Abstract:
Detector of Slickline Irregularities (DILA) is a electronic system to detect and assess irregularities in production wells or to a new slickline by measuring eddy currents or eddies or Foucault currents. The system lines can vary in diameter depending on the operation to be performed on each well. The electronic system includes an optical encoder, eddy current sensor, eddy current reader, an electronic module for data acquisition and a computer. The detector monitors the integrity of the slickline in the well, interprets and records the data for graphing and reduces failures in the slickline as a result of rupture caused by excessive stress or collisions within the producing wells, detects flattening and bending, lack of nickel coating, porosity and corrosion.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit and priority to Mexican application No. MX/a/2012/007271 with a filing date of Jun. 21, 2012, the disclosure of which is incorporated herein by reference in its entirely. 
       FIELD OF THE INVENTION 
       [0002]    The present invention named “Detector of Slickline Irregularities” (“DILA” for its acronym in Spanish) is within the field of the instruments used to measure or determine abnormalities in the slickline used to operate oil wells. 
       BACKGROUND 
       [0003]    Among the many activities that take place in an oil well, there are those undertaken by Slickline area, which with a Motor Unit in which a spool is installed with a steel line (wire) with special tech specs, performs mechanical works such as installation and removal of tools, bottom inspections, etc. 
         [0004]    Slickline area, belonging to the Operative Base for Servicing Wells, operates mobile units carrying a slickline spool of special features in terms of geometry, strength, hardness and composition. Due to the nature of these operations, the line is at risk of suffering changes, breakdowns, stretching or deformation caused either by rubbing the line with the other mechanical elements such as oilers, blowout preventers, etc., or chemical attack from sulfhydric gas or carbonic acid. This may cause abnormalities in the line and increases the likelihood of breaking it during operation, which entails that the tools being used at that time are trapped within the well, so it is necessary to retrieve the tools lost at the bottom when the slickline breaks. 
         [0005]    The difficulty of a fishing operation will depend on many factors, of which, one that complicates the most tool recovery is when rupture occurs in the moment in which the line has been lowered to a considerable depth, and when rupture occurs and recovery is to be performed, the presence of a large amount of tangled wire in the intermediate zone between the surface unit and the tool complicates the fishing operation. In addition, there is an economic loss, since the line that was left downhole is practically unusable. 
       SUMMARY OF THE INVENTION 
       [0006]    Therefore, the Systems and Tools for Information Acquisition from Wells (“SHAIP” for its acronym in Spanish) group of the Instituto Mexicano del Petróleo (IMP) [Petroleum Mexican Institute] was given the task of developing a system to detect and assess changes suffered by the slickline used in field operations, such as reduced diameter, nicks, severe scratches and pores, that could put on risk the tools used in well operations. 
         [0007]    This system was named with the initials DILA-IMP (Detector of Slickline Irregularities of the IMP). 
         [0008]    Therefore, one object of the present invention is to provide a device which can adapt to the field units and allows to monitor the status on the line before, during and after an operation, in order to allow timely cutting the damaged line sections. 
         [0009]    Another object of the present invention is to reduce failures in the slickline as a result of rupture, deformations for excessive efforts or collisions in the various elements (centering roles, mechanical counter, anchor pulley, stuffing box, preventer, valve shaft and output tubing) by passing the slickline from the spool to the bottom of the well. 
         [0010]    The features of the invention are provided by a detector system of slickline irregularities to operate in oil wells, comprising: a) an eddy current sensor, wherein the slickline passes through the eddy current sensor; b) an eddy current reader, which detects a change in diameter in such slickline, c) an optical encoder, which conditions the analog signal; d) an electronic module for data acquisition, which acquires and conditions the signals from the sensors and processes the signals to the computer; and e) a computer, which displays the measurement made. 
         [0011]    The eddy current sensor measures slickline abnormalities within diameters of 0.092 to 0.125 inch by changing the diameter of the sensor&#39;s adapter. 
         [0012]    The detector of the invention detects flattening and folds on the slickline, lack of nickel coating (darkest zones on slickline), porosity and corrosion from acid attack without interfering with the line or in testing workshop before the specified service during operation. 
         [0013]    The depth gauge has a 1.1997 m pulley perimeter with 500 pulses and CCW direction. 
