Method to predict sealing element and bearing assembly remaining useful life using real-time drilling parameters

Abstract

A method for overall monitoring of a sealing assembly wear and / or failure where there is a recorded log of all operational parameters in the operational history of said sealing assembly to which said sealing assembly was exposed, said operational parameters comprising: hookload; fluid temperature; wherein each one of said operational parameters comprised in said recorded log is processed in the algorithm to determine a wear value of said sealing element, and wherein said wear value is a determination of the remaining operating life of said sealing element.

Description

[0001] METHOD TO PREDICT SEALING ELEMENT AND BEARING ASSEMBLY REMAINING USEFUL LIFE USING REAL-TIME DRILLING PARAMETERS

[0002] FIELD OF THE INVENTION

[0003] The present invention is directed to a method of assessing the wear on the sealing element of a rotating control device used in oilfield operations, more specifically the method monitors various parameters to determine the remaining useful life of such sealing elements.

[0004] BACKGROUND OF THE INVENTION

[0005] When drilling for oil and gas, one encounters geological formations that have a narrower tolerance for changes in bottom hole pressure. Constant improvements are being sought to reduce any downtime of equipment and expedite any repairs that become necessary. A widely adopted solution to this problem is the so called 'Managed Pressure Drilling' (MPD). In this method of drilling, the annular space is closed to the atmosphere by means of a Rotating Control Device (RCD). Rotating equipment requires maintenance as the drilling environment produces forces, elevated temperatures and abrasive cuttings detrimental to the longevity of seals, bearings, and packing elements. An RCD is a pressure- control device used during drilling for the purpose of making a seal around the drillstring during its rotation and / or tripping in and out of a well. The RCD is designed to contain or divert hydrocarbons or other wellbore fluids and pressure and prevent their release to the atmosphere. The RCD diverts the fluid into a manifold equipped with a specialized choke that allows manipulation of the well's bottom hole pressure. Right before breaking a connection to add a new stand, the pumps are ramped down. At the same time, the dynamic component of the bottom hole pressure drops and needs to be compensated for, in order to maintain a near-constant bottom hole pressure.

[0006] In the oil and gas industry, it is paramount to ensure the safety of employees, a problem that may jeopardize employees' safety on a drilling rig is known as a "blowout". When a zone of high geopressure is encountered during a drilling operation and the pressure exceeds the hydrostatic pressure exerted by the drilling mud, and the formation has sufficient permeability to allow fluid flow, then the formation fluid will move into the wellbore and displace the drilling mud. This is referred to as a "kick"; and if unchecked it will result in a "blowout" which is an uncontrolled release of crude oil and / or natural gas from an oil well Through the use of an MPD system which includes an RCD a kick can be safely controlled.

[0007] During drilling operations, the drill pipe or tubular is axially and slidably moved through the rotating control head. The axial movement of the drill pipe along with other forces experienced in the drilling operation, some of which are discussed below, causes wear and tear on the bearing and seal assembly and the assembly subsequently requires repair. Typically, the drill pipe or a portion thereof is pulled from the well and the bearing and seal assembly in the rotating control head is then released.

[0008] The internal sealing elements may be either passive or active. Passive sealing elements, such as stripper rubber sealing elements, can be fabricated with a desired stretch- fit. On the other hand, an active sealing element typically requires a remote -to-the -tool source of hydraulic or other energy to open or close the sealing element around the outside diameter of the tubular. An active sealing element can be deactivated to reduce or eliminate the sealing forces of the sealing element with the tubular. Several types of RCDs have been proposed with combinations of active and passive seals or sealing element, usually combining a stripper rubber sealing element and an active sealing element.

[0009] A tubular typically comprises sections with varying outer surface diameters. The passive and active sealing elements mentioned above must be designed to adapt to seal around all of the rough and irregular surfaces of the components of the tubular, drill pipe, tool joints, and drill collars.

[0010] The continuous movement of the tubular through the sealing element while the sealing element is under pressure causes wear of the interior sealing surface of the sealing element. When drilling with a dual annular sealing element RCD, the lower of the two sealing elements is typically exposed to the majority of the pressurized fluid and cuttings returning from the wellbore, which communicate with the lower surface of the lower sealing element body. The upper sealing element is exposed to the fluid that is not blocked by the lower sealing element. When the lower sealing element blocks all of the pressurized fluid, the lower sealing element is exposed to a significant pressure differential across its body since its upper surface is essentially at atmospheric pressure when used on land or atop a riser. The highest demand on the RCD sealing elements occurs when tripping the tubular out of the wellbore under high pressure.

