Patent Application
20170145760
Exploring, drilling and completing hydrocarbon and other wells are generally complicated, time consuming and ultimately very expensive endeavors. As a result, over the years well architecture has become more sophisticated where appropriate in order to help enhance access to underground hydrocarbon reserves. For example, as opposed to wells of limited depth, it is not uncommon to find hydrocarbon wells exceeding 30,000 feet in depth with deviated or horizontal sections aimed at targeting particular underground reserves.
While such well depths and architecture may increase the likelihood of accessing underground hydrocarbon reservoirs, other challenges are presented in terms of well management and the maximization of hydrocarbon recovery from such wells. To this end, during the life of a well, a variety of different interventional applications may be performed within the well with a host of different tools. However, providing downhole access to wells of such challenging architecture may require more than simply dropping a wireline into the well with the applicable tool located at the end thereof For example, a spool of wireline cable, slickline, coiled tubing or other conveyance line may be outfitted with the application tool and forcibly directed through tortuous well architecture to the targeted downhole location where the application is to take place.
In order to properly deliver the application tool to the target location, an operator at the oilfield surface may monitor the deployment of the conveyance line from the spool. The operator may have available readings regarding the speed at which the spool or line is being advanced into the well. Additionally, tension on the line may be monitored from a surface position at the well. Thus, in theory, the operator may be able to direct a change in the speed or even direction of the line as needed by exercising control over a corresponding winch, or reel (or injector) that in turn is able to control the advancing line. So, for example, where the line is advancing at an unacceptable rate, or not at all due to an unexpected obstruction in the well, the operator may be alerted to this condition based on available speed or line tension readings and take appropriate corrective action.
Unfortunately, the above technique of monitoring and adjusting the conveyance application relies heavily on operator alertness and inherent human limitations. For example, any adjustment to the conveyance application, such as altering injector speed, may involve a specialized level of skill that not each operator possesses. Further, even with sufficient training and experience, the variable of human error remains, particularly where the conveyance application takes several hours to complete and may involve non-stop alertness on the part of the operator.
Complicating matters further is the fact that the available conveyance application readings are likely to be inaccurate to begin with. That is, measurements of speed, tension and others are generally taken at the oilfield surface. This is understandable given that the coiled tubing injector or spooling device from which the line is taken is also located at the oilfield surface. However, the application tool, tractor and any other equipment is advancing within the well, likely several thousand feet away from the location where such measurements are being taken. Further, it is this more distant location at which measurements are more likely to be of consequence. For example, the surface measurement and application protocol may both call for a tractor at the end of the conveyance line to advance at about 3,000 feet/hr. Yet, in reality, the actual speed of the tractor may be 2,500 feet/hr. due to slipping, intermittent downhole obstructions, etc. However, due to preceding stretch in the line, cable weight and other factors, the slower rate of tractor advancement might not be detected by measurements taken on the line at the oilfield surface.
In the case of slickline or wireline conveyance, such an undetected condition of slower downhole advancement than apparent at surface leads to a lack of tension and slack in the line. In the case of a coiled tubing conveyance, this may result in an undetected increased load being undesirably placed on such downhole tools. In the case of wireline or slickline, this lack of tension in the line may result in knotting, unwinding of braided cable, entanglement of the line with a tractor or other downhole tools or a variety of other undesirable conditions.
It is known that such inadequate line tension often presents in tractoring applications through a deviated well where slack in the line may accumulate near the “elbow” transition between the vertical and horizontal well sections. For example, due to its own weight, a line may be of sufficient tension in a vertical well section. However, this same line may actually be in a low or even zero tension state within the horizontal well section near, and downhole of, the noted elbow. However, due to the nature of surface readings as described above, the operator may not be alerted to this undesirable low tension condition of the line in the horizontal section.
