1. Field of the Invention
The present invention relates to methods, apparatus, and systems for obtaining information regarding a geological formation or a well passing through a geological formation. The present invention more particularly relates to methods, apparatus, and systems for exchanging information and power between an interrogating tool located in a cased borehole and sensors attached to the casing.
2. State of the Art
The extraction of oil and natural gas from a geological formation is usually accomplished by drilling boreholes through the subsurface formations in order to reach hydrocarbon-bearing zones, and then using production techniques for bringing the hydrocarbon to the surface through the drilled boreholes. To prevent the boreholes from collapsing, boreholes are often equipped with steel tubes called casings or liners which are cemented to the borehole wall. Once they are put in place, casings and liners preclude direct access to the formation, and therefore impede or prevent the measurement of important properties of the formation, such as fluid pressure and resistivity. For this reason, the logging of wellbores is routinely performed before the casing is set in place.
In order to optimize the depletion of the reservoir, it is highly desirable to monitor the temperature, pressure, and other formation parameters at different depths in the well, on a permanent basis, over most of the life of the well. Valuable information regarding the integrity of the wellbore can be gained from continuously monitoring parameters such as well inclination and casing thickness. A common approach to such monitoring consists of attaching sensors to the outside of the casing, interconnecting the sensors via cables to provide telemetry and power from the formation surface, and cementing the sensors and cables in place. A description of such a system is provided in U.S. Pat. No. 6,378,610 to Rayssiguier et al. Such a system has numerous apparent drawbacks such as complicating the installation of the casing and the impossibility of replacing failed components. Another monitoring system is disclosed in U.S. Patent Application 2001/0035288 to Brockman et al. which discloses means for exchanging information and power through the casing wall via inductive couplers. These couplers, however, require extensive modification of the casing and are not suitable for an installation in situ. In previously incorporated U.S. Pat. No. 6,070,662 to Ciglenec et al., means are disclosed for communicating with a sensor implanted in the formation, but this arrangement requires that the sensor be put in place prior to the installation of the casing. U.S. Pat. No. 6,443,228 to Aronstam et al. describes means of exchanging information and power between devices in the borehole fluid and devices implanted in the wellbore wall, but does not consider the problems introduced by the presence of a casing or a liner.
It is therefore an object of the invention to provide apparatus, methods, and systems for obtaining information regarding a geological formation or a well passing through a geologic formation.
It is another object of the invention to provide methods, apparatus, and systems for exchanging information and power between an interrogating tool located in a cased borehole and sensors attached to the casing.
It is a further object of the invention to provide apparatus, methods, and systems for communicating information between an interrogating tool in a borehole and a sensor attached to a casing without using cables and without significantly altering the casing.
In accord with the objects of the invention an interrogating device and a sensing device are provided. The sensing device (which is either installed on the outer surface of the casing or liner prior to installation of the casing in the borehole, or inserted into an opening cut in the casing after the casing is cemented in place) includes a housing and a sensor with associated electronic circuitry. The interrogating device is located within (and may be movable inside) the wellbore. The sensing device and the interrogator include a magnetic coupling therebetween that is operable when the sensing device and interrogator are positioned in close proximity to one another. Preferably, the magnetic coupling is realized by at least one solenoid winding for the interrogator (whose main axis is substantially parallel to the axis of the wellbore) and at least one solenoid winding for the sensing device (whose main axis is substantially parallel to the axis of the wellbore), to thereby provide a loosely-coupled transformer interface therebetween. The interrogator and sensing device communicate in a wireless manner over the magnetic coupling therebetween.
In a preferred embodiment of the present invention, when the interrogating device is placed in close proximity to the sensing device, an alternating current is circulated in the winding of the interrogating device to produce magnetic flux in the local region of the wellbore that is adjacent the interrogating device and sensing device. Part of this flux is collected by the sensor's winding, causing current to flow through the sensor winding. The current flowing through the sensor winding induces a voltage signal across a load impedance. By modulating the current circulating in the winding of the interrogating tool, information can be passed from the interrogating tool to the sensor device. Likewise, by modulating the load impedance of the winding of the sensor device (or by modulating the current circulating in the winding of the sensing device), information can be passed from the sensor device to the interrogating tool.