[0011] Several components are used to control the fluid pressure. Typically, one or more blowout preventers (BOP) are mounted with the well forming a BOP stack to seal the well. In particular, an annular BOP is used to selectively seal the lower portions of the well from a tubular that allows the discharge of mud. In many instances, a conventional rotating control head is mounted above the BOP stack. An inner portion or member of the conventional rotating control head is designed to seal and rotate with the drill pipe. The inner portion or member typically includes at least one internal sealing element mounted with a plurality of bearings in the rotating control head. The thrust generated by the wellbore fluid pressure, the radial forces on the bearing assembly and other forces cause a substantial amount of heat to build in the conventional rotating control head. The heat causes the seals and bearings to wear and subsequently require repair. The conventional rotating control head typically includes a cooling system that circulates fluid through the seals and bearings to remove the heat.

[0012] RCDs have a rubber sealing element (see Figure 1, in light shading) that provides a seal between the wellbore space, which holds the well pressure at surface level, and the atmosphere. The sealing element is considered a consumable because pipe rotation and axial movement eventually wear it to the point where its geometry changes and it is no longer capable of effectively acting a sealing barrier

[0013] It is critical for operators to know when the element needs to be replaced, but so far no methodology is available in the market to properly predict when the sealing element needs to be replaced. Operators often replace it when the elements fail (break) in situations where the consequences are not critical, or they replace the element prematurely if the circumstances dictate that a loss of pressure created by the sealing element would be critical to operations.

[0014] It is critical for operators to know when the element needs to be replaced, but so far no methodology is available in the market to properly predict when the sealing element needs to be replaced. Operators often replace it when the elements fail (break) in situations where the consequences are not critical, or they replace the element prematurely if the circumstances dictate that a loss of pressure created by the sealing element would be critical to operations.

[0015] Elements can be replaced proactively to avoid a scenario where they fail and leak fluid, causing downhole pressure to drop, which results in a formation collapse or a reservoir fluid influx. Depending on how critical the well is, customers can opt to replace them during a pipe trip (when surface pressure can be released) as replacing them under pressure could be a risky operation.

[0016] Because it is done on operational convenience and not on actual life, it is difficult to have an estimate on how much life is remaining when they are replaced. When wells are not critical, sealing elements are allowed to leak a little bit, could be an indicator that they need to be replaced and that is right now the only way to determine elements were used to their full useful life. Other options to assess the analysis of the wear on sealing elements have been to install sensors on the RCDs to determine its operating parameters and potentially determine the remaining bearing assembly’s sealing element’s useful life. Some drawbacks associated with the use of additional sensors to assess the wear on a sealing element includes, additional problems and issues and equipment breakdowns associated with additional add-ons, wires, and hoses sticking out of the RCD. It is also safer for the personnel involved as well as quicker. Also, any additional sensor or equipment used for monitoring has to be installed, removed, and re-installed every time the RCD bearing assembly is replaced, this result in a waste of costly rig time.

[0017] In light of the state of the art, there exists a need to assess the remining useful life of a critical component of a rotating control device, the sealing element. As sealing elements are consumables and are critical to managed pressure drilling operations, it is important for operators to derive as much value as possible from such elements so as to operate in a safe manner for their crews but to maximize the costs of the equipment and optionally, manage crew downtime to coincide with a pre-determined break in the operations.