Given known tendencies of low tension conditions such as this, operators may often overcompensate during a conveyance application. For example, in the particular circumstance noted above, a tractor in a horizontal well section may be directed to tractor at a rate of 3,000 feet/hr. while 2,500 feet/hr. of line is deployed. This does lessen the likelihood of the emergence of an undesirably low tensions condition in the horizontal well section. Unfortunately, it also increases the odds that the tractor motor or associated features will prematurely wear and/or fail. Indeed, given the nature of current conveyance applications, operators are generally left balancing between such inefficient maneuvers and risking undesirable slack in the line.
A method for adjusting an interventional application is disclosed. The adjusting may comprise dynamically adjusting the interventional application. The method may comprise conveying an interventional tool into a well over a conveyance from an oilfield surface from a reel thereat. A dynamic characteristic measurement of the well, the conveyance, the formation, the flow or even the tool itself may be acquired. Based on such measurement, the manner of conveying the tool through the well may be automatically adjusted in real-time. Once more, the dynamic characteristic measurement may be re-acquired following the adjustment. Thus, the manner of conveying the tool may be automatically re-adjusted based on the re-acquired measurement.
Embodiments are described with reference to certain modes of conveyance for downhole interventional applications. For example, as shown, a tractor driven communicative slickline system is utilized to deliver an interventional tool to a horizontal section of a well for an application thereat. As defined herein, an interventional tool is a tool or at least a portion of a tool that enters an existing well. The interventional tool may perform, without limitation, a service, sense a property, or obtain a sample within the existing well or the interventional tool may perform a function related to a downhole tool string such as, but not limited to, providing a tractoring force or the like. The interventional tool, or a portion of the interventional tool, may be in communication with the surface of the well or wellbore in real-time or the interventional tool, or a portion of the interventional tool, may be operated in memory mode. However, a variety of other modes of conveyances and lines may be utilized for any number of interventional applications. For example, alternative conveyance lines may be utilized, with or without the aid of a tractor. These may include coiled tubing, coiled tubing with fiber optic, e-line coiled tubing, wireline, wireline or slickline deployed within drill pipe, and even cabled or wired drill pipe. So long as the system allows for automatic conveyance adjustment and re-adjustment based on real-time downhole dynamic characteristics, appreciable benefit may be realized.
Referring now to
The above referenced conveyance line 125 allows for a convenient manner of tool retrieval once the downhole interventional application has been completed. Specifically, the line 125 may be unwound from the reel 117 of the surface drive system or winch system 115 in order to deploy the tool 150 into the well with the reel 117 later rewound for retrieval thereof along with the tool 150 once the application is complete. Once more, while the depicted line 125 may be a communicative slickline as noted above, where coiled tubing or other heavier line types are utilized, the surface drive system 115 may comprise an injector or other appropriate surface equipment such as, but not limited to, surface equipment for pumping a fluid into a tubular or the well to enable the pumped fluid to convey the tool 150 into the well.
As indicated above, the overall system 100 is also dynamically adjustable. That is, while a surface control assembly 101 may direct and/or operate the surface drive system reel 115 to deploy the line 125 at a given speed, to a certain depth, etc., the downhole assembly 110 may acquire readings or measurements that lead to adjustments in the deployment. Specifically, as noted above, the line 125 includes a communicative capacity. Therefore, sensors 111, 112 of the downhole assembly 110 may be used to acquire dynamic data such as speed, tension or well position during the deployment.
In the embodiment shown, the sensors include a telemetry cartridge 111 for communicating various readings from the downhole assembly 110 such as tension and shock and movement sensing capacity as well as a depth correlation cartridge 112 for providing tool depth with casing collar and gamma-ray sensing capacity. Of course, in other embodiments, different and/or additional sensing capacity may be included, such as, but not limited to, tool location, readings from a borehole caliper sensor and the status of various aspects of the tool (for instance if a jar is open or closed). Further, such sensors may be located elsewhere on the downhole assembly 110 or as part of the conveyance line 125. Regardless, the sensed downhole data is made available to the surface control assembly 101 in real-time.
