals for initiating movement of said valve actuator away from its said first position, first means on said valve actuator adapted to engage said valve member after said valve actuator has moved away from its said first position and operatively arranged for carrying said valve member into engagement with said valve seat as said valve actuator is moved to its said second position, and second means operatively arranged for returning said valve actuator to its said first position and carrying said valve member out of engagement with said valve seat.

6. The apparatus of claim 5 wherein said second means include baising means operative only upon movement of said valve actuator to its said second position for returning said valve actuator to its said first position, and means on said valve actuator adapted to engage said valve member as said valve actuator is returned toward its said first position for carrying said valve member out of engagement with said valve seat by the time that said valve actuator reaches its said first position.

7. The apparatus of claim 5 wherein said second means include means adapted for reducing pressure differentials across said valve member once said valve member is engaged with said valve seat, and biasing means operative only upon movement of said valve actuator to its said second position for returning said valve actuator to its said first position once such pressure differentials across said valve member are reduced, and means on said valve actuator adapted to engage said valve member as said valve member is returned toward its said first position for carrying said valve member out of engagement with said valve seat by the time that said valve actuator reaches its said first position.

8. The apparatus of claim 7 further including second biasing means adapted for retaining said fluid-impingement surface against said valve member while said valve actuator is in its said first position and said valve member is disengaged from said valve seat.

9. Apparatus adapted for determining at least one downhole condition while excavating a borehole and comprising: a tubular drill string having a borehole-excavating device dependently coupled thereto and adapted for circulating drilling fluids between the surface and said borehole-excavating device; data-signaling means on said drill string adapted for producing electrical signals indicative of at least one downhole condition; and pressure-signaling means adapted for developing pressure pulses in drilling fluids flowing through said drill string for transmission through such fluids to the surface and including first means coupled in said drill string and defining a fluid passage for conducting drilling fluids between said drill string and said borehole-excavating device, second means movably arranged on said first means for movement between a normal position away from said flow passage and an operating position in said flow passage, third means movably arranged on said first means for movement between a normal position allowing flow of drilling fluids through said flow passage and an operating position for cooperating with one of said first and second means to temporarily retard flow of drilling fluids through said flow passage for producing said pressure pulses, actuating means including electrical means operable in response to said electrical signals for selectively moving said second means away from its said normal position, fluid-responsive means operatively arranged on one of said movable means for cooperatively moving said one movable means from one of its said positions to the other of its said positions, and biasing means responsive only after movement of said one movable means from its said one position for respectively returning said second and third movable means to their said normal positions.

10. The apparatus of claim 9 further including means adapted to be located at the surface and responsive to said pressure pulses transmitted to the surface for providing indications of said pressure pulses.

11. Apparatus adapted for determining at least one downhole condition while excavating a borehole and comprising: a tubular drill string having a borehole-excavating device dependently coupled thereto and defining a flow passage for circulating drilling fluids between the surface and said borehole-excavating device; data-signaling means on said drill string adapted for producing electrical signals indicative of at least one downhole condition; and pressure-signaling means on said drill string adapted for selectively developing pressure pulses in drilling fluids flowing through said fluid passage for transmission through said drill string to the surface and including valve means adapted for reciprocating movement between passage-opening and passage-closing positions in said fluid passage, fluid-obstructing means adapted for reciprocating movement back and forth between an inactive position and an active position obstructing said fluid passage, means cooperatively arranged between said fluid-obstructing means and said valve means and adapted for moving said valve means to said passage-closing position only upon movement of said fluid-obstructing means to said active position for producing said pressure pulses, electrical means operable in response to said electrical signals for selectively initiating movement of said fluid-obstructing means toward said active position, fluid-responsive means operatively arranged on said fluid-obstructing means and operable only upon movement thereof away from said inactive position for utilizing drilling fluids flowing through said fluid passage to move said fluid-obstructing means to said active position, first biasing means responsive only to movement of said fluid-obstructing means to said active position for then returning said fluid-obstructing means to said inactive position, and second biasing means responsive only to movement of said valve means to said passage-closing position for then returning said valve means to said passage-opening position.

