Apparatus and Technique to Communicate With a Tubing-Conveyed Perforating Gun

Abstract

A technique that is usable with a well includes providing a string that includes a tubing conveyed perforating (TCP) gun. The technique includes using a downhole component of the string to communicate uphole an indication of at least a depth or an orientation of the gun.

Description

BACKGROUND

The invention generally relates to an apparatus and technique to communicate with a tubing conveyed perforating gun.

For purposes of producing well fluid from a formation, the formation typically is perforated from within a wellbore to enhance fluid communication between the reservoir and the wellbore. To perform the perforating, a perforating gun typically is lowered downhole (on a string, for example) inside the wellbore to the region of the formation to be perforated. The perforating gun typically contains perforating charges (shaped charges, for example) that are arranged in a phasing pattern about the longitudinal axis of the gun and are radially oriented toward the wellbore wall. The perforating charges are fired to pierce the well casing string (if the well is cased) and produce radially extending perforation tunnels into the formation.

Modern perforating technology has evolved from merely making simple holes in the casing string to being customized, objective-oriented services, which are integrated with sophisticated and versatile completion designs. Perforating is now used to optimize both permanent completions and temporary completions, such as drill stem test completions and workover completions. Along with services such as hydraulic fracturing, sand management, directional drilling of extended-reach and horizontal wells, completion fluid engineering and well testing, engineered perforating to achieve communication between the formation and the wellbore has become an important factor in enhancing the well's productivity.

There are many factors to a successful perforating operation, such as the ability to precisely control the depth of the perforating gun or the angular orientation of the perforating gun about the gun's longitudinal axis. Another factor associated with the success of a perforating operation is the time required to perform the operation.

The manner in which a perforating operation is conducted also depends on the type of perforating gun. For example, the positioning of a conventional tubing conveyed perforating (TCP) gun typically is controlled solely on logs and other data that are obtained prior to the perforating operation. Furthermore, parts of the operations' success and performance typically are assessed after the job, i.e., after the gun string is pulled out of hole and other services are performed (a production logging tool to measure downhole flow rates, for example).

SUMMARY

As an example, a technique that is usable with a well includes providing a string that includes a tubing conveyed perforating (TCP) gun. The technique includes using a downhole component of the string to communicate uphole an indication of at least a depth or an orientation of the gun.

As another example, a system usable with a well includes a string that is to be disposed in the well. A TCP gun and a transmitter are disposed in the string. The transmitter communicates uphole an indication of at least a depth or an orientation of the TCP gun.

Advantages and other features of the invention will become apparent from the following drawing, description and claims.

BRIEF DESCRIPTION OF THE DRAWING

FIGS. 1 and 3 are schematic diagrams of tubing conveyed perforating (TCP) gun systems according to different examples.

FIG. 2 is a flow diagram depicting a technique to position and fire a TCP gun according to different examples.

FIG. 4 is a flow diagram depicting a technique to position and fire multiple TCP guns according to an example.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments are possible.

As used here, the terms “above” and “below”; “up” and “down”; “upper” and “lower”; “upwardly” and “downwardly”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments of the invention. However, when applied to equipment and methods for use in wells that are deviated or horizontal, such terms may refer to a left to right, right to left, or diagonal relationship as appropriate.

FIG. 1 depicts an example of a tubing conveyed perforating (TCP) system 5 according to an example. In general, the TCP system 5 includes a tubing string 14 that extends downhole into a wellbore 11. The tubing string 14 may be one of many different types of tubing strings, such as a production tubing string, a test string, a drill stem test (DST) string, etc. Regardless of its particular application, the tubing string 14 includes at least one TCP perforating gun, such as a TCP gun 30 that is depicted in FIG. 1.

In the context of this application, a “TCP gun” means a perforating gun that is constructed to be fired in response to a pressure-based stimulus or pressure-based stimuli that are communicated downhole through a central passageway of a tubing string from the surface of the well to a position near (within 10 feet, for example) or at the TCP gun. The pressure stimulus or stimuli may be in the form of command-encoded pressure pulses, absolute pressures, differential pressures, etc. As a non-limiting example, the perforating charges of the TCP gun 30 may be fired by increasing the internal pressure of the tubing string 14 above a threshold, such that the TCP gun 30 responds to the increased pressure level by firing its perforating charges.

It is noted that, as described below, the string 14 includes a downhole telemetry system 20 for purposes of establishing uphole communication, and the uphole communication may involve, for example, the use of pressure-based stimuli that are communicated uphole through the string, for example, as well as the use of other types of stimuli (acoustic stimuli, electromagnetic stimuli, electrical stimuli, etc.) that may or may not be communicated through the string 14.