[0018] SUMMARY OF THE INVENTION

[0019] According to one aspect of the present invention, there is provided a method of determining the wear on a sealing element found on a bearing assembly used on a rig during an oil and gas operation, by using a hookload sensor on a drillstring, wherein said method comprises the steps of: o providing a rotating control device equipped with said sealing element, wherein said sealing element is made of a type of elastomeric material and having an aperture therethrough to adapted to allow said drillstring to travel therethrough; o providing an electronic data recorder connected to said hookload sensor and a to computer capable of performing an algorithm; o inputting in said algorithm said type of sealing element for which a value of tensile strength is pre-loaded; o obtaining hookload information from said hookload sensor and recording the hookload information on said electronic data recorder connected to said algorithm; o recording the number of tooljoints on said drillstring that go through said aperture over said operation on said electronic data recorder; o determining a force exerted on the sealing element by the drillstring during said operation; o inputting an information related to said force exerted on the sealing element by the drillstring during said operation into said electronic data recorder; o processing said information by implementing said algorithm on said computer and obtaining a processed information; o providing an output based on said processed information comprising a determination of a change of said force as a function of time; and o determining if said change of said force has reached a pre-determined threshold below which the sealing element is considered to require replacement.

[0020] According to a preferred embodiment of the present invention, the detector is given contextual info about the sealing element comprising the following: hours in operation; diameter; and RCD element model.

[0021] According to a preferred embodiment of the present invention, after receiving a new frame from the EDR via WITS (hookload data channel), the method comprising the following steps: running a statistical inference on the data; where the hookload time series is taken from the rig and segment it to isolate a single tooljoint passing through the rubber element so a pair of data (tooljoint number (#), max force) can be collected, where said statistical inference step comprises the sub-steps of: o segmentation (i.e. finding the tooljoint passing); o parsing (i.e. finding the max force value); o storing the pair of data; and o analyzing the result; optionally, determining if a tooljoint has passed through the RCD element; recording the hookload and direction of the pipe when a tool joint has passed through the RCD element; accumulating and recording a history of pair of data recorded, said pair of data consisting of: hookload, tooljoint count; plotting as a time series the history of pairs where the tooljoint count serves as a stand-in for time; and computing a secondary trend detection on the detector.

[0022] According to another aspect of the present invention, there is provided a method for instantaneously detecting, whether the sealing assembly has reached, within a 95% confidence interval, a failure point based on an aggregate exposure over its operating life, of conditions, by using a hookload sensor on a drillstring, wherein said conditions comprises at least one of: hookload overtime; RPM; fluids; pipe, and wherein said method comprises the steps of: o providing a rotating control device equipped with said sealing element, wherein said sealing element is made of a type of elastomeric material and having an aperture therethrough to adapted to allow said drillstring to travel therethrough; o providing an electronic data recorder connected to said hookload sensor and a to computer capable of performing an algorithm; o inputting in said algorithm said type of sealing element for which a value of tensile strength is pre-loaded; o obtaining hookload information from said hookload sensor and continuously recording the hookload information on said electronic data recorder connected to said algorithm; o recording the number of tooljoints on said drillstring that go through said sealing element over said operation on said electronic data recorder; o determining a force exerted on the sealing element by the drillstring during said operation; o inputting said force exerted on the sealing element by the drillstring during said operation into said electronic data recorder; o running a statistical inference step on the data; where the hookload time series is taken from the rig and segment it to isolate a single tooljoint passing through the rubber element so an additional pair (tooljoint #, max force) can be collected, where said statistical inference step comprises the sub-steps of:

[0023] ■ segmentation (i.e. finding the tooljoint passing);

[0024] ■ parsing (i.e. finding the max force value);

[0025] ■ storing the new pair of data; and

[0026] ■ analyzing the result; o processing the information comprising the result by implementing said algorithm on said computer and obtaining a processed information; o providing an output based on said processed information comprising a determination of a change of said force exerted by the sealing element as a function of time; and o determining if said change of said force exerted by the sealing element has reached a pre-determined threshold below which the sealing element is considered to have reached said failure point within said 95% confidence interval. According to a preferred embodiment of the present invention, the history of pairs (hookload, tooljoint count) is combined with fluid temperature at the outlet: the temperature history of the RCD element in the algorithm to assess the wear of the sealing element.

[0027] According to a preferred embodiment of the present invention, the algorithm further takes into account the operational hours tallied for the sealing element.

[0028] According to a preferred embodiment of the present invention, the algorithm further computes into said algorithm an impact on the sealing assembly remaining useful life based on the physical state of said drillstring. (Old pipe vs premium pipe, hard banding (physical grooves in tooljoints that shave RCD elements).

[0029] According to a preferred embodiment of the present invention, the algorithm further computes surface rig parameters: RPM, tripping speed, casing pressure, etc.