12. The apparatus of claim 11 further including means adapted to be located at the surface and responsive to said pressure pulses transmitted to the surface for providing indications of said pressure pulses.

Description:
Those skilled in the art have, of course, long recognized the benefits of obtaining various measurements at the bottom of a borehole during the course of a drilling operation. For instance, such information as the weight on the drill bit, the drill string torque, the inclination and the azimuthal direction of the borehole, bottom hole pressures and temperatures as well as various characteristics of the formations being penetrated are all measurements of significant interest.

Various proposals have, of course, been made heretofore for transmitting such measurements from the bottom of a borehole to the surface. Of the many different tools proposed, perhaps the most promising of all utilize a condition-responsive valve for selectively interrupting the flow of the circulating drilling fluid in a predetermined coded sequence representative of the measurements to produce a series of momentary pressure surges which are successively transmitted through the drilling fluid to the surface for detection by appropriate sensing devices. These proposed tools have, therefore, generally employed a typical solenoid-operated valve which is coupled to one or more condition-sensing devices by means of appropriate electronic circuitry operatively arranged for opening and closing the valve in accordance with this coded sequence.

For various reasons, however, these prior proposals have generally been considered to be unacceptable for commercial drilling operations. For instance, since the signaling valves in such prior tools have customarily been directly operated by solenoids, the mechanical forces required just for operating these solenoids become excessive in even relatively shallow wells. Moreover, by virtue of their substantial power requirements, the physical size of such solenoids make them impractical for the usual sizes of drilling tools.

Accordingly, it is an object of the present invention to provide new and improved data-signaling apparatus for use with well-drilling tools and which is specially adapted for rapidly transmitting downhole measurements to the surface with minimum electrical requirements.

This and other objects of the present invention are attained by providing a well tool adapted to be connected in a drill string having a drill bit dependently coupled thereto for excavating a borehole as a drilling fluid is circulated through the drill string and a fluid passage arranged in the tool. Data-signaling means are arranged on the tool and include condition-measuring means which are coupled to measurement-encoding means adapted for producing coded electrical signals indicative of one or more selected downhole conditions which may be experienced during the course of a drilling operation. To generate distinctive pressure pulses in the circulating drilling fluid representative of such measurements, the measurement-encoding means operatively drive pressure-signaling means arranged on the tool and including valve means adapted to momentarily block or close the fluid passage for developing each pressure pulse. Biasing means are operatively arranged for returning the valve means to a passage-opening position to await the next electrical signal. The pressure-signaling means further include an actuator which, in response to the electrical signals produced by the measurement-encoding means, only initiates the operation of the valve means. Means are operatively associated with the valve means and adapted for utilizing the circulating drilling fluid as a motive force to positively operate the valve means as well as to energize the biasing means each time the actuator is operated.

The novel features of the present invention are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may be best understood by way of the following description of exemplary apparatus employing the principles of the invention as illustrated in the accompanying drawings, in which:

FIG. 1 shows a well tool arranged in accordance with the present invention as it will appear while coupled in a drill string during the course of a typical drilling operation;

FIG. 2 is a schematic representation of a preferred embodiment of the tool shown in FIG. 1;

FIGS. 3-5 schematically depict certain successive operating positions of a preferred embodiment of data-signaling apparatus incorporating the principles of the present invention;

FIG. 6 illustrates an alternative arrangement of one portion of the new and improved data-signaling apparatus shown in FIGS. 3-5; and

FIGS. 7-10 respectively shown the successive operating positions of other data-signaling apparatus of a similar nature and which also incorporates the broader principles of the present invention.

