FR2842245A1 - Managing fatigue in tube used for drilling comprises using individual means of identification to record parameter giving cumulative fatigue for tube - Google Patents

Abstract

The work done by the tube (8) is determined by identifying the start of its descent to operate a drill and the completion of its re-lifting; calculating a parameter which is a function of the fatigue damage to the tube after this work, and writing on the individual means of identification (20) the value of this parameter to obtain an indication of the cumulative fatigue for the tube : The fatigue arises from work done by the tube during drilling operations. The parameter is calculated taking into account at least the architecture of the drill, the characteristics of the tube and the stimuli applied to the pipe. A finite element calculation program is used to determine the loads imposed on the tube during the work done. The indicator of cumulative fatigue sets off an alarm when it reaches a threshold value. A central computer carries out the calculation and records the parameter and controls the updating of the tube fatigue indicator. The computer can be a long way away from the drilling operation and carries out the calculation, recording and updating by a transmission, for example via the Internet. Independent claims are also included for the following: (1) a system for managing fatigue in a tube as above, comprising at least one read/write mechanism (14) for the individual identifications (20); a central computer with databases giving the characteristics of the tube, operating data of the work generating the fatigue, means of collecting the stimuli applied to the tube, means of calculating the fatigue damage and means of controlling the writing on the means of identification, where the tube passes in front of the detector at the start and end of the drilling operation and a portable reading/writing tool (19) is designed to verify the fatigue damage on the tube; and (2) the application of the above process to drill strings and/or extension tubes for risers in offshore drilling.

Description

The present invention relates to the field of drilling operations in

  which use rods, or tubulars, to connect and / or drive a rotary drilling tool from the ground surface. These tubulars are subjected to mechanical dynamic forces which generate fatigue. The lifespan of tubulars is therefore directly linked to the modes of

  stresses, stress levels and accumulated fatigue.

  The development of complex or long offset wells is making the conditions of use of drill pipes more and more severe. These new well architectures, but also the vibrational dysfunctions, can generate premature ruptures of the drill string. Most ruptures that are not yet fully predictable are essentially

  fatigue breakdowns in the broad sense of the term (fatigue, fatigue corrosion, ...).

  When the drill rod is rotating in a "dog-leg", that is to say an acute bend in the trajectory of the well drilled, the mechanical stress is typically a cyclic bending force (force generally much less than the elastic limit of the steel making up the drill pipes), superimposed on a

  quasi-constant axial force (traction or compression).

  Rigorous management of tubular drilling equipment is necessary in order to better control these rupture phenomena and ultimately be able to greatly limit them. This management notably involves means of identifying and monitoring as precisely as possible the history of the loading of each drill pipe. The invention also applies to other tubulars used for drilling operations, for example offshore drilling where tubular elements are used to form an extension column through the slice of water, commonly called "riser" in the profession. These riser elements are subject to significant cyclic stresses due in particular to maritime conditions, waves, swells, currents, etc., which generate

  fatigue as for drill pipes.

  Thus, the invention relates to a method of managing the fatigue of a tubular used for drilling, comprising individual identification means, the fatigue resulting from work carried out by the tubular during drilling operations. According to the invention, the following steps are carried out: - the work carried out by the tubular is determined by identifying the start of the descent of the tubular to operate the drilling and the end of its ascent, the time factor (duration) being taken into account account for each geometrical configuration, - a parameter is calculated as a function of the fatigue damage of the tubular following the work carried out,

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  - the value of the parameter is entered in the individual identification means of the tubular so as to obtain an indicator of cumulative fatigue

for said tubular.

  The parameter can be calculated by taking into account at least: the architecture of the borehole, the characteristics of the tubular, the stresses applied to the tubular. The stresses take into account the drilling parameters as a whole, that is to say in particular the mechanical forces on the tool, the friction, the nature of the fluids in contact with the tubulars,

temperature, etc ...

  A finite element calculation program can be used to

  determine the stresses suffered by the tubular during the work carried out.

  The cumulative fatigue indicator can trigger an alarm when

reaches a determined threshold.

  A central computer can calculate and store the parameter, and control the updating of the tubular fatigue indicator. The computer can be distant from the place of drilling operations and perform the calculation and storage of said parameter, and control the updating of the fatigue indicator of the tubular via a transmission, by

  example of Internet type, or other mode of transmission.