[0030] According to another aspect of the present invention, there is provided a method for overall monitoring of a sealing assembly wear and / or failure where there is a recorded log of all operational parameters in the operational history of said sealing assembly to which said sealing assembly was exposed, said operational parameters comprising: hookload; fluid temperature; etc.; wherein each one of said operational parameters comprised in said recorded log is processed in the algorithm to determine a wear value of said sealing element, and wherein said wear value is a determination of the remaining operating life of said sealing element.

[0031] According to another aspect of the present invention, there is provided a method according to claim 10, further comprising a step of comparing current wear value of said sealing assembly to an established trend obtained from the comparison to identical sealing assemblies whose own historical performance and exposure to various parameters during their operational history have been inputted into said algorithm to obtain said established trend.

[0032] Rotating control devices (RCDs) have a rubber sealing element that provides a seal between the wellbore space, which holds the well pressure at surface level, and the atmosphere. The sealing element is considered a consumable because pipe rotation and axial movement would eventually wear it to the point where its geometry changes and it is no longer capable of effectively acting a sealing barrier. According to a preferred embodiment of the present invention, the system’s electronic data recorder provides a measurement of pull force versus time.

[0033] According to a preferred embodiment of the present invention, by developing an algorithm that tracks the force trend in time, it is now possible to predict with a high degree of confidence the point at which the element will be worn to the point of requiring replacement. As the pipe of a drill string passes through the RCD and is in contact with the RCD, a small fraction of the pipe weight is held by the sealing element. Since the force to push the pipe is affected by the friction between the pipe and the sealing element, and the sealing element wear with time (enlarging its pass-through diameter), the friction force will decrease with time.

[0034] BRIEF DESCRIPTION OF THE FIGURES

[0035] Features and advantages of embodiments of the present application will become apparent from the following detailed description and the appended figures, in which:

[0036] Figure 1 is a side view of a typical rotating control device highlighting the casing (above) and the sealing element (below);

[0037] Figure 2 is a side cross-sectional view of atypical rotating control device; and

[0038] Figure 3 is a graphical depiction of two separate curves of force over time where the force is an indication of the force exerted onto the sealing element over the duration of an operation.

[0039] DESCRIPTION OF THE PREFERRED EMBODIMENT

[0040] According to a preferred embodiment of the present invention, there is provided a method for instantaneously detecting, whether the sealing assembly has reached, within a 95% confidence interval, a failure point based on an aggregate exposure over its operating life, of conditions, by using a hookload sensor on a drillstring, wherein said conditions comprises at least one of: hookload overtime; RPM; fluids; pipe, etc.

[0041] The hookload is easy to measure as it is the sum of all the weight hanging on the hook during a drilling operation and thus can be assessed by placing a hookload sensor connected to the drilling line from the crown block sheave to the anchor. The hookload is associated with a travelling block that carries the weight of the drilling string and various drilling tools. In essence, the block carries the drilling load; it is the actual weight of the drillstring as measured from the surface. The hook load will therefore be at its maximum when all the weight attached to the hook is suspended freely in air with no support. Once the drill string is inserted into the well, the hookload will decrease as the drillstring will be partially supported by the fluid contained in the well. Hook load also decreases when the bit touches the bottom of the hole in a vertical well. In horizontal wells, the hook load also decreases because of the friction and normal force endured on the drillstring as it leans or rests on one side of the borehole.

[0042] The hookload measurement is a standardized value recorded on all electronic drilling systems. There is a specific mechanical operation, pipe tripping which will emit a measurable signal, particularly POOH or pulling out of the hole. The signature that is sought at the moment when the tooljoint of the pipe passes through the rubber element. It is to be noted that the pipe travelling direction matters, pulling out of hole (POOH) has a higher chance of showing this trend simply because of geometry.

[0043] Also, when the driller pulls the pipe out of the hole (or puts more pipe in), the pipe’s tooljoints (which have a slightly larger diameter than the rest of the pipe) will deform the RCD sealing element causing a detectable spike in the hookload trace. By looking at this spike / signal over time, it can be estimated how close the sealing element is to its “failure zone” for that specific type of element.