The system of the invention may include a plurality of sensing devices located along the length of the casing, and at least one interrogating device which is moved through the wellbore. The method of the invention may include locating a plurality of sensing devices along the length of the casing, moving the interrogating device with respect to the casing, using the interrogating device to signal the sensing device, and having the sensing device obtain information regarding the formation and provide that information to the interrogating device in a wireless manner.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.
Turning to
One embodiment of the system of the invention 20 is shown in
As seen in
The sensing device 27 of the invention is shown positioned and fixed in an opening 41 cut in the casing 12, and includes a housing 47, one or more sensors 48 (one shown) with associated electronic circuitry 49 and a winding 50 comprising several turns of an insulated wire 51 wound around a cylindrical body 52 (such as a bobbin as shown) made of material of high magnetic permeability (such as ferrite). The sensor winding 50 is preferably positioned as flush as possible with the inner surface of the casing 12, and is oriented with its main axis aligned parallel to the borehole axis as shown. The housing 47 may be an assembly of several parts made of the same or different materials, including, but not limited to metals, ceramics, and elastomers. Depending upon the type of sensor(s) 48 included in the sensing device 27, the housing 47 may include one or more holes (not shown) which allows formation (or wellbore) fluids to come into contact with the sensor(s) 48. The sensing device 27 preferably does not extend inside the wellbore and therefore allows for unimpeded motion of equipment within the wellbore.
The sensor 48 and electronic circuitry 49 preferably perform multiple functions. In particular, each sensor 48 preferably senses one or more properties of the formation 10 surrounding the casing (e.g., pressure, temperature, resistivity, fluid constituents, fluid properties, etc.), and/or one or more properties of the casing 12 itself (e.g., inclination, mechanical stress, etc.). The sensing may be continuous, at predefined times, or only when commanded by the interrogator 23. If the sensing is continuous or at predefined times, the sensing device 27 may store information it obtains in memory (which may be part of the associated circuitry 49) until the sensing device is interrogated by the interrogator 23. When interrogated, the circuitry 49 associated with the sensor 48 preferably functions to transmit (via the sensor winding 50) information obtained by the sensor 48 to the interrogator 23 as will be described hereinafter. The sensing device 27 may, if desired, incorporate a unique code to unambiguously identify itself to the interrogator 23.
According to one aspect of the invention, the interrogator 23 either includes means for modulating current in its winding 34, or is coupled to such a modulating current generator. By modulating current in the winding 34 of the interrogator in accordance with a data signal (which is to be passed from the interrogator 23 to the sensing device 27), magnetic flux circulates in loops in the local region of the wellbore that is adjacent the interrogator 23 as depicted schematically in
According to one aspect of the invention, the current generated in the sensor winding 50 may be rectified by circuitry 49 in order to provide power to the circuitry 49 and the sensor(s) 48. If the current generated in the sensor winding 50 is too weak to power the electronic circuitry 49 and sensor(s) 48 directly, the current may be accumulated over a suitable period of time in an energy storage component such as a capacitor, a supercapacitor or a battery. The electronic circuitry 49 may wake up and become active when the accumulated charge is sufficient for its correct operation.
According to another aspect of the invention, the sensing device 27 may send information to the interrogator 23 by controlling operation of an electronic switch 54 that is connected across the sensor winding 50 as shown in
In an alternate embodiment as shown in
It should be appreciated by those skilled in the art that the configuration of the winding 34 and/or winding 50 as well as the relative amplitudes and phases of the currents injected into the windings can be adjusted in order to cancel (or strengthen) the magnetic field at specific locations in the wellbore. For example, the interrogator 23 may include a pair of windings that are separated along their common main axis by a small gap. In this configuration, the two windings can be driven with opposite currents (e.g., currents which flow in opposing directions around the common main axis) to create a sharp null in the telemetry's transfer function when the gap is aligned (e.g., directly faces) with the winding 50 of the sensing device 27 (or 27′). Thus, the sensing device 27 may be used as a marker for the purpose of defining or identifying a place of particular interest along the well, as the location of the sensing device can be located very accurately by moving the interrogator 23 past the sensing device 27 and noting the location of a sharp null signal followed by a phase reversal.