The surface control assembly 101, in turn, is equipped with both a control unit 105 for directing the conveyance application as noted, as well as an acquisition unit 107 for management of the acquired data from such sensors 111, 112. Thus, adjustments to the conveyance of the downhole assembly 110 may be made in real-time that are based on actual downhole data and conditions as opposed to measurements taken from surface locations.
Continuing with reference to
As the conveyance application proceeds, however, the likelihood is that the downhole assembly 110 may begin to move at a rate and under line tension that is considerably lower than the preprogrammed speed and tension called for. For example, even with the aid of a tractor 114, there is a likelihood of tractor slippage, a temporary obstacle or line slack developing in a horizontal well section. Once more, due to the length and weight of the line 125, particularly over greater and greater well depths, this slow-down may not be fully detectable at the surface 190 in time to prevent equipment damage. Therefore, in order to prevent the potentially catastrophic circumstance of an entangled or unraveling line, this slow-down may nevertheless be detected by downhole assembly sensors 111, 112. In fact, as detailed further below, downhole measurements from such sensors 111, 112 may be acquired in real-time by the acquisition unit 107 at the oilfield surface 190 over a data line 109. The acquisition unit 107 may then analyze the acquired data for relay and any adjustment to the conveyance application being carried out by the control unit 105. As a result, automatic adjustments may be made to the conveyance application based on actual downhole conditions as opposed to more removed surface detections.
In the embodiment shown, the conveyance line 125 is deployed through a well by way of a tractor 114 as alluded to above along with the winch system 115 and its unwinding reel 117. However, the manner in which the tractor 114 and winch system 115 may be dynamically and/or automatically adjusted based on true downhole conditions such as true speed, line tension, etc. provide a for a self-piloting mode of interventional conveyance. In an embodiment where coiled tubing is utilized in place of the depicted slickline conveyance line 125, an injector may be utilized as part of the winch system 115. Nevertheless, a mode of self-piloting would be attained with algorithms and software of the acquisition unit 107 capable of analyzing the real-time downhole acquired data in a manner to automatically generate adjustments to the control unit 105 as the interventional conveyance application proceeds.
Referring now to
Continuing with reference to the embodiment of
However, the type of well architecture depicted in
Nevertheless, in the embodiment shown, the assembly 110 is outfitted with sensors capable of providing such information to the surface control assembly 101 in real-time. Thus, when speed, tension or other conveyance related characteristics begin to present differently in actuality than what is called for by the preprogrammed conveyance application, the control assembly 101 would be automatically alerted and corrective adjustment automatically taken. In the noted example of a tractor failing to maintain a preprogrammed speed, the corrective action may include slowing down the winch assembly 115 to prevent an undesirable build-up of slack or actual line 125 at a downhole location such as the indicated elbow 289.
Preventing the build-up of downhole slack in the line 125 in this manner avoids issues such as entangling or unraveling of the line 125 as alluded to above. In the case of coiled tubing applications, this may also help to avoid the circumstance of unnecessarily introducing a substantial amount of added weight downhole.
It is also notable that any adjustment, such as an automatic adjustment to the conveyance application as indicated involves automatically aligning the speed of the winch assembly 115 with that of the downhole assembly 110. Thus, no operator at surface is forced to examine surface readings, take an educated guess as to actual downhole conditions, and then adjust winch speed accordingly. This not only reduces the likelihood of slack developing in the line, it also avoids operator overcompensation for such possibilities. That is, the operator need not intentionally slow down the winch assembly 115 and drive up tension in the line 125 with the tractor fighting the slowed winch speed downhole just to ensure that slack does not emerge. Instead, automatically aligning winch speed with that of the tractor or other interventional assembly 110 results in an operation of maximized efficiency. This is also easier on the interventional assembly 110, the winch assembly 115, and even the operator, who may now be freed up to focus on more routine surface tasks.