Turning now to FIG. 1, a new and improved well tool 10 arranged in accordance with the present invention is depicted coupled in a typical drill string 11 having a rotary drill bit 12 dependently coupled thereto and adapted for excavating a borehole 13 through various earth formations as at 14. As the drill string 11 is rotated by a typical drilling rig (not shown) at the surface, substantial volumes of a drilling fluid or so-called "mud" are continuously pumped downwardly through the tubular drill string and discharged from the drill bit 12 to cool the bit as well as to carry earth borings removed by the bit to the surface as the mud is returned upwardly along the borehole 13 exterior of the drill string. As is typical, the mud stream is circulated by employing one or more high-pressure mud pumps (not shown) which continuously draw the fluid from a storage pit or vessel for subsequent recirculation by the mud pumps. It will be appreciated, therefore, that the constantly circulating mud stream flowing through the drill string 11 serves as a transmission media that is well suited for transmitting pressure surges or pulses to the surface.

In accordance with the principles of the present invention, data-signaling means 15 are arranged on the well tool 10 and include condition-measuring means 16 such as one or more condition-responsive devices, as at 17 and 18, which are coupled to an appropriate measurement encoder 19 operatively arranged to produce a series of coded electrical signals that are representative of the measurements being obtained by the condition-responsive devices. Pressure-signaling means 20 coupled to the encoder 19 are operatively arranged to respond to these coded signals for selectively generating a corresponding series of pressure pulses in the circulating fluid by momentarily and rapidly interrupting the flow of the drilling fluid through the drill string 11. It will be appreciated, of course, that these transitory pressure pulses or surges will be similar to those caused by a so-called "water hammer." Thus, these pressure waves will be transmitted to the surface by way of the mud stream flowing within the drill string 11 and at the speed of sound in the particular drilling fluid. Accordingly, as will subsequently be explained in greater detail, the pressure-signaling means 20 produce these pressure pulses to provide encoded representations or data indicative of the one or more downhole conditions sensed by the condition-measuring devices 17 and 18. This data is, in turn, successively transmitted to the surface in the form of these pressure pulses for detection and conversion into meaningful indications or records by suitable surface-located pressure-transducing apparatus 21 such as those disclosed in either U.S. Pat. No. 3,488,629 or U.S. Pat. No. 3,555,504.

Turning now to FIG. 2, a schematic view is shown of the new and improved well tool 10 just prior to the production of a pressure surge or pulse which is to be transmitted to the surface by way of the drilling fluid being circulated through the drill string 11. As illustrated, the well tool 10 is comprised of an elongated tubular member 22 that is coaxially arranged within a thick-wall tubular housing 23 which is tandemly coupled in the drill string 11 just above the drill bit 12.

Although the inner member 22 could just as well be permanently mounted in the housing 23, it is preferred to adapt the inner member for selective retrieval to the surface by way of the drill string 11. To facilitate this, the inner bore 24 of the tubular housing 23 is reduced to provide an annular shoulder 25 on which the lower end of the tubular member 22 is cooperatively seated and releasably latched to the housing by means such as one or more inwardly contractible latch fingers 26 having outwardly enlarged heads as at 27 which are dependently arranged on the inner member and adapted to contract as they pass through the annular shoulder and then spring outwardly again to secure the inner member in its depicted position. Upright collet fingers 28 having inwardly directed shoulders 29 are mounted on the upper end of the inner tubular member 22 and cooperatively arranged for receiving a conventional wireline grapple or overshot (not shown) adapted for being coupled therewith to permit the inner member to be retrieved to the surface through the drill string 11.