Although FIG. 1 depicts the tubing string 14 as extending downhole inside a borehole 11 that is cased by a casing string 13, it is noted that FIG. 1 is merely an example of one out of many possible implementations of a TCP system. In this manner, the wellbore in which the TCP gun 30 extends may be cased or uncased, depending on the particular implementation. Furthermore, the TCP gun 30 may extend in a deviated or highly deviated lateral wellbore, in accordance with other implementations. Additionally, the TCP perforating system 5 may be used in a terrestrial-based subterranean well or in a subsea well, depending on the particular implementation.

Before the perforating charges of the TCP gun 30 are fired, the TCP gun 30 is first run downhole as part of the string and using real time position feedback that is provided by the downhole telemetry system 20 (as described below), the TCP gun 30 is appropriately positioned. Thus, in contrast to conventional TCP systems, the TCP gun 30 is not blindly positioned; but rather, real time downhole position feedback is provided, which permits an operator at the surface of the well to monitor the feedback and make the necessary adjustments to precisely position the gun 30. In general, the TCP gun's “position” refers to the angular orientation of the TCP gun 30 (i.e., the azimuth, or angle, of the TCP gun 30 about the gun's longitudinal axis 19 and referred to herein as the gun's “orientation”) and the depth of the gun 30.

The downhole telemetry system 20 is positioned downhole near (within ten feet, for example) the TCP gun 30 and is constructed to communicate with a telemetry system 12 that is disposed at the surface of the well. The communication between the telemetry systems 12 and 20 may occur through the tubing string 14 (acoustic or fluid pulse-type communication), for example; through wired communication lines; through electromagnetic (EM) communication telemetry through signals 16 and 17 as depicted in FIG. 1; or through another type of wireless or wired telemetry communication scheme or medium, depending on the particular implementation.

In general, a transmitter 27 of the downhole telemetry system 20 is constructed to generate stimuli (pressure stimuli, acoustic stimuli, electrical stimuli, electromagnetic (EM) stimuli, etc) that are received by the surface telemetry system 12 for purposes of communicating an indication of the position (orientation and/or depth) of the TCP gun 30 to the surface of the well in real time. For example, the transmitter 27 may communicate indications of the orientation and depth of the TCP gun 30 to the surface telemetry system 12. Therefore, an operator at the surface of the well may, based on the received position of the TCP gun 30, take appropriate measures to ensure that the TCP gun 30 is at the appropriate position before undertaking measures to fire perforating charges of the gun 30.

The downhole telemetry system 20 may also include a receiver 28. In general, the receiver 28 may communicate with the surface telemetry system 12 for purposes of receiving command-encoded stimuli that direct positioning of the TCP 30, in accordance with some implementations. In other implementations, commands are not communicated downhole for purposes of changing the position of the TCP gun 30; but rather, the string 14 is physically manipulated to change the gun's position, as further described below. It is noted that the receiver 28 may also serve the dual function of receiving a pressure stimulus that encodes a command to fire the gun's perforating charges, although a separate receiver (not shown in FIG. 1) may be part of the TCP gun for this purpose, in other implementations.

In addition to the downhole telemetry system 20, the tubing string 14 may include other devices related to providing feedback of the TCP gun's position and positioning the gun 30. For example, the tubing string 14 may include a downhole stored energy source, such as a battery 22, for purposes of supplying power to the electrical components of the string 14, such as the downhole telemetry system 20. The battery 22 may supply power to other components of the tubing string 14, such as a depth measuring device 24, an orientation sensing device 33, a gun orienting device 31 (if an active power consuming device) and other power consuming components of the TCP gun 30, as non-limiting examples.

The depth measuring device 24 may take on numerous forms, such as a casing collar locator (CCL), a gamma ray device, etc., depending on the particular implementation. In this regard, the signal that is provided by the CCL or gamma ray device in real time to the surface of the well (via the downhole telemetry system 20) may be correlated at the surface with a prior well log to determine the depth of the TCP gun 30. Regardless of its particular form, the depth measuring device 24 is therefore constructed to provide an indication of the depth of the perforating gun 30 and interact with the transmitter 27 for purposes of communicating an indication of the depth of the TCP gun 30 to the surface of the well in real time.

The orientation-sensing device 33 senses the angular orientation of the TCP gun 30. As a non-limiting example, the orientation-sensing device 33 may be a gyroscope in one implementation. The signal that is provided by the orientation-sensing device 33 is provided to the transmitter 27, which relays the signal to the surface of the well in real time.