  The invention also relates to a system for managing the fatigue of a tubular comprising individual identification means. It includes: - at least one device for reading / writing individual identification means,

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  a central computer comprising at least one database of the characteristics of the tubular, a database on the operation generating fatigue, means of collecting the stresses applied to the tubular, means of calculating a fatigue damage, means for controlling the writing in said means for identifying a parameter

  corresponding to fatigue damage to the tubular.

  The device can be placed so that the tubular passes in front

  the sensor at the beginning and at the end of the operation generating fatigue.

  The system may include a portable read / write tool suitable for

  verification of the fatigue damage of the tubular.

  The method can advantageously be applied to drill pipes.

  The method can also be applied to extension tube elements

offshore riser type.

  The present invention will be better understood and its advantages

  will appear more clearly on reading the following description of a mode

  non-limiting embodiment, illustrated by the appended figures below, among which: - Figure 1 schematically shows a drilling installation in which the method and the system according to the invention are implemented;

  - Figure 2 shows a flow diagram of the method according to the invention.

  FIG. 1 shows a drilling installation consisting of a drilling device 2 comprising a lifting tower 3 placed on a substructure 4. A well 5 is being drilled using a drilling tool 6 fixed at the end of a drill-rod train 7 driven in rotation, and maneuvered by a drill-pipe train 8 also in rotation. This drill string ends at the surface by a drive rod 9 comprising suspension means 10 to the lifting tower 3. The borehole 5 is partially cased in its upper part 11, which supports the entire head of well 12 placed in the substructure 4, under the drilling floor 13. A read / write device 14 is placed under the floor so as not to interfere with the floor maneuvers. This read / write device 14 is connected to a control and command unit 15, either by conductors 16, or by radio or any other communication system. The control and command unit 15 includes means for introducing, manually or automatically, relevant parameters allowing, among other things, rigorous monitoring of the life of each drilling tubular. Thus, by integrating the parameters of the location of the tool, the trajectory of the tool and the resulting geometry of the well, the drilling parameters and the geometric and mechanical characteristics of the drill string, one can evaluate, or determine, the forces. suffered by each of the rods during operation. The unit 15 can also include means for calculating the "damage" suffered by each rod, means for memorizing this damage, means for controlling the writing of this "damage" on each rod. The unit also includes means of alert when a rod has reached a threshold life that has been

  determined to be unsafe for continued use.

  In FIG. 1, a rod 17 has been illustrated on a storage "rack" which is inspected by an operator 18 equipped with a controller 19 (portable read / write tool) for the "damage" written on the identification means

attached to each rod.

  The identification means fixed on each rod, not detailed here, consist of an electronic chip, electronic means for receiving and storing, transmitting information, via the means of

  read / write 14, or a controller 19 (portable read / write tool).

  Writing and reading information on this electronic label can be done automatically without contact, in particular using a system using electromagnetic waves. This electronic chip is a means of storing relevant information on each drill pipe, for example a unique identification number and a capital of points representing the remaining life for the tubular in question. all

  other relevant information can of course also be stored there.

  The electronic chip is protected from the aggressive drilling environment (for example pressure, temperature, drilling mud and corrosive effluents). Reading and writing are preferably done automatically under the floor of

drilling during the passage of the rods.

  The application to drilling riser elements is not illustrated, but it is clear that any tubular (drill rod, riser element, etc.) which can be equipped with identification means 20, and which passes in front of the means to

  read / write 14, may be the subject of the method according to the invention.

  FIG. 2 shows an example of organization of the methodology according to the invention. The element 21 schematically represents the reading / writing means on the tubulars, for example drilling, equipped with an electronic chip. Reference 22 designates the displacement of a drill rod in the directions of descent into the well, for drilling or maneuvering. Reference 23

  indicates the rise of this same rod.

  Reference 24 designates the work performed OPE by the rod between its two passages in front of the read / write device 21. This work causes

  fatigue which consumes a certain lifetime of the tubular.

  The identification 25 of the rod starts an acquisition and / or calculation program in the central processing unit UC. The identification code of the rod read automatically enables the central unit to search in an IDP database all the information of the geometric characteristics and of the materials necessary for the calculation of evaluation of the life of the rod. To carry out this evaluation, the drilling project WP is introduced into the central unit and the drilling parameters DP are followed in real time in order to be able to assign to the recognized rod a corresponding fatigue damage. Taking into account these data, a fatigue damage D is calculated for each tubular having spent a certain time in the wellbore of determined configuration and in a given position in the lining. The damage calculation can be done with a finite element calculation program,

  technique known to those skilled in the art.