Although a self-contained power supply could be employed, it is preferred to utilize the flowing mud stream as a motivating source for generating electrical power for operation of the new and improved well tool 10. Accordingly, in the preferred manner of accomplishing this, a reaction turbine 30 is journalled, as by a bearing 31, to the upper end of the inner member 22 and operatively arranged to be rotatively driven by the downwardly flowing drilling fluid for driving a generator 32 coupled to the turbine by an elongated shaft 33. To facilitate the operation of the turbine 30, the inner bore 24 of the outer housing 23 is enlarged to provide an annular cavity or chamber 34 into which the mud stream will be discharged from the outlet ports 35 of the turbine. One or more longitudinal passages, as at 36, are formed in the outer housing 22 for conducting the mud stream from the upper chamber 34 to another chamber 37 formed therebelow in an intermediate portion of the outer housing. It will be appreciated, therefore, that during the operation of the well tool 10, the circulation of the drilling fluid or mud will be effective for continuously driving the turbine 30 and the generator 32 coupled thereto to produce electrical power for operating the data-signaling means 15.

As depicted in FIG. 3, at least a substantial portion of the mud stream leaving the intermediate chamber 37 enters one or more downwardly inclined lateral ports 38 formed at an intermediate location in the inner member 22 and is directed thereby through an annular valve seat 39 coaxially arranged within the longitudinal bore 40 of the inner member and just below the ports on through the lower portion of the inner tubular member. To produce the aforementioned pressure pulses, the pressure-signaling means 20 include an annular valve member 41 which is slidably arranged in the longitudinal bore 40 of the inner member 22 and adapted for reciprocating movement therein between an elevated position just above the fluid ports 38 and a lower port-closing position over the ports where the valve member is cooperatively received within the valve seat 39. To prevent unbalanced longitudinally acting pressure forces from retarding the upward and downward movements of the valve member 41, one or more longitudinal passages 42 are arranged through the valve member. Accordingly, it will be recognized that so long as the valve member 41 remains in its elevated position depicted in FIG. 3, the drilling fluid can freely circulate from the chamber 37 through the lateral ports 38 and the valve seat 39 and pass without significant restriction on through the lower portion of the longitudinal bore 40 to the drill bit 12 therebelow. On the other hand, it will be appreciated that downward movement of the valve member 41 into the valve seat 39 will momentarily at least block or close the fluid ports 38 and produce a corresponding pressure surge or pulse which will be transmitted back up the mud stream in the drill string 11 for detection at the surface.

To actuate the valve member 41, the pressure-signaling means 20 further include an elongated rod 43 which is coaxially arranged within an upright tubular extension 44 secured to the valve member and adapted for sliding axial movement in relation thereto. The lower end of the elongated rod 43 is enlarged, as at 45, to provide a head adapted to closely fit within the longitudinal bore 40 below the valve seat 39 as well as to define an upwardly directed surface 46 which, in the elevated position of the slidable rod depicted in FIG. 3, is located just above the flow path of the drilling fluid passing through the lateral ports 38. To further assure that the upper surface 46 of the enlarged head 45 is out of the flow path of the drilling fluid, the lower end of the valve member 41 is counterbored, as at 47, for complementally receiving the uppermost portion of the head.

It will be appreciated from FIG. 4, however, that a limited downward movement of the slidable rod 43 in relation to the valve member 41 will position the upwardly directed surface 46 at least partially in the main flow path of the drilling fluid passing through the ports 38. Thus, the impingement of the drilling fluid on the surface 46 will be effective for shifting the elongated rod 43 further downwardly in relation to the ports 38 and the valve member 41 to position the head 45 within the longitudinal bore 40 below the valve seat 39. This downward movement of the elongated rod 43 will also bring an enlarged shoulder 48 arranged thereon downwardly into engagement with an enlarged head 49 formed on the upper end of the tubular extension 44 of the valve member 41.

Accordingly, once the rod 43 has moved downwardly a sufficient distance to engage the shoulder 48 with the enlarged head 49, continued downward travel of the elongated rod will be effective for shifting the valve member 41 downwardly to its port-blocking position within the valve seat 39 to halt further flow of the drilling fluid through the ports 38. It will be appreciated, therefore, that the initial downward travel of the elongated rod 43 is readily accomplished by the impingement of the drilling fluid on the surface 46 as the fluid passes through the ports 38. Moreover, once the lower enlarged head 45 has been moved into the longitudinal bore 40 as depicted in FIG. 4, the flow of the drilling fluid will be sufficiently interrupted to produce a pressure surge which is effective for carrying the rod 43 further downwardly to positively shift the valve member 41 to its port-closing position (FIG. 5) by virtue of the pressure forces acting downwardly on the surface 46.