In some implementations, the gun orienting device 31 is an active orienting device that orients the TCP gun based on a command that is communicated downhole and received by the receiver 28. More specifically, in some implementations, the gun orienting device responds to command-encoded stimuli that are transmitted from the surface to incrementally or absolutely orient the TCP gun 30. As a non-limiting example, the orienting device 31 may include an electric motor (as a non-limiting example), which receives electric power from the battery 22 and a command interface (not shown) to receive signals that are received by the downhole telemetry system 20. The command interface decodes any commands for the device 31 and generates the appropriate control signals for the motor to rotate the TCP gun 30 by the desired position.

As a non-limiting example, in one implementation, the surface telemetry system 12 and the downhole telemetry system 20 may communicate wirelessly using extremely low frequency electromagnetic (EM) signals. In this regard, the bidirectional signals 16 and 17, which are communicated between the telemetry systems 12 and 20, may employ electromagnetic carrier waves that have frequencies in the range of 0.1 to 1.0 Hertz (Hz). As a more specific example, the frequency range may be in the range of 0.25 to 8 Hz, as a non-limiting example. As another non-limiting example, the distance between the telemetry systems 12 and 20 may be between approximately 3000 meters (m), in some implementations, although larger or smaller distances may exist in other applications.

In some implementations, the EM communication between the telemetry systems 12 and 20 is accomplished by the injection of a modulated current into the formation via an electrical dipole. The voltage difference induced by the circulating current is measured along the walls of the casing string 12 by a repeater or between the well head and a remote stake at the surface. The voltage is demodulated to extract the information from the signal. The communication itself may be based on phase modulation of the injected current, although other types of modulation (frequency modulation, for example) may be used in other implementations. As a non-limiting example, the bit rate may be approximately one bit per second, and data frames in the messages may be approximately one minute in length, although other data rates and frame rates are contemplated in other implementations.

Referring to FIG. 2 in conjunction with FIG. 1, in accordance with some implementations, a technique 100 may be used for purposes of positioning and firing the TCP gun 30. Pursuant to the technique 100, a string containing a TCP gun is run into a well, pursuant to block 104. A procedure then begins to properly position the TCP gun at the appropriate orientation and depth. In this positioning, an indication of at least a depth or orientation of the gun is communicated in real time from a location downhole near the gun to a location near the surface of the well, pursuant to block 108.

Based on the indication(s), a decision is then made (diamond 112) whether the TCP gun is ready to fire. If not, then at least one iteration is performed in adjusting the position of the TCP gun. For example, an indication of at least one command to regulate the orientation of the TCP gun may be wirelessly communicated from the surface to a position near the gun, pursuant to block 114. These actions may also or alternatively include selectively physically manipulating the string that contains the TCP gun to adjust the depth of the gun, pursuant to block 116. The iteration proceeds by returning to block 108 in which an indication of at least the depth or azimuth of the gun is communicated uphole, pursuant to block 108. The TCP gun is ultimately fired (block 120) when the iteration ends upon the determination that the TCP gun is ready to fire, pursuant to diamond 112.

Other implementations are contemplated and are within the scope of the appended claims. For example, in another implementation, the TCP gun 30 may be oriented by using a passive orientation system, such as swivels and weights, instead of the active orientation system that is described above. For this passive orientation system, the string 14 may be lifted, run further downhole and/or rotated to adjust the orientation of the TCP gun 30 based on the indication of the gun's orientation that is provided in real time by the downhole telemetry system 20. In this manner, adjusting the depth of the string 14 also adjusts the rotation of the TCP gun 30 due to the changing inclination of the wellbore 11.

As another example of a variation, although FIG. 1 depicts a TCP system 5 for a single TCP gun, the systems and techniques that are disclosed herein may likewise be applied to a tubing string 202 that contains multiple TCP guns 30, as depicted in FIG. 3. In this regard, referring to FIG. 3, the tubing string 202 of a multiple TCP gun perforating system 200 includes two or more perforating units 220 (perforating units 220₁ to 220_N, being depicted as examples in FIG. 3), which are spaced apart at desired intervals in the well. For this example, each perforating unit 200 includes a TCP gun 30, a depth measuring device 24, an orientation-sensing device 33 and an orienting device 31.

For each unit 220, the depth measuring device 24 senses the depth of the associated TCP gun 30 and communicates this depth to the transmitter 27, which, in turn, wirelessly communicates an indication of this depth to the surface in real time.

Likewise, the orientation-sensing device 33 for each unit 220 communicates an indication of the measured orientation of the associated TCP gun 30 and communicates this measured orientation to the transmitter 27 which, in turn, communicates an indication of the orientation to the surface in real time. Additionally, the orienting device 31 of each unit 220 passively or actively orients its associated TCP gun 30, as described above.