As shown in
Turning now to
The system of the invention may include a plurality of sensing devices 27 (27′) or 127 and at least one interrogating device 23. The sensing device may be located along the length of the casing 12 and/or at different azimuths of the casing. The interrogating device may be moved through the wellbore.
According to one embodiment of the method of the invention, a plurality of sensing devices are located-along the length of the casing, the interrogating device is moved through the casing, the interrogating device is used to signal the sensing device, and the sensing device obtains information regarding the formation (either prior to being interrogated and/or after being interrogated) and provides that information to the interrogating device in a wireless manner.
According to another embodiment of the method of the invention, at least one sensing device is located along the length of the casing at a desired location along the wellbore, the interrogating device is moved through the casing, and a change in the wireless signal provided by the sensing device to the interrogating device is used to precisely locate the desired location along the wellbore. More particularly, by moving the interrogator past the sensing device and noting the location of a sharp null signal followed by a phase reversal the location of interest (i.e., the location where the sensing device is located) may be identified precisely.
An alternative embodiment of the inventive apparatus is shown in
There have been described and illustrated herein embodiments of systems, methods and apparatus for obtaining formation information utilizing sensors attached to a casing in a wellbore. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while the invention was described with reference to a particular interrogating device and particular sensing devices, other interrogating devices and sensing devices could be utilized. For example, the interrogating device and/or sensing device may utilize a plurality of solenoidal windings in order to provide improved magnetic coupling therebetween. Also, instead of using solenoidal windings, any other magnetic coupling mechanism may be used. Moreover, instead of utilizing the two terminals of the sensor winding as differential input to the load impedance of the sensing device, one of the terminals of the sensor winding may be grounded and the other terminal of the sensor winding used as a single-ended input to the load impedance of the sensing device. Furthermore, with respect to the sensing devices, it will be appreciated that various other types of sensing devices such as disclosed in previously incorporated U.S. Ser. No. 10/163,784 may be utilized. In addition to casings and liners, the sensing apparatus may be deployed in any type of wellbore device, such as sand screens. While preferably deployed in a wellbore device containing conductive fluid, the system can also operate in non-conductive fluid. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as claimed.
This application is a continuation-in-part of co-owned U.S. Ser. No. 10/452,447, entitled “Methods, Apparatus, and Systems for Obtaining Formation Information Utilizing Sensors Attached to a Casing in a Wellbore,” filed on Jun. 2, 2003, and is also related to co-owned U.S. Ser. No. 10/163,784 to R. Ciglenec, et al. entitled “Well-Bore Sensor Apparatus and Method”, and to co-owned U.S. Ser. No. 09/428,936 to A. Sezginer, et al. entitled “Wellbore Antennae System and Method”, and to co-owned U.S. Pat. No. 6,426,917 and to co-owned U.S. Ser. No. 09/382,534 to R. Ciglenec et al. entitled “Reservoir Management System and Method”, and to co-owned U.S. Pat. No. 6,028,534, and to co-owned U.S. Pat. No. 6,070,662, and to co-owned U.S. Pat. No. 6,234,257, and to U.S. Pat. No. 6,070,662, all of which are hereby incorporated by reference herein in their entireties.
Number | Name | Date | Kind |
---|---|---|---|
6028534 | Ciglenec et al. | Feb 2000 | A |
6070662 | Ciglenec et al. | Jun 2000 | A |
6234257 | Ciglenec et al. | May 2001 | B1 |
6378610 | Rayssiguier et al. | Apr 2002 | B2 |
6426917 | Tabanou et al. | Jul 2002 | B1 |
6443228 | Aronstam et al. | Sep 2002 | B1 |
6538576 | Schultz et al. | Mar 2003 | B1 |
6684952 | Brockman et al. | Feb 2004 | B2 |
6691779 | Sezginer et al. | Feb 2004 | B1 |
6693553 | Ciglenec et al. | Feb 2004 | B1 |
20010035288 | Brockman et al. | Nov 2001 | A1 |
20020195247 | Ciglenec et al. | Dec 2002 | A1 |
20030029611 | Owens | Feb 2003 | A1 |
Number | Date | Country | |
---|---|---|---|
20040238166 A1 | Dec 2004 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 10452447 | Jun 2003 | US |
Child | 10740211 | US |