Referring now to
With added reference to
The data transmitted over the line 125 may be obtained from the sensor or sensor devices 111, 112 as alluded to above. More specifically, these devices 111, 112 may constitute entire sensor packages with a variety of sensing capabilities. For example, in one embodiment, one sensor may be a telemetry cartridge 111 for housing a shock measuring accelerometer 315 and deviation sensor 320 in addition to the noted battery 310. The other sensor 112 may be a depth correlation cartridge 112, for example, housing a gamma ray sensor 330 and a casing collar locator 340. Indeed, a separate velocity sensor 350 may also be provided to the assembly 110. Thus, the data made available to surface may relate to both speed in a general sense as well as more specific correlation to known downhole well features. As a result, the accuracy of automatic adjustment and alignment between winch speed and tractor speed may be enhanced. In an embodiment, the tool 100 comprises a logging tool and the speed of the tool 100 may be regulated to a substantially constant speed with the feedback and/or adjustment of the surface drive system operation.
Other types of sensors may also be utilized in addition to those detailed above. Perhaps most notably, a head tension sensor may be incorporated into the downhole assembly 110. However, the assembly 110 may also be outfitted with a pressure sensor, borehole caliper sensor, an inclination sensor, an azimuth sensor, and other types of sensors as well. Furthermore, a variety of different types of high data rate communication lines may also be utilized to support the techniques described above. In an embodiment where fiber optics are utilized as alluded to above, the line 125 may also provide downhole readings such as temperature or be coupled to additional sensors providing pressure or other information such as via an ERD (electrical resonating diaphragm) sensor.
The ability to automatically adjust the conveyance application based on actual downhole conditions and readings as opposed to surface measurements and guesswork, provides for a truly self-piloting manner of operation. That is, not only is the preprogrammed conveyance application adjusted in real-time based on actual readings downhole, but readings of tensions, speed, etc. are ongoing. Thus, a continuous bidirectional, feedback loop is presented. That is to say, as the conveyance application is automatically adjusted to account for real-time readings, the result is that the application changes, thereby affecting the real-time readings. Thus, the process is ongoing and dynamic with the application being truly self-piloting as indicated. In an embodiment, if a tractor is part of the tool 100 and a caliper on the tool detects an obstruction, the system may be able to automatically stop operation of either or both of the tractor and the winch or surface drive system.
Referring now to
In the example application of
A jarring tool 400 and application such as that depicted may also be incorporated into other downhole assemblies, including the assembly 110 shown in
With specific reference to
Referring now to
However, to maximize efficiency, free up an operator during winch and tool movement, and to avoid line entanglement and other potentially catastrophic issues, the operation may be automatically dynamically adjustable. This is achieved in part by acquiring (560) and analyzing (575) real-time downhole data regarding the line, the tool or the well as the tool is moved within the well. Thus, as indicated at 590, both the moving of the tool and winch may be automatically adjusted as needed to ensure proper and aligned speed, tension, etc. Adjustments may also include action beyond attaining speed alignment. For example, a detection of tension increase in the line beyond a pre-set limit during uphole withdrawal may automatically stop the winch to prevent line breakage. Regardless, such automatic adjustments may take place in a feedback loop where the adjusted movements effect follow on readings for further acquisition, analysis and continuing adjustment as needed. Thus, efficiency of the conveyance may truly be maximized on a continuous basis.
Techniques have been described hereinabove for dynamically adjusting interventional conveyance applications as needed so as to avoid deployment issues such as where the line speed or tension within the well is substantially greater than that of the downhole assembly. This is achieved in a manner that also avoids operator overcompensation which might tend to damage the line, tractor, winch or other deployment equipment. Indeed, the operator involvement in the conveyance portion of the application may be substantially reduced with the tool assembly left largely self-piloting through a feedback loop and technique as detailed hereinabove.
The preceding description has been presented with reference to presently disclosed embodiments. Persons skilled in the art and technology to which these embodiments pertain will appreciate that alterations and changes in the described structures and methods of operation may be practiced without meaningfully departing from the principle, and scope of these embodiments. Furthermore, the foregoing description should not be read as pertaining only to the precise structures described and shown in the accompanying drawings, but rather should be read as consistent with and as support for the following claims, which are to have their fullest and fairest scope.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2014/044572 | 6/27/2014 | WO | 00 |
