System and method for sensing and monitoring the status/performance of a downhole tool

[0001] In order to produce oil and gas from a subterranean well, oil field tubulars, commonly called a work string, are inserted in the well bore, or in a casing located in the well bore. Packers and downhole tools are connected to the work string with the packers functioning to isolate formations, and the tools assisting in displacing various fluids into the formations or for retrieving hydrocarbons from the formations.

[0002] Some packers are mechanically set at a desired depth in the casing, or well bore, by picking up on the work string at the surface, turning the work string and then lowering the work string until mechanical slips associated with the packer have extended outwardly to engage, or grip, the casing, or well bore. As additional work string weight is set down on the engaged slips, a series of elastomeric packer elements are deformed to seal off against the casing, or well bore. Fluid is then pumped down the work string so that its pressure is exerted against another set of slips located above the packer. This fluid pressure hydraulically extends the latter slips outwardly until they engage, or grip the casing, or well bore. Thus, various fluids can be pumped down the work string and through internal passages of the packer before they exit below the packer, while the packer slips are kept sealed against the casing, or well bore, by the weight of the work string.

[0003] In other techniques, the packers are set by utilizing the workstring to create hydraulic pressure to expand slips of a setting mechanism into engagement with the casing, or well bore.

[0004] It can be appreciated that these types of packers and downhole tools encompass a number of subsystems and/or components that function together in an integral manner thus allowing the device to be manipulated so that it will perform its intended task. However, there is no method to monitor, evaluate, report, or improve the condition, or function, of these devices or their surroundings during the downhole operation. Therefore, if a problem occurs during the operation, the devices would have to be removed from the well for inspection and repair and then reinserted into the wella procedure that is time-consuming and costly.

[0005] Therefore, what is needed is a system and method for sensing and monitoring the status/performance of components of a packer, and/or downhole tool to enable any problems to be corrected.

[0006] The drawing is a schematic view of a system according to an embodiment of the invention.

[0007] Referring to the drawing, a packer is referred to in general by the reference numeral 10 and is in the form of an elongated tubular body member 12 adapted to be inserted into a casing, or well bore, on a work string, or the like (not shown). Since the packer 10, per se, does not form any part of the present invention, it is shown, and will be described, only generally.

[0008] The packer includes upper slips 14 and 16 mounted on the body member 12 which operate in a conventional manner so that they can be set in response to fluid being pumped down the work string to exert pressure against the slips. This pressure causes the upper slips 14 and 16 to extend outwardly to engage, or grip, the casing or well bore, in a conventional manner.

[0009] Lower slips 18 are also provided on the body member 12 which are mechanically set in a conventional manner by picking up on the work string at the surface, turning the work string for a predetermined angular amount, and then lowering the work string until the lower slips 18 have extended outwardly to engage (grip) the casing, or well bore.

[0010] Packer elements 20 and 22 are provided on the body member 12 and extend between the upper slips 16 and the lower slips 18. The packer elements 20 and 22 deform, usually by compressing or extending, as additional work string weight is set down in the casing, or wellbore, to seal off against the casing, or well bore. A series of drag blocks 24 are angularly spaced around the body member 12 below the packer element 22.

[0011] Since the slips 14, 16, 18; the packer elements 20 and 22; and the drag blocks 24 are all, per se, conventional, they will not be shown or described in any greater detail.

[0012] As a result of the foregoing, various fluids can be pumped down the work string, and pass through internal passages, or bores, of the body member 12 before they exit below the packer 10, while the slips 14,16 and 18 are kept sealed against the casing, or well bore, by the weight of the work string.

[0013] A sensor 30 is disposed inside the bore of the body member 12, three sensors 30 are placed on, in, and/or around the slips 14, 16, and 18, respectively; two sensors 30 are placed on, in, or around the packer elements 20 and 22, respectively; and a sensor 30 is placed on, in, or around the drag blocks 24.

[0014] The sensors 30 are conventional, and, as such, sense and provide information that will be described that is transmitted to the surface to enable personnel on the surface to change parameters that would improve the performance of the packer 10.