To return the elongated rod 43 and the valve member 41 to their elevated positions after the valve member has been closed, biasing means are provided such as a relatively stout compression spring 50 which is coaxially arranged around the upper portion of the rod and supported on an inwardly directed shoulder 51 formed on the inner member 22. A cupped ring 52 is coaxially arranged around the elongated rod 43 and slidably positioned between the upper end of the spring 50 and the lower surface of an inwardly directed shoulder 53 arranged within the inner member 22 above the shoulder 51. In this manner, by arranging an outwardly directed shoulder 54 on the elongated rod 43 to be normally spaced slightly above the slidable ring 52, the initial downward travel of the elongated rod 43 will be effective for bringing the shoulder 54 into engagement with the ring so as to then compress the spring 50 upon further downward travel of the rod. A light spring 55 is mounted between the cup-shaped ring 52 and the shoulder 54 thereabove to normally position the enlarged head 45 in the counterbore 47.

Biasing means such as a relatively weak compression spring 56 are arranged around the tubular extension 44 between an inwardly-directed shoulder 57 on the inner member 22 below the shoulder 51 and the enlarged head 49 on the tubular extension. Thus, it will be appreciated that by arranging the spring 56 as illustrated, downward movement of the valve member 41 and the tubular extension 44 by the elongated rod 43 will be effective for compressing the spring. Accordingly, once the stout spring 50 has returned the elongated rod 43 and the valve member 41 to their respective elevated positions, the lighter spring 56 will be effective for retaining the valve member in its elevated position.

It will be appreciated that by virtue of the longitudinal spacing that is normally present between the shoulder 54 and the ring 52, the rod 43 is free to travel downwardly a short distance and without significant restraint before encountering the upwardly-acting forces of the springs 50 and 56. This will, therefore, assure that the fluid-impingement surface 46 is moved well into the main flow stream of the drilling fluid passing through the ports 38 before the ring 52 is engaged so that the fluid-impingement forces acting on the rod 43 will then be effective for carrying it further downwardly against the increasing upwardly acting spring forces imposed on the rod by the compression springs 50 and 56.

To initiate the operation of the valve member 41, the pressure-signaling means 20 also include a solenoid 58 which is mounted within the inner member 22 and operatively arranged for shifting the rod 43 downwardly at least as far as is necessary for the fluid-impingement surface 46 to be moved into the flow path of the drilling fluid passing through the ports 38. In the preferred manner of operatively coupling the solenoid 58 to the elongated rod 43, the axially movable armature or plunger 59 of the solenoid is adapted to move downwardly upon energization of the solenoid; and, as depicted in FIG. 4, move the upper end of the elongated rod downwardly a sufficient distance to position the fluid-impinging surface 46 in the flow stream of the drilling fluid passing through the ports 38. A diaphragm 60 is arranged across the solenoid plunger 59 to permit the solenoid 58 to be enclosed in oil or the like.

It will be recognized, of course, that by virtue of the streamlined configuration of the enlarged head 45, downward movement of the elongated rod 43 will require only a minimum force so as to make it unnecessary for the solenoid 58 to be either of significant physical size or require excessive power for its operation. As previously noted, once the fluid-impinging surface 46 has entered the main flow stream of the drilling fluid passing through the ports 38, the aforementioned continued downward travel of the elongated rod 43 will be accomplished by the impingement and pressure surge forces developed by this fluid until the valve member 41 has closed the fluid ports.

