System and method for monitoring a packer in a well

Abstract

A system and method for monitoring the compression or deformation of a packer element in a well, according to which at least one member is associated with the packer element and changes its physical state in response to the compression, and the change in the physical state of the member is quantified.

Description

BACKGROUND

[0001] A common operation in well servicing, testing, and completion operations is the setting of a packer in a casing, tubing, or the like in a well in oilfield operations for various reasons, including the ability to isolate certain areas in the well. A packer usually includes one or more toroidal packer elements of an elastomeric material which are generally set by deforming them in a manner to cause them to expand out to engage and seal between the inner diameter of the casing, tubing, or openhole and the outer diameter of a mandrel, or the like, which supports the packer element.

[0002] As the packer element is deformed during setting there is usually a proper and desired sequence and final state for the set packer element. Additionally, after the packer is set it is desirable to know if a proper set state is being maintained.

[0003] Therefore, what is needed is a system and method for monitoring packer element conditions during and after the packer is set so as to insure a proper set and maintenance of same.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] FIG. 1 is a longitudinal cross-sectional view of a packer tool disposed in a well, along with a performance monitoring system.

[0005] FIG. 2 is a view similar to that of FIG. 1 but depicting the packer of the tool of FIG. 1 in a compressed state.

[0006] FIG. 3 is an enlarged transverse cross-sectional view taken along line 3-3 of FIG. 1.

DETAILED DESCRIPTION

[0007] Referring to FIG. 1, the reference numeral 10 refers to, in general, a packer tool disposed in a casing 12 located in a well in an oilfield operation, or the like. The tool 10 can also be disposed in an openhole completion. The term wellbore will be understood to include the cased completion as shown in FIG. 1 as well as an openhole completion. The tool 10 includes a mandrel, or tubular member 14 having a stepped outer diameter to form a reduced diameter end portion 14a, and a tubular member 16 having a stepped inner diameter to form a reduced diameter end portion 16a. A portion of the end portion 16a of the member 16 extends, or telescopes, over a portion of the end portion 14a of the member 14.

[0008] An elastomeric packer element 20 extends around a portion of the end portion 14a of the member 14 and between the shoulders formed by the stepped outer diameter of the member 14 and the distal end of the end portion 16a of the member 16. The members 14 and 16 are adapted for relatively axial, telescoping movement relative to each other from the position shown in FIG. 1, in which the packer element 20 extends between the above-mentioned shoulders in a uncompressed condition, to the position of FIG. 2 in which the packer element 20 is compressed and in its set position. Since the mechanism associated with the members 14 and 16 for causing this relative movement is conventional, it is not shown nor will it be further described.

[0009] A series (in the example shown, five) of highly compliant, silicon rubber optical fibers 22 are embedded within the packer element 20. As shown in FIG. 3 with respect to one of the fibers 22, each fiber 22 forms a circle, or ring, extending around the axis of the member 14.

[0010] A series of electrical conductors 26 extends from the fibers 22, respectively, through an internal passage in the member 16 and to an electronics package 28 embedded in the member 16. The electronics in the package 28 are conventional and include a voltage source connected in an electrical circuit including the fibers 22 and the conductors 26 so that current can flow in the circuit and be monitored under conditions to be described.

[0011] Each of the fibers 22 is conventional, and, as shown in FIG. 3, includes a light emitter 22a on one end and a light detector 22b on the other end as shown in connection with one fiber 22. It is understood that an identical emitter 22a and detector 22b are associated with each of the other fibers 22 and that the detectors 22b are connected, via the conductors 26, to the electronics package 28. Each fiber 22 has optical properties which change when it is subjected to strain. The fibers 22 can be, for example, silicone rubber fibers of a type once marketed by Bridgestone Engineering Products to Oak Ridge National Laboratory for pressure sensing applications.

[0012] Although not shown in the drawings, it is understood that a light source, which can be an infrared source or a light emitting diode, is connected to the light emitter 22a of each fiber 22 so that the light is transmitted through each fiber 22 and received at its corresponding detector 22b. As each fiber 22 is strained as a result of the packer element 20 being compressed to its set position as described above, the light intensity received at its corresponding detector 22b changes. Each detector 22b is connected in the above-mentioned electrical circuit formed by the electronic package 28 so that the current or voltage in the circuit changes in response to changes in the received light intensity to enable the strain of the fibers 22 to be quantified. For example, as the light level increases, the current or voltage level in the circuit increases.

[0013] The current or voltage is monitored and readings taken before and after the setting procedure of the packer element 20 can be compared and checked against known ratios for a normal packer setting. Also, a strain profile can be established which will provide an indication whether or not the packer element 20 is properly set, that is, if optimum compression of the packer element 20, and the corresponding strain of the fibers 22, has been obtained. The changes in the current or voltage over time can be plotted and interpreted either quantitatively (numerical thresholds etc.) or qualitative (shape or curves etc.) using many different calibration techniques such as polynomial or neural networks.

[0014] It is understood that the above-mentioned current, voltage, or light intensity readings can be sent to the surface using any telemetry system including cable, EM, acoustic, mudpulse, etc. Additionally, the packer element 20 can be equipped with an active packer set control system in which case the above readings can be used downhole to correct deficiencies in the packer set. Also, once the packer element 20 is set, its compression or deformation can be continuously monitored.