         [0014]    The detector measures anomalies or irregularities such as pitting, bends or wear areas on the slickline based on the measured changes in an electromagnetic field generated by eddy currents as the slickline passes through the eddy current sensor. The anomalies can be identified, for example, using respective signatures of the anomalies (e.g., selected characteristics of the electromagnetic fields that indicate various types of anomalies) that can be compared with the measured changes in the electromagnetic fields along the length of the slickline. The location of the anomalies on the slickline are recorded in a memory integral or external to the microcontroller. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0015]    The characteristical details of Detector of Slickline Irregularities (DILA) systems are clearly shown in the following description and figures presented. 
           [0016]      FIG. 1  is a perspective view of the Detector of Slickline Irregularities (DILA), the parts of the system comprising: eddy current sensor (part No.  1 ), eddy current reader (part No.  2 ), optical encoder (part No.  3 ), electronic module of data acquisition (part No.  4 ), computer (part No.  5 ), slickline spool (part No.  6 ), counter pulley (part No.  7 ). 
           [0017]      FIG. 2  is a block diagram of the internal structure of part No.  4  in  FIG. 1 , which is the data acquisition module. 
           [0018]      FIGS. 3   a - 3   b  show a first case of the irregularity of line occurred at 164 meters. 
           [0019]      FIGS. 4   a - 4   c  illustrate a second case of irregularities of a line at 2382.3 meters and at 2405.6 meters. 
           [0020]      FIGS. 5   a - 5   d  show a third case of irregularities of a line at 3094, 3095 and 3104 meters. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Detector of Slickline Irregularities (DILA) is a comprehensive electronic system that allows detecting and proactively assessing irregularities present in slickline due to interventions made in the field (production wells) or to a new slickline. It is governed by the principle of eddy currents or eddies, or Foucault currents. 
         [0022]    This comprehensive electronic system allows to detect and assess irregularities of the slickline used in interventions of oil wells. It is noteworthy to mention that these lines can vary in diameter depending on the operation to be performed on each well. 
         [0023]    In accordance with  FIG. 1 , the present invention relates to a system consisting of: an eddy current sensor (part No.  1 ), eddy currents reader (part No.  2 ), optical encoder (part No.  3 ), electronic module for data acquisition (part No.  4 ), a computer (part No.  5 ) with a Windows environment software for interpreting and graphing the results. This system is installed in Slickline Motor Units to operate in oil wells. 
         [0024]    The object of the present invention is to contribute to reduce failures in the slickline as a result of rupture due to deformations for excessive stresses or collisions in the various elements of the slickline that runs from the slickline spool (part No.  6 ,  FIG. 1 ) up to the bottom of the well, passing through: centering rollers, mechanical counter, anchor pulley, stuffing box, preventer, valve shaft and output tubing. 
         [0025]    In order to meet the above mentioned object, irregularities or deformations of slickline are detected by this invention, and obtained values of deformation and depth shall be graphed to allow decision making for using or discarding a length or the whole slickline depending on the risk this represents for execution of the self activity. 
         [0026]    Principle of operation. In accordance with the present invention, the detection of irregularities and anomalies in the slickline is performed using the eddy current principle or eddy currents. Eddy currents are defined as the alternating current induced in a conductor when subjected to a time-varying magnetic field, eddy current then generates its own secondary electromagnetic field which is used to identify or distinguish between a wide variety of physical, structural, metallurgical, ferromagnetic and non-ferromagnetic conditions and in non-metallic parts that are not electrically conductive. This method does not require direct electrical contact with the inspected part. 
         [0027]    In accordance with  FIG. 1 , the operating principle of the detector system of slickline irregularities is based on passing the slickline through the center of eddy current sensor (part No.  1 ), the same upon detecting a change in diameter on the slickline because of deformation, this generates a change in the electrical field becoming a current variation that is transmitted to the eddy current reader (part No.  2 ) for conditioning analog signal sent to the electronic module for data acquisition (part No.  4 ) and this one in turn to a computer (part No.  5 ) which plots and records data with software designed for this purpose. 
         [0028]    Slickline irregularities detector is a comprehensive electronic system to detect and evaluate the irregularities that occur in the slickline due to field operations in oil wells. 
         [0029]    The optical encoder (part No.  3 ) is installed on the side of the counter pulley (part No.  7 ) of the slickline motor unit, which signal is converted into units of length per unit time (speed) and also becomes a longitudinal measure to measure the depth of the line. 