  We simulate the behavior of the entire drill string in place in the well in order to extract the average and alternate stresses for each tubular. Fatigue damage is then calculated from the

  constraints for each tubular by a suitable cumulative method.

  In addition, a dynamic calculation can make it possible to model the dysfunctions of the vibratory type. A suitable post-treatment also makes it possible to take into account certain phenomena leading to rupture such as "heat-checking" (friction on the wall of the drill rods which causes thermal transformation of the steel). These phenomena recorded by the CPU unit can correct the level of damage actually

undergoes through the rod.

  In the case of riser elements, it is the wind, current, swell, recorded conditions which determine fatigue damage in combination

  with the forces due to external loads.

  For each well and packing geometry, the damage is calculated

  fatigue corresponding to the level of stress given.

  Conventionally, fatigue damage is a fraction of the life consumed due to a cyclic load. This cumulative damage can be determined using, for example, the Palmgren-Miner method which adds up the fractions of the life consumed, or damage, for each stress on the structure at different stress levels. The resulting cumulative damage is therefore conventionally 1 when the

lifespan is reached.

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  During the ascent of the rod, event which delimits the operation and the time spent in the well, this fatigue damage is then decremented by the capital representing the life of the tubular. This capital has a value of% when the drill pipe is new. It tends to 0% at the end of the life of the tubular. The results of periodic inspections may also

decrement this capital.

  If the calculations are made in real time, the damage to the rod can be increased as it passes 26 in ascent. If the calculations are not performed in real time, the incrementation can be done at a later pass, the central processing unit UC having stored all the history of the rod between two increments. An alarm system 27 can be provided to warn operators of

  drilling the fatigue state of one or more rods.

  It is clear that the method according to the invention can be entirely automated, insofar as each passage of the individual identification means automatically triggers the procedure. The central computer can be automatically connected to means for acquiring operational data which are involved in calculating the parameter linked to damage, or an operator can enter the data, or corrections,

required.

Claims (8)

  1) Method for managing the fatigue of a tubular (8) used for drilling, comprising individual identification means (20), said fatigue resulting from work carried out by said tubular during drilling operations, characterized in that the following steps are carried out: - the work carried out by said tubular is determined by identifying the start of the descent of the tubular to operate the drilling and the end of its ascent, - a parameter is calculated which is a function of the damage of tubular fatigue following the work carried out, - the value of said parameter is entered in the individual identification means of the tubular so as to obtain an indicator of cumulative fatigue for said tubular.   2) Method according to claim 1, in which said parameter is calculated by taking into account at least: the architecture of the borehole (WP), the characteristics of the tubular (IDP), the stresses applied to the tubular (DP). 3) Method according to claim 1 or 2, wherein a finite element calculation program is used to determine the stresses undergone   by the tubular during the work carried out.   4) Method according to claim 1, wherein the fatigue indicator   accumulated triggers an alarm (27) when it reaches a determined threshold.   ) Method according to claim 1, in which a central computer (UC) performs the calculation and storage of said parameter, and controls   updating the tubular fatigue indicator.   6) Method according to claim 5, wherein said computer is remote from the location of drilling operations and performs the calculation and storage of said parameter, and controls the updating of the fatigue indicator of the   tubular via a transmission, for example of the Internet type.   7) System for managing the fatigue of a tubular comprising individual identification means, characterized in that it comprises: - at least one read / write device (14) of individual identification means (20), - a central computer (UC) comprising at least one database of the characteristics of the tubular, a database on the operation generating fatigue, means of collecting stresses applied to the tubular, means of calculating a damage of fatigue, means for controlling writing in said means for identifying a parameter   corresponding to fatigue damage to the tubular. 12 2842245   8) System according to claim 7, wherein said device is placed so that the tubular passes in front of the sensor at the beginning and at the end of the operation generating fatigue.   9) System according to one of claims 7 or 8, which comprises a tool   portable read / write device (19) suitable for checking damage from tubular fatigue.   ) Application of the method according to one of claims 1 to 6, to 1o drill rods (8, 17).   11) Application of the method according to one of claims 1 to 6, to   offshore riser type riser tube components.