As shown in FIG. 6, it will be appreciated that an upright solenoid armature 59' can alternatively be tandemly mounted on the upper end of the elongated rod 43 and operatively arranged in relation to an annular solenoid coil 58' for shifting the rod downwardly as required to bring the fluid-impinging surface 46 (not shown in FIG. 6) into the stream of the drilling fluid flowing through the ports 38. Then, once the impingement of the drilling fluid urges the elongated rod further downwardly, the armature 59' mounted on the upper end of the rod 43 may well be moved entirely below the solenoid coil 58'.

In any event, it should be noted that the solenoid 58 (or 58') needs only to be capable of shifting the elongated rod 43 downwardly a relatively short distance and that this downward movement requires only the minimal force necessary to compress the light spring 55. MOreover, with either of these alternative arrangements of the solenoids 58 and 58', should the valve member 41 accidentally become jammed in the valve seat 39 by debris or the like lodged in the ports 38, subsequent application of power to the solenoid will not damage it. It is, therefore, of significance to the present invention to realize that the motivating forces supplied by either of the solenoids 58 and 58' are only minimal since the substantial impingement and pressure forces imposed on the surface 46 are fully capable of closing the valve member 41 once the impingement surface is shifted into the flow stream of the drilling fluid passing through the ports 38.

Referring again to FIGS. 1 and 2, once the well tool 10 is in position within the borehole 13, the measuring devices 17 and 18 will function to provide measurements of the particular conditions which are being monitored and cause the measurement encoder 19 to produce the series of electrical signals representative of these conditions. Each of these signals will, therefore, momentarily energize the solenoid 58 to initiate operation of the pressure-signaling means 20 as in FIGS. 3 and 4. Thus, each time the solenoid 58 is energized, the elongated rod 43 will be shifted downwardly so as to bring the fluid-impingement surface 46 into the stream of the drilling fluid passing through the ports 38. Then, as depicted in FIG. 5, the downwardly acting forces imposed on the impingement surface 46 by the drilling fluid will carry the elongated rod 43 further downwardly for shifting the valve member 41 into momentary seating engagement within the valve seat 39 as well as for simultaneously compressing the springs 50 and 56. Once the springs 50 and 56 are energized, the elongated rod 43 and the valve member 41 will be returned to their initial elevated positions as depicted in FIG. 3.

To understand the underlying principle of the operation of the pressure-signaling means 20, reference should be made to FIG. 4. At this point in the sequence, the enlarged head 45 has just moved into the longitudinal bore 40 just below the valve seat 39. This movement will, of course, significantly interrupt the downward flow of the circulating drilling fluid to produce a substantial positive dynamic pressure which is imposed on the impingement surface 46. At the same time, the continued flow of the drilling fluid that is then below the enlarged head 45 will simultaneously produce a reduced pressure in the longitudinal bore 40 below the head. As a result, a substantial downwardly acting pressure force will be imposed on the surface 46 to drive the elongated rod 43 further downwardly to shift the valve member 41 to its port-closing position (FIG. 6). It will, of course, be appreciated that this downwardly-acting pressure force will be equal to the pressure differential imposed on the effective cross-sectional area of the surface 46.

As the rod 43 and the valve member 41 are driven downwardly, the springs 50 and 56 will, of course, be compressed to develop corresponding upwardly acting spring forces tending to return the members to their respective elevated positions. Once the valve member 41 closes the ports 38, the impingement surface 46 will be isolated from the aforementioned positive pressure forces. Thus, once the positive pressure in the longitudinal bore 42 above the enlarged head 45 has been reduced so as to be equalized with the pressure below the head (by way of the passages 42 and the narrow clearance space around the head and the adjacent wall of the inner member 22), the spring force provided by the now-compressed spring 50 will be effective for driving the elongated rod 43 upwardly. This upward travel of the rod 43 will, therefore, reposition the enlarged head 45 in the counterbore 47 and then shift the valve member 41 upwardly as the elongated rod is returned to its initial elevated position by the spring 50.