[0015] The sensors 30 can include, but are not limited to, sensors that sense pressure, load, movement, fluid identification, fluid flow, acoustic properties and/or acceleration. For example, they could provide information about differential pressure across various components of the packer 10 including the slips 14, 16, and 18, and the packer elements 20 and 22, thus providing information about stresses in these components due to pressure loading. Also, the sensors 30 could be utilized to determine if fluid is flowing in areas by measuring the pressure drop between components in these areas. They could also sense, and provide analysis of, stresses within components thus warning of premature failure of a component. Further, the sensors 30 could determine if the initial weight set down on the packer 10 is within proper operating parameters, and, if not, they could send a signal to the surface so that the operator could make adjustments from the surface or to other downhole devices (passive or active) that could be called upon to adjust the force needed to maintain the proper operation of the tool. Still further, the sensors 30 could also sense relative movement between components of the packer 10 including the slips 14, 16, and 18, as well as the packer elements 20 and 22 and the drag blocks 24, to evaluate the position of the components relative to one another and thus help determine if the component may become unstable.

[0016] The sensors 30 could also be used to determine the effects that fluids may have on various components. For example, these effects could include chemical degradation of elastomers or metals to the point they will no longer function within their design limits. Further, the sensors 30 could be used to determine fluid flow through the packer 10, the casing, or the well bore to assist in determining leakage, erosion or imminent removal of components such as the washing off of the packer elements before they are set. Moreover, the sensors 30 could be utilized to determine leakage of fluids or gases past components of the packer 10, such as the packer elements 20 and 22, and/or they could be in the form of acoustic sensors to determine factors involving acoustics, such as the condition of cement behind the casing, or thickness of the casing or components. This would, in turn, provide information as to the condition of the casing prior to setting the packer 10 or the condition of a component that may be experiencing erosion during the job. The sensors 30 could also be in the form of accelerometers which could be utilized to help determine if vibrational forces are exceeding design limits or if fatigue in any of the components of the packer 10 is excessive.

[0017] A series of relatively small video cameras 34 are placed inside the inner diameter of the body member 12; in or around the slips 14, 16, and 18; on each side of the packer elements 20 and 22; and/or in or around the drag blocks 24. The video cameras 34 could be provided in place of, or in addition to, the sensors 30, and function to provide operators with a visual picture of the condition of these components, as well as the packer 10 in general, and its surroundings. This would enable an operator on the surface to observe these components and, if they are not functioning in a normal manner, to make adjustments from the surface.

[0018] The video cameras 34 are conventional and, as a non-limiting example, could be solid state CMOS cameras. Electronic circuits associated with the video cameras 34 could be fabricated using bulk CMOS processes.

[0019] A central processor 36 is disposed on the body member 12 to receive data from the sensors 30 and/or video data from the video cameras 34, process the data, and generate a signal or signals corresponding to the processed data to send to another location such as directly to the surface or to any intervening downhole device. In this context, various methods for transferring this data could be utilized including mud pulse, acoustic transfer through the fluid or tubulars, electromagnetic, fiber optics or hard wire, all of which are known in the art.

[0020] The above enables the packer 10, in general, as well as its various components, to be continuously monitored and evaluated so that any problems detected can be corrected.

[0021] It is understood that several variations may be made in the foregoing without departing from the scope of the invention. For example, the invention is not limited to use with a packer, but is equally applicable to any downhole device. Also, the above-mentioned electronic circuits could be replaced with an optical system. Also, additional sensors can also be placed on other sub-systems, or components, of the packer 10 including, but not limited to, seals (such as o-rings), j-slots, springs, internal tubes, adapters, subs, fasteners, and the like. Further, the sensors 30 and/or the video cameras 34 could be replaced with artificially intelligent devices. It is also understood that spatial references, such as upper, lower, inner, and outer below in between, etc., are for the purpose of illustration only and do not limit the specific orientation or location of the layers described above.

[0022] 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.