[0015] It is understood that finite element modeling of the packer element 20 can be done which allows the fibers 22 to be placed in areas within the packer element 20 where, when subject to strain as discussed above, maximum elongation of the fibers 22 can be obtained without exceeding their elongation limits. This assures the highest resolution in the above readings without the danger of damaging the fibers 22. This type of modeling also allows the time-based “signature” of the fibers 22 to be established for proper packer settings.

Variations and Equivalents

[0016] The fibers 22 can be configured differently than that described above and can be located or orientated in the packer element 20 differently. Also, the packer element 20 does not have to be compressed but can be deformed in any other manner, such as by stretching or extending it. Further, the design may be such that, as light intensity increases, the current in the above-mentioned electrical circuit decreases. Moreover, the fibers 22 described above can be replaced by other systems that change their physical state in response to the compression or deformation of the packer element 20. For example, conductive polymer elements, such as a graphite or powdered metal doped silicon, could be utilized in a manner so that the resistance of the latter elements will change as the packer element 20 is compressed. This change in resistance can be analyzed and monitored as described above. Still further, the above-mentioned electrical circuit can be replaced by an optical system.

[0017] It is understood that spatial references, such as “outer,” “within,” “surround,” “between”, ““inner,” etc. are for the purpose of illustration only and do not limit the specific orientation or location of the layers described above.

[0018] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims

1. A packer system comprising: a packer element adapted to be deformed into sealing engagement with a wellbore; a member associated with the packer element wherein the member is capable of changing its physical state in response to the deformation; and a circuit associated with the member for quantifying the change in physical state.

2. The packer system of claim 1 wherein the member is embedded in the packer element.

3. The packer system of claim 1 wherein the member is an optical fiber that transmits light wherein the light intensity changes in response to strain on the optical fiber caused by the deformation.

4. The packer system of claim 3 wherein changes in the light intensity causes changes in current flow in the circuit to enable the strain on the optical fiber to be quantified.

5. The packer system of claim 1 further comprising two tubular members between which the packer element extends so that relative movement of the tubular members causes the deformation of the packer element.

6. The packer system of claim 5 wherein a portion of the circuit is embedded in the packer element and a portion of the circuit is disposed in one of the tubular members.

7. The packer system of claim 1 wherein the member is a conductive polymer that changes in electrical resistance in response to strain on the conductive polymer caused by the deformation.

8. The packer system of claim 7 wherein the conductive polymer is in the form of graphite or powdered metal doped silicon.

9. The packer system of claim 7 wherein changes in the electrical resistance causes changes in current flow in the circuit to enable the strain on the conductive polymer to be quantified.

10. The packer system of claim 7 wherein the conductive polymer is embedded in the packer element.

11. The packer system of claim 7 further comprising two tubular members between which the packer element extends so that relative movement of the tubular members causes the deformation of the packer element.

12. The packer system of claim 11 wherein a portion of the circuit is embedded in the packer element and a portion of the circuit is disposed in one of the tubular members.

13. The packer system of claim 1 wherein the packer element is deformed by compression.

14. The packer system of claim 1 wherein the circuit is an electrical circuit.

15. The packer system of claim 14 wherein a portion of the circuit is embedded in the packer element.

16. A method for monitoring a packer element in a wellbore, the method comprising the steps of: deforming the packer element; providing a member associated with the packer element wherein the member changes its physical state in response to the deformation; and quantifying the change in the physical state of the member.

17. The method of claim 16 further comprising the step of transmitting light through the member wherein the light intensity changes in response to strain on the member caused by the deformation.

18. The method of claim 17 wherein the step of quantifying comprises the step of changing current flow in a circuit in response to changes in the light intensity.

19. The method of claim 18 further comprising the steps of: disposing the packer element between two tubular members; and moving the tubular members relative to each other to cause the deformation of the packer element.

20. The method of claim 19 further comprising the steps of: embedding a portion of the circuit in the packer element; and disposing a portion of the circuit in one of the tubular members.

21. The method of claim 16 further comprising the step of embedding the member in the packer element.

22. The method of claim 16 wherein the member changes in electrical resistance in response to changes in the strain on the member caused by the deformation.

23. The method of claim 22 wherein the member is in the form of a conductive polymer in the form of graphite or powdered metal doped silicon.

24. The method of claim 22 further comprising the step of passing current through the member wherein the current flow varies in response to strain on the member caused by the deformation.

25. The method of claim 24 wherein the step of quantifying comprises monitoring the current flow.

26. The method of claim 16 further comprising the step of embedding the member in the packer element.

27. The method of claim 16 further comprising the steps of: disposing the packer element between two tubular members; and moving the tubular members relative to each other to cause deformation of the packer element.

28. The method of claim 27 further comprising the steps of: embedding a portion of the circuit in the packer element; and disposing a portion of the circuit in one of the tubular members.

29. The method of claim 16 wherein the packer element is deformed by compression.

30. The method of claim 16 wherein the step of quantifying includes providing an electrical circuit having current flow that changes in response to changes in the physical state of the member.