US20140218206A1

US20140218206A1 - Multi-Scheme Downhole Tool Bus System and Methods

Info

Publication number: US20140218206A1
Application number: US14/239,542
Authority: US
Inventors: Theodorus Tjhang; Yuichi Kobayashi; Takeaki Nakayama; Motohiro Nakanouchi; David Santoso
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 2011-09-12
Filing date: 2012-09-11
Publication date: 2014-08-07
Also published as: EP2748427A2; CA2847094A1; EP2748427A4; WO2013038336A2; WO2013038336A3

Abstract

A multi-scheme downhole tool bus system is provided. The system may comprise a tool bus master and a number tool bus slaves coupled together via a communications link The communications link may include an uplink communication and a downlink communication. The uplink communication and the downlink communication may include a number of communication schemes or data rates.

Description

BACKGROUND

Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. A variety of downhole tools may be used in all areas of oil and natural gas services. In some cases, downhole tools may be used in a well for surveying, drilling, and production of hydrocarbons. These downhole tools may communicate with the surface via various telemetry systems.
Tool bus systems may be used to transmit data. However, legacy tool bus systems have a single scheme construction enabling only a low data rate. According to new downhole tool development, higher acquisition data should be transmitted to surface.

SUMMARY

The present disclosure provides systems, tools and methods for transmitting data to surface. In some embodiments, the disclosure provides downhole tool bus systems, tool bus slave systems, and methods for communicatively coupling a tool bus master to one or more tool bus slaves. In some embodiments, contrary to new tool bus systems which may be developed for use with the new downhole tools to permit higher acquisition data transfer to surface and are not compatible with legacy tools, the multi-scheme tool bus systems according to this disclosure enable a higher data rate than the legacy single scheme tool bus systems and thus can be used with new downhole tools while also maintaining backward compatibility to legacy tools.
In some embodiments, the tool bus system may comprise a tool bus master and one or more tool bus slaves communicatively coupled together via uplink and downlink communication. Each of the one or more tool bus slaves may communicate with the tool bus master via two or more communication schemes. In some cases, the two or more communication schemes may be the same scheme at two or more data rates. Each uplink and downlink communication may include one or more communication schemes.
In some embodiments, the tool bus slave includes a transceiver electronics receiver, a transceiver electronics transmitter, a first communication scheme demodulator (decoder), a first communication scheme modulator (encoder), a second communication scheme demodulator (decoder), a second communication scheme modulator (encoder), and the transceiver electronics receiver receives a multi-coding scheme, the transceiver electronics transceiver transmits a multi-coding scheme, the first communication scheme of the multi-coding scheme is processed by the first communication scheme demodulator (decoder) and the first communication scheme modulator (encoder), and the second communication scheme of the multi-coding scheme is processed by the second communication scheme demodulator (decoder) and the second communication scheme modulator (encoder). In some embodiments, the first communication scheme is biphase and the second communication scheme is 8b/10b. In some embodiments, the multi-coding scheme can be changed in the slaves. For example, the communication scheme of the multi-coding scheme may be processed by the first communication scheme demodulator (decoder) and the second communication scheme modulator (encoder). In such embodiments, the effective data rate may be the same but the scheme can be chosen according to the downhole environment, for example taking into account a longer communication path in between tools, and/or a protocol change such as addition of an error coding correction.
In some embodiments, the method for communicatively coupling a tool bus master to one or more tool bus slaves includes communicatively coupling a tool bus master to one or more tool bus slaves via an uplink communication and a downlink communication such that the uplink communication and the downlink communication each include one or more schemes. In some embodiments, the one or more communication schemes includes a first communication scheme at a first data rate and a second communication scheme at a second data rate. In some embodiments, the first communication scheme is the same as the second communication scheme. In some embodiments, the first communication is different than the second communication scheme. In some embodiments, the first communication scheme is biphase and the second communication scheme is 8b/10b.
Other or alternative features will become apparent from the following description, from the drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the present disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying drawings illustrate only the various implementations described herein and are not meant to limit the scope of various technologies described herein. The drawings are as follows:

FIG. 1 is a multi-coding scheme tool bus system according to an embodiment; and

FIG. 2 is a series of mixed modulation schemes in time-division according to an embodiment; and

FIG. 3 is a schematic of a tool bus slave design for a multi-coding scheme tool bus system according to an embodiment; and

FIG. 4 is a schematic of a multi-data rate tool bus system according to an embodiment; and

FIG. 5 is an actual experimental result to show multi-scheme switching between biphase and 8b/10b.