It is noted that FIG. 3 merely depicts an example of a multiple TCP gun string. Other variations are contemplated and are within the scope of the appended claims. For example, in other arrangements, each perforating gun unit 220 may include a telemetry system, similar in design to the telemetry system 20. As another example, orienting or depth sensing devices may be shared by one or more TCP guns 30. As another example, a single motor or single weight and swivel system may be used to orient multiple TCP guns 30.

Multiple TCP guns of a particular tubing string may be positioned and fired, according to a technique 300 that is depicted in FIG. 4. Referring to FIG. 4, the technique 300 includes running a string that contains multiple TCP guns into a well, pursuant to block 304. For each of the TCP guns, an indication of at least the depth or orientation of the gun is communicated to the surface of the well in real time, pursuant to block 308. Based on these indications, a determination is then made, pursuant to diamond 312, whether the TCP guns are ready to fire. If so, then the TCP guns are fired, pursuant to block 320. Otherwise, for each gun that is not appropriately positioned, an indication of at least one command may be wirelessly communicated downhole to regulate the orientation of the gun, pursuant to block 314. Furthermore, the string may be physically manipulated to adjust the depth of the guns, pursuant to block 316. Alternatively, the string may be physically manipulated to control a passive orientation system. When a decision is ultimately made that the guns are appropriately positioned, pursuant to diamond 312, then the perforating guns are fired, pursuant to block 320.

It is noted that FIG. 4 is merely an example, as other variations are contemplated and are within the scope of the appended claims. For example, as another variation, all of the guns may not be finally positioned before being fired. In this regard, in this implementation, one or more TCP guns may be positioned and then fired, another set of one or more TCP guns may then be positioned and fired, etc.

While the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.

Claims

1. A method usable with a well, comprising:

providing a string comprising a tubing conveyed perforating gun in the well; and

using a downhole component of the string to communicate uphole an indication of at least a depth or an orientation of the gun.

2. The method of claim 1, wherein the act of using comprises communicating the indication in real time.

3. The method of claim 1, wherein the act of using comprises wirelessly communicating the indication.

4. The method of claim 1, wherein the act of using comprises communicating an electromagnetic signal having a frequency in the range of 0.1 to 1.0 hertz.

5. The method of claim 1, further comprising:

measuring at least the depth of the perforating gun or the orientation of the perforating gun.

6. The method of claim 1, further comprising:

communicating downhole from the surface of the well an indication of a command to control the orientation of the perforating gun.

7. The method of claim 1, further comprising:

physically manipulating the string to adjust the depth of the perforating gun in response to the communication.

8. The method of claim 1, further comprising:

physically manipulating the string to adjust the orientation of the gun in response to the communication.

9. The method of claim 1, further comprising:

firing the perforating gun after the communication.

10. A system usable with a well, comprising:

a string to be disposed in the well;

a tubing conveyed perforating gun to be disposed in the string; and

a transmitter to be disposed in the string to communicate uphole an indication of at least a depth or an orientation of the gun.

11. The system of claim 10, wherein the transmitter is part of a wireless telemetry system to wirelessly communicate the indication.

12. The system of claim 10, wherein the transmitter is adapted to communicated the indication in real time.

13. The system of claim 10, further comprising:

an orientation device to be disposed in the string near the perforating gun to orient the gun in response to a remote communication from the surface of the well.

14. The system of claim 10, further comprising:

a battery to provide power to the transmitter.

15. The system of claim 10, wherein the transmitter is adapted to communicate the indication using an electromagnetic carrier wave having an associated carrier frequency in the range of 0.1 to 1.0 hertz.

16. The system of claim 10, further comprising:

a depth measuring device to be disposed in the string to measure the depth of the perforating gun.

17. The system of claim 10, further comprising:

an orientation sensing device to be disposed in the string to measure the orientation of the perforating gun.

18. The system of claim 17, wherein the orientation device comprises a motor to selectively rotate the perforating gun in response to a command received at a position near the perforating gun and communicated from a position near the surface.

19. The system of claim 10, further comprising:

a receiver to be disposed in the string to receive an indication of a indication of a command to control an orientation of the perforating gun, the indication being communicated from a position near the surface of the well to a position near the perforating gun.

20. The system of claim 10, further comprising:

at least one additional tubing conveyed perforating gun to be disposed in the string, wherein

the transmitter is part of a transmission system to be disposed in the string to communicate from a first position near the perforating gun to a second position near the surface of the well, an indication of at least a depth or an orientation of each of said at least one additional gun.