         [0030]    The optical encoder (part No.  3 ,  FIG. 1 ) is a transducer that obtains the depth or displacement of the slickline and converts the mechanical motion into electrical signals that are sent to the electronic module for data acquisition (part No.  4 ) for processing speed and depth. Being both signals obtained from eddy currents reader (part No.  2 ) and the optical encoder (part No.  3 ), these are sent to the electronic module for data acquisition (part No.  4 ) where they are processed by the general-purpose microcontroller ( FIG. 2 ) that conditions the sensor signals and sends them via a serial communication cable to the computer (part No.  5 ) containing the visualization software for such measurements. 
         [0031]    With reference to the  FIG. 1 , Detector System of Slickline Irregularities (DILA) of the present invention also consists of software whose function is to display and plot data acquired from the optical encoder (part No.  3 ) and eddy current sensor (part No.  1 ), as well as an electronic module for data acquisition (part No.  4 ) which is in charge of acquiring input signals from the sensors, process them and send them to computer via an RS232 serial communication cable. 
         [0032]    Part No.  1  in  FIG. 1  shows the primary sensor where the slickline crosses and causes an electrical signal that is sent to eddy current reader (part No.  2 ). This sensor varies in dimensions according to the diameter used in the steel line. The sensor interprets this signal and transmits it to the electronic module for data acquisition (part No.  4 ) as ±5 v signals of horizontal and vertical measurement channels. 
         [0033]    The detection of irregularities or anomalies in the slickline is performed using the eddy current principle or eddy currents. Eddy currents allow the detection of surface and subsurface discontinuities in the material structure, as seams, overlaps, cracks, porosity and inclusions. 
         [0034]    The eddy current sensor (part No.  1 ) is placed in front of the counter pulley (part No.  7 ) through which the slickline passes, and the optical encoder (No.  3 ) is placed on the side of the same counter pulley. Signal from eddy current sensor (part No.  1 ) is connected to the eddy current reader (part No.  2 ), which generates two ±5 v electrical signals of horizontal and vertical measurement and together with optical encoder signal (No.  3 ) are connected to the electronic module for data acquisition (part No.  4 ) and these are sent to the computer (part No.  5 ) via a serial communication cable ( FIG. 2 ) RS232. It is noteworthy to mention that the eddy current reader (part No.  2 ), the electronic module for data acquisition (part No.  4 ) and the computer (part No.  5 ) are located inside the cab of the motor unit (Slickline Unit). 
         [0035]    Part No.  5  shows a computer containing the visualization software. This visualization software called DILA-WIN is a program developed with Windows operating system, so that the user graphic panels are easy to use and understand. The computer screen shows the software that displays and plots the speed and depth information of the slickline operation. The software has a recording capacity in the range of 60 to 80 m/min. 
         [0036]    Part No.  3  in  FIG. 1  shows an optical encoder, which is a transducer that enables the measurements of depth (displacement of slickline through the well) and speed of operation of the same line. These signals are sent to the electronic module of data acquisition as shown in part No.  4 . 
         [0037]      FIG. 2  shows the parts of the electronic module for data acquisition (part No.  4 ,  FIG. 1 ), which represents the main part of the detector system of slickline irregularities, as this acquires, conditions the signals from the sensors and processes the signals for subsequent delivery to the computer (part No.  5 ,  FIG. 1 ), by means of a RS232 serial communication cable. This system basically consists of a general purpose microcontroller that performs the conversion and adaptation of analog to digital signals, processes them, and sends the information by a communication protocol RS232 to the computer. 
         [0038]    This electronic module has a keyboard for entering parameters settings such as: the slickline diameter, pulley diameter and number of optical encoder pulses. These parameters are shown on a LCD dot matrix character display, which displays alphanumeric data of 2×16 (2 lines, 16 characters). Similarly, the electronic module contains a battery as a backup alternative, because if the main power source for any reason is interrupted, this battery would keep operating DILA system. 
         [0039]    During the data acquisition with the DILA, the following information channels are obtained: PROF, VEL ANH AND ANHV ANV, PROF channel refers to the depth in units of meters (m). VEL Channel is the speed of rising or falling in units of meters per minute (m/min). ANH channel refers to the measurement performed by the eddy current sensor in the horizontal orientation. ANV channel refers to the measurement performed by the eddy current sensor in the vertical orientation. ANHV channel measurement refers to both channels ANV and ANH 
         [0040]    DILA-IMP is a system that identifies slickline irregularities in qualitative form from a threshold 160 pre-established value as a fault indicator. The channel ANALOG ANHV uses 0-200 scale without units as an indicator of irregularity in slickline. 
         [0041]    Based on visual inspection and touching the slickline, the data values above the pre-established fault indicator are considered noticeable irregularities of the line and need operator strict review. Table 1 shows the typical configuration parameters of DILA-IMP system for use in the field. 
         [0000]    
       