DETAILED DESCRIPTION

Illustrative embodiments and aspects are described below. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
Reference throughout the specification to “one embodiment,” “an embodiment,” “some embodiments,” “one aspect,” “an aspect,” or “some aspects” means that a particular feature, structure, method, or characteristic described in connection with the embodiment or aspect is included in at least one embodiment of the present disclosure. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” or “in some embodiments” in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, methods, or characteristics may be combined in any suitable manner in one or more embodiments. The words “including” and “having” shall have the same meaning as the word “comprising.”
In the specification and appended claims: the terms “connect”, “connection”, “connected”, “in connection with”, and “connecting” are used to mean “in direct connection with” or “in connection with via one or more elements”; and the term “set” is used to mean “one element” or “more than one element”. Further, the terms “couple”, “coupling”, “coupled”, “coupled together”, and “coupled with” are used to mean “directly coupled together” or “coupled together via one or more elements”. As used herein, the terms “up” and “down”, “upper” and “lower”, “upwardly” and downwardly”, “upstream” and “downstream”; “above” and “below”; 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 disclosure.
As used throughout the specification and claims, the term “downhole” refers to a subterranean environment, particularly in a wellbore. “Downhole tool” is used broadly to mean any tool used in a subterranean environment including, but not limited to, a logging tool, an imaging tool, an acoustic tool, a permanent monitoring tool, and a combination tool.
For digital broadband transmission, the terms demodulator and decoder are used in the alternative, are synonymous and have the same meaning. Similarly, for digital broadband transmission, the terms modulator and encoder are used in the alternative, are synonymous and have the same meaning.
The various techniques disclosed herein may be utilized to facilitate and improve data acquisition and analysis in downhole tools and systems. In this, downhole tools and systems are provided that may utilize arrays of sensing devices that are configured or designed for easy attachment and detachment in downhole sensor tools or modules that are deployed for purposes of sensing data relating to environmental and tool parameters downhole, within a borehole. The tools and sensing systems disclosed herein may effectively sense and store characteristics relating to components of downhole tools as well as formation parameters at elevated temperatures and pressures.
Chemicals and chemical properties of interest in oilfield exploration and development may also be measured and stored by the sensing systems contemplated by the present disclosure. The sensing systems herein may be incorporated in tool systems such as wireline logging tools, measurement-while-drilling and logging-while-drilling tools, permanent monitoring systems, drill bits, drill collars, sondes, among others. For purposes of this disclosure, when any one of the terms wireline, cable line, slickline or coiled tubing or conveyance is used it is understood that any of the referenced deployment means, or any other suitable equivalent means, may be used with the present disclosure without departing from the spirit and scope of the present disclosure.
Moreover, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this disclosure.
Referring generally to FIGS. 1( a)-(d), various schematics of multi-coding schemes tool bus systems are shown according to embodiments of the present disclosure. In the systems FIG. 1( a) through FIG. 1( d), both 8b/10b and biphase schemes are used to illustrate general communication schemes for in the interest of simplifying the description. As readily apparent to a person of skill in the art, many types and combinations of schemes may be used in accordance with the teachings of this description. For example, a non-limiting listing of schemes may include FSK (Frequency Shift Keying) modulation, 64b/66b, and LVDS (Low Voltage Differential Signaling), among others not expressly identified.
In some embodiments, the downhole tool bus system for data communication coupling between downhole tools may include a tool bus master in a telemetry cartridge and a tool bus slave in one or more of the various downhole application tools. Data communication includes all forms of communicative coupling such as instructions, time stamps, synchronization signals, data transmission, among other forms of communicative coupling. The downhole tools may include sonic, seismic, and other various forms of tools, such as analytical and logging, among others.
As shown in FIG. 1( a) and FIG. 1( d), both the uplink and downlink communication couplings may use the same scheme. For example, in FIG. 1( a) 8b/10b are used for both the uplink and downlink communication couplings whereas in FIG. 1( d) biphase schemes are used. In addition to using the same scheme for uplinks and downlinks, various combinations of schemes may be used.
In FIG. 1( b) 8b/10b is used for the uplink communication and biphase is used for the downlink communication. Alternatively, in FIG. 1( c) biphase is used for the uplink communication and 8b/10b is used for the downlink communication. As stated earlier, 8b/10b and biphase are used for the purposes of illustration in order to simplify the description, scheme 1 and scheme 2 could be substituted as more general descriptors of communication systems.
Referring generally now to FIG. 2, various schematics of mixed modulation in time-division are shown according to embodiments of the present disclosure. For example, in some embodiments, an uplink communication may use a combination of 8b/10b and biphase coding scheme in a time-division manner. The downlink communication may use a biphase coding scheme as illustrated in FIG. 2( a). Whereas in other embodiments, the uplink communication may use a combination of 8b/10b and biphase coding scheme in a time-division manner while the downlink communication uses an 8b/10b coding scheme (as shown in FIG. 2( b)).