It will be appreciated, therefore, that each time the solenoid 58 (or 59') is energized, the valve member 41 will be rapidly closed and then quickly reopened so as to produce a momentary pressure surge without unduly retarding the continued circulation of the drilling fluid. As previously mentioned, the pressure pulses which are sequentially produced by the repetitive closing and opening of the valve member 41 will be transmitted to the surface by way of the stream of drilling fluid being circulated downwardly through the drill string 11. Thus, as these pressure pulses sequentially arrive at the surface, the surface apparatus 21 will detect them to produce a meaningful record which is indicative of the conditions being monitored by the condition-responsive devices 17 and 18.

Turning now to FIG. 7, the intermediate portion of a well tool 100 is shown to illustrate an alternative embodiment of pressure-signaling means 101 which broadly incorporate the principles of the present invention. As depicted, the well tool 100 includes a tubular inner member 102 which is coaxially arranged within an outer tubular housing 103. Although the inner member 102 could be releasably secured to the outer housing 103 in a manner similar to that previously described with reference to the well tool 10, it is preferred to permanently mount the inner member within the housing as illustrated.

Although it is not illustrated, the upper portion of the well tool 100 is arranged in a similar fashion to the well tool 10 and carries a turbine-driven electrical generator (not shown) which is driven by the continuous circulation of the drilling fluid passing from the drill string 11 into the upper end of the well tool 100. The well tool 100 is cooperatively arranged with either one or more longitudinal passages or the annular space 104 between the inner and outer members 102 and 103 through which the drilling fluid will pass after leaving the turbine-generator (not shown) thereabove. In either case, the downwardly flowing drilling fluid is directed into one or more downwardly inclined ports 105 arranged near the lower end of the inner member.

The pressure-signaling means 101 include a valve member 106 coaxially mounted within the inner member 102 and adapted for axial movement therein between an elevated position as depicted in FIG. 7 and a port-closing position where the valve member is cooperatively received within the upper end of a tubular valve seat 107. As will subsequently be explained, the valve seat 107 is slidably mounted in the inner member 102 and normally retained in its depicted elevated position by biasing means such as a compression spring 108 supported on an inwardly directed shoulder 109 on the outer housing 103 and engaged with the lower end of the valve seat. To support the valve member 106 for reciprocating movement within the inner member 102, an upright extension or rod 110 is secured to the valve member and extended upwardly through an annular guide 111 arranged thereabove within the inner member 102. Biasing means, such as a compression spring 112 compressed between the guide 111 and the valve member 106, are operatively arranged for urging the valve member downwardly toward its port-closing position.

To releasably retain the valve member 106 in its elevated position, latching means are provided such as one or more upright leaf springs or yieldable fingers 113 which are secured within the inner member 102 and releasably coupled to the rod 110 by inwardly directed lugs as at 114 on the mid-portion of each finger which are adapted to remain engaged under one or more outwardly enlarged shoulders 115 spaced along the upper portion of the elongated rod so long as the fingers are retained in their respective inwardly contracted positions illustrated in FIG. 7. To retain the fingers 113 in their latching positions, a solenoid 116 is coaxially mounted within the inner member 102 and includes a vertically reciprocating armature 117 carrying a downwardly opening cup-like member 118 which is adapted for movement between an elevated position above the latch fingers and the lower position depicted in FIG. 7 wherein the cup at least partially encloses the upper ends of the fingers.

In the preferred embodiment illustrated, upwardly directed wedge-shaped heads, as at 119, are mounted on the upper ends of each of the several fingers 113 and an annular ring 120 is arranged around the cup 118 to define an internal downwardly directed wedge-like surface 121 which is complemental to the opposed surfaces of the wedge-shaped heads. Thus, so long as the cup 118 is disposed over the upright fingers 113, the ring 120 will cooperatively engage the wedge-shaped heads 119 to restrain the fingers against moving outwardly from their respective positions shown in FIG. 7. In this manner, so long as the fingers 113 are retained from moving outwardly, the inwardly directed lugs 114 will be maintained in coengagement under one of the enlarged shoulders 115 on the elongated rod 110. It will, therefore, be recognized that the spring 112 is urging the valve member 106 and the rod 110 downwardly and that it is only the coaction of the lugs 114 under the shoulder 115 which maintains the valve member in its elevated position.