[0044] As seen in Figures 1 and 2, as the sealing assembly (10) of the RCD (5) can have pipe (not shown) passing through the aperture (15) of the sealing element (12). In operation, a small fraction of the pipe weight is held (frictionally) by the sealing element (12). Since the force to push the pipe is affected by the friction between the pipe and the sealing element, and the sealing element wears with time (enlarging its pass-through diameter), the friction force will decrease over the time the seal has been in operation and will also be affected by the number of tooljoints which will have travelled therethrough eventually wearing out the seal. An electronic data recorder (EDR) (not shown) provides a measurement of pull-force versus time. By taking note of the various stresses imposed on the sealing element and developing an algorithm that tracks the force trend in time, it has now become possible predict when the sealing element is worn to the point of requiring replacement and prior actual failure of the sealing element.

[0045] Referring to Figure 3, net force on the drillstring exerted by the sealing element is shown on the ordinate as a function of time. 'Force' in Figure 3 is the equivalent of hookload. One expects to observe this same signature / trend in actual rig data. The numbers will be much higher but the analysis is the same.

[0046] According to a preferred embodiment of the present invention, there is provided a method of determining the wear on a sealing element found on a bearing assembly used on a rig during an oil and gas operation, by using a hookload sensor on a drillstring, wherein said method comprises the steps of: providing a rotating control device equipped with said sealing element, wherein said sealing element is made of a type of elastomeric material and having an aperture therethrough to adapted to allow said drillstring to travel therethrough; inputting in an algorithm said type of sealing element (i.e. model and diameter) for which a value of tensile strength is pre-loaded; obtaining hookload information from said hookload sensor and continuously recording the hookload information on an electronic data recorder connected to said algorithm; recording the number of tooljoints on said drillstring that go through said sealing element over said operation on said electronic data recorder; determining the force exerted on the sealing element by the drillstring during said operation; inputting the force exerted on the sealing element by the drillstring during said operation into said electronic data recorder (input); determining the change of said force as a function of time (output); and determining of said change of force has reached a pre -determined threshold below which the sealing element is considered to require replacement.

[0047] According to a preferred embodiment of the present invention, for each sealing element’s model and diameter a baseline curve is generated. These curves are what powers the algorithm: deviation from the baseline is quantified into an alarm / waming / health state.

[0048] Analysis of the output allows operator to accurately determine the quality of the sealing element at any point in time. Preferably, it allows an operator to determine whether or not an operation can be carried out in its entirety prior to failure of the sealing element which would cause a work stoppage in middle of the operation. Preferably, this is based on the initial value for the force of the sealing element as it acts on the drillstring and the expected duration of the operation (generally in hours) as well as the various expected variables which will impact and affect the force of the sealing member exerted on the drillstring (such as but not limited to number of tool joints, duration of the operation. Preferably, the method provides an expected remaining useful lifetime value for the sealing element through the use (or application) of an algorithm which is adapted to take into account of those factors as well as other factors which are not listed above. Preferably, all rubber element models of all diameters need to be fingerprinted, that is, it is desirable to establish what "expected behavior" means for each one of them. This information is encoded in the same that is done in the field where the live curve is computed and compared against the "lab" version.

[0049] According to a preferred embodiment of the present invention, the electronic data recorder works in connection with a detector which is provided with (or has information uploaded thereinto) contextual info about the element such as: time of installation, diameter, RCD element model, etc. Preferably, after receiving a new frame from the EDR via WITS (hookload data channel), the system performs a statistical inference on the data and determine if a tooljoint has passed through the RCD element. Preferably, the system also records the hookload value and direction of the pipe. As the operation progresses, the detector accumulates a history of pairs (hookload, tooljoint count) which can be plotted as a time series where the tooljoint count serves as a stand-in for time. According to another embodiment of the present invention, the system generates a secondary trend detection by computing such on the detector. A downward trend over time is a strong indicator of element wear. According to a preferred embodiment of the present invention, the detection model is trained offline (machine learning algorithms / general linear models) and then deployed to the field.