         
               
             
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Configuration Parameters of DlLA-IMP system 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 For depth gauge 
               
               
                   
                 Pulley perimeter = 1.1997 meters*. 
               
               
                   
                 Pulses = 500* 
               
               
                   
                 Direction = CCW 
               
               
                   
                 Eddy current reader 
               
               
                   
                 Sensor Frequency = 100 kHz 
               
               
                   
                 Measurement angle = 0 
               
               
                   
                 Horizontal gain = 60.0 dB 
               
               
                   
                 Vertical Gain = 60.0 dB 
               
               
                   
                 Filter passes low detection = 150 Hz 
               
               
                   
                 Filter passes high detection = 30 Hz 
               
               
                   
                 Continuous measurement = 1.0 Hz 
               
               
                   
                 In DilaWin-IMP Software 
               
               
                   
                 Record speed = 60 to 80 meters per minute (m/min). 
               
               
                   
                   
               
               
                   
                 *Depends on the pulley and encoder to be used. 
               
             
          
         
       
     
       EXAMPLES 
       [0042]    DILA system has been installed and operated in Slickline Units of Services for oilfield wells. To date the inspection was made with 0.092″ (92 mils) in diameter slickline in routine well operations, achieving also work with other slickline diameters up to 0.125″ if the diameter adapter used in the eddy current sensor is changed (part No.  1 ,  FIG. 1 ). 
         [0043]    In these evaluations the steel The irregularities were detected at different lengths, being 3 cases shown below: 
         [0044]    First case:  FIG. 3  shows the irregularity of the line occurred at 164 meters as can be seen at point A on the graph ( FIG. 3   a ). Also, on the slickline ( FIG. 3   b ), a flattening indicated at point A is detected, which corresponds to point A on the graph in  FIG. 3   a.    
         [0045]    Second case:  FIG. 4   a , shows irregularities on line at 2382.3 and 2405.6 meters (points A and B, respectively).  FIGS. 4   b  and  4   c  show the lack of nickel coating on the slickline (darkest) corresponding to the irregularities shown in the graph as points A and B of  FIG. 4   a , respectively. 
         [0046]    Third Case:  FIG. 5  shows irregularities of the line at 3094, 3095 and 3104 meters respectively in sections A, B and C.  FIGS. 5   b ,  5   c  and  5   d  show porosity and corrosion due probably to acid attack on the line which correspond to irregularities shown at points A, B and C on the graph in  FIG. 5   a.