On the other hand, as will subsequently be described in further detail, it will be appreciated that once the solenoid 116 is energized to withdraw the cup 118 from over the enlarged heads 119, the cooperative camming action between the enlarged shoulder 115 and the inwardly directed lugs 114 will be effective for momentarily springing the fingers 113 outwardly to free the elongated rod 110 and the valve member 106 for downward movement. Thus, once the solenoid 116 is energized, the compression spring 112 will be effective for forcefully driving the valve member 106 downwardly once the enlarged shoulder 115 has expanded the mid-portions of the fingers 113 sufficiently to disengage the enlarged shoulder from the inwardly directed lugs 114.

Accordingly, as depicted in FIG. 8, once the valve member 106 enters the valve seat 107, the circulating drilling fluid will be momentarily halted so as to produce a transitory pressure surge or pressure pulse in the nature of a water hammer. THose skilled in the art will, of course, appreciate that the dynamic pressures produced by such water hammers are quite substantial. Thus, by virtue of the rapid movement of the valve member 106 into seating engagement within the valve seat 107, the substantial dynamic pressure force which is developed will be imposed on the upper end 122 of the valve seat and will be effective for urging the valve seat downwardly in relation to the outer housing 103. In view of the substantial magnitude of this pressure force acting on the effective cross-sectional area of the upper end 122 of the valve seat 107, the valve seat will be shifted downwardly to begin compressing the spring 109. This same dynamic force will also be imposed on the upper face of the valve member 106 to also move it downwardly into the valve seat 107.

It will be noted from FIG. 9 that as the valve seat 107 begins moving downwardly, the valve member 106 will be abruptly halted as an enlarged shoulder 123 on the elongated rod 110 engages the guide 111. Thus, the dynamic pressure force imposed on the upper end 122 of the valve seat 107 will be effective for shifting the valve seat away from and out of engagement with the momentarily halted valve member 106. Moreover, once the valve seat 107 is withdrawn from over the valve member 107 as depicted in FIG. 10 to equalize the pressure differential, a spring 124 arranged between the guide 111 and the shoulder 123 will now have been compressed so as to quickly return the valve member and the elongated rod 110 upwardly toward their initial elevated positions.

During this same time interval, it will be noted by comparison of FIGS. 9 and 10 that the solenoid 116 has now been de-energized so as to reposition the cup 118 back over the enlarged heads 119 of the latch fingers 113. Thus, once the upper ends 119 of the fingers 113 are again reconfined, it will be appreciated that as the enlarged shoulders 115 on the elongated rod 110 move upwardly past the inwardly directed lugs 114, the mid-portions of the fingers will be momentarily cammed outwardly. Then, once one or more of the shoulders 115 are above the lugs 114, the mid-portions of the fingers 113 will again contract to resecure the elongated rod 110 and the valve member 106 in their elevated positions as depicted in FIG. 7. Similarly, the downwardly-acting dynamic pressure forces acting on the valve seat 107 will be quickly terminated as the valve member 106 is withdrawn therefrom so that the compression spring 124 will rapidly return the valve seat upwardly to its elevated position as illustrated in FIG. 7.

Accordingly, it will be appreciated that the new and improved data-signaling apparatus of the present invention is particularly adapted for producing pressure pulses which are selectively coded for transmitting information through the drilling fluid from a borehole to the surface. To produce these pressure pulses, an electrically operated actuator is operatively arranged for initiating the operation of valve means which, once initiated, employ the circulating drilling fluid as a motive force for operating the valve means.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects; and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.