[0050] According to a preferred embodiment of the present invention, the history of pairs (hookload, tooljoint count) are found to be the strongest indicators of when an RCD “sealing” element could fail. Preferably, This information can be expanded by incorporating additional contextual information about the operation (historical data of): fluid temperature at the outlet: the temperature history of the RCD element; hours that the element has been installed / rotating; physical state of the pipe (i.e. old (used) pipe vs new or premium pipe, hard banding (physical grooves in tooljoints that shave RCD elements); and surface rig parameters: RPM, tripping speed, casing pressure, etc.

[0051] According to a preferred embodiment of the present invention, an operator can assess the level of wear on a RCD sealing element via the use of surface rig sensors. Preferably, this is achieved by using a signal in hookload sensor data. This is achieved by collecting data during RCD element testing. Preferably, the use of an algorithm along with the historical data collected for a particular type of sealing element allows the determination of the failure zone of said sealing element with 95% confidence. Preferably, the method of the present invention proposes to use a variety of parameters including historically generated data to instantaneously determine the degree of wear and the possible risk of failure of the sealing element used as part of a RCD in managed pressure drilling.

[0052] According to a preferred embodiment of the present invention, an operator can assess the level of wear on a sealing element which may be considerably different than the manufacturer provided life expectancy as it takes multiple factors into account. Preferably, the method can also detect manufacturing defects in a sealing element as it will monitor its service history and compare such to identical sealing elements and thus chart an “expected” lifetime based on an accumulation of parameters and indicate deviations therefrom which could potentially be an indicator of manufacturing defect.

[0053] By referring to Figure 3, the ordinate drifts downwards during the useful life of the sealing element. This is an indication of the reducing force applied thereon by the drillstring and consequently the tightness of the seal between the sealing element and the drillstring.

[0054] Rather than looking for the optimum sealing element life, the method according to a preferred embodiment of the present invention aims at anticipating sealing element failure and at instantaneously knowing the remaining useful life of said sealing element while it is being used in an oil and gas operation.

[0055] According to a preferred embodiment of the present invention, this method is based on the realization that knowing how long a particular sealing element is expected to have a useful operating life does not account for every day's experience where a catastrophic failure might occur before the predicted end of the useful life. The failure of a sealing element can be attributed to various factors, such as the number of tooljoints traveling through the aperture located on the sealing element; the number of hours of operation of said sealing element; the amount of force exerted over the life of the sealing element, and other factors.

[0056] According to a preferred embodiment of the present invention, the method relies on a combination of two factors, the historical hookload to which the sealing element has been exposed and the aggregate number of tool joints which have circulated through the sealing element to approximate the remaining useful life of said sealing element. Preferably, the method takes this pair of factors into account in its algorithm. Also preferably, the algorithm generates a force value which indicates with statistical confidence (for example, a 95% confidence interval) the remaining useful life of the sealing element. According to a preferred embodiment of the present invention, the force measurement is obtained from the algorithm as an expression combining the effect of the speed of rotation of the drillstring, the hookload measurement and optionally other variables or parameters affecting the sealing element. The speed of rotation of the drillstring is obtained from the operator from the rig (either as a rotary table or as a top drive). Preferably, the force measurement acts as a bootstrap confidence interval over the difference of means (lab curve - field curve). This is a standard statistical technique / tool. Preferably, the bootstrap confidence interval is computed using a difference of forces (baseline "lab" curve for the element, minus the same curve that's being computed live at the rig). If this confidence interval contains the value zero, it's statistical evidence in favor of both curves (distribution of values) having the same mean. An interval (over a difference of means) that doesn't capture zero is evidence in favor of a trend with statistical significance, as opposed to just noise. A "wear" value can be easily derived from the difference in force. It is worth noting that the larger the difference, the poorer the health of the rubber element. Preferably, baseline curves are to be created to establish what this scale would look like. According to a preferred embodiment of the present invention, the curves would be different for different sealing elements (model, diameter).

[0057] According to a preferred embodiment of the present invention, the speed of rotation signal is digitized by a circuit prior to being into input the microprocessor. The digital signal is subsequently treated into the algorithm to aid in generating a real-time force value as output of the system.