In still other embodiments, a downhole tool bus system may use a biphase coding scheme for the uplink communication coupling while using a combination of 8b/10b and biphase coding schemes in the downlink communication coupling, as shown in FIG. 2( c). Alternatively, some embodiments may use an 8b/10b coding scheme for the uplink communication coupling while the downlink communication coupling may use a combination of 8b/10b and biphase coding schemes in a time-division manner, as seen in FIG. 2( d).
In some cases, an embodiment of a downhole tool bus system may include a combination of biphase coding schemes and 8b/10b coding schemes in both the uplink and downlink communication coupling. The schematic shown in FIG. 2( e) is an illustration of this exemplary embodiment. Additional combinations and configurations of schemes including alternative or additional schemes are considered within the scope of this disclosure. In some configurations, more than two schemes may be used. In some embodiments, guard bands may be used to separate the various schemes and allow the electronics to recognize and receive the different communication coupling schemes.
Turning generally to FIG. 3, this drawing shows a schematic of an illustrative example of a tool bus slave design for a multi-coding scheme tool bus system, according to an embodiment of this disclosure. As with previous examples, biphase and 8b/10b coding schemes are used as illustrative examples in order to simplify the detailed descriptions, and embodiments of this disclosure should not be limited to these schemes or to the schematic shown in FIG. 3.
In general, in some embodiments, a tool bus slave design includes a transceiver electronics receiver, a transceiver electronics transmitter, a first communication scheme demodulator, a first communication modulator, a second communication scheme demodulator, a second communication scheme modulator, and the transceiver electronics receiver receives a multi-coding scheme, the transceiver electronics transceiver transmits a multi-coding scheme, the first communication scheme of the multi-coding scheme is processed by the first communication scheme demodulator and the first communication scheme modulator, and the second communication scheme or the multi-coding scheme is processed by the second scheme demodulator and the second communication scheme modulator. In either case (whether referring to the first communication scheme or the second communication scheme), the term demodulator is synonymous to the term decoder for digital base baseband transmission, and the term modulator is synonymous to the term encoder for digital base band transmission.
In the embodiment of FIG. 3, the tool bus slave design includes transceiver electronics as a receiver in which an incoming signal is split between a biphase decoder and a 8b/10b decoder. The biphase decoder may then take the biphase portion of the signal and send via FIFO (First in First Out) to a biphase encoder. The biphase encoder will then pass the signal along to transceiver electronics as a transmitter for sending along a communicative pathway.
The 8b/10b decoder may take the 8b/10b signal portion of the signal and send via FIFO to an 8b/10b encoder. The 8b10b encoder will then pass the signal to transceiver electronics as a transmitter for sending along the communicative pathway.
In some configurations of a tool slave design, a CDR (Clock and Data Recovery) module may be used for example to detect the various schemes in the data stream automatically. Other configurations may include a method for detecting and repeating a mixed 8b/10b and biphase uplink and downlink from the adjacent tools.
Referring generally to FIG. 4, a schematic is shown comprising an illustrative configuration of five tool bus slaves communicatively coupled together with a tool bus master. In some embodiments, a mixture of tool bus slave schemes and speeds may be present depending upon the availability of tools and the type of function required downhole. In this schematic, there are biphase schemes of varying bit rates (e.g., 1 Mbps and 2 Mbps for example) and an 8b/10b scheme of 8 Mbps. In some embodiments, the multi-scheme approach facilitates backward compatibility with legacy tools and thus the systems of the present disclosure may be used simultaneously or alternatively with new downhole tools as well as legacy downhole tools.
In some embodiments, the lower bit rate biphase tools may be located farthest away from the tool bus master and increase in bit rate capability as the tools are located closer to the tool bus master along the communicative coupling. A configuration structured as such may allow the data to communicate at high speed. Without wishing to be bound by theory, if a 2 Mbps tool were located lower (in terms of the figure) than a 1 Mbps tool, the data from the 2 Mbps tool may be constrained by the capability of the 1 Mbps tool as it traveled from the 2 Mbps tool to the tool bus master. As shown in FIG. 4, in addition to various schemes, embodiments of the disclosure may accommodate various data rates as well.
The graphs of FIG. 5 illustrate use of multi-scheme switching between biphase and 8b/10. As shown, a bi-phase scheme and an 8b10b scheme are processed in one slave, and the two schemes are mixed in time division multiplexing. Further as shown, the scheme is changed from bi-phase, which has about 2 Mbps speed performance, to 8b10b, which has about 8 Mbps speed performance in a certain frame period. The multi-scheme selection is automatically done by the CDR part.
While the detailed description has been made 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 there from. It is intended that the appended claims cover such modifications and variations as fall within the true spirit and scope of this disclosure.

Claims

What is claimed is:

1. A downhole tool bus system comprising:

a tool bus master;

one or more tool bus slaves communicatively coupled to the tool bus master via an uplink communication and a downlink communication;

wherein the uplink communication and the downlink communication each includes one or more communication schemes.

2. The downhole tool bus system recited in claim 1, wherein the one or more communication schemes include a first communication scheme at a first data rate and a second communication scheme at a second data rate.

3. The downhole tool bus system recited in claim 2, wherein the first communication scheme is the same as the second communication scheme.

4. The downhole tool bus system recited in claim 2, wherein the first communication scheme is different than the second communication scheme.

5. The downhole tool bus system recited in claim 2, wherein the first communication scheme is biphase and the second communication scheme is 8b/10b.

6. A tool bus slave system comprising:

a transceiver electronics receiver;

a transceiver electronics transmitter;

a first communication scheme demodulator;

a first communication scheme modulator;

a second communication scheme demodulator;

a second communication scheme modulator;

wherein demodulator and modulator are synonymous to decoder and encoder respectively in digital baseband transmission, and wherein a multi-coding scheme is received on the transceiver electronics receiver and transmitted on the transceiver electronics transmitter.

7. The tool bus slave system recited in claim 6, wherein:

the first communication scheme of the multi-coding scheme is processed by the first communication scheme demodulator and the first communication scheme modulator; and

the second communication scheme of the multi-coding scheme is processed by the second communication scheme demodulator and the second communication scheme modulator.

8. The tool bus slave system recited in claim 6, wherein the first communication scheme of the multi-coding scheme is processed by the first communication scheme demodulator and the second communication scheme modulator.

9. The tool bus slave system recited in claim 6, wherein the first communication scheme is biphase and the second communication scheme is 8b/10b.

10. A method for communicatively coupling a tool bus master to one or more tool bus slaves comprising:

communicatively coupling the tool bus master to the one or more tool bus slaves via an uplink communication and a downlink communication;

11. The method recited in claim 10, wherein the one or more communication schemes include a first communication scheme at a first data rate and a second communication scheme at a second data rate.

12. The method recited in claim 11, wherein the first communication scheme is the same as the second communication scheme.

13. The method recited in claim 11, wherein the first communication scheme is different than the second communication scheme.

14. The method recited in claim 11, wherein the first communication scheme is biphase and the second communication scheme is 8b/10b.