[0058] According to a preferred embodiment of the present invention, the system comprises an input / output circuit which receives a code digitally identifying the type of sealing element as well as the specific sealing element. Preferably, the system then accesses the historical data of said sealing element and determines the baseline threshold of the sealing element and preferably also provides information to the operator regarding the remaining useful life of the sealing element. According to a preferred embodiment of the present invention, the system provides information in real-time to the manufacturer to enable the latter to perform real-time assessment of its sealing elements performance in the field. Preferably, this real-time assessment feature allows the manufacturer to detect manufacturing defects as the products are being used. More preferably, the real-time assessment feature allows the manufacturer to warn the operator of a possible impending failure.

[0059] According to a preferred embodiment of the present invention, the system and method provides for continuous data sampling in order to improve the accuracy of the historical data collection. According to a preferred embodiment of the present invention, the system and method provides for intermittent data output depending on the needs of the operator. Preferably, the data output can come at a rate of every minute, every 2 minutes, every 3, minutes, every 4 minutes, every 5 minutes, every 10 minutes, every 15 minutes, every 20 minutes every 30 minutes, every hour, and so on. More preferably, the data output can be custom-designed by the operator to be generated at their own requirement.

[0060] According to a preferred embodiment of the present invention, the system and method provides for an output display which indicates whether the particular sealing elements is operating in the safe zone, e.g. in its useful life, or whether it has entered a critical zone where the risk of sealing element failure is in the 95% confidence interval. Preferably, information of impending failure is fed back by a programmed I / O circuit.

[0061] According to a preferred embodiment of the present invention, the curves obtained such as those in Figure 3, once recorded are part of the historical data set for a specific type of sealing element .

[0062] As seen in Figure 3, net force as a function of time is derived and the resulting values are provided by a microprocessor. A baseline set provides a threshold level below which the operator will have been warned that the sealing element (or sealing assembly) is at an increased risk of sudden failure. Figure 3 shows the monitoring feature exhibiting the force applied by the sealing element on the drillstring over time. It can be observed on curve 1 (blue graph bar) that there is a sudden spike in the force recorded in the early instances of the monitoring, followed by a slow drop-off over time and a stabilized force being exerted on the drillstring. Each of the sections of the curve are compared to previous operational runs using the same sealing element. According to a preferred embodiment of the present invention, the system takes into account and computes various parameters of the aggregate of the operational runs. This is converted to a historical data set which helps in determining the remaining useful life of the sealing element.

[0063] According to a preferred embodiment of the present invention, the system recognizes each singular sealing element entered therein through an identifier specific to each one. Preferably, this is a serial number, but could be any one or several numerical identifier which would identify and distinguish between all sealing elements.

[0064] According to a preferred embodiment of the present invention, the system centralized all of the various parameters of the aggregate of the operational runs. Preferably, the resulting historical data set which helps in determining the remaining useful life of the sealing element is maintained in a centralized database. Preferably, the historical data set pertaining to a sealing element is shared with the operator and maintained with the manufacturer to enable the latter to monitor in “real-time” the performance of its sealing element products.

[0065] According to a preferred embodiment of the present invention, the system may further comprise an alarm which alerts the operator when a pre-determined threshold is about to be crossed and / or has been reached.

[0066] According to a preferred embodiment of the present invention, the operator can simply assess that data collection is being done for all parameters of relevance. This can be done by referring to the system and the hookload sensor or simply referring to the system output which will confirm the values generated as well as the measurements taken by the sensors.

[0067] When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components. The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS1. A method of determining the wear on a sealing element found on a bearing assembly used on a rig during an oil and gas operation, by using a hookload sensor on a drillstring, wherein said method comprises the steps of: o providing a rotating control device equipped with said sealing element, wherein said sealing element is made of an elastomeric material and having an aperture therethrough to adapted to allow said drillstring to travel therethrough; o providing an electronic data recorder connected to said hookload sensor and a to computer capable of performing an algorithm; o inputting in said algorithm said type of sealing element for which a value of tensile strength is pre-loaded; o obtaining hookload information from said hookload sensor and recording said hookload information on said electronic data recorder connected to said algorithm; o recording the number of tooljoints on said drillstring that go through said aperture over said operation on said electronic data recorder; o determining a force exerted on the sealing element by the drillstring during said operation; o inputting an information related to said force exerted on the sealing element by the drillstring during said operation into said electronic data recorder; o processing said information by implementing said algorithm on said computer and obtaining a processed information; o providing an output based on said processed information comprising a determination of a change of said force as a function of time; and o determining if said change of said force has reached a pre-determined threshold below which the sealing element is considered to require replacement.

2. The method according to claim 1, where said detector is given contextual info about the sealing element comprising the following: hours in operation; diameter; and RCD element model.

3. The method according to claim 1, where, after receiving a new frame from the electronic data recorder via WITS (hookload data channel), said method comprising the following steps:running a statistical inference on the data; where the hookload time series is taken from the rig and segment it to isolate a single tooljoint passing through the rubber element so a pair of data (tooljoint number and maximum force) can be collected, and where said statistical inference step comprises the sub-steps of: o segmentation (i.e. finding the tooljoint passing); o parsing (i.e. finding the max force value); o storing the pair of data; and o analyzing the result; optionally, determining if a tooljoint has passed through the RCD element; recording the hookload and direction of the pipe when a tool joint has passed through the RCD element; accumulating and recording a history of pair of data recorded, said pair of data consisting of: hookload, tooljoint count; plotting as a time series said history of pairs of data recorded where the tooljoint count serves as a stand-in for time; and computing a secondary trend detection on the detector.

4. A method for instantaneously detecting, whether the sealing assembly has reached, within a 95% confidence interval, a failure point based on an aggregate exposure over its operating life, of conditions, by using a hookload sensor on a drillstring, wherein said conditions comprises at least one of: hookload over time; RPM; fluids; pipe, and wherein said method comprises the steps of: o providing a rotating control device equipped with said sealing element, wherein said sealing element is made of a type of elastomeric material and having an aperture therethrough to adapted to allow said drillstring to travel therethrough; o providing an electronic data recorder connected to said hookload sensor and a to computer capable of performing an algorithm; o inputting in said algorithm said type of sealing element for which a value of tensile strength is pre-loaded; o obtaining hookload information from said hookload sensor and continuously recording the hookload information on said electronic data recorder connected to said algorithm; o recording the number of tooljoints on said drillstring that go through said sealing element over said operation on said electronic data recorder;o determining a force exerted by the sealing element on the drillstring during said operation; o inputting said force exerted on the sealing element by the drillstring during said operation into said electronic data recorder; o running a statistical inference step on the data; where the hookload time series is taken from the rig and segment it to isolate a single tooljoint passing through the rubber element so an additional pair (tooljoint #, max force) can be collected, where said statistical inference step comprises the sub-steps of:■ segmentation (i.e. finding the tooljoint passing);■ parsing (i.e. finding the max force value);■ storing the new pair of data; and■ analyzing the result; o processing the information comprising the result by implementing said algorithm on said computer and obtaining a processed information; o providing an output based on said processed information comprising a determination of a change of said force exerted by the sealing element as a function of time; and o determining if said change of said force exerted by the sealing element has reached a pre-determined threshold below which the sealing element is considered to have reached said failure point within said 95% confidence interval.

5. The method according to any one of claims 1 to 5, where the history of pairs (hookload, tooljoint count) is combined with fluid temperature at the outlet: the temperature history of the RCD element in the algorithm to assess the wear of the sealing element.

6. The method according to any one of claims 1 to 5, where the algorithm further takes into account the operational hours tallied for the sealing element.

7. The method according to any one of claims 1 to 6, where the algorithm further computes into said algorithm an impact on the sealing assembly remaining useful life based on the physical state of said drillstring. (Old pipe vs premium pipe, hard banding (physical grooves in tooljoints that shave RCD elements).

8. The method according to any one of claims 1 to 7, where the algorithm further computes surface rig parameters: RPM, tripping speed, casing pressure, etc.

9. A method for overall monitoring of a sealing assembly wear and / or failure where there is a recorded log of all operational parameters in the operational history of said sealing assembly to which said sealing assembly was exposed, said operational parameters comprising: hookload; fluid temperature; and other factors / parameters; wherein each one of said operational parameters comprised in said recorded log is processed in the algorithm to determine a wear value of said sealing element, and wherein said wear value is a determination of the remaining operating life of said sealing element.

10. The method according to claim 10, further comprising a step of comparing current wear value of said sealing assembly to an established trend obtained from the comparison to identical sealing assemblies whose own historical performance and exposure to various parameters during their operational history have been inputted into said algorithm to obtain said established trend.

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